EssForty wrote on 09/26/08 at 15:37:58:What is the gear ratio for the top gear on the 4 speed and 5 speed transmission? I've searched and I can't find it. Also, has anyone calculated what the rpms should be for a Savage at various speeds and gears assuming stock tires and proper tire inflation?
I'm curious how accurate my tach is. It is very repeatable but I am not sure if it is accurate for a 5-speed.
Don't remember where I got the info, but:
Primary Reduction: 1:1.81 (crank to transmission)
1st -- 1:2.333
2nd -- 1:1.578
3rd -- 1:1.142
4th -- 1:0.956
5th -- 1:0.884
Final Drive: 1:2.96
rear tire diam 24.4" (This will vary with size and brand of tire)
The math:
4500 rpm engine speed / 1.81 primary reduction =
2486 rpm into transmission / gear (fifth = 0.884) =
2812 rpm front sprocket / 2.96 final drive =
950 rpm wheel spin * 24.4" (tire diameter) * pi (3.14.16) =
72863 inches/minute ground speed * 60 min/hour / 63360 inch/mile =
69 mph
Get a stopwatch and a measured mile. 4500 rpm through the mile should take just a hair over 52 seconds.