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11-28 & 11-32 chain length

by MoutonDeMontagne
Mon, Mar 06, 2017 12:03
12

I'm considering changing my groupset, and tossing up the option of a mid cage rear mech that can cope with 11-32 as opposed my current 11-28. My question is how much of a difference will it make to chain length, as normally 11-28 is fine, but for occasional hilly and long rides, or silly climbs, an extra bail out gear may be welcome. The rub is I don't want to have to keep switching chains all the time, thus would just changing the cassette be feasilbe.  

My thinking is that an 11-32 would probably have a 28t ratio, and therefore just running an 11:28 would be like not using the extra 1/2 gears. Other than the weight of carrying around a few extra links, is this likely to affect the drivetrain/mech performance? 

Cheers

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12 comments

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Butty | 7 years ago
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I get around moving from 11-32 to 11-28 by swapping the two RD cage sides from the SS to GS versions.

It takes a mater of minutes and is only two allen head bolts.

The chain length stays the same on a Synapse and the parts cost around £25 for an Ultegra RD.

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beezus fufoon | 7 years ago
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I have had it set up for 11-25, with a short cage mech, and still run a 34 tooth xtr cassette for particular climbs...

the only thing to remember if you do that is to not cross chain on the big ring

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Yorkshire wallet replied to beezus fufoon | 7 years ago
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beezus fufoon wrote:

I have had it set up for 11-25, with a short cage mech, and still run a 34 tooth xtr cassette for particular climbs...

the only thing to remember if you do that is to not cross chain on the big ring

 

It can be done, I'm a dirty cross-chainer myself. I've went from 28 to 32 on the back on the same chain and you can still just about get away with running big/big. Admittedly I only do it when I've been 'caught out' on a climb and knocking down to the 34 would be too much of a sudden spin fest and you'd lose momentum.

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Stef Marazzi replied to Yorkshire wallet | 7 years ago
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Yorkshire wallet wrote:

beezus fufoon wrote:

I have had it set up for 11-25, with a short cage mech, and still run a 34 tooth xtr cassette for particular climbs...

the only thing to remember if you do that is to not cross chain on the big ring

 

It can be done, I'm a dirty cross-chainer myself. I've went from 28 to 32 on the back on the same chain and you can still just about get away with running big/big. Admittedly I only do it when I've been 'caught out' on a climb and knocking down to the 34 would be too much of a sudden spin fest and you'd lose momentum.

Same here, sometimes its nice to cross chain just to power on up an undulating climb. Been doing it for years and its been fine.

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MoutonDeMontagne | 7 years ago
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Brilliant, cheers for the info. Seems in round terms it'd work, although if I'm running 11-28 90% of the time, then it could make sense to have a seperate chain to match that cassette. Good to know if I swap wheels from 32 to 28 it'd likely work fine in the short term. 

Cheers for the info all. 

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CXR94Di2 | 7 years ago
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Chain too long whilst on small front and small back gears   https://www.google.com/imgres?imgurl=https%3A%2F%2Fi.stack.imgur.com%2Fw...

 

Chain too short  whilst on big front and big back gears  https://www.google.com/imgres?imgurl=http%3A%2F%2Fgp1.pinkbike.org%2Fp4p...

I buy the kmc 116 links, try bike in gears as above then shorten as required

 

 

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VeloUSA | 7 years ago
1 like

I use this online Machineheaad Cycling chain calculator. It is spot on.

http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc....

Using a 50/28 combo & 405mm chain stay length chain length came to 53 links

Using a 50/32 combo & 405mm chain stay length chain length came to 54 links

Does one extra link make a difference? Yes and no. I tested on my Tarmac running  52/34 combo and found on smooth roads, or climbs, it was fine. However, on bumpy/rough roads, or going over railroad tracks, the chain would occassionaly bounce off the big ring to the small, not all the time but like I said occassionaly.

 

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TypeVertigo replied to VeloUSA | 7 years ago
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VeloUSA wrote:

I use this online Machineheaad Cycling chain calculator. It is spot on.

http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc....

Awesome find!

I do find that its results have to be multiplied by two to mesh with the way KMC, Shimano et al size their chains - they count one link as one link, regardless if it's inner or outer. The calculator counts in inches, where one inch is made up of one inner link and one outer link.

Given my earlier post for my own bike (30T max cog, 50T max chainring, 430 mm chainstay), it judged 56 inches or 112 links as perfect length.

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DaveE128 | 7 years ago
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If the chain works for 11-32 I think it should work for 11-28 too - it can't be too long as they both have the same smallest sprocket. I suppose it's possible that the chain length might be slightly sub-optimal at the 28 end of things but I doubt you'll notice the difference. You may need to change the b-tension setting when you swap cassettes. As others have said, beware of unmatched wear, which can lead to slipping accelerated wear. Even if you have a chain for each cassette, if one chain gets a lot more wear than the other, you might still run into problems with wear mismatch on the chain rings, including the dreaded chain suck.

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gunswick | 7 years ago
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I had an 11-32 on, with 114 link chain (KMC x11-93).

 

I swapped to an 11-28 (both Shimano 5800), and used the same chain length (new chain though) and there is no difference or problem and visually it all looks fine.  Therefore, I conclude that if moving from 11-32 to 11-28 you can just use the same length.

 

If you moved up from 11-28 to 11-32 you might want an extra link.

 

I asked Evans workshop at the time, and they said its often fine, you just eye ball it in the largest and smallest gears as well as when cross-chained and check the tension / derailleur position is OK.

 

Therefore I think you can just use the same chain length.  The chain wear'n'tear is another matter as you really want them to be the same wear rate all together.  Having a chain per cassette may still make sense  for this reason, but at least it can be the same length.  Try it with one chain but watch when you put the new cassette on for skipping / ghost shifting etc under load.

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beezus fufoon | 7 years ago
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shouldn't be an issue for drivetrain/mech performance - but maybe not a good idea for long term use with two different cassettes on a single chain due to uneven wear.

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TypeVertigo | 7 years ago
1 like

An 11-32T cassette would likely have a 28 and a 32 for its two biggest cogs, as seen on the Shimano 105 CS-5800 unit. Those extra four teeth will help you when your legs run out.

As for chain length - it sort of depends on how long your chainstays are, in addition to the capacity of the rear derailleur you're using, because it counts toward the physical distance your chain has to span. For your reference, I've been on a Shimano Tiagra CS-4600 12-30T cassette ever since on my Giant TCX cyclocross bike, which has a 430 mm chainstay length and is currently equipped with a Shimano 105 RD-5700-GS medium-cage rear derailleur. (If you're on a road bike you'll likely have shorter chainstays.)

I've used chains in both 112- and 114-link lengths. The 112-link chain is perfectly fine, and it makes the big cog/big chainring test shift okay, but adding more links will ease the tension on the rear derailleur and its hanger. I'm told that too short a chain length will stress out your rear derailleur hanger. I haven't yet tried a 116-link chain though.

Good luck, and I hope this helped.

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