1x solution without a clutch RD?

Jan 6, 20 15:05

Post #1 of 67 (5642 views)

I know that SRAM recommends against going 1x without a clutch RD. I know people have hacked together 1X systems without a clutch RD with positive results, but others have had negative results (chain drops).

I’m stuck trying to understand why using a chain guide attached to the braze-on mount, combined with a narrow-wide chainring, wouldn’t prevent a chain from dropping, or at least be AS successful at keeping the chain from dropping as a front derailleur is on a 2x system.

On a 2x system, the front derailleur isn’t adding tension. It can prevent the chain from moving too far left or right, or even upwards, but that’s it. A chain guide that sits over the chainring like a FD would do the same thing…it would keep it from dropping to the left or right, or from jumping upwards and off. If anything, the guide could be adjusted to even closer tolerances than a FD. Paired with a narrow wide ring, how would that be worse than a FD on a 2x system? Even if the chain bounces off the bottom of the chainring because of slack caused by the RD, the chain should remain on the narrow wide ring as the top, and pedaling should get the chain back on, right?

I guess if/when the chain drops on a normal 2x, you can shift the FD to help get the chain back on. That’s the only advantage I can think of that a FD would provide over a chain guide.

I have the original eTap on my gravel bike. I want to ditch the front derailleur because the battery is the limiter to my tire clearance. There is not a clutch RD that can be paired with the original etap levers.

My other thought is that I could run a bar end shifter coming out of my drop handlebar that connects to a regular Red FD. That would allow me to keep using eTap levers and RD, but I could still keep my 22 gear combos and not have to worry about dropped chains from not having a clutch. But, that would be pretty ugly.

Any thoughts before I spend about $120 to buy a 1X chainring and chain guide? Wolf, Praxis, and K-Edge all make chain guides that connect to the braze on clamp.

edit: here is a photo from Wolf Tooth:

Last edited by: rob_bell: Jan 6, 20 15:06

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Xing triathlete

Jan 6, 20 15:12

Post #2 of 67 (5633 views)

1x red etap RD on road, A-OK - been riding it for countless thousands of miles with 1 drop (carpet covered train tracks that I didn't prepare for). 1x red etap on gravel, not a chance I'd go that route even with a chain guide.

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 6, 20 15:34

Post #3 of 67 (5604 views)

Been riding 1x off and on since 1988

Never dropped the chain. Never had a chain keeper

Is it possible clutch rear derailleurs and chain catchers are to make more money for parts manufacturers?

Re: 1x solution without a clutch RD? [MrTri123] [ In reply to ]

Jan 6, 20 16:11

Post #4 of 67 (5581 views)

MrTri123 wrote:

Is it possible clutch rear derailleurs and chain catchers are to make more money for parts manufacturers?

I've dropped a ton of chains on my 1x TT bike, got a clutch RD, haven't had one since. Context is that I live in an area with a lot of brutal roads. Paris-Roubaix-like at times.

If you ride mountain or CX, you'll see that they're hugely effective at the function they serve. Probably not necessary in areas with smoother roads. Though a narrow-wide ring is always necessary in 1X.

To the OP, the combination of a narrow-wide and a chain catcher should be fine. I went with the clutch RD instead of chain catcher just to keep the TT bike clean-looking. :). Didn't seem to make much sense to get more aero by getting rid of the FD, then add something almost as big as an FD.

Re: 1x solution without a clutch RD? [trail] [ In reply to ]

Jan 6, 20 16:20

Post #5 of 67 (5576 views)

trail wrote:

I've dropped a ton of chains on my 1x TT bike, got a clutch RD, haven't had one since. Context is that I live in an area with a lot of brutal roads. Paris-Roubaix-like at times.

[..]

To the OP, the combination of a narrow-wide and a chain catcher should be fine. I went with the clutch RD instead of chain catcher just to keep the TT bike clean-looking. :). Didn't seem to make much sense to get more aero by getting rid of the FD, then add something almost as big as an FD.

