I posted about this before - a vibration that starts at about 65 and gets worse the higher the speed.
I have not been able to track down the source. Both axle shafts have been replaced, as have the hubs and front wheel bearings, and rotors.
It seems worse with the 13x7 Keizers and race rubber, but I'm not reaching speeds much in excess of 65 mph, and not driving it hard. Last weekend I was above 80 on one stretch of the course.
I'm due for new tires, so I'll ask them to pay close attention to balancing. However, this will be my 3rd set mounted on these wheels, with several additional flips to keep the wear even, and the shop I take them to is no stranger to racing tires.
New development this weekend though. On Saturday, the right front wheel was rubbing on the caliper. A little odd, since it should only go on one way, but I do take them on and off, and it's a tight fit clearance wise. I removed the wheel and reseated it and the rubbing went away.
It was back on Sunday and I could not get rid of it. I was also worse in low speed tight turns on the course. It seems to me that things are moving around that should not be. That's a problem that needs to be resolved before my next event.
I need to take a look at the hub/bearing/steering knuckle assembly. I'm sure it's not broken, but perhaps the bearing has worked it's way out, which seems odd since it's supposed to be held in by a spring clip.
Any other ideas? Bent hub perhaps?