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Rear Derailleur 32 tooth compatibility?
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I picked up a new PS2 last year and am looking at swapping my 11/28 cassette out for a 12/32 as I am fat and struggled on the hills in Louisville last year (Mont Tremblant coming up this summer). It looks like the current P2 comes with a 105 5800 GS rear derailleur that the Shimano site says is compatible with a 32 tooth cassette. Does anyone know how to tell if this is the model I have? There don't seem to be any GS markings on it.
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Toefuzz wrote:
I picked up a new PS2 last year and am looking at swapping my 11/28 cassette out for a 12/32 as I am fat and struggled on the hills in Louisville last year (Mont Tremblant coming up this summer). It looks like the current P2 comes with a 105 5800 GS rear derailleur that the Shimano site says is compatible with a 32 tooth cassette. Does anyone know how to tell if this is the model I have? There don't seem to be any GS markings on it.

I just looked at mine and the model information on it is found on the side of the parallelogram facing the wheel. It's probably easier to see if you remove the wheel. Hope that helps. I'm also running a 32 due to age, weight, fitness and the gradient of local hills. You'll be glad you have it on the Duplis sp? climb.

Hugh

Genetics load the gun, lifestyle pulls the trigger.
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Re: Rear Derailleur 32 tooth compatibility? [sciguy] [ In reply to ]
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Thanks Hugh! My eyes never would have found that in a dark basement. I'm assuming I might need a new longer chain to go with the larger cassette?
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Yes def need a new chain to be precise. I do believe you can make your current chain work with it temporarily.

I downloaded a chain size calculator from the Google play store that was helpful. I'm sure there's other myriad of tools that could calculate chain length.
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Toefuzz wrote:
Thanks Hugh! My eyes never would have found that in a dark basement. I'm assuming I might need a new longer chain to go with the larger cassette?

I agree with Chan with the caveat that if your current chain was by chance installed on the long end you might be lucky. Chains are cheap though so not a big worry.

Have fun at IMMT. Most of the roads are so smooth you'll be in heaven.

Hugh

Genetics load the gun, lifestyle pulls the trigger.
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Toefuzz wrote:
I picked up a new PS2 last year and am looking at swapping my 11/28 cassette out for a 12/32 as I am fat and struggled on the hills in Louisville last year (Mont Tremblant coming up this summer). It looks like the current P2 comes with a 105 5800 GS rear derailleur that the Shimano site says is compatible with a 32 tooth cassette. Does anyone know how to tell if this is the model I have? There don't seem to be any GS markings on it.


Good advice so far. You may not need a new chain, but it's really difficult to tell without looking at it. If you can take a picture of the chain in the big-big combo, we could probably point you in a better direction. I'm one to always use a new chain with a new cassette though. If your chain has 1,000 or more miles (this is a totally made up number), that could be a good choice for using a new one with your new cassette. The other thing is that the circumference of the 32 ring isn't drastically larger than the 28. My CX wheels are 11-32, 11-32, and 11-28 and it's really hard to eyeball any difference in chain length when they are in the big-big combo.

All 11 speed Shimano derailleurs can handle a 32 tooth. It's the 'chain wrap' that the GS sizing is for. An 11-32 in a 1x application works just fine on a SS 'short' cage derailleur. You need the medium (sometimes called 'long') GS cage for using an 11-32 in a 2x application just because of the extra chain needed.

I need to do a little bike work tonight, so I'll try to remember to taking a picture of the actual measurements of a short cage vs a medium cage. The distance between the wheels on the cage is the only real difference between the SS and GS rear derailleurs.

Who makes a 12-32 11 speed cassette? I haven't seen one that I remember.
Last edited by: dangle: May 10, 17 7:11
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Re: Rear Derailleur 32 tooth compatibility? [dangle] [ In reply to ]
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I'm running a 2x and could have been mistaken on the 12-32 cassette. I think I will swing by the shop and talk to the guys. I mentioned it at another shop and they immediately told me it wouldn't work, which didn't seem right so I thought I would post here. I'll definitely need a new chain...lots of miles on this one and I despise sloppy shifting. Speaking of sloppy shifting...what makes the biggest difference in smooth/proper shifting from a mechanical standpoint? If it's the shifters, what model should I look for (Tri bike)?
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Toefuzz wrote:
I'm running a 2x and could have been mistaken on the 12-32 cassette. I think I will swing by the shop and talk to the guys. I mentioned it at another shop and they immediately told me it wouldn't work, which didn't seem right so I thought I would post here. I'll definitely need a new chain...lots of miles on this one and I despise sloppy shifting. Speaking of sloppy shifting...what makes the biggest difference in smooth/proper shifting from a mechanical standpoint? If it's the shifters, what model should I look for (Tri bike)?
Sloppy shifting could have a few causes but I doubt it's the shifters. Most likely suspect is the cables, I would think. If they are dirty, poorly routed, heavily liners or coatings, or unlubricated if plain cables, any of those would hurt the crispness and consistency of shifting.
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Toefuzz wrote:
I'm running a 2x and could have been mistaken on the 12-32 cassette. I think I will swing by the shop and talk to the guys. I mentioned it at another shop and they immediately told me it wouldn't work, which didn't seem right so I thought I would post here. I'll definitely need a new chain...lots of miles on this one and I despise sloppy shifting. Speaking of sloppy shifting...what makes the biggest difference in smooth/proper shifting from a mechanical standpoint? If it's the shifters, what model should I look for (Tri bike)?