Same experience here. With the relatively recent addition of the RD-RX805 rear derailleur, there is now a clutch RD for Di2 users. And Ceramicspeed even makes an OSPW for it, if that's your thing. This is the combo I run.

Amateur recreational hobbyist cyclist
https://www.strava.com/athletes/337152
https://vimeo.com/user11846099

Last edited by: refthimos: Jan 6, 20 16:20

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 6, 20 17:50

Post #6 of 67 (5531 views)

Been using 1x on my TT for the last 3 years with a Sram 1x chainring and normal RD and need dropped a chain. 1x on my roadie the last year with no issue.

No science behind it but I wonder if the issue some have is a chain that’s too long which is creating slack and causing dropped chains.

Twitter - Instagram

Re: 1x solution without a clutch RD? [jrielley] [ In reply to ]

Jan 6, 20 18:12

Post #7 of 67 (5513 views)

My thoughts exactly —a chain that is a bit too long probably has more chance of jumping off. I have had great success with 1X without a clutch RD. Also of note is it has been proven that higher chain tension is actually more efficient with less chain friction loss.

Re: 1x solution without a clutch RD? [J7] [ In reply to ]

Jan 6, 20 20:06

Post #8 of 67 (5463 views)

J7 wrote:

Also of note is it has been proven that higher chain tension is actually more efficient with less chain friction loss.

Source for that?

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 6, 20 20:42

Post #9 of 67 (5446 views)

Two issues, but this is more prevalent on wide range gearing (gravel) set ups:

Due to the very nature of its design (super wide range cassette and a very long chain), a 1x system has a much bigger range of chain tension than does a 2x system. Meaning that there are times when the chain on a 1x system is going to be a lot looser than the chain on a 2x system ever is.

Finally, the enormous cassettes used for 1x have another interesting but lesser known property. When the chain is positioned on some of the smallest cogs on these huge cassettes (like the 10t, 11t, 12t, etc.--cogs which you are far more likely to use in a 1x vs a 2x set-up), and you are pedaling like a madman, and then you quickly stop pedaling to, say, fly over some potholes or a set of railroad tracks, something really unfortunate happens. The combination of freewheel friction plus the big mass and inertia of the huge forward spinning cassette plus the physics/mechanical disadvantage of the chain being on a tiny cog makes the drivetrain (actually, just the chain "powered" by its own intertia and the inertial of the huge cassette) rapidly feed the chain forward toward the cranks (even though you have stopped pedaling). This makes the top run of chain between the cranks and cassette get SUPER loose and floppy (this is in addition to a 1x chain already being quite loose in these gear combos). Then, add to all of this, a big jarring impact as you jump the potholes or tracks (or whatever) and, bingo, you get an instant chain drop when you try to resume pedaling after the obstacle.

Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
--

Last edited by: DarkSpeedWorks: Jan 8, 20 9:52

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 6, 20 20:46

Post #10 of 67 (5442 views)

etap 11 speed, tri bike, standard chain rings, no front derailleur, thousands of miles no issues except 1 time when i hit another ride in T1 - i don't blame the setup on that one.

Re: 1x solution without a clutch RD? [DarkSpeedWorks] [ In reply to ]

Jan 6, 20 21:06

Post #11 of 67 (5429 views)

DarkSpeedWorks wrote:

Two issues, but this more prevalent on wide range gearing set ups:

Due to the very nature of its design (super wide range cassette and a very long chain), a 1x system has a much bigger range of chain tension than does a 2x system. Meaning that there are times when the chain on a 1x system is going to be a lot looser than the chain on a 2x system ever is.

