Hey, what do you guys use for speedometer correction with larger tires? I just bought a 1997 Dakota. It's a 2WD truck with a 3" body lift and 32x11.50R15 tires. It doesn't look too bad. The original tires were 215/75R15. It has the original axle ratio (as far as I know), 3.55:1. I think 4x4 Dakotas were available with 31x10.50s with this same axle ratio. My questions are two:

1) Can I use the speedometer gears meant for a 4x4 truck with 3.55 gears and 31x10.50 tires in my 2WD truck? I assume the tailshaft of the transmission is different to accomodate the transfer case, but I'm thinking that the VSS would at least be the same. Also, do all trucks use the same drive gear in the transmission, and change just the driven gear for the different speedometer calibrations? I know this set up wouldn't get be exactly on, in terms of exact calibration, but it'd be much closer than what I have now.

2) Would I be better off to buy one of the electronic boxes for speedometer calibration? Is there a particular one that you guys have used, and know works?

Again, this is a '97 model with the 44RE transmission. Thanks.

 

I just use my superchips to correct my tire size, or you can go to the dealer and they will reprogram it for you.

 

moe in wichita ks

get in touch with these guys. i have known them from the 60 s they are honest. 90% of ALL trans shops get parts from a & reds. they will know the answer to any question.

 

The dealer can actually re-program the PCM to account for a non-stock tire size? Or they'd at least be able to fix it so that it thinks the truck has 31x10.50s?

How does it work with your chip? Are you able to program a correction ratio (like -20%),or do you plug in before/after tire sizes, etc?

Thanks much for the help.