frank-id
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 05, 2005 - 2:30 am: | |
I know there is a speed calclator on the bus BBs but I cannot make the numbers work for me. I just changed my Crown bus trans from a 5 speed to a 10 speed Fuller with an overdrive of .08. the rown was able to achieve a top speed of 59 MPH, but now the bus will go about 71-72 MPH. I want to go about 70 MPH with an engine speed of 1750-1800. Another guy said I need a 3:55 and another guy said 3:73 ring and pinion ratio. The bus has 11.00 X 22.5 tires and wheels. What ratio is good for my needs??
Frank in Idaho |
RJL
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 05, 2005 - 3:36 am: | |
Frank -
To answer your question, you need to use the overall rear axle ratio, which, in overdrive 10th gear is 0.8 x (actual rear axle ratio). Using Daris's calculator, here are three examples:
4.10 x 0.8 = 3.28. Yields 63 mph @ 1700 and 67 mph @ 1800.
3.73 x 0.8 = 2.98. Yields 70 @ 1700 and 74 @ 1800.
3.55 x 0.9 = 2.84. Yields 73 @ 1700 and 78 @ 1800.
You can even come up with speeds for each of the lower gears, using the same formula of multiplying the rear axle ratio by each gear's ratio to get the overall, then plugging the overall into Daris's calculator. As his site says, use your actual tire's diameter for the most accurate results.
http://www.freewebs.com/darisb/ (MPH Calculator link on left)
HTH,
RJ
PD4106-2784
Fresno CA |