Finally, the enormous cassettes used for 1x have another interesting but lesser known property. When the chain is positioned on some of the smallest cogs on these huge cassettes (like the 10t, 11t, 12t, etc.--cogs which you are far more likely to use in a 1x vs 2x set up), and you are pedaling like a madman, and then you quickly stop pedaling to, say, fly over some potholes or a set of railroad tracks, something really unfortunate happens. The combination of freewheel friction plus the big mass of the huge cassette plus the mechanics of the chain being on a tiny cog makes the drivetrain rapidly feed the chain forward toward the cranks (even though you have stopped pedaling). This makes the top run of chain between the cranks and cassette get SUPER loose and floppy (this is in addition to a 1x chain already being massively loose in these gear combos). Then add to all of this a big jarring impact as you jump the potholes or tracks (or whatever) and, bingo, you get an instant chain drop when you try to resume pedaling after the obstacle.

I will probably run either an 11-36 or 11-32 with a 46t front.

Wouldn’t the chain tension essentially be the same as it is now in my 50/11 as it would in the 46/11 on a 1x, and the same in my 50/32 as it would be with a 46/32 (if I optimize chain length to the 46, which would probably mean dropping one link out or so from where I am now). It would be much more tension than I have in my 34/11.

I see your point on being in those smaller rear cogs more often though. At any given time I’ll be in one smaller cog than I would have been with my 50t front.

Regarding point 2, wouldn’t something like the Wolf tooth chain guide pictured above keep the top run of the chain on the teeth?

The etap FD is just so flakey for me. Just when I think I have it dialed in I realize the cage is rubbing the crank arm. Or it over shifts. Or it gets jumpy in the big/big. In most races I find myself trying to stay in the big ring all the time anyway because I’m afraid of a bad shift. Not to mention I have a frame that fits 43c, but a 38 is almost rubbing the etap battery.

Edit: in defense of etap, I’m running stock Red chainrings that are two years old and have seen a lot of abuse. I think I’d see significant improvement by buying some praxis rings. The clearance between the crank arm and FD will still be tight, but I think the shifting would dramatically improve over my shark finned rings that are on the bike right now. I can either spend $150 to buy praxis rings, or about $150 to buy a sram xsync 46t and a chain guide, and ditch my FD. I’d rather not buy both options and experiment, although I am tempted. I haven’t heard of anyone trying the chain guide with an etap RD yet.

Last edited by: rob_bell: Jan 6, 20 21:11

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 6, 20 21:30

Post #12 of 67 (5412 views)

When my TT bike is setup with an 11-25 or 11-23 I don't have chaindrops. When it is setup with an 11-32, 11-28 then I have had chain a few drops but still less fuss than with a FD. Having a 11-32, 11-28 means more chain length. The chain usually will have problems when in the lowest gears, IE 54t-11t for me.

Save: $50 on Speed Hound Recovery Boots | $20 on Air Relax| $100 on Normatec| 15% on Most Absorbable Magnesium

Blogs: Best CHEAP Zwift / Bike Trainer Desk | Theragun G3 vs $140 Bivi Percussive Massager | Normatec Pulse 2.0 vs Normatec Pulse | Speed Hound vs Normatec | Air Relax vs Normatec | Q1 2018 Blood Test Results | | Why HED JET+ Is The BEST value wheelset

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 7, 20 2:44

Post #13 of 67 (5342 views)

Maybe I'm getting the geometry wrong but I don't see why you need a chain catcher or even a narrow-wide chain ring. You just need to swap the a chain ring and set up the FD as a chain keeper. Top Shimano sponsored CX pros have done this for several years to create a shimano 1x electric system.

Ideally you use the inner ring and set the FD as an inside chain catcher. The outer ring is then a 100% effective chain catcher (and if you are really pro you dremmel off the teeth on the outer ring). Shimano makes 46 and 48 tooth inner rings, but they are pro team only, but I'm guessing someone is making after market parts that do the same thing. You can go a step further and replace a FD with a chain catcher but you really only need a tiny tab to prevent inside drops. You can accomplish a similar thing by using the outer ring and adjusting the FD accordingly.

Edit: I left out the key part which is you remove the battery from the FD in the about setups. This gives you the additional clearance which is a key part of your problem.

