Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars.

Mar 13, 21 18:53

Post #1 of 71 Views: 2130

Yes, clickbait title. Now help me! Thanks in advance.

TLDR: I sprint, chain pops off sometimes, this time I went over handlebars. I don't want to again.

Click here for me all scraped up:
https://www.strava.com/activities/4931974697

Is the frame flexibility the issue or is it the chainrings? Something else?

My bike:
Cannondale SuperSix Evo HiMod, Hollowtech cranks, Vision chainrings (unsure on model... but they look thin). I think this is the ring

I am hopeful someone can say with some confidence that it's the chainrings or some other component and not the bike because I don't want to buy a new bike!

Relevant info:

Chain is nearly new.
Cassette is nearly new.
Chainrings are 2 yrs old.
Chain pop-off happens to either side. Inside of small or outside of big.
Chain pop-off happens under high force situations (>1500 & <100rpm)
No other shifting issues, ever.

Any thoughts appreciated!

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Last edited by: DrAlexHarrison: Mar 13, 21 18:53

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 13, 21 18:56

Post #2 of 71 Views: 2119

Classic sign of worn out chainrings.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jaretj] [ In reply to ]

Mar 13, 21 18:58

Post #3 of 71 Views: 2115

jaretj wrote:

Classic sign of worn out chainrings.

Agree. Or an improperly installed quick link.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 13, 21 21:07

Post #4 of 71 Views: 2024

Gonna go with a worn out chainring here. I believe the carbon rings only last 5000 miles or so. Beingbthat youre a powerful dude, prob just wore it out. If the chain is new then it mustve slipped off the ring, i doubt the bike is the problem

If you want to do 2000w use a metal bike, carbon isnt great for shear torquing efforts... for drivetrain stuff that is

Last edited by: RossJ: Mar 13, 21 21:41

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [RossJ] [ In reply to ]

Mar 13, 21 21:12

Post #5 of 71 Views: 2014

Doubt it was the frame. Sean Kelly, one of the best road sprinters of his era, raced on a Vitus 979 for years, and that thing was an absolute noodle compared to anything that cannondale has ever produced.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [RossJ] [ In reply to ]

Mar 13, 21 21:48

Post #6 of 71 Views: 1985

RossJ wrote:

Gonna go with a worn out chainring here. I believe the carbon rings only last 5000 miles or so. Beingbthat youre a powerful dude, prob just wore it out. If the chain is new then it mustve slipped off the ring, i doubt the bike is the problem

If you want to do 2000w use a metal bike, carbon isnt great for shear torquing efforts... for drivetrain stuff that is

Oh man - I'm SURE my 10-year old chainring on my Cervelo P2c is probably toast - I've never even thought about changing it! I've been going about everything else - new chains, new cassettes, new shifters and derailleurs, but I'm still using the original crank+chainrings from when I bought my bike.

I'm almost certainly going to have to chain mine - is this something that you just swap out the chainring and leave the crank, or do you have to buy the whole new front crankset?

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [JasoninHalifax] [ In reply to ]

Mar 13, 21 21:48

Post #7 of 71 Views: 1985

JasoninHalifax wrote:

Doubt it was the frame. Sean Kelly, one of the best road sprinters of his era, raced on a Vitus 979 for years, and that thing was an absolute noodle compared to anything that cannondale has ever produced.

I have a caad5 I have as my primary trainer bike and was my old road bike. I topped out about 1450w for sprints (nowhere near that now) and that did flex all over the place. The front mech used to catch the rings on occasion. The stronger I got the slower I became as the rear rim spent more time pushed against the brake pad. ;-)

Local bike shop owner gave it a test ride after it had been in for some work and after that spent ages checking the frame to find which weld had snapped as he couldn't believe everything was connected given the movement going on.

However, back to the OP. My non hi-mod Synapse is the most solid bike I've ridden, and so I cannot imagine the issue is with your frame, or even cranks/chainset.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [RossJ] [ In reply to ]

Mar 13, 21 22:09

Post #8 of 71 Views: 1969

RossJ wrote:

I believe the carbon rings only last 5000 miles or so...

If you want to do 2000w use a metal bike, carbon isnt great for shear torquing efforts... for drivetrain stuff that is

They are alu chainrings, FWIW.

lightheir wrote:

I'm almost certainly going to have to chain mine - is this something that you just swap out the chainring and leave the crank, or do you have to buy the whole new front crankset?

I think there are a few one-offs with rings that are basically onepiece, but yeah, vast majority you can just buy the rings and replace. 15 minute job with the right tools. For bonus points, check your BB bearings while you're at it. I did my roadie's rings last weekend; super easy.

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Last edited by: justinhorne: Mar 13, 21 22:12

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 13, 21 23:04

Post #9 of 71 Views: 1935

That almost happened to me. Terrifying. Turned out it was a worn out chain even though it was only 6 months old. Anyway, you should try different chainrings. Flat plate will never be as stiff as the wider Dura-Ace chainrings.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 5:18

Post #10 of 71 Views: 1852

Talk to Nacer Bouhanni 2016 about apparently crappy (FSA) chainrings...
https://www.cyclingnews.com/news/bouhanni-i-felt-i-was-going-to-win-milan-san-remo/

Louis :-)

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jaretj] [ In reply to ]

Mar 14, 21 9:21

Post #11 of 71 Views: 1754

jaretj wrote:

Classic sign of worn out chainrings.

