gearing - can 32t cog fit on Ultegra 6700 RD

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tharmor
Posts: 394
Joined: Thu Jun 03, 2010 6:20 am

by tharmor

Sweet. Thanks! Will the model of 10 speed cassette matter, provided that it is a 12-30? 6700 cassettes are easy to find, 6600sl not so much, and anything newer/nicer is out of the price range.

by Weenie


eric
Posts: 2196
Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
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by eric

All models of shimano/Sram 10sp are compatible.

I use them interchangeably on my Shimano and Sram bikes. I think the Shimano cassettes shift very slightly better and are a little quieter but the difference is small. I mostly use Shimano unless there's an Sram cassette that has better ratios for what I want.

tharmor
Posts: 394
Joined: Thu Jun 03, 2010 6:20 am

by tharmor

Weightweenies came through big time. I appreciate the help fellas.

Cheers!

Velomann
Posts: 1
Joined: Mon Aug 06, 2018 2:23 am

by Velomann

I just installed a Shimano 12-30 paired with RD6600 Ultegra derailleur and 50-34 chain rings. The clearance between the high pulley and the largest cog was very close. I added a hanger extender and it's now fine. I went to 54 links, but I think 53 may be a little better. 52 links weren't enough. I cannot access the small chain ring with the smallest cog (short cage cannot take up teh slack), but would never want to. Here's the part number for the extender:
https://wheelsmfg.com/derailleur-hanger ... anger.html

alcatraz
Posts: 1137
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

If the original poster wants more accurate info the best is to borrow a rear wheel that has a 32/30 cassette on it. Doesn't matter if it's 9 or 11 speed. Set the B-screw and see if it can clear the cog. Chain will be too short but keep it on the small ring.

The second option is to measure the gap between the upper pulley and largest cog. How?

1. put the bike in the 1st gear
2. loosen b-screw
3. swing the derailleur back and forward and notice that the upper pulley moves in an arc.
4. at one point in this arc the space between pulley and cog appears largest
5. set b-screw so the derailleur stays in this position
6. with vernier calipers measure between the tip of a tooth between largest cog and upper pulley.

Increasing the casstte by 2t requires 4mm (if memory serves, to check just measure 25 to 23 on your cassette). The gap needs to be at least 6mm after maxing the cassette.

Lets say you measure 18mm and have a 26t cassette. It means that this setup could run at most a 32t cassette. (18mm - 6mm = 12, 12/4=3, 3 x 2t = 6t, 26t+6t=32t)

Because this method doesn't allow much B-screw adjustment the chain needs to be sized extra carefully.

/a

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