i am going to try a 13.5 in a spec truck this weekend. we are using 4 cell 1600 spec packs. my tires are 2.440 caps and i need to know where to start my gearing. the track is 350ft concrete with 5 deg of banking. the gearing for a 21 turn spec motor is usually between 2.30-2.40.

thanks
john mc

more than 21t!

I really don't know what it's like to run on a track that size. BUT, you are going to be able to go pretty large on the rollout. I run 13.5 on tracks that are less than 120' runline and we run rollouts between 2.45 and 2.65.

our roll out with the spec motor is 3.2.

should i go higher?

Yeah, I think you could go considerably higher.

Again, having never ran on a track that big, I would not want to guess a rollout for you.

im going to try to start with 3.44

I have never run the 1600 spec packs, but my guess you'll gear it up until it dumps and then back off 1 tooth.

For perspective if I was running the 13.5 on your track with with 4200s I would probably start in the 4.10 neighborhood.