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School me on Cassettes
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So, I'm building up some training wheels, grabbed some Askiums from the Performance Bike going out of bidness sale. They were still selling cassettes for much higher than what you can get a Ultegra R8000 on Amazon.

The cassette that came with my Argon 18 E119 is an R8000 11/28 and there are a lot of other options I've noticed and it seems clear as mud. In the back of my mind I'd think an 11/32 gives more range but from what I can read that may not be the case.

Washed up footy player turned Triathlete.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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Ensure your derailleur cage can support the largest cog you want. After that pick the range you need, especially if you’re going 1x. 52/36 or 50/34 with 11-28 would cover (best guess) 95% of the gearing range for any condition. Exceptions obviously for large front rings (descent from Hawi or anything in excess of 40mph) or dinner plate 58/60T TT use to mitigate chainline friction loss.

Edit: You can also play with calculator at http://www.bikecalc.com/speed_at_cadence to confirm your selection.
Last edited by: TriFluid: Dec 9, 18 8:56
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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An 11-32 cassette does give you more range than an 11-28.
Last edited by: jimatbeyond: Dec 9, 18 9:22
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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Funny: I picked up a 11/32 Ultegra cassette from Performance the day before yesterday for $40. I also picked up a couple of Castelli jerseys for $25/apiece. Pricing seems inconsistent across stores but there are deals to be had if you poke around a bit.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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TheStroBro wrote:
The cassette that came with my Argon 18 E119 is an R8000 11/28 and there are a lot of other options I've noticed and it seems clear as mud. In the back of my mind I'd think an 11/32 gives more range but from what I can read that may not be the case.
Do you feel like you need more than a 28 now? You should choose based on how your current cassette is working for you and the rides you anticipate coming up...

I switched my TT bike to a 11-25 when I bought it. I have rarely needed the 25, so I just switched it to an 11-23. I am doing Lake Placid 70.3 at the end of next year, so I will switch my TT bike back to the 11-25 or get an x-28 just for that race.

I have an 11-28 on my road bike so that it can be a great all-arounder. I have ridden it in a few rides with some very steep or very long climbs, and I have learned that an 11-28 is all I need for the worst climbing I have ever seen. I just switched my road bike to an 11-25 for better all-around riding. I have the 11-28 that I can easily swap back on if I need it for a ride with big climbs.
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Re: School me on Cassettes [exxxviii] [ In reply to ]
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exxxviii wrote:
TheStroBro wrote:
The cassette that came with my Argon 18 E119 is an R8000 11/28 and there are a lot of other options I've noticed and it seems clear as mud. In the back of my mind I'd think an 11/32 gives more range but from what I can read that may not be the case.

Do you feel like you need more than a 28 now? You should choose based on how your current cassette is working for you and the rides you anticipate coming up...

I switched my TT bike to a 11-25 when I bought it. I have rarely needed the 25, so I just switched it to an 11-23. I am doing Lake Placid 70.3 at the end of next year, so I will switch my TT bike back to the 11-25 or get an x-28 just for that race.

I have an 11-28 on my road bike so that it can be a great all-arounder. I have ridden it in a few rides with some very steep or very long climbs, and I have learned that an 11-28 is all I need for the worst climbing I have ever seen. I just switched my road bike to an 11-25 for better all-around riding. I have the 11-28 that I can easily swap back on if I need it for a ride with big climbs.

I would say I'm fairly ignorant of this part of cycling, so when it came to building these wheels up I figured I'd ask. Your last paragraph gives me some ideas. I have ridden it like once since I picked it up from Moxie, so I couldn't say if I need anything more tbh.

Washed up footy player turned Triathlete.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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What chainring(s) are you running up front? 50/34? 52/36? 53/39?

Typically, a 11-32 cassette would be for A.) Someone who lives in a very hilly region and needs the gears, B.) Is on a 1x cyclocross bike and needs a bit of range, or C.) Is 'older' and needs the easier gears to spin.
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Re: School me on Cassettes [kppolich] [ In reply to ]
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R8000 52/36

Washed up footy player turned Triathlete.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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Apologies if I misread your post but it might be worth mentioning you don't necessarily have to get an R8000 cassette. Any Shimano or Sram 11 speed cassette is compatible. It's best to stick to road cassettes since mtb ones might go past the capacity of your rear derailleur. I'd check the capacity of the rear derailleur anyway.

