RoadBikeReview.com's Forum Archives - Components


Archive Home >> Components(1 2 3 4 5 6 7 8 9 10 )


Quick newbie question from a grizzled veteran...(5 posts)

Quick newbie question from a grizzled veteran...Silverback
Jul 30, 2003 7:58 AM
I've been building my own bikes for 20 years, but most of my experience is with retroid, friction-shift stuff. Got a quick, easy question:
A neighbor just bought a used bike with Ultegra triple crank and nine-speed cassette. He needs lower gears than that 30-tooth granny. I've switched lots of small rings down to 26 or 24, but in the back of my mind I think I remember reading that there are Issues doing that with this driveline. Anybody know for sure?
Thanks.
problemDougSloan
Jul 30, 2003 8:05 AM
The problem is that the front derailleur cage is only so tall. If it is high enough to clear the big ring, and the big ring is a 52 or 53, then with a really small granny, the chain will drag the bottom of the cage when in the smaller cogs in back. Exactly where this happens depends upon the particular setup. If he uses a smaller big ring and lowers the front derailleur, the problem may be fixed, or else just don't use smaller cogs with the granny.

Also, when I've tried this, I found the chain jumped off the insider more in front. Might want to use one of those chain watcher things.

I would suggest using a mountain bike cassette instead, like a 11/12-32.

Doug
Thanks; that's what I was thinking of (nm)Silverback
Jul 30, 2003 8:13 AM
re: Quick newbie question from a grizzled veteran...Chen2
Jul 30, 2003 9:12 AM
My wife's new bike came with the standard Ultegra triple and 12-25 cassette. She needs lower gearing so I put together a 14-28 cassette using parts I got from www.sheldonbrown.com. It includes a 16 in the middle.
~Al
I'm using a 24 w/ 12-27pitt83
Jul 30, 2003 9:31 AM
Some small chain rub in the 27 cog, but works OK. It is slow to get off of the 24ring back up to the 42, but it works. Definately don't try it under heavy pedal load.

Mt Washington here I come!