Originally Posted by
busdriver1959
I think your calculations concerning the head angle change are off. I just measured 3 different bikes, this time with a 9mm block and I keep coming up with a .5 to .6 degree change. That measurement seems to be supported by some of the other posters although I don't know the source of their information.
I hope I'm not coming across as argumentative for the sake of arguing. I'm trying to learn as much as I can about what really effects bike handling. I can't trust any sources that originate from the marketing departments at the big bike companies. Most of what they put out to sell their bikes ends up being utter BS.
I'm having to start from scratch here.
I arrived at the 0.2° difference by measuring the HTA without and then with a 9mm thick paperback book under the fork dropouts with a Wixey WR300 digital angle gauge on the head tube. I have a jig that I use for measuring frame geometry that gives me accurate, repeatable numbers.
But I could be wrong. I'm not trying to be argumentative either.
The front and rear brackets sit on two extruded aluminum box beams which are used as a level reference by zeroing the WR300. I measured the HTA without the 9mm paperback to get the HTA using the stock fork, then inserted the paperback between the box beams and the bottom of the bracket and measured the HTA again. With the paperback, the HTA was 0.2° slacker than with the front bracket sitting directly on the box beams.