I'd go out and ride up your steepest nearby hill before buying. 11-28 is a cassette with plenty of range designed for rides including hills. You may simply not need any more than that. Alternatives to getting a new cassette are 1) buy the tools to swap cassettes over - you learn a bit and could try the 28 you already own. 2) if you absolutely have to buy a bigger cassette now maybe get an 11 speed Shimano 105 or Sram Rival having checked your rear derailleur.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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Do you have a long or short cage rear derailleur?

Short cage R8000 derailleurs can handle up to a 30T cassette

Long cage R8000 can handle a 34T cassette.
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Re: School me on Cassettes [OddSlug] [ In reply to ]
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This was more a fact finding mission. Sitting in my cart on Amazon is an 11/28. There are some hills around here that I ride up and down frequently...or rather was: Usery Pass and Hunt Highway.

I already have the tools to change out my cassette as the once used Wahoo I picked up had a SRAM 10 S on it and put the Shimano 11 S back on it.

Washed up footy player turned Triathlete.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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The stock 52/36 & 11-28 that came on your bike is a nice setup. Plenty of range on both ends. If you think you need an even easier granny gear, go with the 11-32, if you don't want to worry about it and want the same setup on your training wheels and race wheels get another 11/28. I believe the stock R8000 regular cage derallieur can handle the 11-32, no need for the mid/long cage Rear Der in order to run the 11-32.

Have you noticed riding the 11-28 on your other wheels that the gear jumps are large? Maybe a nice 11-25 or 11-23 would give you smoother gears without the jumps. I don't know where you live, so the terrain and typical riding conditions come into play. If it were me, 11-28 on everything.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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I prefer this gear calculator to the one above:
http://ritzelrechner.de/


the current options under discussion:
http://ritzelrechner.de/?GR=DERS&KB=36,52&RZ=11,12,13,14,15,17,19,21,23,25,28&UF=2135&TF=90&SL=2.6&UN=KMH&DV=teeth&GR2=DERS&KB2=36,52&RZ2=11,12,13,14,16,18,20,22,25,28,32&UF2=2135
<edit: that gets cut off. Quote my post and it should bring up the full string to copy and paste>


11-28 is a good allrounder, provided it can comfortably get you up the biggest hill you'll face.
11-32 will give you one more lower gear (14% slower than the 28), with the same top end.
The downside to the wider range is different jumps between gears in the middle of the cassette. Not a dramatic issue with 11 speed though, but you do lose the 15T sprocket.


NOTE:
THe RD-R8000-SS (short cage) is officially only rated to 30T max on the cassette.
The RD-R8000-GS (medium cage) is rated to 34T max.
Shimano do tend to be conservative though.


Last edited by: MattyK: Dec 9, 18 12:45
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Re: School me on Cassettes [exxxviii] [ In reply to ]
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exxxviii wrote:
TheStroBro wrote:
The cassette that came with my Argon 18 E119 is an R8000 11/28 and there are a lot of other options I've noticed and it seems clear as mud. In the back of my mind I'd think an 11/32 gives more range but from what I can read that may not be the case.

Do you feel like you need more than a 28 now? You should choose based on how your current cassette is working for you and the rides you anticipate coming up...

I switched my TT bike to a 11-25 when I bought it. I have rarely needed the 25, so I just switched it to an 11-23. I am doing Lake Placid 70.3 at the end of next year, so I will switch my TT bike back to the 11-25 or get an x-28 just for that race.

I have an 11-28 on my road bike so that it can be a great all-arounder. I have ridden it in a few rides with some very steep or very long climbs, and I have learned that an 11-28 is all I need for the worst climbing I have ever seen. I just switched my road bike to an 11-25 for better all-around riding. I have the 11-28 that I can easily swap back on if I need it for a ride with big climbs.

Finally. It seems I'm not crazy after all. I've ridden 11-25 for years, with 52 or 53/39 front chainrings. And I keep reading about 28 and 32 cassettes, and I'm like "am I nuts"? It's not crazy hilly here, but not flat either - there's some nasty steep rollers. And yet I hardly ever need to go into to small ring. For giggles I got myself an 11-28 this year and the 28 is still spotless. I'm going back to 25 on that wheel as well.