There might be one out there. It would be a practical cassette. Some guy will tell you to make your own, but the last time I looked the individual cogs from 11-17 and 12-17 on a 11-32 and 12-25 had different SKU's, meaning they probably are less than ideal to mix and match unless you literally buy two cassettes and use half of one and half of the other. I think going with the 11-32 makes sense. Are you on a 50/34 crank already?

The statement I made in the previous post doesn't fall within Shimano's recommendation, but I have had my hands on many bikes where a SS cage RD is running an 11-32 or even Shimano road RD's running an 11-36 cassette with a maxed out b screw. If you are running 2x, you need the GS rear derailleur. Some may know the specs of the GS vs. SS cage off the top of their head, but I'll try and measure it tonight if I remember.

To actually answer your question about the biggest difference in sloppy shifting, here's my (opinion) of order of importance (assuming the derailleur is adjusted correctly): 1) Derailleur hanger alignment 2) Shifter cable cleanliness/condition. The 'housing' can affect that too, but I usually replace housing only half as much as cables. It could be worth popping another $5 cable in there after you have the shop check the hanger alignment (with the actual tool, not eyeballing it). 3) That's it. Shifter, RD, chain, cassette are pretty minor details after that. A worn chain and cassette will still shift fairly well if everything else is good to go.

TT/far end shifters would have to be drastically messed up to be causing an issue. You could buy any shifter in the world and it's not going to shift your chain across the cassette any better if the hanger is out of alignment or the shifter cable is gummed up at any point in the housing. The TT/bar end shifter is such a simple mechanism that it's nearly impossible for it not to work if all the pieces are in it. The RD really does whatever the shifters tell it to do, so that would have to be pretty messed up to not work. I have dropped a RD in a parts washer and then re-lubed the moving parts after, but that was mostly for making it more shiny. They just do their thing unless they are covered in sports drink, dirt and tears.

Maybe not for OP specifically, but the Park Tool link on adjusting derailleurs is a good reminder for all levels of ability the correct steps (in order) when tuning a rear derailleur. http://www.parktool.com/...erailleur-adjustment
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Re: Rear Derailleur 32 tooth compatibility? [dangle] [ In reply to ]
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Campy will have a 12-32 as part of the new 11sp Centaur group.
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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FWIW, I have a 2015 P2 (105) and I have successfully switched back and forth between an 11-28 and an 11-32 with no issues. I was told all you really needed to be sure about was that you were running a LC RD. Coulda been shit advice, but it was true for my bike. I didn't switch chains, either.

Good luck.
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Re: Rear Derailleur 32 tooth compatibility? [FatandSlow] [ In reply to ]
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FatandSlow wrote:
Campy will have a 12-32 as part of the new 11sp Centaur group.

Cool! If they really do stick with the idea of "105 level pricing" that would be an excellent cassette.
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Re: Rear Derailleur 32 tooth compatibility? [dangle] [ In reply to ]
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Who makes a 12-32 11 speed cassette? I haven't seen one that I remember.

Very options for 11 speed 12-ANYTHING cassettes. There are a few 12-25, 12-28 for example, but I rather have an extra cog in the middle than a 11 tooth on a 11-30 or 11-32.

I'd submit that 11 tooth small cog not needed by most riders, even those with a 50/34 crankset.

Eddy rode a 52/13 - 103 gear inches. A 48/12 is 105, 50/12 is 109, 52/12 is 113 and 50/11 is 119 gear inches.

Suffer Well.
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Re: Rear Derailleur 32 tooth compatibility? [jmh] [ In reply to ]
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jmh wrote:
Eddy rode a 52/13 - 103 gear inches. A 48/12 is 105, 50/12 is 109, 52/12 is 113 and 50/11 is 119 gear inches.

Can we label this flawed logic the Merckx/gearing (or perhaps Allen/Huffy) fallacy?
...asserting someone rides fast because of old tech, not in spite of it.
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Are you sure you need to go all the way to 32? You could buy DA 9100 11-30 right now
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Re: Rear Derailleur 32 tooth compatibility? [JoeO] [ In reply to ]
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JoeO wrote:
Are you sure you need to go all the way to 32? You could buy DA 9100 11-30 right now

Joe,

Have your ridden up Duplis? They get to do it twice and it's really a bitch the second time near the end of the IM if you're the least bit overgeared. It's one you see folks walking their bikes up with tears in their eyes.

Genetics load the gun, lifestyle pulls the trigger.
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Re: Rear Derailleur 32 tooth compatibility? [sciguy] [ In reply to ]
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sciguy wrote:
JoeO wrote:
Are you sure you need to go all the way to 32? You could buy DA 9100 11-30 right now


Joe,

Have your ridden up Duplis? They get to do it twice and it's really a bitch the second time near the end of the IM if you're the least bit overgeared. It's one you see folks walking their bikes up with tears in their eyes.