Is there a way to visually inspect to confirm this? Telltale visual signs? Seems plausible, but I'm a little skittish to just throw on some stiffer/newer chainrings and go test sprints.

If it popped off at 1000W I'd more prone to try, but putting out 1500-2000W and having the chain come off is a pretty non-negligible chance of injury.

Thanks for your time!

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [Renault78law] [ In reply to ]

Mar 14, 21 9:22

Post #12 of 71 Views: 1750

Strongly considering. Just a little skittish to play test-dummy since it's only happening at near all-out exertion!

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 9:59

Post #13 of 71 Views: 1708

On a side note, we very rarely see pro roadies, or trackies falling when fails happen. The chain breaks, or drops, that's about it.
Good technique and balance is the key here.
If you go over the bars from a chain drop, something's done wrong IMO. Might put lots of watts on the little gadget on the crank (even more if you're a heavy rider), but not very efficient, might want to correct this also.

Louis :-)

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [louisn] [ In reply to ]

Mar 14, 21 10:04

Post #14 of 71 Views: 1700

louisn wrote:

On a side note, we very rarely see pro roadies, or trackies falling when fails happen. The chain breaks, or drops, that's about it.
Good technique and balance is the key here.
If you go over the bars from a chain drop, something's done wrong IMO. Might put lots of watts on the little gadget on the crank (even more if you're a heavy rider), but not very efficient, might want to correct this also.

Louis :-)

Yes, that has been my experience 9 times out of 10 too. Thankfully. It happened so fast this time that I'm unsure what exactly happened. I THINK that when the chain jumped off this time, because I was using the little ring (for fear of chain jumping off the big ring), I got chain suck which immediately froze my cranks in place and I think launched me up over the bars.

When the chain drops off the big ring during a sprint or snaps, the pedals continue to freely spin. I think that's probably the difference this time.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 10:13

Post #15 of 71 Views: 1688

Oh! small ring ?
Happened on a good incline I suspect ? That's another story !
The small ring is usually straighforward in terms of machining, without any ramps or pins.
So yes, ring wear doubled with chain angle ( you must have been on little cogs at the back) might end up with a chain drop for sure when force is applied, add to that the chain tension must have been pretty low on "small-small", maybe just a bump on the road...

Louis :-)

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [louisn] [ In reply to ]

Mar 14, 21 10:18

Post #16 of 71 Views: 1684

Yeah 6% grade. Mt. Lemmon. Just finishing a fun ride with some sprints on tired legs. But the chain pops off on this bike at high watts whether using small or large ring. I just have never used the small ring or gone over the bars until a few days ago. I think I was in small ring and maybe 6-7th cog.

Chose the small ring because I was leery of chain popping off if using the big ring which happened earlier in the day at closer 35mph going downhill. No crash then, obviously. Figured surely the chain wouldn't jump off the small ring. Wrong!

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 11:17

Post #17 of 71 Views: 1650

You are probably just putting out too many watts. This rarely happens to professional cyclists, so you should probably dial it back to their sprints to the 1200 to 1800 watts range. Easier than replacing parts on your bike or, y'know, checking your chain length.

***

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [JasoninHalifax] [ In reply to ]

Mar 14, 21 11:31

Post #18 of 71 Views: 1630

JasoninHalifax wrote:

Doubt it was the frame. Sean Kelly, one of the best road sprinters of his era, raced on a Vitus 979 for years, and that thing was an absolute noodle compared to anything that cannondale has ever produced.

Those Vitus frames were really something. I swear you could get a good 2" of bottom bracket deflection under a reasonable load. We are soooo spoiled these days with stiff, light and reasonable comfortable bikes

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [grumpier.mike] [ In reply to ]

Mar 14, 21 11:48

Post #19 of 71 Views: 1610

grumpier.mike wrote:

Those Vitus frames were really something. I swear you could get a good 2" of bottom bracket deflection under a reasonable load. We are soooo spoiled these days with stiff, light and reasonable comfortable bikes

My first real race bike was a Japanese Vitus clone. It didn't take too long for the seat tube to debond from the bottom bracket. I didn't even notice for awhile; every thing was still in place but the bike was more "springy" than before. I actually liked it in sprints. Sucked on mountain descents though. Got an SL steel Olmo after that which wasn't much stiffer. Then got a Klein which was a whole 'nother world of stiffness and control.

My cheap Chinese carbon frame just keeps going. ~70k miles now and rides great.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 12:08

Post #20 of 71 Views: 1592

DrAlexHarrison wrote:

jaretj wrote:

Classic sign of worn out chainrings.

Is there a way to visually inspect to confirm this? Telltale visual signs? Seems plausible, but I'm a little skittish to just throw on some stiffer/newer chainrings and go test sprints.

If it popped off at 1000W I'd more prone to try, but putting out 1500-2000W and having the chain come off is a pretty non-negligible chance of injury.

Thanks for your time!

A picture of them could help.

I went up Mt Lemmon twice this week :)

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 12:22

Post #21 of 71 Views: 1572

DrAlexHarrison wrote:

Chose the small ring because I was leery of chain popping off if using the big ring which happened earlier in the day at closer 35mph going downhill. No crash then, obviously. Figured surely the chain wouldn't jump off the small ring. Wrong!