Citizen of the world, former drunkard. Resident Traumatic Brain Injury advocate.
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Re: School me on Cassettes [Richard Blaine] [ In reply to ]
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Richard Blaine wrote:
Finally. It seems I'm not crazy after all. I've ridden 11-25 for years, with 52 or 53/39 front chainrings. And I keep reading about 28 and 32 cassettes, and I'm like "am I nuts"? It's not crazy hilly here, but not flat either - there's some nasty steep rollers. And yet I hardly ever need to go into to small ring. For giggles I got myself an 11-28 this year and the 28 is still spotless. I'm going back to 25 on that wheel as well.
The gearing needs of different riders vary pretty dramatically. The strongest cyclists are several times more powerful than the weakest. On steep hills, where gravity is the dominant resistance force, that results in the strongest cyclists being several times faster than the weakest. Preferred cadences don't vary by anywhere near that much across cyclists, so some cyclists have use for gears twice as low or more than what some other cyclists have use for, even before accounting for variations in regional hilliness.
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Re: School me on Cassettes [TriFluid] [ In reply to ]
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to mitigate chainline friction loss.


Always surprised to find when I go riding with triathletes, how many DON'T seem to understand this and ride on completely crossed up chain-lines!!

I kindly try and help out explaining that forget gears, power and all the stuff and think about running as straight a chain-line as you can in every situation when riding!


Steve Fleck @stevefleck | Blog
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Re: School me on Cassettes [Fleck] [ In reply to ]
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Anyone actually spend the premium for the DuraAce cassette? I recently found one sale and got it for my race wheels. Still double the cost of Ultegra, but about 50 bucks cheaper than I had seen it anywhere before. Don't really know if it's at all worth it. I've heard they wear faster. But this will be on a race wheel that might see 250 miles a year. Had the money earmarked for the bike anyway. Realize weight isn't a huge deal on my tri bike, but it never hurt anyone to shed it either.
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Re: School me on Cassettes [KG6] [ In reply to ]
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Don't really know if it's at all worth it. I've heard they wear faster. But this will be on a race wheel that might see 250 miles a year.


This is the perfect application for a Dura Ace cassette.

Just be sure to check things out with a test-ride before the actual race, to ensure chain is not too worn ( or measure the chain) and still works with the DA cassette


Steve Fleck @stevefleck | Blog
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Re: School me on Cassettes [Fleck] [ In reply to ]
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I ride inside now, so the plan is to actually have a dedicated waxed "race chain" as well. My previous cassette (Ultegra I believe) will stay on the trainer along with a separate chain.
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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Someone say "cassettes?"



"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin
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Re: School me on Cassettes [RandMart] [ In reply to ]
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RandMart wrote:
Someone say "cassettes?"


Randy, sometimes I wonder if I'm the only one laughing at (or otherwise relating to) your punk rock jokes.

That cassette is classic - "Home taping is killing record industry profits - we left this side blank so you can help".

Of course forgetting that while they're busy killing the record industry, they are still helping "big cassette", "big guitar amp", and "big drumstick"

Citizen of the world, former drunkard. Resident Traumatic Brain Injury advocate.
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Re: School me on Cassettes [Richard Blaine] [ In reply to ]
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Richard Blaine wrote:
Randy, sometimes I wonder if I'm the only one laughing at (or otherwise relating to) your punk rock jokes.


I like to think of them as "observances" or "recollections"

"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin
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Re: School me on Cassettes [RandMart] [ In reply to ]
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RandMart wrote:
Richard Blaine wrote:
Randy, sometimes I wonder if I'm the only one laughing at (or otherwise relating to) your punk rock jokes.



I like to think of them as "observances" or "recollections"

I said I'm not just laughing at them, I'm relating to them as well.

Citizen of the world, former drunkard. Resident Traumatic Brain Injury advocate.
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Re: School me on Cassettes [Richard Blaine] [ In reply to ]
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Richard Blaine wrote:
RandMart wrote:
Richard Blaine wrote:
Randy, sometimes I wonder if I'm the only one laughing at (or otherwise relating to) your punk rock jokes.



I like to think of them as "observances" or "recollections"


I said I'm not just laughing at them, I'm relating to them as well.

