Recalibrating Speedometer after Getting Bigger Tires - Toyota Tundra Forums : Tundra Solutions Forum

laxwyo · #1 (**permalink**) 06-29-2006, 01:15 AM

Since all you guys have helped me choose which type of lift I'll be getting for my Tundra, what happens after I get bigger tires? What will I have to do or how do I go about getting the speedometer calibrated to the new tire size? I've heard a lot about programers where you can change shift points and tire sizes etc. What's everyone's take on this?

T100driver · #2 (**permalink**) 06-29-2006, 01:18 AM

Did you do a search on this? Their should be some old posts on this topic already.

yspert · #3 (**permalink**) 06-29-2006, 10:47 AM

you can not calibrate the speedo. yspert

IStan · #4 (**permalink**) 06-29-2006, 11:56 AM

Quote:

Originally Posted by yspert

you can not calibrate the speedo. yspert

??

TruSpeed?

01 Tundra · #5 (**permalink**) 06-29-2006, 02:10 PM

Use a GPS to determine actual speed.

student's tundra · #6 (**permalink**) 06-29-2006, 02:33 PM

Quote:

Originally Posted by IStan

??

TruSpeed?

And it didn't take very long either

.

mustang67408 · #7 (**permalink**) 06-29-2006, 03:44 PM

The TRUSPEED speedo recalibrator will recalibrate and send the proper signal to the speedohead. You can double check it and fine tune its accuracy with a hand held GPS.

Mine has been in for a long time and it works flawlessly.

laxwyo · #8 (**permalink**) 07-02-2006, 05:35 PM

Shouldn't a guy be able to plug in new tire circumference compared to the old one and get a recal? If your wheel turns one rotation and your vehicle moves forward a known distance based on the circ. of the tire, couldn't the new circ. be used?

Mr. Creosote · #9 (**permalink**) 07-02-2006, 05:59 PM

That is an indirect calibration. A small compromise is made versus the GPS / chassis dyno method because an indirect calibration assumes the original calibration was correct to begin with.

cupidstoy · #10 (**permalink**) 07-02-2006, 06:59 PM

my oem speedo w/ oem tires is off 1-2 mph at 70 mph. using an average of mile markers vs. time method as well as local radar guns set up at construction sites. it actually reads a bit higher then actual speed. not enough to make a difference and probably within the accuracy of the dial hash marks on the dash speedometer.

when i can afford it, the truspeed would probably be what i would get since i run winter tires of a different size and i believe it allows you to switch between two different calibrations for different tire and wheel setups.

4x4ROCKSHOP.com - (877) 4x4-ROCK

fwiw, the manufacturer claims accuracies of within 1% which is about what the tundra speedometer is capable of anyway.

inquiring minds want to know....