Celica Forums General Discussion General Wheel diameter n ODO speedo calibration?

So from the dealership you can get a Celica with 15, 16, and in the case of some of the special editions 18 inch wheels;

I know this must have an effect on odometer and speedometer calibration. What kind of adjustments do they make at the dealership to compensate for this?

I'm very interested in the responses you get for this. My speedometer is all f-ed up. I have 17's, which started the problem. Now, the speedometer reads 12% too fast. If it says I'm doing 70, I'm really only going 62. I even paid to have it calibrated, but the dude said there was no way to correct it to read right since the car is so new. I'm with you though, Toyota has to know how to correct it, but I don't want to pay a dealer to do it.

Short of getting a custom speedometer, I haven't heard of any way to fix it.

there was a link in ecelica about this it was a calculator that converted from the rim and tire size from before an after swapping shoes.

i know someone in here has the link... ... just wait...

oh yeah you can alway "ghetto" fix it by riding beside your boy while his driving beside you telling when he gets to a certain speed talking on the cell and you can recalibrating your speedometer like that


^^^ sorry about the run oon sentence. i'm drunk

Yeah I've seen the calculators:

http://www.paspeedo.com/calculator.htm

https://celicahobby.com/tech/speedcalc.html

But there must be a way that Toyota re-calibrates the computer on the special editions that have 18 inch wheels.

Another one of their guarded trade secrets I guess.

http://www.toyota.com/motorsports/spotlight/widebody.html

It's not only the wheel diameter that hurts the speedometer, but the "overall wheel+tire" diameter that hurts it. If you keep the overall diameter close to the stock size, there will be ver little effect on speedometer. For example stock GTS 205/50/16 has a diameter of 24.07 inches. With 215/40/17, new diameter will be 23.77 inches. Speedo error is only 0.75 mph when you are driving at 60 mph.

TIRES.COM [discounttiredirect.com]

They tell you what tire to run to keep the odometer close to OEM...you can order tires them...and they're pretty cheap, too.