Last edited by: scott8888: Jan 7, 20 2:56

Re: 1x solution without a clutch RD? [refthimos] [ In reply to ]

Jan 7, 20 3:33

Post #14 of 67 (5321 views)

refthimos wrote:

trail wrote:

I've dropped a ton of chains on my 1x TT bike, got a clutch RD, haven't had one since. Context is that I live in an area with a lot of brutal roads. Paris-Roubaix-like at times.

[..]

To the OP, the combination of a narrow-wide and a chain catcher should be fine. I went with the clutch RD instead of chain catcher just to keep the TT bike clean-looking. :). Didn't seem to make much sense to get more aero by getting rid of the FD, then add something almost as big as an FD.

Same experience here. With the relatively recent addition of the RD-RX805 rear derailleur, there is now a clutch RD for Di2 users. And Ceramicspeed even makes an OSPW for it, if that's your thing. This is the combo I run.

I have run both versions of that Shimano rear derailleur in mechanical and di2 with the clutch it is awesome!

Re: 1x solution without a clutch RD? [scott8888] [ In reply to ]

Jan 7, 20 5:41

Post #15 of 67 (5275 views)

scott8888 wrote:

Ideally you use the inner ring and set the FD as an inside chain catcher. The outer ring is then a 100% effective chain catcher (and if you are really pro you dremmel off the teeth on the outer ring). Shimano makes 46 and 48 tooth inner rings, but they are pro team only, but I'm guessing someone is making after market parts that do the same thing. You can go a step further and replace a FD with a chain catcher but you really only need a tiny tab to prevent inside drops. You can accomplish a similar thing by using the outer ring and adjusting the FD accordingly.

Edit: I left out the key part which is you remove the battery from the FD in the about setups. This gives you the additional clearance which is a key part of your problem.

It’s a good thought. The 3T Exploro has a pretty small max for the inside ring. I forget exactly what size it can go up to, but not 46. 46 is the max 1x size.

I did consider just using a non etap FD with the min and max limit screws set to align the FD on top of the 1x chainring. I have a Red FD is a drawer i could use. It just looks like a dedicated guide has tighter tolerances to prevent drops better.

Re: 1x solution without a clutch RD? [DarkSpeedWorks] [ In reply to ]

Jan 7, 20 5:46

Post #16 of 67 (5271 views)

This exact situation happened to me twice at DK in the first few miles. Di2 RX derailleur with 11-40 and a Wolf Tooth front ring.

I was 2nd row from the front entering the first gravel. Potholes everywhere and I dropped the chain. The entire passed while I fought the chain back into place. Desperate to make up time I rode back through at least 90% of the field over the next couple miles. Another sharp turn with potholes and I dropped it AGAIN.....and to the very back of the field I went.

First thing I did when I got home was swap to an XTR RD. I rode that hundreds of miles more and never dropped a chain. I'm not sure if there's a real difference between RX and XTR for managing chains.

24 Hour World TT Champs-American record holder
Fat Bike Worlds - Race Director
Insta: chris.s.apex

Re: 1x solution without a clutch RD? [cmscat50] [ In reply to ]

Jan 7, 20 6:02

Post #17 of 67 (5261 views)

Yikes. Does the RX have a switch for the clutch? Was it on?

Here are the right tolerances I’m talking about in the FD area. Pardon the dirty bike.

Last edited by: rob_bell: Jan 7, 20 7:06

Re: 1x solution without a clutch RD? [cmscat50] [ In reply to ]

Jan 7, 20 6:04

Post #18 of 67 (5260 views)

It is unfortunate, but no surprise at all that that happened to you.

1x seems to be a solution in search of a problem for gravel. Worse, in many applications, it seems to be a solution that creates more problems and headaches ...

I hope the irony is not lost that many 1x riders end up needing to use FDs as chain keepers and 2nd chainrings (with ground down teeth or whatever) as chain guides/barriers. And all this effort just to be able to use compromised gearing options.

