Technical FAQ: MTB front shifting problems, master links, and more

This week, Lennard Zinn answers readers' questions about a mountain bike that won't shift right, master chain links, and more

Stubborn front shifting on a GT Zaskar

Dear Lennard,
I have been dealing with a full carbon GT Zaskar that came OEM with an X9 2×10 setup. The rings are the 39-26 pairing. The customer had us replace every drivetrain component except the rear derailleur due to wear issues. I replaced every part to exact spec SRAM replacements.

Since the change, the front derailleur is chaotic. The shifting vacillates between not shifting to the big ring (as if the H limit screw is too tight) and throwing the chain to the outboard side (as if the H limit screw is too loose) with no adjustments made to the limit screw. Half the time it won’t shift, and in that other half it throws. The chain also tends to be out of sync in terms of chain bushing/tooth alignment when it attempts to shift to the big ring. Surely that is the root of the issue, as the chain just wobbles over a few teeth before it either throws or drops.

I have spoken to the SRAM tech guys three times. They are a fantastic group of guys. We spent half an hour on the phone checking specs, compatibilities, positions, spacers, yada, yada, yada. Everything is right. They also sent free replacements for some parts as a “might as well try” offer even though we all knew the parts were perfectly functional. I also switched the entire drivetrain to another bike to test and it worked flawlessly. The frame has no signs of damage or misalignment issues. Three front derailleurs, two chainring pairs, three chains, two front shifters, two full cranksets, crying, cursing, flinging of tools (and one chainring) and horridly spoken things about Zaskar’s mom and it still does not work. Customer swears it worked great before. SRAM is out of ideas. I am out of ideas. So … any ideas?
— Caleb

Dear Caleb,
First of all, since you didn’t mention it and you did mention the chain and the teeth being out of sync, make sure the chainrings are oriented properly and are not “clocked.” In other works, look for the chain-drop pin on the outer ring and make sure that it’s right behind the crankarm. On the inner ring, there will be a triangle or similar indicator on it; make sure that’s lined up behind the crankarm. And of course, make sure that the inner ring is not inside out (if the chainring nuts don’t seat into recesses in the face of the chainring, the chainring is facing the wrong way). I don’t mean to insult your intelligence; I know you’re a professional mechanic and would probably check these things always. And this column is also for the benefit of those reading who are not professionals.

If everything is correct with chainring orientation, try a non-SRAM chain. We have run into some of these problems in my shop, and a Wippermann chain, while it did not fix everything, reduced some of the shifting problems. It’s worth a try, as you’ve tried everything with the recommended parts.
― Lennard

XTR 980 vs. 985 pedals

Dear Lennard,
Do you think there is a noticeable difference between the XTR 980 vs. 985 pedal, or is a bigger platform just a mirage?
— Stedman

Dear Stedman,
It does indeed have a bigger platform, which works well with softer-soled shoes.
― Lennard

Master link help

Dear Lennard,
All this talk about waxing chains has made me want to try it. But I have run into some confusion about how to select the right master link so that I can remove, wax and reinstall my chain. I run a SRAM red cassette and derailleur with a PC1091R 10-speed chain. The 10-speed SRAM chain only comes with a PowerLock — not reusable. I’ve asked around at several bike shops if I can use a reusable master link from Wippermann, KMC or any others with SRAM 10-speed. I have had numerous conflicting responses.

Some say the Wippermann is too wide, the KMC is too narrow, and others say either will work. Some suggest just using the SRAM PowerLink that comes with other chains. Can you please help?
— Patrick

Dear Patrick,
I suggest you try either a Wippermann or KMC 10-speed master link. I personally have ridden with both on many different 10-speed setups with chains of different brands (usually Shimano or Campagnolo) and found them to shift great and do whatever I expected them to do. We use both of them, especially the Wippermann links, regularly on travel bikes we build. The chains have to come apart to pack them into the travel case, and whether it’s a SRAM, Shimano, or Campagnolo group on the bike, we supply it with a master link that’s able to be opened.

On SRAM 10-speed chains on my own personal bikes, I don’t know that I’ve ever used a 10-speed Wippermann or KMC master link on them, because I just open the PowerLock link and reuse it. It takes Park MLP-1 master link pliers to do it, but with them, it’s literally a snap. Since SRAM specifically says that the link is not reusable, I cannot recommend this. All I can say is that I have opened and closed them often on my own bikes and have never broken the link or had any other kind of problem with it. To be totally safe and by the book, you could open the chain with master link pliers and close it with a new PowerLock link; you could just buy yourself a pile of them.
― Lennard

’Cross bike maintenance request

Dear Lennard,
I have your road bike book and it’s my constant companion when I’m working on my bikes. This spring, I bought a ‘cross bike with disc brakes. I don’t need your mountain bike book for but a few parts of it. Has it ever occurred to you and VeloPress to release a ‘cross supplement to the road book with just bits of the mountain bike book to cover disc brakes, U brakes, and other things roadies only see for ‘cross and gravel bikes? It’d be super helpful, and you’d sell a lot of copies.
— JL

Dear JL,
Thanks for the nice suggestion, and I’m pleased my book has been so useful to you.

We have not done a stand-alone supplement like that. But I recently completed the fourth edition of Zinn and the Art of Road Bike Maintenance, and that has extensive cyclocross sections that include cantilevers and disc brakes, both hydraulic and cable-actuated.
― Lennard