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Help for Ultegra with XT (11-34) freewheel.(6 posts)

Help for Ultegra with XT (11-34) freewheel.SGrouts
May 8, 2002 12:24 PM
Can i use an ultegra crank (39-53) with my XT cassette (11-34) and XT rear der on a road bike?

Can i keep my XT BB (star splined) with the ultegra crank or i must change it?
re: Help for Ultegra with XT (11-34) freewheel.davet
May 8, 2002 12:53 PM
I can answer part of your question. Yes, you can use a road crankset (Dura-Ace, Ultegra, 105 etc.) with a mtb cassette and rear derailluer. I have a bike with just such a set-up.
The part I can't answer is if you can use the mtb bottom bracket in a road bike with the Ultegra crankset. If you cannot, it is fairly inexpensive to buy the correct Ultegra bottom bracket.
re: Help for Ultegra with XT (11-34) freewheel.laffeaux
May 8, 2002 1:20 PM
The XT spline is the same as the Ultegra so, yes it will fit your cranks. However it may give you an incorrect chainline as the XT meant for a triple and the Ultegra is a double. You need to check your spindle length.
I don't think that's right.Spoke Wrench
May 8, 2002 2:24 PM
The XT 8-spline bottom bracket is deeper and has wider splines than Ultegra. They won't mix.

What are you putting this onto? If it's a road bike frame with a 68mm bottom bracket shell, just use an Ultegra 109.5 bb and you're good to go.

If it's a mountain bike with a 73mm bottom bracket shell, it could get interesting. An XTR bottom bracket has the same spline pattern as the road bikes. It comes in two spindle lengths, 112.5 and 116. I'd GUESS you'd need about a 114.5 to get the perfect chain line so that's right in the middle. I think I'd try the shorter one and use one of the spacers that comes with it to move the spindle 2mm to the right.

Oh - If this is going on a bike with a flat bar, what are you using for a front derailleur and shifter?

Good luck.
I know it's not right,but you're more diplomatic....Rusty Coggs
May 8, 2002 4:37 PM
nm
Oops, you're rightlaffeaux
May 9, 2002 11:19 AM
I was thinking XTR spline, even though the question was about the XT. My bad. The XTR and Ultegra/DA are interchangable on road bikes (68mm), although chain lines can be an issue as I stated.