Yeah, we're not alone ... check out the Wattie Ink thread, for example, or some of the music threads in the LR

"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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TheStroBro wrote:
So, I'm building up some training wheels, grabbed some Askiums from the Performance Bike going out of bidness sale. They were still selling cassettes for much higher than what you can get a Ultegra R8000 on Amazon.

The cassette that came with my Argon 18 E119 is an R8000 11/28 and there are a lot of other options I've noticed and it seems clear as mud. In the back of my mind I'd think an 11/32 gives more range but from what I can read that may not be the case.
There's nothing complicated or mysterious about this. 32 teeth is more than 28 teeth and they both have 11 at the other end. An 11-32 does give more range than 11-28. Pretty simple.
The only reason you may not get more range via a simple cassette swap is if something else in your drive train was preventing you from using those extra teeth. For example if your rear derailleur doesn't have sufficient capacity or your chain is too short.

However, more range is not necessarily better. It depends on such factors as where you ride, how you ride, your ability, your weight, whether you're willingness to change setup between rides, whether you favour nominal setup for most common routes over flexibility of setup for all potential routes, etc.

I occasionally ride my Tri bike in the mountains but usually bring my road bike. I don't mind switching cassettes for special occasions but don't bother doing it every week. I'm fairly heavy for a triathlete (usually over 80kg, except at my leanest mid season on good years!). I don't mind a low cadence but don't like being forced to high intensity on long hills late in a long ride just because I have insufficient gears to do otherwise.
I used to use 50/34 and 11-28 on my road bike but put on a 11-32 cassette for climbing Gallibier, Glandon and Alpe D'Huez in the Alps last year. It turned out I didn't need that gear but it was nice to have it just in case my knees started suffering. I planned to switch back when i got home but actually never bothered. With 11 sprockets, I don't find myself missing the smaller gear ratio spacing and that small gear, though not essential, does come in handy now and again on steep climbs.
On the Tri bike I've got 52/36 chainrings and generally use 11-25 as it spends most of it's time on the trainer or riding flat or rolling routes. However I've used 11-28 in the past for hillier courses and it is only a 5 minute job to switch.

Unless you're new to cycling, or plan to ride a route that's dramatically different to what you're used to, surely you already know what gears you want/need?

Bear in mind that so long as you have the ability to switch cassettes, and if you do a lot of riding, there may not be much additional cost to having more than one cassette. You'll be spreading the wear and tear around and they'll obviously last longer if you're using them less because duty is shared.
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Re: School me on Cassettes [Fleck] [ In reply to ]
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Fleck wrote:
to mitigate chainline friction loss.


Always surprised to find when I go riding with triathletes, how many DON'T seem to understand this and ride on completely crossed up chain-lines!!

I kindly try and help out explaining that forget gears, power and all the stuff and think about running as straight a chain-line as you can in every situation when riding!

Do you (or someone else) mind explaining this to me now? On my tri bike, I have a 50/34 and 11/28. I ride in the big ring about 98% of the time. Is the idea that I should adjust my cadence to increase speed/power instead of shifting rear gears in order to keep the chain straight? Also, I guess I would assume keeping the chain straight would mean keeping the rear gear towards the middle? Or am I totally misunderstanding this?
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Re: School me on Cassettes [MRid] [ In reply to ]
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If you are in the big chainring, you want to stay out of the two largest gears on the cassette.

If you are in the small chainring, you want to stay out of the two smallest gears on the cassette.
Last edited by: jimatbeyond: Dec 10, 18 11:57
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Re: School me on Cassettes [jimatbeyond] [ In reply to ]
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Can a 11-30 ultegra 8000/dura ace cassette work with a short cage 6800 Rear Der. Would I need to change the chain or derailleur at all. Currently have a 11-28 but would like another lower gear because live near mountains
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Re: School me on Cassettes [transgress4] [ In reply to ]
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transgress4 wrote:
Can a 11-30 ultegra 8000/dura ace cassette work with a short cage 6800 Rear Der. Would I need to change the chain or derailleur at all. Currently have a 11-28 but would like another lower gear because live near mountains

My best guess is that it will work with no changes to chain or derailleur (except adjusting the b screw a little).