Hmm, now that's interesting. I've had a mare with the chainline on my new 'dale' and it wanting to drop inside the inner ring. What chainset are you using? You say hollowtech cranks, but is this on a powermeter chainset, etc?

The other thing is that if you were cross chained, and you way rather than lube that can stiffen the chain and make it more likely to pop off on the inside of the inner (and outside of outer if cross chained). Note that the way you are doing has the mech needing to take up the most slack, and so the riskiest too.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [M----n] [ In reply to ]

Mar 14, 21 14:21

Post #22 of 71 Views: 1514

Serious question... is chain length a possible cause of this? Off top of head, I can't figure out why this would cause issues. But I'm a very entry-level mechanic so please enlighten if this might genuinely be contributing to my problems! I had just assumed that if chain length was an issue I'd have had shifting issues much earlier on or some other symptom.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 14:27

Post #23 of 71 Views: 1503

What does your rear derailleur look like when you are in small chainring and the smallest cog?

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jaretj] [ In reply to ]

Mar 14, 21 14:33

Post #24 of 71 Views: 1496

jaretj wrote:

DrAlexHarrison wrote:

jaretj wrote:

Classic sign of worn out chainrings.

Is there a way to visually inspect to confirm this? Telltale visual signs? Seems plausible, but I'm a little skittish to just throw on some stiffer/newer chainrings and go test sprints.

If it popped off at 1000W I'd more prone to try, but putting out 1500-2000W and having the chain come off is a pretty non-negligible chance of injury.

Thanks for your time!

A picture of them could help.

I went up Mt Lemmon twice this week :)

Perhaps we should ride! My wife and I have been riding it every day the last couple weeks (except the snow day).

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 14:45

Post #25 of 71 Views: 1482

DrAlexHarrison wrote:

Perhaps we should ride! My wife and I have been riding it every day the last couple weeks (except the snow day).

Da-Dum. Da-Dum. Da-Dum. Da-Dum. Da-da-da -da-da -da-da -da-da -da-da -da-da-dum.

Those chainring teeth are worn to shark fins. Time to replace.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 14:55

Post #26 of 71 Views: 1017

1 • hearable signs .. each chain link makes a more single rattling sound at the chain wheel tooth ..
2 • feelable signs .. the chain can be moved around and lifted more from the chain wheel at 9 o'clock with two fingers ..
3 • visible signs .. small & bigger gaps at 6 o'clock between the chain and the teeth of the chain wheel .. the teeth look like shark fins ..

// dropped my chain two times today uphill out of the saddle .. phase 3 showed up end of winter .. just waited to replace the drive train for the new saison .. oSo >>

*
___/\___/\___/\___ the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>

Last edited by: sausskross: Mar 14, 21 23:29

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jimatbeyond] [ In reply to ]

Mar 14, 21 15:08

Post #27 of 71 Views: 1006

jimatbeyond wrote:

What does your rear derailleur look like when you are in small chainring and the smallest cog?

Like my chain might be too long...

I'm running a 53-39 and 11-32.

Would that cause it to jump off under load, when not in the 39-11 position? I'm virtually certain I was no further cross-chained than 39-13 and would guess I was in 39-14.

I'm having a hard time visualizing how a too-long chain causes chain pop-off under load. Not enough chain contact around the front/bottom of the chainring?

In potentially related news: I just discovered that no matter what I do with my B screw on my rear mech, there is no adjustment of how close or far the rear mech sits from the cassette cogs. When I screw it all the way in or all the way out, it makes no difference. The rear mech seems to just fall past the position (closer to cogs) with no effective limit.

Is something broken in my rear derailleur? It has taken some hits in a couple crashes. Is there something I can do to fix it?? It's it's a Dura Ace di2 9070, I think.

Oddly, there is no weird shifting, and only weird noise when the cassette jockey wheel appears to be contacting the 32t cog. This issue WAS present before the chain started coming off... so potentially related.

Any ideas from anyone are appreciated. Have already learned a bunch. Thanks to all.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [Karl.n] [ In reply to ]

Mar 14, 21 15:12

Post #28 of 71 Views: 1003

Karl.n wrote:

DrAlexHarrison wrote:

Perhaps we should ride! My wife and I have been riding it every day the last couple weeks (except the snow day).

Da-Dum. Da-Dum. Da-Dum. Da-Dum. Da-da-da -da-da -da-da -da-da -da-da -da-da-dum.

Those chainring teeth are worn to shark fins. Time to replace.

Noted. I've at least gained the confidence that if I learn how to keep my bike components properly maintained/replaced as needed, I won't need to replace my frame. Thank you very much to all.

Now just to address the issue of if my rear mech is broken. Would love input on that! (my previous comment, posted a couple minutes ago)

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 15:17

Post #29 of 71 Views: 999

• small - small .. there should be space for a finger between the chain and the guide jokey wheel ..
• big - big .. the rd should not be overstressed and the guide jokey wheel not touch the cassette ..
• the wrapping angle and distance to the cassette of the rd is adjusted with a screw facing the drop out ..

*
___/\___/\___/\___ the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>

Last edited by: sausskross: Mar 14, 21 15:24

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [sausskross] [ In reply to ]

Mar 14, 21 15:28

Post #30 of 71 Views: 988

sausskross wrote:

• small - small .. there should be space for a finger between the chain and the guide jokey wheel ..
• big - big .. the rd should not be overstressed and the guide jokey wheel not touch the cassette ..
• the wrapping angle and distance to the cassette of the rd is adjusted with a screw facing the drop out ..

