Monday, October 13, 2008

Grease that steerer tube!...

With steerer tubes on most higher end bikes these days being aluminum or carbon fiber, it's easy to forget to apply a light coat of grease to the steerer tube if you find yourself installing a fork with a steel steerer tube. Why grease a steerer tube? Well, glad you asked. The steerer tube is invisible when on the bike. It's also trapped between the upper and lower headset cup so if water or any moisture gets in, it's not getting out easily. And there is sits clinging to the steerer tube, eating away at the steel.

Greasing an aluminum steerer isn't normally necessary, but can be helpful because it's possible for the aluminum to corrode in some situations. A thin coat of grease prevents this. And carbon just doesn't corrode or rust, but a bit of grease on a carbon steerer in the area where it is near the headset cups/bearings can't hurt.

So, why all this blabbering about greasing your steerer tube? I was working on a really nice Serotta ti bike with a Serotta made carbon fork with steel steerer tube last week. The first indication that something was wrong came when the aluminum headset spacers were corroded in place. Then the King bearing cap would not budge. It too was frozen to the steerer. When I finally got the bearing cap off, I was treated to a lot of dirt spewing out from the bottom of the head tube. It wasn't actually dirt, but was rust dust. Bad sign. This is what the steerer tube looked like when it was finally freed. Pretty awful.
As bad as this steerer tube looks, it cleaned up rather nicely. A 12" strip or abrasive cloth about 1" wide scoured the rust off and polished the steerer tube to a shiny finish. Hold the abrasive cloth in both hands and run it over the steerer much like the shoe shine guy polishes shoes.

I learned this bit from Chuck at Pacific Coast Cycles long ago. Before you grease the steerer tube, write your name, phone number, and driver's license number if you want on the steerer with a sharpie. Let it dry and then apply grease. This is a great form of identification if you ever find yourself having to identify your bike in a police station.

(What's playing: Aesop Rock Coffee on MPR's The Current)


laffeaux said...

Thanks for the advice! That steerer tube looks bad. I'm glad you were able to save it.


Bushpig.vrc said...

I thought you should grease carbon since the lube can break down the laminates?

blackmountaincycles said...

Bushpig: I think you meant to say "you shouldn't grease carbon..."

If that's the case, that may be true if the carbon was totally raw. However, there is so much resin and a final clear coat that the carbon in the tubes is very well protected. I've read comments from both Easton, Lennard Zinn, and Craig Calfee that greasing the interface between carbon components is okay - and required if you are using an aluminum seat post in a carbon frame as that is a recipe for disaster.

Jeff said...

Just a note grease allows a tighter clamping of parts with less bolt torque. A little counter intuitive, but I have seen stems slip on steer tubes even when quite tight. A thin layer of grease will usually help in the situation.

blackmountaincycles said...

Yes. I like a dab of grease on all threads.