It's not so much the max cog size as the ability of the short cage to manage all the chain. Assuming you have a 16 tooth cog difference up front (50/34 or 52/36 crank) then 11-28 is the limit of the published chain wrap capacity. Those numbers are conservative by a couple teeth so an 11-30 will likely work. 11-32 is well beyond the chain wrap capacity and I just couldn't get it where I was happy when I went to a 50/34 and 11/32 for a climbing event. I swapped in a GS cage from another bike and everything was fine.

Another thing to consider is that the 30 tooth is only ~4% lower than the 28 tooth. Most people wouldn't be able to tell the difference. Going to the 11-32 or 11-34 will definitely give you a lower bailout gear, but most likely necessitate a longer cage (GS) rear derailleur and slightly longer chain.
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Re: School me on Cassettes [dangle] [ In reply to ]
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^ This.
http://productinfo.shimano.com/...C-453&acid=C-454 - the RD-6800-SS is rated to max 28T.
However Shimano are notoriously conservative, so you most likely can fit a 30T without issue; just avoid the big-big combo.

Google says people have tried a 32T cassette and it'll work except for the big-big combo.
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Re: School me on Cassettes [MRid] [ In reply to ]
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MRid wrote:
Fleck wrote:
to mitigate chainline friction loss.


Always surprised to find when I go riding with triathletes, how many DON'T seem to understand this and ride on completely crossed up chain-lines!!

I kindly try and help out explaining that forget gears, power and all the stuff and think about running as straight a chain-line as you can in every situation when riding!


Do you (or someone else) mind explaining this to me now? On my tri bike, I have a 50/34 and 11/28. I ride in the big ring about 98% of the time. Is the idea that I should adjust my cadence to increase speed/power instead of shifting rear gears in order to keep the chain straight? Also, I guess I would assume keeping the chain straight would mean keeping the rear gear towards the middle? Or am I totally misunderstanding this?
The idea is that you should select your gearing so that you can spend as much time as possible with a straight chainline, ie closer to the middle of the cassette, at your preferred cadence and power output.
This is why world class cyclists run massive front rings in time trials. Not because they need the 58-11 gearing, but so they can push 58-15 on the flat (assuming the course is flat).
But yes in general, stick to the middle of the cassette if you can. If you're nearing the big-big combo, you'd be more efficient in a small-mid combo.
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Re: School me on Cassettes [MattyK] [ In reply to ]
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That makes sense. Thank you
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Re: School me on Cassettes [TheStroBro] [ In reply to ]
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My personal preference is a 50/34 upfront and a 11/25 in the back on a tri bike and a 53/39 - 11/28 on a road bike. Plenty of gear to spin out of for my rides around the Los Angeles area, and I am from an uber cyclist.

Next races on the schedule: none at the moment
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Re: School me on Cassettes [MattyK] [ In reply to ]
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MattyK wrote:
MRid wrote:
Fleck wrote:
to mitigate chainline friction loss.


Always surprised to find when I go riding with triathletes, how many DON'T seem to understand this and ride on completely crossed up chain-lines!!

I kindly try and help out explaining that forget gears, power and all the stuff and think about running as straight a chain-line as you can in every situation when riding!


Do you (or someone else) mind explaining this to me now? On my tri bike, I have a 50/34 and 11/28. I ride in the big ring about 98% of the time. Is the idea that I should adjust my cadence to increase speed/power instead of shifting rear gears in order to keep the chain straight? Also, I guess I would assume keeping the chain straight would mean keeping the rear gear towards the middle? Or am I totally misunderstanding this?

The idea is that you should select your gearing so that you can spend as much time as possible with a straight chainline, ie closer to the middle of the cassette, at your preferred cadence and power output.
This is why world class cyclists run massive front rings in time trials. Not because they need the 58-11 gearing, but so they can push 58-15 on the flat (assuming the course is flat).
But yes in general, stick to the middle of the cassette if you can. If you're nearing the big-big combo, you'd be more efficient in a small-mid combo.

We seem to spend a lot of time worried about cross chaining and its corresponding friction losses here. While the concept makes sense, I wonder if it's a holdover from back in the day. Chains were wider, stiffer (laterally), and there was more space between cogs when we only had 5 cogs in the back on a 126mm hub vs. having 11 on a 130mm (rim brake) hub. I would love to see a test that shows what the wattage loss is for cross changing.

There was a test a few years ago (posted on slowtwitch, iirc) showing that for an equivalent gear-inch and cadence, it was more efficient to be on the big ring. I believe the theory was that it reduced friction in the chain because the links didn't bend as acutely, similar to running larger pulleys. So, small ring and smaller cog was not more efficient.

