Originally posted by pokemon
how do u calculate the internal ratios for 705. u have front diff pulley, mid, 2 pulley, rear 2 pulley and rear diff pulley
For a 3 belt car, you have a pulley system like this;
Internal ratio for the front is as follows;
(24/16) x (24/18) = 2
Internal ratio for the rear is as follows;
46/23 = 2
For the optional 22T/47T/17T internal pulleys, the internal ratios are as follows;
Internal ratio for the front;
(24/16) x (24/17) = 2.118
Internal ratio for the rear;
47/22 = 2.136
In this case, there is a very slight front overdrive which should be nothing to worry about.
It is important to make sure that the front and rear internal drive ratios are the same (or about the same) when you run the same diameter tires. If the front has a lower internal drive ratio than the rear, then you need to use different tire diameters (smaller front and rear) to make the front and rear TIRE ROLLOUT the same if you do not want any front overdrive. How much difference in front and rear tire diameter (split)? That you need to calculate also.