Re: Shays and Universal Joints

Chris:
Outstanding review on Shay u-joints. I fired or engineered the Pine Creek shay (Ely-Thomas #6) for many years. Except for some straight sections, Pine Creek runs in a circle so the engine is always turning to the left. We always had a problem of snapping teeth on the front axle of the rear truck. That particular area was always noisy as well and the joint had a lot of movement as it ran. The front shaft ran very true and relatively quiet. I'd have to double check but I believe the rear shaft was shorter than the front shaft. So I kind of wonder if running continuously to the left, with a shorter shaft in the rear, and the pounding you describe in u-joints, was the reason we snapped teeth on that rear truck.
Thanks for the explanation on joints.
J.R. May