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What's the largest size cog an Ultegra der. can handle?(11 posts)

What's the largest size cog an Ultegra der. can handle?NatC
Jul 17, 2003 7:03 AM
I'm thinking about using a low-geared mtb cassette for an upcoming mountain ride.
re: What's the largest size cog an Ultegra der. can handle?jtolleson
Jul 17, 2003 7:25 AM
Shimano says 27. Above that, you need to go with a mt derailleur.
re: actually,Rusty Coggs
Jul 17, 2003 7:43 AM
Shimano spec is 27,because 27 is the biggest they sell in a road cassette. the derailer will handle 30 and sometimes more in some applications.
Running a 32 with 105 GS on CX bike; B-screw maxed out! (nm)Dale Brigham
Jul 17, 2003 8:09 AM
please tell me more...Frith
Jul 17, 2003 8:31 AM
Who sells compatible cassettes?
99% Pretty sure...Dwayne Barry
Jul 17, 2003 8:39 AM
the hubs, cassettes and chains (at least 9-speed) are the same for mountain bikes/road bikes. I know i've put road cassettes on mountain bike wheels and vice/versa with no issues. As long as your derailleur can handle the big teeth a mountain bike cassette should work fine on a "road hub".
Shimano and SRAMDale Brigham
Jul 17, 2003 9:13 AM

Here's a list of available large max-cog 8 and 9 spd cassettes that can be made (in some cases, "forced") to work with Shimamo road rear derailleurs, given a judicious use of the B-screw and as short a chain length as possible (still allowing "big-big" combo).

In my experience, the 28 and 30 tooth max-cog cassettes work readily; the 32 tooth ones are a real stretch. BTW, I have had good luck with the SRAM cogsets and actually prefer them to the Shimano ones.

Shimano 9 spd: 11-32
Shimano 8 spd: 11-28, 11-30, 12-28, 12-32

SRAM 9 spd: 11-32
SRAM 8 spd: 11-28, 11-32

Jul 17, 2003 9:55 AM
For my wife I assembled a 14-28 using parts from a D-A 12-25 and cogs from Sheldon Brown. I've heard that he may be currently out of 28's. You could do the same with a 29 or 30. Bigger than 30 go to a mountain rear derailleur. 'course the first cog must have a built-in spacer to work with the lock ring.
Cheap alternative to new Ult or XT cassette.pack_fodder
Jul 17, 2003 2:39 PM
I also have run 12-28 on a Dura Ace rear dr. I can confirm that Harris out of stock on 28 cog. I ordered one but got a response that they were out of stock. Instead I bought a cheap mountain cassette on sale at Performance for $10. I disassembled it by removing the 3 allen screws that hold it together and took the 28 from it. I then removed the 13 cog (second-position) from my road set up and added the 28 at the end behind the 25. I used the same spacer that was originally between the first and second cogs. It works fine.
Running 12-28 cyclocross setupgeeker
Jul 17, 2003 8:55 AM
with old 600 RD (Ultegra predecessor). Took a 11-28 XT MTB cassette and swapped the 11 cog for a 12.
Thanks for your input everyone. nm.NatC
Jul 18, 2003 8:44 AM