Guys, this may pee some of you off so look away if you dont want that.

I just wanted to know what a 30 rollout or 42 rollout is, as in how do you work it out to get the 30, 42 or be whatever number it is, previuslly when i started racing electrics i jst used one spur one pinion and that was it. and had the same stock motor for 8months without a cut(still went hard--till it seized).
So any helo is appreciated. thanks

Rollout is the simple name for calculating how many millimetres the car will travel per one motor revolution. It is mainly used for recalculating gear ratios for foam tyres because as they wear they get smaller.

The formula is:

Tyre diameter multiplied by pi (3.14159) divided by overall gear ratio

example: 63mm*3.14159/6.5= 30.44 rollout (30.44 millimetres per motor revolution.)

dimo

if you go to this web site www.gearchart.com you can put in the required info and print out a rollout chart, an 04 x ray fk has a 1.177 ratio, put in tyre diameter & few other tid bits & print it off.as long as you know the gearbox ratio you can get 1 for any car just follow the prompts cheers

We also have a rollout calculator on our club website.
just go to the link below.

http://www.actmcrc.org.au/technical.htm

Dimo

FK Xray has a internal ratio of 1.77 not 1.177. You might get some crazy results if you put in 1.177.

yeah thats right dimo, sorry to early in the morn & trying to do to many things at once professor

Hey Thanxs Guys, so whats a diameter

Just kidding

Owe you all one, whos going winterchumps