Hey all, I just received my ProFlash Programmer in the mail yesterday...I'm having a problem and I thought somebody with it might be able to help...I bought it because I bought a new set of larger wheels and tires. I measured the wheel & tire combo from bottom to top as it said in the manual and entered that number. However when I drove it instead of the speedometer reading a little high, the speedometer read WAY high...

Is there some sort of ratio you have to use for comparing the stock wheels to the new wheels? My new wheel measured at 31.5" whereas I believe according to the ProFlash, the stock setting is set to something in the high 20's (which I know is wrong)? Can anybody help?

Thanks!

Hey all, I just received my ProFlash Programmer in the mail yesterday...I'm having a problem and I thought somebody with it might be able to help...I bought it because I bought a new set of larger wheels and tires. I measured the wheel & tire combo from bottom to top as it said in the manual and entered that number. However when I drove it instead of the speedometer reading a little high, the speedometer read WAY high...

Is there some sort of ratio you have to use for comparing the stock wheels to the new wheels? My new wheel measured at 31.5" whereas I believe according to the ProFlash, the stock setting is set to something in the high 20's (which I know is wrong)? Can anybody help?

Thanks!

Hey all, I just received my ProFlash Programmer in the mail yesterday...I'm having a problem and I thought somebody with it might be able to help...I bought it because I bought a new set of larger wheels and tires. I measured the wheel & tire combo from bottom to top as it said in the manual and entered that number. However when I drove it instead of the speedometer reading a little high, the speedometer read WAY high...

Is there some sort of ratio you have to use for comparing the stock wheels to the new wheels? My new wheel measured at 31.5" whereas I believe according to the ProFlash, the stock setting is set to something in the high 20's (which I know is wrong)? Can anybody help?

Thanks!

Hello,

We've discussed the Proflash programmer instructions before. Although they say to measure top to bottom to get tire height, that measurement is dependent on tire pressure and tread height (and probably other variables that my feeble mind can't envision!). Make a mark on your tire at the 6:00 position and a the ground (level ground) and roll your vehicle through one complete tire revolution and mark the groung again at the completed revolution. Now measure the distance between the two ground points (this equals the circumference of your tire). C=2 x pi x R and D (tire height)=2 x R.
Pi is roughly 3.1416.

Hope this helps.

Thanks, I will give that a try. If I did that with the stock tires it should come out to be whatever the "stock" setting on the programmer is, right? Hopefully they won't be off too much else I will have to start guessing till I can get it right.

Anybody else with other ideas?

Thanks!

When it asked you to input the axle ratio, what did you input? You should have entered 4:10. If you entered another ratio, maybe this is the problem.

Yea that could definitely be it...I think I just skipped right over the gear ratio because I figured it just left the stock setting in there if I didn't change it. I wrote S&P and asked them the same thing and the gear ratio was the first thing they suggested to me as well. So I bet you I am wrong wrong wrong. Thanks for the help though, much appreciated!

Just wanted to let everybody know that it was indeed the gear ratio...no wonder I was only going 50 when it said I was going 90, I had the ratio set to something like 2.73 as opposed to 4.10...doh!

Thanks again for the advice...