Supershafts
We race, so You win
- Joined
- Feb 27, 2010
- Messages
- 421
This is completely incorrect. Even in the OEM stock gears the front is always faster then the rear. If it wasn't then when in 4wd the rear would try to push the front binding the tcase. With the front being faster it pulls the rear along. in pulling we run a faster gear in the front sometimes. Since the back is doing 75% of the work you over drive the front to get more traction from the front end. If the front and rear are close to the same then you only get the same speed out of the front as the rear. By over driving it you are essentially getting more cleat on the ground per foot traveled which would be a greater pulling force to help the rear keep the truck moving. I ran a 36" tire on the front and a 35" on the back will do the same thing. You can safely over drive the front 7%. Some do more but much more then that gets sketchy
With a 44 in back and 35 up front the 4.9 at back and 3.8 ratio holds the same driveline rpm , while the tires are at the same speed at the that diameter.
If you put 44 back and 35 front and run 4.9 back and 4.9 front you are tripping over yourself as the back tire is faster than the the front from it's height, so you need the 4.9 ratio rear and 3.9 ratio front to keep them at the same speed.
If you run the same size tires and run 4.9 and 4.5 then you would or should have less stability, take 2 rear wheel drive vehicles, the front one is spinning it's tires and it is swaying back and fourth because it can't over come the rear that is set and moving slower.
They are both doing the same work, one end is seeing or dragging more weight, that shift from drag pulls the back in and transfers more weight to it unloading the front, but they do the same work as in speed, or you want them to do the same.
As you get further the weight comes on and forces the truck to transfer to the back, you would want lots of weight up front and spring and tire.
But if the vehicle is now sliding along at 20 mph and the rear tires are spinning at 60 mph and the front at 70mph on the same plane then they fight eachother for traction, and as traction comes on braking starts or you'll lose traction.
My idea is you want to get going fast, having say 35 and 35 tires and 4.8 rear and 4.1 front ratio is either binding or breaking traction and forcing wheel spin.