2x10 mtb crank on road bike?

Triathlon Forum
1

Thinking of putting gxp 39x26 sram xx crank on my trek madone for some climbing. Any suggestions for which Q factor to use, guessing to use the widest one to minimize clearance issues. Main concern is spindle length and whether f. der will go low enough to allow proper shifting in front. Has anyone done this and able to confirm it works (spindle and crank arm clearance)?

Thanks,
Jeff

2

Just guessing… My thoughts would be that it will fit no problem, but likely to have a wider chainline, and imagine you would probably have to use mtb front derailleur.

3

Well, for starters, the Madone will have a BB width of 68mm, and the crank will be made for a 73mm width BB. So you’ve got 5mm to deal with that may be a non-starter.

4

Interesting configuration.

Try a road triple front derailleur if you can’t get you double low enough. IRD Alpina-D works nice with smaller ringed triples, the Shimano ones are shaped for 52/39/30 rings and have some shaping on the inner plate that might be a problem. No idea on Q factor width, although I would bet the narrow would work as the chainstays on road bike are far narrower than on 29ers.

Also, take a look at the Sugino OX601D crankset.

24mm spindle (Shimano), 110/74 bcd. Lots of chainring options. Might fit if your bike can accommodate a road triple. I imagine some clearance issues with the 74 bcd and carbon. Not sure if you could get your front derailleur low enough for it, but again with a triple front mech it could/might work.

5

I agree that the FD won’t go low enough. I just looked at my Kestrel 4000 and Colnago Dream road bike and no way would in go that low.

An easier option might be to go with a mt bike cassette and RD. You can get up to 12-36 even in 9 speed.

6

hopefully I can work that out with spacers - this is the issue that concerns me the most. I have the crank coming in the mail so time will tell.

7

actually, the hill hard enough that I will only use the small 26 ring on the 2x10 crank so I am going to mess around with trying to not use a front der. I will only be using the 5-6 largest cogs (probably 16-26) on the rear cassette so I’m hoping I can get away with no front der/small ring combo giving me 26x16-26 for gears.

I did consider using my mtb rear der and cassette and will probably try that if the small ring only scenario doesn’t work.

Thanks

8

I think if you check on a gear calculator you will find using a Sram wifi set up with a 34 or 36 big cog cassette and a 34 small chainring on the front you will have similar gearing. You can get the Sram Apex stuff for low cost and you could even just use a Sram mtb derailleur.