High(er) Speed Stability Problem
In rolling hills, I used to take it easy on the downhills with the idea that I was resting for the uphill portion. Then I started riding a fixie some and learned to appreciate momentum. Now on my geared road bike I tend to keep the cadence up downhill, bring up the speed, and have an easier time on the unsuing uphill. Bottom line is that I am reaching higher speeds than I used to.
Here is the problem: at speeds around 32-33mph, the rear of the bike starts oscillating. I can brake to bring it under control, but its not comforting. Moving my weight a bit forward on the saddle also seems to help.
Judging by distance from the brakepads, the wheels appear to be within a mm of true. Is that too far out? What is a reasonable expection for a safe maximum speed on a descent?
The bike in question is a 1982 531 steel Holdsworth Special, kind of an in between road racing -training bike, 73/ 73 angles, 40" wheelbase. Never abused, no crashes.