Are you sure that you are dealing with a Triumph here? Just joking, but your problem is one that I do not believe that I have ever heard before.
The only remedy that I can think of is that you may have over tighened the adjustments on the brakes. When you adjusted the brakes could you spin the wheels with very little or no drag from the brakes? If you have much drag on the wheels when spun with the car off of the ground then the brakes should be adjusted back at least to where the wheels spin with very little if any drag.
What changes did you make in the brake system just lately? New brakes or hoses, adjusted the emergency brake? Knowing what you did recently can better give us an idea of what is causing the current problem.
Charley
