Hey everyone,

I have a Specialized Allez Comp APEX Mid-Compact. The current, stock setup is 52/36 chainring and SRAM Apex, 10-speed, 11-28t cassette.

I want to swap out the 28t cassette with a 36t cassette that SRAM makes and this would also require me to swap out the derailleur for a mountain bike one since the stock derailleur can only handle up to a 28t.

My question is this. Would this new setup require me to swap out the chain as well, or would the current one be alright? (KMC X10 CP)

Thanks in advance!

It is pretty much normal to install a new chain when changing your cassette. In this particular case where you will be adding 8 extra teeth to your biggest cassette cog and changing to a longer cage derailleur you will have no choice about installing a new chain

ok, thanks for the reply! I assumed as much, but I don't have the parts yet to test it out. Figured I would a chain to the order if needed. I know more about cassettes and derailleurs, but nothing about chain lengths....

Any clue what I should get?

use a 10 speed width chain for 10 speed cassettes.. brand less important.. KMC is well priced.

you only shorten new type chains, if too short you use 2 quick links. and a portion of the same chain from someone else's new chain.

a bike shop may save the short bits.. online buying that is not a thing.. you can do..

Ok, Thanks. My current chain is for my 10 speed so I will just have to add links. Like alcjphil said, i'll be adding teeth and a longer cage derailleur which will more than likely require more length.

you buy your existing chain new , separately already replaced the stock one once? or is this your first replacement on a new bike?

maybe 100% of the new chain will work .. but I cannot blindly guess ..

On my long chainstay MTB with a 32-48t combo to get around I used over 100% of a boxed Chain.

The derailleur change won't effect the required chain length but the larger largest cog will. The same model chain will be fine but you will need one 2" (4 half-links) longer to allow the extra 8 teeth assuming your current chain is adequately long to allow shifting into big-big. As a general rule, unless your chain and cassette are very new, plan on buying a new chain for use with the new cassette, rather than splicing in extra links to the one you have.

No, It's still the chain that came stock with the bike, KMC X10 CP. I wasn't sure if I could just add links or if I should just replace the chain altogether. The bike is about two years old and has roughly 300 miles on it. (We had a baby last summer and I didn't get to rode all season.....)

Ok, thanks! I might as well just buy a new chain then. The cassette I am looking at buying was on Craigslist and the guy said it was used for one season and was in excellent condition. With this new gearing, the ratio will be 1:1 which is much better than what the Allez came standard with. I went from a hybrid to this bike for the Bike MS event, and I had a rough time with the road bike. I'm trying to get the gearing a bit easier so I can have more fun and get in better shape

At only 300 miles, your chain has very little wear. However adding links to a 10 speed chain requires special replacement pins.However, KMC chains do not use that type of replacement pin. With a KMC chain you use a master link to close the chain after it has been cut to the required length. This is actually a good thing. When you remove the old chain and cassette, put them aside. You can easily switch back to that chain if you want more closely spaced gears for flat rides. I would not buy a second hand cassette. Someone who rides a lot can easily wear out a cassette in a single season, especially if they always ride in the same cogs. Your best choice is a new cassette to go with your new chain

I would buy a new chain and the tools to swap out the cassette.
Then, you can keep the old chain & cassette together as a pair and ditto with the new chain & cassette.

When riding conditions warrant, swap back & forth.
After a couple swaps (practice), it'll be a 10 minute job.

Hmmm, this could be more of a problem than you think. "Excellent condition" for a cassette is impossible to tell by inspection and "one season" could have been 100 miles or 5000 miles. Even with a new chain you might have skipping problems on the cogs the former owner used the most. I hope this cassette is very cheap or you have return privileges because you might be buying a new one after trying it.

+1 I wouldn't buy a used cassette unless the price was a tiny fraction of the price of a new one. By tiny, I mean much less than 25%

I know that my 52-34 took 100% of my brand new SRAM chain per the instruction sheet that came with it. It is a hard tail bike.
Cheers,
David in Alaska

I would not pay for a used cassette. With 52/36 gearing, you are going to need a lot of chain. Check Ribble or the other UK sites for your new chain, cassette and RD.

Thanks for all of these advice everyone. I will definitely think twice about buying it used. I was always weary of buying 2nd hand bike hardware, but a buddy of mine located it and mentioned it looked like a good deal. Luckily I didn't purchase anything yet, so I will take all of this into consideration.