11-32 with ultegra rd - mix/match parts build
 

up to now i've had road bikes and mtn bikes. i'm building up something to try some light cross style riding for fun, will seldom use it.

fuji america 80s touring frame with 126 spacing, horizontal drop outs.
45t chainring
1x9
ultegra (read road) rd

question is, will rd work with 11-32 cassette, or do i need to stick with 11-25 type range?

i know all the problems that this build will create. nothing will be just perfect. THAT'S FINE. just want to know if a 11-32 cassette will stretch the rd too far. consider too that it'll be only 45 in the front. thanks for replies!

You will need a MTB rear deraillear if you want a 32 cog cassette. The problem is that the Ultegra SS short cage derailleur will not fit a 32 cog. The factory has a 27t max cog size specification for Ultegra, however most will accept 30t and the GS will often (but not always) go up to 32t in practice.

Harris Cyclery makes a 13-30 nine speed cassette made from Shimano parts that will fit with an Ultegra ss derailleur.

so regardless of the stretch from 32 to 45, the ultegra travel will only match road cassettes? all right, 11-20s it is

thanks!

Actually, I'm going to offer a contrary opinion. I've never tried it with Ultegra, but I had a Tiagra road derailleur setup once with an 11-32 cassette. It shifted OK, but the derailleur hopped a little when the chain was on the big ring, like it was bouncing on shift ramps or something. I swapped in a MTB derailleur because that was my primary bike, but it would have been mostly OK like that.

Of course, this is assuming that you have the mid-cage derailleur. If your derailleur is short cage, it won't even be close.

It can work sometimes. Some derailleur hangers are more conducive to using rear derailleurs outside of their normal range.

I mentioned that the "GS" (long arm Ultegra) could work. However, he has the SS (short arm Ultegra), so he would need to change derailleur in any case.

I did just that with a short cage Ultegra rear der for a couple of years on the Major Jake when I used to find myself out with the mountain bikers on the lunch rides. 48/38 up front...12/32 on the rear. No problems whatsoever.

If you already have the ultegra and you know you want to run that cassette, you have nothing to lose by giving it a shot (make sure you set it up well).

If it doesn't work you can just pick up an old 7 or 8 speed deore lx or xt rd for cheap. Since you're running 1x9, I would think that an 11-32 would be a must.

Doubt you will get much use out if that 45-11 gear, in a CX course,
may find a 39t chainring more useful.

and cramming a 130 hub into 126 dropouts will get old after a while.

I ran an 11-34 cassette on my old Crosshairs with an old short cage Ultegra derailer. Worked fine, but I was also using friction mode.

You can get the 9 speed LX real cheap, I just snagged one for $42 from my local bike forum (MORC), and used XT's are all over ebay for like $60 maybe a little more.