|Can Ultegra STI levers (ever) work with XTR crankset ?||snuggleman308|
Jul 3, 2002 7:39 PM
|Which front derailleur - XTR or Ultegra?
Want to build a bike using Shimano mountain crankset with Ultegra triple levers. Would you use Ultegra triple derailleur on XTR crank (not good) or use an XTR derailleur with the Ultegra levers (also not good).
Consider it a mountain bike with drop bars and STI levers.
|re: Can Ultegra STI levers (ever) work with XTR crankset ?||Atombomber|
Jul 3, 2002 8:57 PM
|I believe you have to make your choice based on the type of clamp style and cable pull you will need. Ultegra front deraileurs are only bottom pull. XTR will give you the choice of top or bottom pull. The operation of the derailleurs are very similar, with same movement per amount of cable pull.
Total Top-low Max. Capacity 22T
Top-middle Min. Capacity 12T
Top Gear Teeth 44/46/48T
Cable Routing System top & bottom routes available
Mount Type-Seat Tube
Band Clamp 28.6/31.8/34.9mm
Top Gear Teeth 52T
Total Top-low Max. Capacity 22T (triple use).
Use the Shimano website for more technical info.
|Two issues:||Spoke Wrench|
Jul 4, 2002 6:23 AM
|The first is chainring size. Road style front derailleurs don't work well with mountain cranksets and vice versa due to the arc of the chainring. The derailleur has to match the arc of the big chainring pretty closely or else you have to mount the derailleur too high up on the seat tube.
The second is the cable pull of the shifters. I suspect its the same because I've had good luck using rapid fire shifters with road derailleurs. I must admit I've never tried using an STI with a mountain front derailleur, but they work swell on the rear.
|re: Can Ultegra STI levers (ever) work with XTR crankset ?||Chen2|
Jul 5, 2002 6:22 AM
|It seems to me that it could work with a mountain (XTR,XT)front derailleur, probably need a pull down type. But they are clamp-on so you'll need a metal frame that will accept a clamp-on in the available sizes. We tried running a Deore XT crank set on my wife's OCLV and that didn't work because the Ultegra "braze-on" der could not be lowered far enough and the shape of the cage wasn't right, as "Spoke Wrench" pointed out. We eventually installed a Campy Racing T crank-set with 50-40-30 chain rings, leaving the rest of the components 9-speed Shimano. This works fine. I wish that Shimano would offer quality triple cranks with ring sizes smaller than the typical road rings. There are a lot of riders who could better use somithing like a 48-38-30 or 50-38-30 set. Of course you can run a mountain cassette and mountain rear der with a road crank, but the ratios get awfully wide. We tried that and my non-mechanical wife even knew the gaps were too big.
|Thanks to all, but more questions: Atombomb, others, how do||snuggleman308|
Jul 10, 2002 4:15 AM
|you know that the cable pull is the same? There's certainly not much "tech" info at the Shimano site.
I'll need a bottom pull FD to clamp a 31.8 seat tube.
Normally, I just try stuff to see if it can be made to work, but an XTR crankset, BB, FD, aren't cheap. (Doesn't have to be XTR).
Thanks again, all.
Jul 10, 2002 11:11 AM
|many people have had great succes with running an Xt/XTr rear der with STI levers. Since the amount of cable pull is the same it stands to reason that you can swap it back. Some cyclocross guys will use MTB drive trains with STI levers.|
|Grzy, I've often used STI levers with MTB rearends but I'm not||snuggleman308|
Jul 10, 2002 2:33 PM
|sure what you mean by "same amount of cable pull" Do you mean the front? That's what I'm looking at now. Where do you find cable pull specs, or have you measured it?
I've tried to find cyclocross sites that discuss STI-MTB setups but w/o any luck. Know any links?
thanks, John Tomac
(not that one)