arlo1

I did some calculations like this I got a mesurement for my tires from the websight I bought it from. they say they are 86mm x3.14159 (circumfrance=pie x dia) that equils 270mm for a revalution then I figured out what 70km/h is in mm/h = 70 000 000 then from there devided that by 270 to get wheel rev per hour =25925 then devided that by 60 to get wheel rpm =4320 wheel rpm at 70km/h then on that same websight they list hi and low gear ratios and it says 5.84 for high so I multiplied that 4320x5.84 =25 234 engine rpm This is not counting any tire swell and anyone who has reved their car in their hand can tell you at top speed their is a lot So the tire swell will meen that the engine rpm for 70 km/h is less than 25 234 rpm i cant tell you how much less because I have now way of mesuring a loaded wheel at top speed for swell. Then to test my calculations I tried the calculator on the websight gman sugested and entered in 25000 rpm and tranny ratio of 5.84 and diff at 1:1 and tire radius at 1.74 inches that gave me a speed of 44.3 mph to turn that into km/h you divide it by .62 to get 71.45 km/h I initialy guess by saying my tornado bb with the vertex .18 engine sounds like 20 000 rpm I think it might be more like 22 000-24 000 on the ground. Note I did lots of calculations to find out the websight for my car must have listed the overall ratio for gear reduction including tranny and diffs.