ok im about to buy gears. i need some advise. right now my stock tire is 31.4 inches tall and i have 3.23 gears. the tires im looking at buying are 29 inches tall and i race on 28 inch drag slicks. my truck does see the highway quite a bit. im trying to decide between 3.73s or 4.10s. i dont plan on FI anytime soon. so what do you guys think?

 

I would just do the 4.10s. I can see your hesitation though, with tires that small. I always jump at least 2 ratios. 3.42==>4.10 3.23==>3.73 It's really a tough call.

 

This is what RPM you will be pushing cruising in 4th on the highway
29in tire
3.23 @ 65mph = 1703 rpm
3.73 @ 65mph = 1966 rpm
4.10 @ 65mph = 2161 rpm

31.4 tire
3.23 @ 65mph = 1573 rpm
3.73 @ 65mph = 1816 rpm
4.10 @ 65mph = 1996 rpm


Since you are droping tire size and different ratio I think you should go with 3.73 with a 29in tire or 4.10 with a 31.4 tire. that would keep you in the 1800-2000rpm range for best MPG.

I hope that helps. if you want to try other ratio's and tire size check out this link.

http://www.richmondgear.com/101032.html

 

3.90s are always an option too, but i would go with 4.10s

 

i have 410s right now with a 30" tire and cruise at 70mph at 2200rpms and get decent mileage

for racing i wouldgo steep gears. im having issue now with only crossing the traps at 5700rpms in 3rd with a 28" slick

 

I have 4.10's with 275/50/17 Nittos (27.8") and do about 2250 at 65mph.

 

well thanks for the advise. i just ordered 3.73s for the truck. i figured with those and the shorter tires that will be just fine. i found a calculator and with the smaller 29 inch tall tires and the 3.73s my final ratio will be 4.03. that will work for me.