Tire size and speedometer error

Ok, So on my Jeep JK I could program the computer to adjust the speedo for different tire sizes. I know that that Taco cant be reprogrammed to do this? So what does everybody do to adjust the speedo to read correctly....or do you do nothing and just accept the speed error.

Thanks
Patrick

 

In most cases, moving up one tire size actually corrects the speedometer to read accurately, and makes the odometer read a little slow.

 

Very Good,

Thanks.

 

You can calibrate it and correct it perfectly using a Dakota Digital signal generator.

 

That's correct!

STOCK: 265/70-16 when my speedo showed 68 mph, my GPS showed 65.

NOW: 265/75-16 (1" taller tire), both speedo and GPS are the same!

 

I have the Hypertech In-Line calibrator in my 2010 and it works fine.. It can be programmed for tires and gears..

 

My speedo was off 3-4 at highway speeds. Its correct now with 265/75/16 on.

 

assuming these trucks are all calibrated the same, anyone know the best tire size for accurate reading with the 4x2 17" trd sport setup?
I have those radar speed signs in my area but havent used one yet to tell my speed. Another way I do it is timing and watching my speed over a known mile or half mile, but thats not as accurate.

 

I just use my GPS and cruise control. According to my GPS at 70 mph when I run my stock 245/75/16 Dungflops I'm going 2 mph slower than my speedo says & when I put on the 255/85/16 BFG KM2s I'm going 4 mph faster than the speedo says.

Those came with 265/65/17s so move up to 265/70/17s and your speedo should be correct.