The Gapping Dilemma

Chris Clinton, June 02

A couple months ago I began a project with the mindset of making life easier for the neutral mechanic. With the recent introduction of numerous aftermarket forks and with exotic materials causing rear drop out spacing to fluctuate, I was experiencing difficulty getting wheels gapped right. Having spoken to many other mechanics I was glad to hear that I was not the only one.

I had been gapping the rear wheels to steel and the front to alloy however this didn’t seem to fit most of the equipment being used. In fact, I was finding great difficulty getting some rear wheels to drop in enough for me to make quick skewer adjustments. Plus, I was carrying two sets of gapping tools and this was added weight in the box.

So, I thought it would be a great idea to compile all the drop out measurements for the existing bikes and forks that were being raced in the US. Armed with this information I could find the average width and gap to that. Having done this I could then adjust the skewer a small amount in either direction and cover everything quickly. I even set up an Excel form to layout the information and determine the correct size for me.

The problems with this project quickly arose while attempting to contact the companies and acquire their dimensions. Very few actually responded thus requiring me to locate the frames on my own and measure them myself. The results so far have been very sporadic and have kept me from completing the project.

Things began to change last week while working neutral at the Cascade Classic. I had brought with me a set of gapping tools made from a busted Colnago Dream Plus. The overall gap of the drop outs is 15mm and are only slightly fatter than most alloy frames and carbon forks. I gapped all my front and rear wheels with this set and the wheel dropped into every frame and fork. All I had to do was make a couple quick adjustments and away the rider went.

This was much faster than my previous method and never got stuck under the drop outs. Thus, I am a converted man. From now on, my gapping tools will always be broken Colnago Dreams. Know of anyone who crashed lately?

For those who are interested, the results of the project are located below:

gap11.gif gap21.gif


Owner of and long time professional race mechanic.