I think I have achieved the first two.

But the screw you mention here, which I called the B screw (not sure if correct), does nothing. No change in derailleur position for any amount of turning. It's as if something internal to the rear derailleur just allows it to move right beyond the typical catch point.

I can confirm the screw is contacting the hanger.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 15:33

Post #31 of 71 Views: 985

.. does the tension spring in the rd work .. proper ??

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___/\___/\___/\___ the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 15:41

Post #32 of 71 Views: 976

https://si.shimano.com/...DM-DA0001-10-ENG.pdf .. page 30 [& 64 ..]

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___/\___/\___/\___ the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>

Last edited by: sausskross: Mar 14, 21 15:49

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 16:34

Post #33 of 71 Views: 932

Yep, that chainring is cactus!
BUT, also check your bottom bracket bearings
Several years ago I had an issue where I would drop the chain and found it was the non-drive side bearing had worn enough that whole rocked rocked back and forth and it was enough that in the right circumstances it would drop the chain

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [sausskross] [ In reply to ]

Mar 14, 21 16:44

Post #34 of 71 Views: 928

Feels like yes, there still is some spring action but maybe not enough?? Seems to swing pretty freely beneath the cassette.

I've got snap ring pliers arriving tomorrow from amazon to investigate further. I'll report back. Thank you!

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [Andrew69] [ In reply to ]

Mar 14, 21 16:44

Post #35 of 71 Views: 926

Duly noted! I'll investigate.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 16:55

Post #36 of 71 Views: 916

I wouldn't be so quick to blame the chainring, especially when you say it happens on both the small and big ring.

Those 'shark fin' shaped teeth on there are normal, see attached pic, thats how they look new, at least to my eyes....

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [SBRcanuck] [ In reply to ]

Mar 14, 21 17:41

Post #37 of 71 Views: 898

Yeah, I was going to say that ring is worn, but not crazy worn. Might as well replace, but not convinced it's 100% of the issue.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 14, 21 18:01

Post #38 of 71 Views: 888

That chainring is done. It's not so much the pointy teeth it's the wear between the teeth that concerns me. You can see how deep they are getting.

I'm flying out of Tucson tomorrow. I'll try to hook up with you next year.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [SBRcanuck] [ In reply to ]

Mar 14, 21 23:48

Post #39 of 71 Views: 858

.. even on mine .. there is a kind of fin shape [reminds me nicely on the old da stuff that could be mounted in the wrong direction] .. so it's the distance between the contact flange .. and a more & more shark fin shape .. oSo >>

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___/\___/\___/\___ the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>

Last edited by: sausskross: Mar 14, 21 23:49

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [trail] [ In reply to ]

Mar 15, 21 0:25

Post #40 of 71 Views: 844

trail wrote:

Yeah, I was going to say that ring is worn, but not crazy worn. Might as well replace, but not convinced it's 100% of the issue.

Those are my thoughts. The chainring is worn and possibly getting towards/at replacement (difficult to be sure from that pic), but it's unlikely that both big and small have worn equally such that they both start throwing the chain at the same point in time. It definitely won't be the frame, but I'd be doing more investigation to see if there is any movement coming from anywhere (loose chainring bolts, worn bottom bracket bearings etc) and doing more investigation into that rear derailleur - if it isn't providing enough chain tension that is a very likely candidate. Try and look at a friends known good derailleur and see if yours provides similar tension. Also check the chain for a bent link, or something similar.

Oh, it won't be the frame!

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [SBRcanuck] [ In reply to ]

Mar 17, 21 8:57

Post #41 of 71 Views: 745

SBRcanuck wrote:

I wouldn't be so quick to blame the chainring, especially when you say it happens on both the small and big ring.

Those 'shark fin' shaped teeth on there are normal, see attached pic, thats how they look new, at least to my eyes....

I agree.

I've also purchased a new Ultegra crankset, so now moot point re: chainrings.

But, if it was a chainring issue, I'd love to have your insight on what it might be before I go "test." Thoughts?

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [trail] [ In reply to ]

Mar 17, 21 8:58

Post #42 of 71 Views: 744

trail wrote:

Yeah, I was going to say that ring is worn, but not crazy worn. Might as well replace, but not convinced it's 100% of the issue.

Open to other suggestions. Crankset is being replaced with new Ultegra.
I'm investigating the derailleur spring as I write this.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 17, 21 9:06

Post #43 of 71 Views: 736

DrAlexHarrison wrote:

SBRcanuck wrote:

I wouldn't be so quick to blame the chainring, especially when you say it happens on both the small and big ring.

Those 'shark fin' shaped teeth on there are normal, see attached pic, thats how they look new, at least to my eyes....

I agree.

I've also purchased a new Ultegra crankset, so now moot point re: chainrings.

But, if it was a chainring issue, I'd love to have your insight on what it might be before I go "test." Thoughts?

Well, if you want to cover all bases....
- get new cranks installed
- replace chain
- maybe replace cassette if you think might be worn? Just throw a cheap 105 cassette on, they work fine.

