wheelinthai

Bianchi Steel Vigorelli comes with CASSETTE : SRAM 10sp 11-32T. I don't need the 11T sprocket. Can I buy Sram 36T sprocket, remove the 11T spro0cket, and replace with the 36T sprocket? I'll need to change the rear derailluer to accommodate the longer chain obviously.

Continuity

You won't necessarily have to change the RD - it might have the capacity needed to change your cassette to a 36T.

To do this, you would just buy a new cassette with a 36T low end, and a 12T top if that's what you want.

Here's a 12-36T 10-sp SRAM PG-1070, for example - but they ain't exactly *cheap*.


You will prolly have to get a new chain, so as to cut it that bit longer than your existing one (it's very likely too short as is).

If you post what model RD you have, as well as the size of your chainrings, you can calculate whether your RD has the 'takeup capacity' to deal with this change.

According to United Bicycle Institute:

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

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

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

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

Bill Kapaun

The smallest cog has a built in spacer, so it's different than the other "flat" cogs that have a separate spacer.

Retro Grouch 

Smallest cog is serrated to fit the lock ring more securely. Largest cog is often riveted to a carrier.

Continuity

I have drilled out the rivet heads before now to "mix'n'match" different sized sprockets between cassettes, but the OP's problem would be from where to get the larger sprocket from. (if not from a new cassette, which they might as well just install as-is anyway)

wheelinthai

First of all, I'd like to thank all of you who posted recommendations. Particularly for 12-36T 10-sp SRAM PG-1070. I can let the local BS figure out the rest.

wheelinthai

Bianchi Steel Vigorelli
REAR DERAILLEUR : SRAM Apex
FRONT DERAILLEUR : SRAM Apex
CRANKSET : SRAM Apex Compact 50/34
CASSETTE : SRAM PG-1070 10sp 12-36T per your recommendation.

Continuity

No worries - I'd just hold on that purchase though until we can figure out if your RD has the capacity to cope with the 36T - I suspect it may not, as SRAM made a big thing about the introduction of the 32T with the Apex, and it may well not take a 36T.

Confusingly, SRAM list the Apex as being only short cage, and having a capacity of only 28T, which is contradictory (of their use of the 32T) - I know these limits are often on the conservative side, but...

I'd hang on until me or someone else can say for sure if this is possible with your present RD.

Continuity

Although SRAM seem only to mention the short cage Apex (28T) on their site, it looks like they also do a med. cage version (32T) which is the one that you must have on your bike.

I think that the 36T cassette may actually be an MTB part, designed to work with their SRAM MTB RDs which have larger capacities, but their have been reports online of some people using the 36T on their 32T-rated Apexes and it working OK with a longer chain.

It might just come down to - are you really sure that this is what you need? And if so, maybe just suck it and see.

Do try and make sure that you can return/sell the parts if it doesn't work, though - but as I said - many of these gear specs are quite conservative, and it doesn't really suprise me that the medium 32T Apex can actually work with a 36T.

Apparently, the RD cage gets to a pretty crazy-looking angle when in big-big with the 36T, but you should never be using that combo anyway.

FastJake

If you can find a 36T cog, it might work with your current RD. But I would really plan on getting a MTB RD, 36T is a big cog and not many RDs will handle it. The second position cog will not be serrated to mate with the lockring but it may still work as a first-position cog. You'll have to try it and see.

wheelinthai

Thanks for all concerned. This is what I have in mind. Buy the SRAM PG-1070 10sp 12-36T and see if the REAR DERAILLEUR : SRAM Apex will work. If not, buy a new SRAM MTB RD. Spending money here is not a problem. But I'd rather not look like an idiot, if the new SRAM MTB RD will not work with SRAM Apex SHIFTERS. What do you guys think?

Continuity

I'm afraid that SRAM MTB RDs use a different cable pull ratio to their road stuff, so you wouldn't be able to do that.

I think that there is a good chance that your 32T-rated Apex RD will work with a 36T sprocket, though - just so long as you avoid actually riding in the large/large crosschained combo. (It should *shift* into this gear OK, without damaging anything - you just don't want to be actually *using* that combo)

wheelinthai

Thanks for curbing my wandering dreams. I heed your advice. I never used big-biggest and small-smallest combination.

Werkin

SRAM Apex shifters will work just fine with SRAM MTB derailleurs (XX1 excluded), just as I said in the other thread wheelinthai has going. My bike with SRAM Force shifters and SRAM long cage MTB derailleur (X9 Type2) shown below.

wheelinthai

Thanks Werkin. What frame have you got there? I never knew that disc brake could work with brifters. I know Surly LHT has disc model, but only seen with bar end shifters.

Continuity

Hunh - how about that? All the reading I've done so far seemed to imply that SRAM roada/MTB gear has different cable pull ratios.

But, I've just found someone saying, "SRAM 10 speed stuff is the same road and MTB, but 9 speed isn't.", so there doesn't seem to be a simple yes/no answer.

Rockrat

Hi all have been reading with great interest and would like our that's on a very very similar question to the OP.

I have a compact 34/50 sram force group set.
i am about to do the etape-du-dales sportive, and want to change the current 11-26 cassette.

I have ordered a SRAM PG 1070 Cassette / 10 Speed / 1132
and a SRAM Apex mid/long derrailluer from here - https://www.chainreactioncycles.com/M...?ModelID=51845

i am left with a few questions I would appreciate your advise on as I have read that much that I now find myself a little confused.

1. Do I HAVE to buy a new chain. If so should it be the 114 or 120 links and can you please give a link example of which one i need.
2. If I bought a 12-36 cassette, would the same derailleur and chain work fine

Continuity

If your current chain is the correct length (and not a bit on the long side), then going from 26T to a 32T will almost certainly require a new chain.

The chain should be able to be draped over the large front chainring and the largest rear sprocket (bypassing the RD) with 2 full links overlap.

I would just put your existing chain (if not too old and worn) into a bag with your old 26T cassette so you can use them together again in the future, maybe when/if you're fitness levels increase.

*Some* people have reported success using a 36T (MTB) cassette with the 32T-rated RD, but it's not a *given* that it will definitely work.

As for a new chain - just choose anything from the range of 10-speed (SRAM/Shimano compatible (as opposed to Campagnolo) available.

Rockrat

At continuity.. One last thing, should the chain be a 120 or 114 link.. I suppose logic says just get the longer one

Continuity

Just get the longer one, all else being equal, and break the chain to the correct length. You could count the links in your old chain, and anticipate having to add about 2 links to accommodate the new 36T sprocket. So, say your old chain has 110 links (and was cut to the right length originally), then the 114 would be OK.

The chain is the right length when it can be pulled over the largest chainring and largest rear sprocket, bypassing the RD, and have 2 full links overlapping.