Why? What is the big advantage of running 1x then?

Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
--

Last edited by: DarkSpeedWorks: Jan 7, 20 6:08

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 7, 20 6:08

Post #19 of 67 (5251 views)

100% the clutch was engaged.

24 Hour World TT Champs-American record holder
Fat Bike Worlds - Race Director
Insta: chris.s.apex

Re: 1x solution without a clutch RD? [DarkSpeedWorks] [ In reply to ]

Jan 7, 20 6:16

Post #20 of 67 (5238 views)

The only good reason I'd ride 1x at this point is removing the FD.

For Gravel Worlds myself and my teammate were both top 10 and did so on Ultegra Di2. I ran standard 2x. He had his set on syncro. Tons of punchy climbs and his setup was flawless. Now of course Gravel Worlds is generally hero gravel at its finest vs. DK which was probably best suited to a legit mountain bike setup this year, but Di2 is so crazy perfect in 2x form that to improve on that is real hard!

What would get me to 1x at this point:

Shimano Microspline 12 speed. That way I can do road, gravel, MTB all with cross compatible components.

Why not SRAM 1 x 12 right now? They don't offer the proper range in a cassette. If they made a 36 or 38 cassette I'd probably try it for gravel in 1x form. Maybe....as I've had severe reliability issues with eTap.

Again...for me....the only disadvantage I see of running 2x is the FD. It's not aero. It causes tire clearance issues on my Domane and other bikes. That said I believe those tire clearance issues can be mostly resolved with the new GRX FD.

24 Hour World TT Champs-American record holder
Fat Bike Worlds - Race Director
Insta: chris.s.apex

Re: 1x solution without a clutch RD? [rob_bell] [ In reply to ]

Jan 7, 20 7:06

Post #21 of 67 (5197 views)

rob_bell wrote:

I know that SRAM recommends against going 1x without a clutch RD. I know people have hacked together 1X systems without a clutch RD with positive results, but others have had negative results (chain drops).

I’m stuck trying to understand why using a chain guide attached to the braze-on mount, combined with a narrow-wide chainring, wouldn’t prevent a chain from dropping, or at least be AS successful at keeping the chain from dropping as a front derailleur is on a 2x system.

On a 2x system, the front derailleur isn’t adding tension. It can prevent the chain from moving too far left or right, or even upwards, but that’s it. A chain guide that sits over the chainring like a FD would do the same thing…it would keep it from dropping to the left or right, or from jumping upwards and off. If anything, the guide could be adjusted to even closer tolerances than a FD. Paired with a narrow wide ring, how would that be worse than a FD on a 2x system? Even if the chain bounces off the bottom of the chainring because of slack caused by the RD, the chain should remain on the narrow wide ring as the top, and pedaling should get the chain back on, right?

I guess if/when the chain drops on a normal 2x, you can shift the FD to help get the chain back on. That’s the only advantage I can think of that a FD would provide over a chain guide.

I have the original eTap on my gravel bike. I want to ditch the front derailleur because the battery is the limiter to my tire clearance. There is not a clutch RD that can be paired with the original etap levers.

My other thought is that I could run a bar end shifter coming out of my drop handlebar that connects to a regular Red FD. That would allow me to keep using eTap levers and RD, but I could still keep my 22 gear combos and not have to worry about dropped chains from not having a clutch. But, that would be pretty ugly.

Any thoughts before I spend about $120 to buy a 1X chainring and chain guide? Wolf, Praxis, and K-Edge all make chain guides that connect to the braze on clamp.

I've yet to find any non-clutch 1x setup that I'm happy with. I started experimenting long ago, with a 1x9 disc brake cyclocross bike in ~2005ish, using a MTB rear derailleur, a single speed non-ramped front ring, and various chain guides. I could never get it to really work reliably and not throw chains. Fast forward to today, the ready-made 1x systems (with clutch RDs) work quite well - so personally I wouldn't mess with the non-clutch / chain guide route. The SRAM narrow/wide rings work great, too. The only chain drop I've had on a modern 1x clutch system was with a Praxis Wave Tech chainring - they had to ditch using the narrow-wide design because SRAM started cracking down on their patent.