Then maybe try some hard sprints on an indoor trainer so you don't face plant if it happens again

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 17, 21 9:12

Post #44 of 71 Views: 732

Since you are replacing the crankset, you should replace the bottom bracket too. They are cheap.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 17, 21 9:43

Post #45 of 71 Views: 710

It really sounds, and now looks, like worn chainrings. There's a decent chance your chain might have 'stretched' at a quicker rate to compensate for the worn chainring too and not be very new anymore. A stranger on the internet can't confirm that for you, but this is why people will replace the chain any time they introduce new chainrings or a cassette to a drivetrain.

The third post about a quick link not being installed correctly tends to manifest more on the cassette than the chainrings. It happens with some frequency on 12 speed MTB drivetrains with curved quick links.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 17, 21 10:03

Post #46 of 71 Views: 695

1) Chainring in the pic looks toast to me (I know you said it's all been replaced anyway, just furthering the discussion about drivetrain maintenance, etc). It's not so much the sharkfin profile, some of which is by design for shifting performance as others have mentioned, but rather how rounded off and short they are relative to how big the 'valleys' in between have gotten. Basically, the gaps get sloppy relative to the spacing of the link rollers in the chain so they don't mesh snugly enough anymore; over time, the chain elongates too (commonly referred to as 'stretching' but it's just the cumulative play in the rollers adding up as they wear, rather than the plates actually stretching) so it will still work w/ the old chainring as they wear together, but then when you replace the chain the new links are shorter again like they're supposed to be so they don't mate w/ the worn ring like the old chain did.

2) I realize the natural tendency is to assume the chain is jumping off both rings for the same reason, but it could be that they are showing 2 different issues that just happen to present similar symptoms. I'm thinking the chain jumping off the big ring is just classic wear as above, but jumping off the small ring may or may not be so simple. It's certainly possible that wear is also an issue since they're presumably of the same age (although smaller rings will often wear faster since they don't spread the load over as broad a contact surface per revolution, but they also don't tend to get used as much depending on how hilly your typical ride is and of course they aren't usually subject to sprinting loads; before someone says a climbing load is the same while standing, the downforce might be similar but the RPMs are way different so it's easier to throw a chain on a road bump or some such during a sprint than during the slower rhythm of a standing climb). However, the chainline most likely being sharper is a contributing negative factor, as well as the possible issue of chain tension if the new chain is too long and/or the RD tensioning spring isn't working like it's supposed to.

3) easiest way to test the B-screw function to tension the chain rearward is to just slip the chain off the front rings so it's slack ~ does the RD automatically swing all the way back? You can simply pivot it forward/back on the hanger w/ your hand and feel the spring tension (or at least you should if it's working properly). That won't be an issue so much in the big ring since there's more system tension anyway having to wrap around a larger circle, but it could show up when in a small/small(ish) combo.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [rmt] [ In reply to ]

Mar 17, 21 10:34

Post #47 of 71 Views: 676

rmt wrote:

trail wrote:

Yeah, I was going to say that ring is worn, but not crazy worn. Might as well replace, but not convinced it's 100% of the issue.

Those are my thoughts. The chainring is worn and possibly getting towards/at replacement (difficult to be sure from that pic), but it's unlikely that both big and small have worn equally such that they both start throwing the chain at the same point in time. It definitely won't be the frame, but I'd be doing more investigation to see if there is any movement coming from anywhere (loose chainring bolts, worn bottom bracket bearings etc) and doing more investigation into that rear derailleur - if it isn't providing enough chain tension that is a very likely candidate. Try and look at a friends known good derailleur and see if yours provides similar tension. Also check the chain for a bent link, or something similar.

Oh, it won't be the frame!

Thank you! It might be the rear derailleur. It doesn't behave like my wife's bike. More in a moment in reply to another user.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 17, 21 10:39

Post #48 of 71 Views: 673

I recently had to replace a frame where the bottom bracket area went all noodly. The first symptom was the chain scraping the sides of the front derailleur during high torque situations. I also dropped chain a couple times, like you're seeing.

I verified the cause by locking the rear triangle firmly in a fixed turbo trainer (the kind that doesn't let you rock). Then I placed my phone under the BB, put it in a big gear, cranked some high torque, and recorded some video. I could see the chain ring moving laterally nearly a full centimeter (more than enough to crash the chain into the FD). It was pretty shocking to see the video. I wondered how long I'd been riding like that.

My next step was to verify it wasn't the bearing or bearing assembly, so I swapped with a new BB assembly. No difference.

So I tossed out the frame.

Last edited by: trail: Mar 17, 21 10:41

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [sausskross] [ In reply to ]

Mar 17, 21 11:07

Post #49 of 71 Views: 649

sausskross wrote:

https://si.shimano.com/...DM-DA0001-10-ENG.pdf .. page 30 [& 64 ..]

The B tension spring appears to be allowing travel in both directions, pretty easily. Do these wear out? Are they sold separately somewhere? Any info helpuful!

Is this compatible? Or must it be dura-ace?

Results of my investigation:

I can install as pictured on page 30, no prob.

When I adjust B screw as pictured on page 64, nothing happens, because....

As pictured and discussed on page 93, I DON'T even have to use a 3mm hexagon wrench to get the claw on the stopper plate to cross the claw on the bracket body. I can do it with my hands/fingers. It's not tension-free, and it is challenging with fingers, but definitely no 3mm hex wrench needed. This makes me think the spring is worn out or loosened. I've uninstalled and reinstalled twice to ensure that I'm doing it in the correct orientation.

