Hey everybody

I have a question on Gearing.

I am running a Stock 27turn motor and a 4200mah battery. If i run a 4 second lap on a 46ft drive line track. Would it be 4-1 gear so if i am running a 116t spur and a 31 pinion with a 2.2 tire size that would mean i need to take 4 and divide it by 116 and that would come out to 29. Would that be the pinion i need to run or is that a diffrent thing. I was told to run the Roll out at 1.7 to 1.8 on a 46ft drive line track. But if i switch and run a 35 pinon istead of a 31 that gives me more speed in the strights but less in the turns. So what would be a good gear ratio and roll out for a 46ft drive line track.

Thanks taylor
Taylorbaney@yahoo.com
:thumbsup:

That post honestly doesn't make a lot of sense to me, but I'll try.

First off I assume you mean 146' not 46'. 46' really doesn't make sense.

I'm not sure where you are getting this 4 to 1 gear ratio you talk about about. I don't know if that is something you extrapolated from 4 seconds to 1 lap or what.

You should only be interested in rollout. A good way to find out would be to ask someone who runs well at your track and start with that as a baseline. Try going up and down from there and see whether you get faster or slower for a 4 minute run. Use the rollout that is netting you the fastest runs.

It is a 104 ft runline......

if you don't know roll out = tire diameter*3.14*pin/spur....
2.2*3.14*31/116=1.85
2.2*3.14*35/116=2.08

im sorry its 104foot drive line. When i asked a person at our track i get diffrent number. I get 1.7 i get 1.8 , 2.0, 1.5 and so on. I was just woundering what a good roll out is.

Taylor

Hey bud the rollout has a lot of variables that make it difficult to dictate over the internet.Driving style,handling in the corners,motor condition,track condition to name a few.If I were you I would try to get more practice time(I was practicing my 13.5 car tonight).

Btw roolout is the inches traveled per revolution of the motor. Also a torque based motor will have a different rollout than an rpm based motor.(more variables)

For example if you are using a higher rpm stock motor you will want a smaller rollout number to let the motor work in its power band.If your car is not handling well in the corner it sometimes helps to run less rollout.

Hope that helps, I'll be at Pete's tomorrow night if you need more help.

Alex

Thanks Alicks

hi l4oval a old friend always told me, you have to go slow to go fast. gear low
if roll out is 1.80 go to 1.70 you gain more corn speed you have rollover