oldokie

Just about finished with a rebuild of a 96 Bianch San Remo and I am now making test rides to get it tuned in. Today I noticed that I was unable to keep it in a straight line when riding hands free. It insisted on very quickly drifting to the left unless I shifted my weight to the extreme right. Bike works fine when hands are on the bar.
During my rebuild, I had frame checked to make sure it was straight and my wheels are very true. What adjustments am I missing that might be able to help this?
About the only thing I can think of is the adjustment screws in the rear dropount. The screw holes are there but no screws were on the bike when I got it. Even if I did install screws and made some adjustment to the rear wheel, I don't think I could make much because the wheel is true and centered in the frame as is.
What am I missing?

operator

How badly is pulling to a side? This could indicate a bent fork, which is most likely.

randomgear

First make sure your headset isn't too tight and starting to index.

freako

If your good with eyeballing the rear wheel centered into the stays then the adjustment screws would not be the problem. You could check your wheels to make sure the spokes are dished correctly; other then that your looking at probably a bent fork or rear stay or dropouts. The headset is another possiblity but I can't recall a headset ever doing that, but I ain't no mechanic. You could test the headset yourself by lifting the front wheel off the ground by the frame and see if the wheel prefers to turn one direction naturally, also check to see if the front wheel moves smoothly with no roughness or notchiness.

operator

Only the latter is useful, the former test is worthless diagnostically.

DannoXYZ 

bent fork, bent frame, mis-dished wheels.

neil0502

I was thinking rear wheel dish, too.

Unless the OP was drunk.

Could be both, though, I guess.

europa

What'd you drink before the test ride?

Richard
twisted forks were my first thought

oldokie

Head set is brand new 105 and I only had one six pack before the ride. Wheels are a brand new build and have correct dish. In fact, 100% of components are new. Only frame is used. I am sure it is a frame issue. Had not thought about the front fork twist....will check on that. I will relook at the alighnment of the rear vs front wheel and make sure they have good alighnment. Obviously something is not straight. I would suspect that a small amount of misalighnment between front & rear would amplify the problem.