Visual inspection of spring looks fine. Only thing to note is that the springs ends (y) and (z) (Page 93) appear exactly opposite each other when the spring is unloaded, which is not the case in the Diagram 1 on page 93.

Global question for my understanding. At what point should that spring allow disengagement of the claw on the stopper plate from the claw on the bracket body, during normal bike operation?

That claw interface is what appears to communicate the B screw "limit" at all times, on my wife's bike. As in, the derailleur can't go past (closer to cogs) than the limit screw at any time. Hard stop.

On my bike, there is no hard stop at all. It floats right past what should be the stop, though there is a tactile "stop" there, but the aforementioned "claws" don't stay engaged.

FYI: A year ago, probably when the derailleur started functioning as it does now (apparently improperly but good enough to ride for a year without much concern), I had crashed by sliding out on the right side of the bike so the derailleur took an upward-directed hit from the ground, which seems to have eliminated that "hard stop" and allows it to swing past the B limit, closer to the cogs.

Biggest question: is the RD issue likely to cause chain pop-off? I guess maybe yes... especially if paired with worn rings. And probably-worn bearings... I'll check those out when I install the new Ultegra crankset.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 17, 21 11:21

Post #50 of 71 Views: 641

.. huuh .. my technical english competence makes it hard to answer .. maybe some one can jump in to sort the movings of the rd out and give an advice for correct geometrical function ..

.. the chain can jump of the small chainring easier with not enough "pre-tension" ..

Sorry & Cheers

*
___/\___/\___/\___ the s u r f b o a r d of the K u r p f a l z is the r o a d b i k e .. oSo >>

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jimatbeyond] [ In reply to ]

Mar 17, 21 11:22

Post #51 of 71 Views: 1291

jimatbeyond wrote:

Since you are replacing the crankset, you should replace the bottom bracket too. They are cheap.

This Enduro Bearings BB is what's on there. $200.

The cheap ones I'm seeing online look different. Does any $20 Hollowtech II BB work??

It's a 2019 Cannondale Supersix Evo HiMod with "BB30" printed near the bottom bracket.

Someone educate me here. I know nothing about bottom brackets but would love to learn.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [sausskross] [ In reply to ]

Mar 17, 21 11:23

Post #52 of 71 Views: 1290

sausskross wrote:

.. the chain can jump of the small chainring easier with not enough "pre-tension" ..

Makes sense! Thank you for all your insight in this thread.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [OneGoodLeg] [ In reply to ]

Mar 17, 21 11:29

Post #53 of 71 Views: 1285

OneGoodLeg wrote:

3) easiest way to test the B-screw function to tension the chain rearward is to just slip the chain off the front rings so it's slack ~ does the RD automatically swing all the way back?

Nope! It sure doesn't. It has enough tension to hold it all the way back but barely. It mostly will just flop around without much pressure applied to cause movement.

OneGoodLeg wrote:

You can simply pivot it forward/back on the hanger w/ your hand and feel the spring tension (or at least you should if it's working properly).

Not much tension at all. Very slack, but not completely free-pivoting.

Safe to assume replacing that spring solves the RD-specific issues completely?

This has been a very educational experience for me!

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 17, 21 12:37

Post #54 of 71 Views: 1271

DrAlexHarrison wrote:

jimatbeyond wrote:

Since you are replacing the crankset, you should replace the bottom bracket too. They are cheap.

This Enduro Bearings BB is what's on there. $200.

The cheap ones I'm seeing online look different. Does any $20 Hollowtech II BB work??

It's a 2019 Cannondale Supersix Evo HiMod with "BB30" printed near the bottom bracket.

Someone educate me here. I know nothing about bottom brackets but would love to learn.

That Enduro bottom bracket should be good. Just put your finger inside the bearing when the crankset is removed and rotate the inner race to make sure that the bearings are smooth.

A standard Shimano bottom bracket will not fit your frame.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jimatbeyond] [ In reply to ]

Mar 17, 21 13:25

Post #55 of 71 Views: 1259

Thank you!!

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jimatbeyond] [ In reply to ]

Mar 27, 21 23:01

Post #56 of 71 Views: 1206

Update if you're still following and I still need help!

How do I get a Shimano Ultegra crankset to work with this bike? Spindle is smaller than that of the Cannondale hollowtech stuff I pulled off.

New bottom bracket needed?

If so, can someone point me in the right direction to something that will last? Links very much appreciated!

Ps. I also bought a B tension spring and plan to install once it's delivered.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [jimatbeyond] [ In reply to ]

Mar 27, 21 23:05

Post #57 of 71 Views: 1204

This work?
https://www.backcountry.com/...Mfrgu-xoCL3oQAvD_BwE

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 28, 21 0:42

Post #58 of 71 Views: 1187

DrAlexHarrison wrote:

How do I get a Shimano Ultegra crankset to work with this bike? Spindle is smaller than that of the Cannondale hollowtech stuff I pulled off.

New bottom bracket needed?

Soooo...you don't have the BB in your bike that you linked above in post 51 (Enduro Bearings TorqTite PF 386EVO to 24mm). What BB is currently in there? If it's a good one you could keep it and just use an adapter, something like:

https://wheelsmfg.com/...shimano-fsa-etc.html

They have slightly different versions of the above depending on what BB standard your bike has (BB30/PF30 vs. BB30a/PF30a)

I think you need to definitively determine:

1)What is the BB standard of your frame? Take a photo of the bike and the experts here can tell you. Measure the shell width (not counting any extra from the bottom bracket. Is it 68 or 73mm?

