Bicycle Mechanics - shifting problem in cold weather?

I posted this first in the commute forum by accident.:o

This morning's commute was 32 and an old problem resurfaced.

Rapid fire shifters. The front shifter will not grab the cable only when going from the middle to the big ring. It's like the shifter's not attached to anything. If I do it repeatedly and coax it by slightly lifting up on the lever I eventually get it to grab. This is only in cold weather.

The cables are new. That was the first thing I tried.

Any ideas?

Flush the shifter with spray solvent, use the straw & get it into as many spots as possible. Do this several times while working the shifter. It should start to catch. Let the solvent dry & relube. For the solvent I've had great luck with White Lightning Cean Streak. Anything that won't eat plastic and leaves little residue should work. Relube with Tri-flow, T-9 etc. something lite, no wet lube or heavier oil. This is a pretty common problem & usually can be fixed as described. Good luck.

One more thing. If there is tons of play in the thumb lever it can be adjusted on some models. Remove the plastic cover under the shifter, tighten the center nut (most of these are left hand thread, but not all) tighten just enough to remove most of the play, you want to leave some. Done.

Great advice. I'll give it a try first chance I get and report back.

...but what is it about the cold that makes it malfunction?

I had the same problem with the cold. Lots of Tri-Flow penetrating oil into the shifter solved the problem for me. I don't know why, but it works...

...but what is it about the cold that makes it malfunction?

Cold temps make the grese more viscous. More drag on the mechanism.

Yep, the springs that engage the catch against the shifting pawls are very light and can't move the catch as well when the grease gets harder.

Thanks everybody. I'm surprised my LBS mechanic didn't know this. He's a pretty experienced bike guy that does a lot of commuting himself. I guess I'll get to enlighten him on the subject.

I have been suffering from this shifter problem for probably a year. My various repair manuals don't seem to address it, but a quick search on this board found the solution. My shifter is back working the way it did years ago.

Thanks!
pete

...but what is it about the cold that makes it malfunction?

It's not just the cold. A proper shifter will work just fine in the cold. You have something additional wrong.

The cold went away so I couldn't report on my efforts to fix the problem. We just now got under freezing temps again.

Just as was recommended, a bit of lube in the shifter and it works just fine. Thanks

Use a lube that's rated for colder temps/weather. Boeshield T-9 for instance is good from -40°F to +250°F and Tri-Flow is good from -60°F to +475°F. Although I prefer T-9 because it leaves a coating, making it less likely to attract moisture that could freeze and light penetrating lubes like Tri-Flow tend to contain more solvents than lube. One has to experiment with various lubes and greases to find one that works under the conditions you ride in. I know more than a few that pack their cables with grease used in freezers, Lubriplate Mag-1 (NLGI #1; good to -60°F) or Schaeffer's #274 (NLGI #0 or #1; good to -45F), but yet stay flowable/flexible at extreme low temps to prevent any cable hangups or freezing. They believe that by packing grease, any moisture will not be able to form to freeze the cable to the housing. Or switch cables to Dry Cables or Gore Ride-On Cables (discontinued?/hard to find). Those cables may be expensive but haven't heard any complaints about those cables freezing inside the housing or short cable life.

...but what is it about the cold that makes it malfunction?
WHAT IS IT ABOUT YOUR BRAIN THAT NEVER WORKS NO MATTER WHAT SEASON OR TEMPATURE???? http://www.slayer.net/

WHAT IS IT ABOUT YOUR BRAIN THAT NEVER WORKS NO MATTER WHAT SEASON OR TEMPATURE???? http://www.slayer.net/

WTF? What funny farm did you come from? And learn how to spell or you end up looking like an ignorant fool but I guess that's pretty obvious to begin with.

WHAT IS IT ABOUT YOUR BRAIN THAT NEVER WORKS NO MATTER WHAT SEASON OR TEMPATURE???? http://www.slayer.net/

Quit listening to all that devil music...and go wash your dishes
or something productive. "slayer"...sheesh :rolleyes:

I'm waiting for someone to invent a small element-based heater to keep components warm for sub-zero riding.