At 12:54 PM -0400 10/6/09, <oroboyz@aol.com> wrote:
> << Wixey also makes a similar gauge for about the same price, available all
>over North America.?http://www.wixey.com/anglegauge/index.html >>
>
>What a neat little gadget! Thanks so much John for that link, I just
>ordered one... (This is a great group, thanks folks!!!)
The nice thing about the digital gauges is that you can re-set them to zero on any surface. So if your table isn't level, it doesn't matter. (You also could measure your table and add/subtract the difference from level.) Make sure both tires are the same model and width! (And don't assume your top tube is level - it rarely is.)
Most other methods aren't accurate enough. After all, 2 degrees make a huge difference in the bike's handling. (For our book "The Competition Bicycle," we measured all the featured bikes, dating from the 1890s until the 1990s. All angles were between 66 and 75 degrees, a spread of only 9 degrees. So even without seeing your bike, I can tell you its head angle is somewhere around 70 degrees, plus or minus 4 degrees.)
However, the angles of your frame don't tell you all that much about the handling - you need the fork offset (rake), and that is tricky to measure. Ideally, you remove the fork and put it on an alignment table, with V blocks. For our Bicycle Quarterly tests, we made a square that is clamped on a dummy axle, then aligned with the fork steerer. Scribed markings let us read off the fork offset. The problem is aligning the square with the steerer axis - easier on older bikes with the fork bend near the bottom and very hard on bikes with straight fork blades that are "bent" only at the crown.
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.vintagebicyclepress.com