2)What BB is currently in the frame?

3)What route do you want to take to make the Shimano cranks fit? There should be a Wheels Mfg adapter kit that would work, for approx $40. The simple answer to all the above is if the measured shell width is 68mm, get the linked adapter above and if the measured shell width is 73mm get the BB30a/PF30a adapter kit(unless you already have some type of outboard bearing adapter bb...also measure the over bearing width). A new bottom bracket would be a bit more $

Last edited by: Nelo: Mar 28, 21 0:49

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [Nelo] [ In reply to ]

Mar 28, 21 9:19

Post #59 of 71 Views: 1127

Nelo wrote:

DrAlexHarrison wrote:

How do I get a Shimano Ultegra crankset to work with this bike? Spindle is smaller than that of the Cannondale hollowtech stuff I pulled off.

New bottom bracket needed?

Soooo...you don't have the BB in your bike that you linked above in post 51 (Enduro Bearings TorqTite PF 386EVO to 24mm). What BB is currently in there? If it's a good one you could keep it and just use an adapter, something like:

https://wheelsmfg.com/...shimano-fsa-etc.html

They have slightly different versions of the above depending on what BB standard your bike has (BB30/PF30 vs. BB30a/PF30a)

I think you need to definitively determine:

1)What is the BB standard of your frame? Take a photo of the bike and the experts here can tell you. Measure the shell width (not counting any extra from the bottom bracket. Is it 68 or 73mm?

2)What BB is currently in the frame?

3)What route do you want to take to make the Shimano cranks fit? There should be a Wheels Mfg adapter kit that would work, for approx $40. The simple answer to all the above is if the measured shell width is 68mm, get the linked adapter above and if the measured shell width is 73mm get the BB30a/PF30a adapter kit(unless you already have some type of outboard bearing adapter bb...also measure the over bearing width). A new bottom bracket would be a bit more $

Thank you very much for the detailed reply.

Apparently I did not have the BB I thought I did! Sorry for the rookie error there.

Got the calipers out and the carbon shell is 73mm. I took the bottom bracket out to measure and clean.
Enduro Bearings TorqTite BB30/PF30 68-73mm. This is the text on the bottom bracket.
The chainring side bearings of the removed BB roll rough. I think I'll replace the bottom bracket. Can the bearings be easily swapped and purchased independently? (thinking about making this current BB a spare with some adapters on-hand.)

I purchased this Wheels Mfg BB last night. Does that work? (Shipped to Amazon locker so that if it does not work, per ST guidance, I can leave at locker and it will be automatically returned & refunded.)

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 28, 21 11:31

Post #60 of 71 Views: 1097

Yes,that should work. You do technically need a bearing press to get one of the sides in.
I used the exact same one with a Felt IA frame with BB30 BB shell and they work great.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 28, 21 12:01

Post #61 of 71 Views: 1082

Note:
BB30 and PF30 are NOT the same thing.
Bearings will be the same, but bb30 the bearings are a direct fit in the frame; PF30 bearings are usually fit in a Delrin housing to make up for any manufacturing tolerences in a carbon bb shell.
As a result, theres a difference in the diameter of the shell aperture of about 2mm I think.

Despite it saying its bb30, I would be very surprised if it is. I'd be more inclined to believe its pf30.

If your bearings are already rough, don't bother getting new bearings and adaptors to fit, it will most likely end up creaking.
Get a decent pf30 to ht2 complete bb such as a cbear.

Edit- having done some digging, your bike should have a pf30a bb shell. It’s asymmetrical which is why it is wider than normal (bb30=68mm)

Last edited by: philg: Mar 28, 21 12:51

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [philg] [ In reply to ]

Mar 28, 21 13:16

Post #62 of 71 Views: 1056

Everything I see about that bike is the BB is a PF30

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 28, 21 14:14

Post #63 of 71 Views: 1038

As people are mentioning, there are some confusing BB standards being thrown around for Cannondales...BB30, BB30a, PF30, PF30a

With a shell width of 73mm you have narrowed it down to PF30a or BB30a.

What's the BB shell ID? 42mm = BB30a (or BB30 but you ruled that out). 46mm = PF30a (or PF30 but you ruled that out)

https://www.bicyclepartsdirect.com/bb30-vs-pf30/

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [SBRcanuck] [ In reply to ]

Mar 28, 21 14:17

Post #64 of 71 Views: 1037

SBRcanuck wrote:

Yes,that should work. You do technically need a bearing press to get one of the sides in.
I used the exact same one with a Felt IA frame with BB30 BB shell and they work great.

What's a bearing press, as it relates to bikes? I worked alongside a mechanic (learning for a day) while "we" installed the current BB, which he sourced for me (hence, I know nothing more than what's written on it, and what's discussed on this thread).

I don't recall a bearing press tool being used. Just a rubber mallet. (EDIT: nvm that was my wife's bike... though i was able to pull this BB out of my bike by hand, millimeter by millimeter, budging one side at a time with my fingers only. I suspect I could easily reinstall it with the same rubber mallet used on my wife's 2018 Cervelo s5)

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Last edited by: DrAlexHarrison: Mar 28, 21 14:20

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 28, 21 14:26

Post #65 of 71 Views: 1033

DrAlexHarrison wrote:

SBRcanuck wrote:

Yes,that should work. You do technically need a bearing press to get one of the sides in.
I used the exact same one with a Felt IA frame with BB30 BB shell and they work great.

