Cassettes and chains

Kupe

I am considering changing my cassette from the 11-23 that I am currently running to 11-28. What I want to know is do I need to replace my chain at the same time? The componentary level for both cassette and chain is ultegra, with the chain only having +/- 800km on it.

Any assistance would be appreciated.

cyclist_44060

My initial thought is that your current chain should be fine. Worst case is that you my need to take a link or two out of it, but I would doubt it.

cyclistphil

The chain should probably be fine. Try it you will know right away if its not gonna work it iwll make allot of noise or have probelm sitting on the gears properly.. Most chains are good for 2-3k miles. If it was my bike I would just put the cassette on.

danrough

I'd definitely just replace the cassette. In fact I've done just that.

I'd keep a close eye on the chain going forward though - probably worth investing in a chain checker. You might see wear sooner.

Dan.

slocyclist

It isn't chain wear that you should be concerned about, but chain length. By going from 23 to 28 on your new cassette, you are most likely going to want to add three links you your chain to maintain the optimal length (unless your chain was too long in the first place.)

Here's the tried and true method to determine chain length:

The first step is to wrap the chain around the largest sprockets on the front and rear, so that the ends meet on the largest front chainring. For this step, it really important to not run the chain through the rear derailleur.

Next, position the chain on the chainring’s teeth at the tightest spot you could connect the chain. Now add one whole inner and outer link, so that you have approximately one extra inch of slack in the chain. That will be the optimal length for most systems.

Here's Sheldon Brown's chain length article: http://sheldonbrown.com/derailer-adjustment.html#chain

Slo

ghost15026

Essentially, what slocyclist said.

You're going to be short 3 chain links on the new 28 cog - which may or may not be a problem. If your chain already had a decent amount of slack then you may get away with it. If not, you'll notice the tension pulley (lower spring-loaded gear) pulled out towards your crankset with the new cassette. This will be particularly pronounced in your large chainring and your 28 cog.

**In the worst case, this could lead to shifting problems and could destroy the derailleur (or worse) under heavy load.** Try it, but my vote is a new chain. 1-2 links would probably be fine. 3 links is starting to push your luck.

matsprt1984

Essentially, what slocyclist said.

You're going to be short 3 chain links on the new 28 cog - which may or may not be a problem. If your chain already had a decent amount of slack then you may get away with it. If not, you'll notice the tension pulley (lower spring-loaded gear) pulled out towards your crankset with the new cassette. This will be particularly pronounced in your large chainring and your 28 cog.

**In the worst case, this could lead to shifting problems and could destroy the derailleur (or worse) under heavy load.** Try it, but my vote is a new chain. 1-2 links would probably be fine. 3 links is starting to push your luck.

Anyone who cross torques a chain like that (big ring and the 28 cog) needs to learn how to ride....that's just cruel.

AlwaysInMotion

IMO, a new cassette warrants a new chain. But yes, you can lengthen most chains safely (I don't advise it for flush-pin chains, though). Since I personally don't like lengthening chains, I would probably wait until the current chain is worn and then swap the cassette AND chain together.

Also, don't forget to check whether your existing rear derailleur can accommodate the wider cassette. When you go from narrow (11-23T) to wide (11-28T), a short cage derailleur may not cut it, thus requiring a medium cage. If the cage is too short, the drive train could lock up and cause damage to your components. You likely won't run into this problem (it's more likely to be an issue if you went 30T or larger), but still check first. Search online for the specs for your rear derailleur - it should specify the min/max gear range that it's designed to accept.

beatpig

Going against the grain, I'd get a new chain. New cassette, new chain - the slightest wear on the chain can cause issues with the new cassette. Your old cassette would have been worn to suit the chain.

/sorryrunsandhides.

jacksonpt

I agree on the chain length issue.

It also depends on how worn the chain is. If it's got a lot of wear on it, I'd change it out as well. For the extra $35 or whatever, it's worth doing to avoid any headaches. If it's still pretty new, then you should be fine. I know you said it's got about 800km on it, but it could still have meaningful chain stretch.

This assumes both cassettes are the same gear count.


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Cyclingbonnie

I kind of go with the new cassette new chain rule weather I'm changing size or not. I may go through multiple chains for one cassette, but when I change cassettes I change my chain. Although a good chain can be expensive ease of shifting and ensuring no early damage to a new cassette is important to me.