prosport

iTrader: (21)

I've searched through threads on our 2 cars but numbers are all over the place. We are gonna race at an indoor dirt track with alot of jumps.

AE B4.2 with 84/20 (4.20)gearing

Losi xxx-cr with 81/19 (4.26) gearing

Both cars run Speed Passion Reventon-R esc and SP 10.5R MMM motors.

Thanks for any advice, just want to make sure we're in the ballpark.

ThePanda

iTrader: (68)

I would go more with a 3.4-3.6 ratio on just the spur to pinion.

prosport

iTrader: (21)

Ok thanks will pick up a couple pinion gears tomorrow.

prosport

iTrader: (21)

I found a new 75t spur gear which would have helped but the pinion gear wouldn't reach it to mesh. Looks like I'll stick with the 84 and buy pinions.

thecman26

iTrader: (112)

With a 10.5 I would gear it to the track to give you enough torque to clear the jumps. But would also make sure it doesn't get too hot also.

prosport

iTrader: (21)

So a smaller pinion will give me more torque for clearing jumps and a bigger pinion will give me more speed and possibly more heat, correct?

RacerX11

iTrader: (6)

Talk to the local racers to see what they are running. That should help you get into the ball park for the track as far as gearing goes.

prosport

iTrader: (21)

Will do

thecman26

iTrader: (112)

Yup! Exactly!
No need to keep gearing it up just to make it fast on the straight and not being able to clear the jumps. Odds on your not going to overheat a 10.5 unless your track has a 150' long straight...

prosport

iTrader: (21)

You guys were correct, we were geared perfect for our track, cleared jumps nicely and more than enough straight away speed.