What's a bearing press, as it relates to bikes? I worked alongside a mechanic (learning for a day) while "we" installed the current BB, which he sourced for me (hence, I know nothing more than what's written on it, and what's discussed on this thread).

I don't recall a bearing press tool being used. Just a rubber mallet. (EDIT: nvm that was my wife's bike... though i was able to pull this BB out of my bike by hand, millimeter by millimeter, budging one side at a time with my fingers only. I suspect I could easily reinstall it with the same rubber mallet used on my wife's 2018 Cervelo s5)

You might be able to get away without one, but here is a video from wheelsmfg showing the installation. Go to about the 25 second mark.

https://www.youtube.com/watch?v=3i66Nmo8Eyw

BTW - using a rubber mallet etc to install remove cups can result in them pushing in uneven at first. They may straighten once in, but you can cause some wear on the carbon BB shells doing that. Ask owners of Treks....

Last edited by: SBRcanuck: Mar 28, 21 14:29

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [Nelo] [ In reply to ]

Mar 28, 21 14:32

Post #66 of 71 Views: 1030

Nelo wrote:

As people are mentioning, there are some confusing BB standards being thrown around for Cannondales...BB30, BB30a, PF30, PF30a

With a shell width of 73mm you have narrowed it down to PF30a or BB30a.

What's the BB shell ID? 42mm = BB30a (or BB30 but you ruled that out). 46mm = PF30a (or PF30 but you ruled that out)

https://www.bicyclepartsdirect.com/bb30-vs-pf30/

Shell internal diameter is 46mm.

So I need PF30a, assuming you're correct....

Which means this one I already bought will NOT work.... right??
Do I need this one? If so, cool! I just bought that too.
Does PF in PF30, stand for Press Fit?
Am I going to need a special tool to install these BB's? If so, I would be so grateful for direct link from amazon to something that would work.

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [SBRcanuck] [ In reply to ]

Mar 28, 21 14:42

Post #67 of 71 Views: 1025

SBRcanuck wrote:

DrAlexHarrison wrote:

SBRcanuck wrote:

Yes,that should work. You do technically need a bearing press to get one of the sides in.
I used the exact same one with a Felt IA frame with BB30 BB shell and they work great.

What's a bearing press, as it relates to bikes? I worked alongside a mechanic (learning for a day) while "we" installed the current BB, which he sourced for me (hence, I know nothing more than what's written on it, and what's discussed on this thread).

I don't recall a bearing press tool being used. Just a rubber mallet. (EDIT: nvm that was my wife's bike... though i was able to pull this BB out of my bike by hand, millimeter by millimeter, budging one side at a time with my fingers only. I suspect I could easily reinstall it with the same rubber mallet used on my wife's 2018 Cervelo s5)

You might be able to get away without one, but here is a video from wheelsmfg showing the installation. Go to about the 25 second mark.

https://www.youtube.com/watch?v=3i66Nmo8Eyw

BTW - using a rubber mallet etc to install remove cups can result in them pushing in uneven at first. They may straighten once in, but you can cause some wear on the carbon BB shells doing that. Ask owners of Treks....

Very handy video. Thank you! Noted re: mallet.

Just purchased wheels mfg bearing press tool.

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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [SBRcanuck] [ In reply to ]

Mar 28, 21 14:46

Post #68 of 71 Views: 1023

I also have this double-ended BB removal/install tool. Do I need ANYTHING else for this job?

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 28, 21 14:50

Post #69 of 71 Views: 1019

DrAlexHarrison wrote:

I also have this double-ended BB removal/install tool. Do I need ANYTHING else for this job?

I bought the same press, its really good.

That tool looks right, but you need two of them, one for each side. Look at 1:04 into the youtube video. He is using a torque tool on one side and a wrench like yours on the other, but you can just use two like you have and tighten it well.

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [DrAlexHarrison] [ In reply to ]

Mar 28, 21 14:53

Post #70 of 71 Views: 1015

DrAlexHarrison wrote:

Shell internal diameter is 46mm.

So I need PF30a, assuming you're correct....
Do I need this one?

I think you need this one:

https://wheelsmfg.com/...s-shimano-black.html
On Amazon
https://www.amazon.com/...ing-goods&sr=1-1

You might not need to press the drive side in (but I wouldn't use a mallet), but generally you press in the drive side then screw in the non-drive side. The Wheels Mfg drifts are really nice (you can buy two then use threaded rod from Home Depot, or just buy the more expensive kit with drifts/rod/handles. You'll also need the correct notched flat wrench.

https://www.amazon.com/...ing-goods&sr=1-2
https://www.amazon.com/...ing-goods&sr=1-3

Random side note...I bought the Wheels Mfg notched socket, but it doesn't fit any of the handful of Wheels Mfg BBs that I've put in since buying it...even though it is listed as being compatible...your mileage may vary....

Re: Is the frame too flexible? Or is it the chainrings? Something else? I went over the bars. [Nelo] [ In reply to ]

Mar 28, 21 15:55

Post #71 of 71 Views: 1002

Thank you!

Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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