Replacement chainrings/set and cassette

big_southern_jesse

Hi folks,

I have a Specialised Allez, I guess 5 years old. The chainrings and cassette are seriously worn, with the chain skipping on some of the sprockets under pressure. So looking for replacemments.

Currently have Sora kit, 9 speed compact double 34/50. 110 BCD and 175 cranks.

A couple of simple questions, but afraid I can't find the answers anywhere. And if anyone has some recommendations, then that would be fab too!

9 speed cassettes are easy enough to find, but the front end is being trickier. 2 chainrings seems to cost about the same as a new chainset on a decent deal. Bottom bracket and cranks are fine, but a replacement wouldn't hurt.

Having trawled the usual shops, I can't find a direct replacement.

Many chainrings are spec'ed as 10 speed; are these still okay with a 9 speed cassette and chain? I don't want to shift the whole thing to 10 speed. Some of the chainsets I've seen advertised have been "9/10 speed"

What's the equivalent of Sora now?

And would it make much difference for the derailleur to step up to 39/53? I understand my gearing would change and the chain would be a little tighter...

Found this: http://www.chainreactioncycles.com/Mode ... elID=67233 but the "10 speed" is worrying me...

That's the 4650, they also have the 4600 for the same price; what's the difference?

Any help please?

Jess.

Bar Shaker

A 10 speed chainring will work with a 9 speed chain width, but the other way round may not work.

big_southern_jesse

That was kind of what I thought, but guessed the chainrings will be slightly thinner than a 9 speed. Likely to cause quicker wear or pretty negligble?

doug5_10

Sora still exists, 2300 as well. 4650 is compact double, 4600 is standard double. You could upgrade to full 9 speed Tiagra pretty cheaply with eBay and classifieds etc.

Anonymous

4600 means double (130mm BCD 39/53 teeth chainrings). 4650 means compact (110mm BCD and 34/50 chainrings) - compact generally means slightly lower gearing, so easier for climbing.
That said, 50-11 is a harder/faster gear than 53-12 so you can get the speed on a compact!

Yours is the compact. I think the direct replacement would be "Shimano 3550" if it is 9 speed. I'm surprised that its 5 years old and a 9 speed at the back. I have a feeling it would be 8 speed, in which case it is "3450". There are loads of parts on ebay and the classifieds here.

I am not sure what bottom bracket your bike takes, but if it is a hollowtech one, then it should be compatible with all the newer shimano chainsets.

big_southern_jesse

okay, thank you guys.

The age is a guess, I bought it second hand from a friend for £70 a year and a bit ago. I never got the exact details...

Right... shopping time I guess....

doug5_10

Big Southern Jesse wrote:

And would it make much difference for the derailleur to step up to 39/53? I understand my gearing would change and the chain would be a little tighter...

Gearing changes will have no effect on either derailleur, but you will need to adjust your chain accordingly (don't lengthen an old chain!) Check Sheldon Brown/Parktools website as to how to measure your chain length properly.

EDIT: unless you change to a triple, then FD and lever need to change

Bobbinogs

Tiagra 4550 should work, same BCD, 5 arm and 9 speed. I reckon a set of chainrings would cost about £55 from here:

http://www.evanscycles.com/categories/c ... %20Compact

Might be worth getting a second opinion before committing though.

Anonymous

62.50 for the new sora from here - the whole thing! Flog the old one (ok a short wait, though)

http://www.jejamescycles.co.uk/shimano- ... tAodzVsAYA

big_southern_jesse

Sorted, thank you folks.

A quick bit of Google, and I have a Tiagra replacement set for £60. That'll do... Happy Friday!