Fork Crown / steertube failure
I recently converted a vintage Bottecchia road bike into a cyclocross bike, added cantilevers to the fork.
After several miles of use, I noticed that something felt wierd with the steering and there was a mild shudder when braking. Then, rather unexpectedly the front brakes locked up and I flipped over the bars. Inspection revealed that the fork steer tube had separated from the cast fork crown, looked to be really insufficient factory brazing. I suspect that the shuddering cantilevers stressed the joint more than the original fork crown mounted centerpulls ever had. Nothing was actually bent or damaged in the crash (besides my hands), the crown was so loose I was able to remove it from the steer tube by hand. Once I cleaned away the scant remaining brass, the OD of the steering tube is 25.4mm and the ID of the cast hole in the crown is 26.0mm, makes for a really loose fit between the two. Is a 0.6mm loose fit at all typical at the fork crown? If I were to braze it back together and completely fill the void between the tube and crown with brass, should it hold together OK with such a large brazed gap or are there other measures I should take to fix?
Last edited by GrayJay; 05-13-11 at 01:13 PM.