I'd be at least mildly surprised to find that world-class time trialists spend much time in a 58x15 on a flat course. A look at a gear, cadence and speed chart shows when using a 58 big ring with a 23 tire, that for 34mph with a 15 cog, a cadence of 112 is necessary. For a 14 cog, the cadence is 105. For a 13, its 97-98 . For a 12, it's 90. For an 11, it's 82-83. Changing to a 25mm tire changes the required cadence to 111-112, 104, 97, 88-89, and 82. I don't believe we see cadence over 100 very often anymore, with the exception of descents. In his heyday, he-who-shall-not-be-named was in the 102-105 range. Tony Martin looks more like low 90s to me. Using 34mph and a cadence of 95, the rider is spending a lot of time in the 13. Not a big/small, but not likely to be a big/15, either.
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Re: School me on Cassettes [FatandSlow] [ In reply to ]
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FatandSlow wrote:
We seem to spend a lot of time worried about cross chaining and its corresponding friction losses here. While the concept makes sense, I wonder if it's a holdover from back in the day. Chains were wider, stiffer (laterally), and there was more space between cogs when we only had 5 cogs in the back on a 126mm hub vs. having 11 on a 130mm (rim brake) hub.

There was more space between cogs, but due to the smaller cog count, the freewheels were still considerably narrower than modern 11-speed cassettes. The width of modern cassettes is the main reason that rear hub OLD switched from 126mm to 130mm, and despite the extra real estate provided by 130mm, modern rear wheels also need much steeper drive-side spokes at very high tension. The wider cassette actually results in cross-chaining experiencing far more extreme angles on current-gen drivetrains than on drivetrains circa 1980.

But yes, concerns regarding cross-chaining go way back. Many racers used to be extremely concerned about chain behavior in general... in retrospect it's hard to know how much of it was ever justified, and if so, when it was justified. Some of it definitely got pretty silly, like the efforts in the 30s and 40s to use derailleurs on racing bikes while keeping the amount of bends in the chain to a minimum (resulting in a variety of strange mechanisms that provided less than 10 teeth of chain wrap and didn't shift particularly well).

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I'd be at least mildly surprised to find that world-class time trialists spend much time in a 58x15 on a flat course. A look at a gear, cadence and speed chart shows when using a 58 big ring with a 23 tire, that for 34mph with a 15 cog, a cadence of 112 is necessary. For a 14 cog, the cadence is 105. For a 13, its 97-98 . For a 12, it's 90. For an 11, it's 82-83. Changing to a 25mm tire changes the required cadence to 111-112, 104, 97, 88-89, and 82. I don't believe we see cadence over 100 very often anymore, with the exception of descents. In his heyday, he-who-shall-not-be-named was in the 102-105 range. Tony Martin looks more like low 90s to me. Using 34mph and a cadence of 95, the rider is spending a lot of time in the 13. Not a big/small, but not likely to be a big/15, either.

I think you'd have to accumulate some data to answer the question, because cadence choice varies a lot from cyclist to cyclist. Anyone could tell any narrative if they just picked a couple cyclists from any given era. Eddy Merckx and Bradley Wiggins set their hour records on very similar cadences to each other, for instance, both a bit over 100rpm.
Last edited by: HTupolev: Dec 10, 18 18:40
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Re: School me on Cassettes [KG6] [ In reply to ]
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Dura-Ace is lighter. Also noisier- I prefer an Ultegra cassette.
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Re: School me on Cassettes [FatandSlow] [ In reply to ]
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FatandSlow wrote:

We seem to spend a lot of time worried about cross chaining and its corresponding friction losses here. While the concept makes sense, I wonder if it's a holdover from back in the day. Chains were wider, stiffer (laterally), and there was more space between cogs when we only had 5 cogs in the back on a 126mm hub vs. having 11 on a 130mm (rim brake) hub. I would love to see a test that shows what the wattage loss is for cross changing.
Reference to testing that is now ceramicspeed proprietary:
https://www.bikeradar.com/...oper-shifting-44016/

