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Tech FAQ: Mixin’ and Matchin’ Drivetrains

  • By Lennard Zinn
  • Published Dec. 28, 2010
  • Updated Oct. 11, 2012 at 5:00 PM EDT

Dear Lennard,
Since you seem to be pretty much a leading authority on cross compatibility when it comes to bicycle shifting and drivetrains I had a question regarding 2×10 compatibility between Shimano and SRAM systems.

What are your thoughts on running a Shimano XTR double ring crankset, a Shimano 10 speed MTB chain and cassette with SRAM 2×10 shifters, rear and front derailleurs? Do you have any insight or experience with a similar system?
-Scott

Dear Scott,
I haven’t tried that specific combination, but I’m confident it would work just fine. The cogsets are completely cross-compatible, and the asymmetrical Shimano chain will work quite well on the Shimano chainrings and cogs on the front and rear, as long as you orient the chain properly (you need to be able to read the “Shimano” stamped on the cage plates when looking at the bike from the drive side). The shifters and levers, of course, will all work perfectly together. I’m sure this setup will work nicely.
-Lennard

Dear Lennard,
Since I cannot seem to get a straight answer elsewhere, I was hoping you may be able to help. I have a drop bar 29er with Shimano 9-speed bar end shifters with an XTR rear derailleur and XT front derailleur and Tektro RL520 drop bar brake levers with Avid BB7 brakes. I would like to switch over to integrated shifters.

I know I will have to use the Problem Solvers Travel Agents for the brakes, but my question is with the front derailleur. I have been told that a mountain front derailleur has a different cable pull than a road shifter and probably won’t work with a triple. Since I have removed the large chain ring and only use the 22-32 can I still use a mountain derailleur? Or do I need to go to a road derailleur, which leads to another question: Since a road derailleur is designed to work with either a 34-50 or 39-53 set of rings, is there any issue with using it with a 22-32 set-up?

The bike has bottom pull cable routing.
-David

Dear David,
What you say is true; the cable pull on MTB front derailleurs is indeed generally different from road ones. That said, I ran an XTR front derailleur on a cyclocross bike with Campagnolo Ergo Power levers for a number of years with no problem. The left Ergo Power lever does not care about the pull of the front derailleur because it does not have fixed shifting positions. Rather, it has a number of closely spaced clicks, which allow you to find the optimal position to avoid chain rub (This does not apply to left Campy QS levers; those are fixed-two-position with a cheaper, simpler mechanism and won’t work well with an MTB front derailleur.).

So, assuming you have a 9-speed cogset, my recommendation would be to run 9-speed Campy levers. With a Shimano MTB rear derailleur, you will need to attach the cable to the opposite side of the derailleur’s cable-fixing bolt from the cable groove. This change will adjust the lever pull to match the rear derailleur. And the left Ergo Power lever will work great with any MTB or road front derailleur.

As 9-speed is dead in Campy terms, I’d be surprised if you couldn’t find a set of these levers cheaply online.

If you are set on using Shimano STI road levers, it may be that you could get that front derailleur to work since you only have two chainrings. I suppose you could just try that front derailleur on a road bike and see if it works before investing in the levers. Maybe switching the cable to the opposite side of the cable-fixing bolt might work in this case as well…

I’m pretty sure you’d be disappointed in the mating of a road front derailleur with your chainrings. The radius of curvature of the outer cage plate is so much larger that it wouldn’t come close to matching your chainrings, and you would consequently have a large gap between it and the top of the chainring at the tail of the derailleur.

Your bike has bottom pull cable routing, so using a road front derailleur will be no problem in that regard. But I know that this will beg the questions that will pour into my inbox if I don’t nip it in the bud and answer the inevitable one, so here it is:

Yes, you can still use a road front derailleur on a frame with top-pull cable routing. There are a number of ways to do this, and you’re now once again in cyclocross territory. One way is to just loop the cable under the chainstay bridge and up to the front derailleur. You’ll be amazed at how well this works. Another is to use a clamp-on cable roller on the back of the seat tube. A third is to Riv-Nut on a threaded water bottle boss on the back of the seat tube 1-2cm above the bottom bracket, and then screw a ‘cross cable roller into it. The fourth option is to use an Umlenker, which clamps to the arm of the front derailleur and adapts it to a cable pulling from the top.
-Lennard

Readers can send brief technical questions directly to Lennard Zinn.

Technical writer Lennard Zinn is a frame builder (www.zinncycles.com), a former U.S. national team rider and author of numerous books on bikes and bike maintenance including the pair of successful maintenance guides “Zinn and the Art of Mountain Bike Maintenance” – now available also on DVD, and “Zinn and the Art of Road Bike Maintenance,” as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”

Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and feeding and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

Follow Lennard on Twitter.

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Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, as well as Zinn and the Art of Triathlon Bikes and Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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