I think we still have a pretty long way to go until 1x can truly work for more situations, though. As you mentioned, there are a lack of parts combinations for some key setups, and a lack of cassette sizes. If you're on 12-speed eTap, the biggest cassette size is 10-33 (not enough for 1x gravel)... or you have to go all the way to a 10-50 and an expensive MTB eTap derailleur if you want more. I'll get excited about 1x once it hits 105/Rival level (or cheaper), in 12 speed, with a clutch, with more than one cassette size option.

Last edited by: gregk: Jan 7, 20 7:09

Re: 1x solution without a clutch RD? [gregk] [ In reply to ]

Jan 7, 20 7:47

Post #22 of 67 (5181 views)

I have not used a RD with a clutch, so I am curious, do clutch RDs have a system where the clutch "disengages" during shifts? Are most RD clutches hydraulic or mechanical?

Greg @ dsw

Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
--

Re: 1x solution without a clutch RD? [DarkSpeedWorks] [ In reply to ]

Jan 7, 20 7:54

Post #23 of 67 (5174 views)

DarkSpeedWorks wrote:

I have not used a RD with a clutch, so I am curious, do clutch RDs have a system where the clutch "disengages" during shifts? Are most RD clutches hydraulic or mechanical?

Greg @ dsw

It doesn't disengage during shifts... the clutch can still be overridden with enough force applied - and some of the Shimano ones even have an adjustable threshold, similar to setting the lockout threshold in a front suspension fork. You end up with higher chain tension in general, which also eliminates chain slap on the chainstay. Does it have more drag? I dunno... I've seen it argued both ways.

Most clutches are mechanical. I believe that the new 12-speed eTap stuff has some sort of a fluid damper that isn't quite as powerful... so it has tension that's somewhere between a "normal" non-clutch RD and the mechanical clutch RDs that the first systems began with. I have heard of some chain drops with the fluid style when used for 1x, so my current preference is for the stronger mechanical type.

Re: 1x solution without a clutch RD? [gregk] [ In reply to ]

Jan 7, 20 8:01

Post #24 of 67 (5165 views)

Good info, thanks. I looked up some youtubes about the shimano RX RD and I see how it works. It is clever in that (apparently) the clutch only actuates in one direction (i.e., it prevents the chain from getting slacker, but does not resist the chain in getting tighter).

But this makes me think of another quesion, when you shift up to a larger cog (when using a mechanical RD with a mecahanical clutch like a shimano RX mech), during the shift, can you feel the extra resistance of the clutch as it fights the chain tension as you try to shift up and onto bigger cogs?

Advanced Aero TopTube Storage for Road, Gravel, & Tri...ZeroSlip & Direct-mount, made in the USA.
DarkSpeedWorks.com.....Reviews.....Insta.....Facebook
--

Re: 1x solution without a clutch RD? [gregk] [ In reply to ]

Jan 7, 20 8:03

Post #25 of 67 (5161 views)

Thanks for all the help, everyone. This is all making me lean towards sticking with 2x and dealing with the lack of tire clearance. In the past I offset the dish of my rear wheel on this bike to fit a 43c tire, so I can always do that again if I need to run something wider. I have a 40c tire from a different manufacturer than I usually use that should arrive today. I’m hoping it fits without dishing, but we will see.

The thing that still puzzles me is what is happening with a 2x system that prevents chain drops. It’s not like my chain just gets thrown off the inside or outside of my big chainring when I ride gravel (unless I’m shifting the FD).

Our Partners

transition-DOT-area-AT-slowtwitch-DOT-com

Advertise with us

©1999-2024 Slowtwitch, Inc., and Slowtwitch.com
Reproduction of material from any Slowtwitch.com page
without written permission is strictly prohibited.