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Ultegra chainring question.(8 posts)

Ultegra chainring question.dave woof
Dec 5, 2001 3:24 PM
I'm thinking of doing the Everest Challenge next year - what's the smallest chainring size I can put on an Ultegra double? Was going to put on a 25 or 27 cassette, but don't know if Ultegra R.D. can handle that.

re: Ultegra chainring question.Chen2
Dec 5, 2001 3:46 PM
I think it's fairly common to use a 38T inner ring on a Shimano double, although Shimano doesn't offer it. As for the cassette, an Ultegra rear derailleur is rated to a 27 tooth cog and Shimano does offer a 12-27 cassette, that's what I use. I have heard of people going to a 28 but Shimano says 27 is the maximum.
Dec 5, 2001 3:54 PM
on the situtation. You should be able to run a 27 cog in back with a normal RD and a 53/39, but 27 is the absolute limit and chainsizing is critical.

If you want run more than a 27 cog and a 53/39 combo, you will need a triple RD. The reason is that you need a longer cage to take up the slack of the chain if you want to be able to use all the gear combos. You maybe able to squeak out a 28/29 cog in back, but you won't be able to run a 39/11 or 12 (Chain too loose) or 53/27 or higher (Chain too tight).

I'd say if your going to do a lot of climbing, forget the big ring up front, throw a 11-32 cog on back and run a 39 only up front. I did just that for Mt. Washington Last year with no problems. You should not need to resize your chain if you normally run a 53/39 with a 21 or 23 (max cog) in back and won't have to change derailluers. You also have plenty of 'bail' gear if you get tired.

Where'd you get 11-32 nmjagiger
Dec 5, 2001 7:00 PM
Dec 5, 2001 7:03 PM
It's a common MTB offering from SRAM among some others.
Dec 10, 2001 9:41 AM
re: Ultegra chainring question.Len J
Dec 6, 2001 4:00 AM
One other option is to replace your rear Der with an XT or XTR rearn der which are both compatible with STI and will allow a rear cog up to 34. Just watch the chain sizing.

re: Ultegra chainring question.pmf1
Dec 6, 2001 1:36 PM
For Ride the Rockies bike tour I did last summer, I used a 12x27 cassette and a 38 small ring made by Siguno. You can get them from Excel for $18 and they work great. It was all the gear I needed. The climbs were sometimes very long and at high altitudes (over 12,000 feet at two passes), but not super steep. If its really nasty, you might want to get a mtn bike rear derailer (XT) and run a mtn bike 12x32 cassette.