Now you have me worried I need to take the gearing off my fat bike and make it work, hahahahaha!

I haven't done much course recon yet... how long is Duplis? Average and max grade? I live in MI and we have some short punchy climbs (similar to IMLOU, but shorter) so it's tough to replicate.
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Re: Rear Derailleur 32 tooth compatibility? [sciguy] [ In reply to ]
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Just making a suggestion that might make it easier on his derailleur, if 32 gave it trouble. 34x30 is a seriously easy gear for almost any climb, once, twice, etc. But if he can make 32 work more power to him.
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Toefuzz wrote:


I haven't done much course recon yet... how long is Duplis? Average and max grade? I live in MI and we have some short punchy climbs (similar to IMLOU, but shorter) so it's tough to replicate.


As with most courses, your gears will feel a lot easier if you don't overbike the first half. But here's a thread on the course




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Re: Rear Derailleur 32 tooth compatibility? [sciguy] [ In reply to ]
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Then there's the Praxis front crank option to run a 32x48...
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Re: Rear Derailleur 32 tooth compatibility? [Toefuzz] [ In reply to ]
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Toefuzz wrote:
I picked up a new PS2 last year and am looking at swapping my 11/28 cassette out for a 12/32 as I am fat and struggled on the hills in Louisville last year (Mont Tremblant coming up this summer). It looks like the current P2 comes with a 105 5800 GS rear derailleur that the Shimano site says is compatible with a 32 tooth cassette. Does anyone know how to tell if this is the model I have? There don't seem to be any GS markings on it.


I measured the cage length of a Shimano road 6800 "GS" rear derailleur cage. It's right about 86mm from jockey wheel center to jockey wheel center. There's no known markings on the actual cage, so you're stuck measuring it if you want to be sure you have a GS rear derailleur.



Edit: The SS short cage version measured ~60mm from jockey wheel center to jockey wheel center on a 5800 - no picture because I didn't feel like taking the derailleur off.
Last edited by: dangle: May 13, 17 6:51
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Re: Rear Derailleur 32 tooth compatibility? [dangle] [ In reply to ]
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Wow! Thanks for taking the time to do that! Definitely above and beyond.
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Re: Rear Derailleur 32 tooth compatibility? [jmh] [ In reply to ]
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[/quote]
Eddy rode a 52/13 - 103 gear inches. A 48/12 is 105, 50/12 is 109, 52/12 is 113 and 50/11 is 119 gear inches.[/quote]
Merckx ran a 175 crank on the road, and sometimes rode a 55chainring. At 175 his gear inches 52/13 would be 108.

Also, much of the discussion here would be helped with some reading up on drivetrain capacity and how to calculate.
According to United Bicycle Institute:

  1. Determine Maximum Chainring Difference by subracting the number of teeth in the smallest chainring from the number of teeth in the largest chainring

  2. Determine Maximum Cassette Cog Difference by subtracting the number of teeth on the smallest cassette cog from the number of teeth on the largest cassette cog

  3. Determine Total Drivetrain Capacity by adding Maximum Chainring Difference to the Maximum Cassette Cog Difference

  4. Record the Maximum Cassette Cog (the number of teeth on the largest Cassette Cog)

For Shimano:
SS - Short Cage Road Double - Maximum Cassette Cog is 27 and Total Capacity is 29
GS - Medium Cage MTB/Road Triple - Maximum Cassette Cog is 34(MTB)/27(Road) and Total Capacity is 33(MTB)/37(Road)
SGS - Long MTB - Maximum Cassette Cog is 34 and Total Capacity is 45
For SRAM:
Short - Maximum Cassette Cog is 34(MTB)/28(Road) and Total Capacity is 32(MTB)/31(Road)
Medium - Maximum Cassette Cog is 34 and Total Capacity is 37
Long - Maximum Cassette Cog is 34 and Total Capacity is 45
For Campagnolo:
Short - Maximum Cassette Cog is 26 and Total Capacity is 27
Medium - Maximum Cassette Cog is 29 and Total Capacity is 36
Long - Maximum Cassette Cog is 29 and Total Capacity is 39
NOTE - THIS INFORMATION IS SUBJECT TO CHANGE BY MANUFACTURER
And a great source for all of this is Sutherland's 7th edition
http://www.sutherlandsbicycle.com/7th_Edition.html

Anne Barnes
FIST/SICI/FIST DOWN DEEP
Live Grit
anne@livegrit.com
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Re: Rear Derailleur 32 tooth compatibility? [ABarnes] [ In reply to ]
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That info is outdated for the latest Shimano releases. They've support 28 tooth cassettes with short cage derailleurs for the last few years and the newest DA will support 30 teeth. I'd assume the next iterations of the Ultegra and lower cost competent lines will follow wr to the 30 tooth cassette capacity.
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Re: Rear Derailleur 32 tooth compatibility? [ABarnes] [ In reply to ]
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Holy crap Anne! We will have to chat about this next Friday morning during my fitting.
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