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There was a test a few years ago (posted on slowtwitch, iirc) showing that for an equivalent gear-inch and cadence, it was more efficient to be on the big ring. I believe the theory was that it reduced friction in the chain because the links didn't bend as acutely, similar to running larger pulleys. So, small ring and smaller cog was not more efficient.
Depends how far across the cassette you are. See link above.
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I'd be at least mildly surprised to find that world-class time trialists spend much time in a 58x15 on a flat course. A look at a gear, cadence and speed chart shows when using a 58 big ring with a 23 tire, that for 34mph with a 15 cog, a cadence of 112 is necessary. For a 14 cog, the cadence is 105. For a 13, its 97-98 . For a 12, it's 90. For an 11, it's 82-83. Changing to a 25mm tire changes the required cadence to 111-112, 104, 97, 88-89, and 82. I don't believe we see cadence over 100 very often anymore, with the exception of descents. In his heyday, he-who-shall-not-be-named was in the 102-105 range. Tony Martin looks more like low 90s to me. Using 34mph and a cadence of 95, the rider is spending a lot of time in the 13. Not a big/small, but not likely to be a big/15, either.

Numbers were for example only.
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Re: School me on Cassettes [FatandSlow] [ In reply to ]
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Put your bike on the work stand, put it in the big ring, big cog cross over gear and slowly spin the cranks. Now put it in a gear with a straighter chainline. When I do this I can feel the difference in resistance. As a road racer I will use this gear when it makes sense for a period of time, like a short hill where I or someone else is attacking and I don't want to shift out of and then shortly thereafter back into the big ring. But I wouldn't say do a whole climb crossed over like that. Nor would I want to time trial for 20 minutes into a head wind in that gear.

Another reason for the super large chainrings besides chainline is to avoid the added drivetrain drag from small cogs. This is the same reason that everybody is spending $500-$600 on those ceramic speed large jockey wheel derailleur cages. There is a lot more drag wrapping that chain around an 11 tooth cog than a bigger cog. If for example a 58x15 gives you the best chainline, riding in the 58x13 would still be better than an equivalent gear on the 11 cog.

Kevin

http://kevinmetcalfe.dreamhosters.com
My Strava
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Re: School me on Cassettes [nslckevin] [ In reply to ]
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Thank you for weighing in. I appreciate your expertise. Tried your suggestion and I can feel the difference, too. Between a 52x15 and a 52x11, but not for a 52x15 and a 52x14. But that's just me.

I get the concept. And I had read the article referenced above when it came out, but had forgotten it. In addition to being fat and slow, I'm old too.The 2 takeaways were that leaving chainline losses out, bigger rings and cogs were always more efficient than smaller ones and that in most cases, the big/big combination should be avoided.

What I was trying to say is that I don't think a 58x15 is going to work for world-class time trialists on the flats because I don't believe they're turning a cadence above 110 to go 34mph - on average. In my pea brain, it was a bad example that didn't support the argument. My suspicion is that the main reason the pointy end of the field uses 56 and 58 rings is for speed, but I have no data.
Last edited by: FatandSlow: Dec 11, 18 10:34
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Re: School me on Cassettes [FatandSlow] [ In reply to ]
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FatandSlow wrote:
Thank you for weighing in. I appreciate your expertise. Tried your suggestion and I can feel the difference, too. Between a 52x15 and a 52x11, but not for a 52x15 and a 52x14. But that's just me.

I get the concept. And I had read the article referenced above when it came out, but had forgotten it. In addition to being fat and slow, I'm old too.The 2 takeaways were that leaving chainline losses out, bigger rings and cogs were always more efficient than smaller ones and that in most cases, the big/big combination should be avoided.

What I was trying to say is that I don't think a 58x15 is going to work for world-class time trialists on the flats because I don't believe they're turning a cadence above 110 to go 34mph - on average. In my pea brain, it was a bad example that didn't support the argument. My suspicion is that the main reason the pointy end of the field uses 56 and 58 rings is for speed, but I have no data.

On the other hand, a 58x13 at 100 rpm is good for 34.9 mph. Maybe not a perfect chain line or friction due to small cogs, but it's better than being in the 12 tooth cog. Every little bit adds up.

Kevin

http://kevinmetcalfe.dreamhosters.com
My Strava
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Re: School me on Cassettes [MRid] [ In reply to ]
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MRid wrote:
I guess I would assume keeping the chain straight would mean keeping the rear gear towards the middle?



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