Shays and Universal Joints

Toque is measured in foot-pounds (newtons in metric.) If there is 1000 lbs on one end of an axle and the bearing block is 4" from the wheel (I'm making these numbers up for demonstration) then you have
1000*4/12=333 foot-pounds
333 foot-pounds of torque on the axle at the wheel. Now if you slide the wheel in, say 10.25" you now have
1000*14.25/12=1187.5 food-pounds
You now have 3.5 times the torque on the axle at the wheel. This is a simplified model, but it demonstrats the point. The top of the axle is in tension and the bottom in compression. As the axle rotates it is effectively bent in circles. The less torque applied, the less shear stress is on the axle at the wheel.