Technical FAQ: Drivetrain compatibility issues

We’ve received a number of e-mails recently asking about drivetrain compatibility. Some readers are checking in on Shimano 9000 compatibility and others are piecing together Campagnolo or SRAM drivetrains. This week, I will address a few of these letters.

Campy 11/10-speed mating

Dear Lennard,
Can an 11-speed Campy crank (53/39) work with a Campy 10-speed system without problems or do you need to change the crank and/or chainrings?
—Roger

Dear Roger,
I’ve done it a number of times with no problems. For instance, I set up a cyclocross bike with Campy 11-speed cranks and Campy 10-speed drivetrain for my daughter, and she never had a front shifting issue throughout the summer and the ’cross season, including in the sticky, freezing mud of the elite women’s race at cyclocross nationals in Verona, Wisconsin, where she, like most riders, was pitting twice per lap.

Yes, it will work fine.
―Lennard

Worn out G-springs

Dear Lennard,
I currently have 9-speed Record shifters, possibly 2000 model, I think — the very first models with carbon blades. The rear derailleur is the early 10-speed model, the first carbon model, but the pulley holders, front and back, are alloy, also around 2000 I think. Upshifts with the paddle are smooth on the 9-speed Campagnolo cassette, but downshifts with the thumb button seem to shift too far and need to be trimmed with the paddle. I’ve tried the barrel adjusters to slacken and tighten the cable, but can’t seem to remedy the problem. Is it a compatibility problem or can it be adjusted by more careful attention to the barrel adjusters?
—Ben

Dear Ben,
I doubt it’s a compatibility problem. I think your G-springs are toast. Replace those and I’ll bet it will work fine.

The G-springs are little springs shaped like a capital “G” inside of the lever. They stop the index gear inside the lever that determines how much cable is let out with each shift. As the G-springs wear, they flatten and don’t spring as forcefully into each valley of the index gear. If they can’t stop the index gear precisely, it will rotate a bit further than it ought to and let more cable out than it is designed to. If your lever is that old, I’m betting that’s what’s going on.

Instructions for overhauling that lever and replacing the G-springs (which are available from bike shops) are in any edition of my book, Zinn and the Art of Road Bike Maintenance.
―Lennard

(Not) cutting Ultegra Di2 wires

Dear Lennard,
I have a Litespeed Titanium frame that I am adapting an Ultegra Di2 shift group to. I’m having two issues. First, the Shimano wire cover set will not stick to the frame and, second, the wires to the front and rear derailleur are 5cm too long.

Can you offer any suggestions to correct these problems? Can the wires be cut or folded?
—Ken

Dear Ken,
Don’t cut the wires!

Take up any wire slack in the Di2 Junction B looping pegs (under the cover); you can wind 120mm of slack into it. Bolt Junction B to the threaded cable-guide hole under the bottom bracket shell with 1.5–2.0 N-m of torque. This is explained in the newly released (yay!) fourth edition of Zinn and the Art of Road Bike Maintenance.

I’m sure you can figure out something to tape or zip-tie your wires down. I’ll bet it’s just that it won’t stick to the coating of Lemon Pledge, WD-40, or other oil or wax that is traditionally applied to a titanium frame after bead blasting or Scotchbriting; oil or wax is put on the frame to prevent oily fingers touching the frame leaving fingerprints.
―Lennard

Matching up new and old Dura-Ace

Dear Lennard,
Will the new Dura-Ace 9000 derailleurs (front and rear) work with previous Dura-Ace shifters?

I’d like to upgrade components but wanted to do it a few at a time, and since the new 9000 shifters are very pricey, I’d like to be able to do those last.
—Scott

Dear Scott,
No, they won’t work together. There will be zero stroke compatibility between the shifters and either the front or rear derailleur.
―Lennard

SRAM and Rotor

Dear Lennard,
My bike is equipped with SRAM Apex, but I ‘m looking at the Rotor Q crankset. Do I need to change anything else if I install the Rotor Q, or will it work with the SRAM components?
—Bryan

Dear Bryan,
The Rotor Q crank will work fine with your SRAM Apex drivetrain.
―Lennard

Replacing Ultegra 6500 brakes

Dear Lennard,
I have an Ultegra 6500 9-speed groupset on one of my bikes and need to replace a rear brake caliper. I am having trouble locating a replacement at my LBS and they do not seem to be of much help. Any suggestions as to what would be compatible that is easily obtainable via the Internet?
—Marco

Dear Marco,
The new Ultegra 6700 and Dura-Ace 7900 and 9000 brake calipers will not work well with your levers, as the calipers are designed with higher leverage to mate with a low-leverage lever.

However, basically any other road brake in the world will work fine with your Ultegra 6500 lever.
―Lennard

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