Do you need to reprogram if you have a manual

[Happycoop]

I realize adding larger tires alters shift point on the automatic, but is there any need or benefit to having something like AEV pro cal if you’re running a manual transmission with larger tires?

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[SteveInOrlando]

I realize adding larger tires alters shift point on the automatic, but is there any need or benefit to having something like AEV pro cal if you’re running a manual transmission with larger tires?

other than having an accurate speedometer, probably not!

You control the shift points.

 

[Happycoop]

other than having an accurate speedometer, probably not!

You control the shift points.

Thanks! Just wanted to make sure I wasn’t missing something else computer-related in the ECM that would be altered.

 

[Toyfrog]

What about an 8 speed auto? Just went from 285 to 315’s on my Mojave. Took it in the Freeway and at 65 it was the same in Speedo and GPS. I was just wondering about shift points and MPG? Thanks

 

[SteveInOrlando]

What about an 8 speed auto? Just went from 285 to 315’s on my Mojave. Took it in the Freeway and at 65 it was the same in Speedo and GPS. I was just wondering about shift points and MPG? Thanks

I am an MT person, but from what I have read on this forum.

If you only change tire width, you should need to recalibrate.

Changing diameter will require you to recalibrate. The larger diameter will throw your shift points off causing you to be out of your power bands.

-- No I don't know how much of a difference in diameter is needed to require re-calibration, but I would think anything less than approximately an inch total diameter wouldn't make much of a difference

 

[Kevin_D]

-- No I don't know how much of a difference in diameter is needed to require re-calibration, but I would think anything less than approximately an inch total diameter wouldn't make much of a difference

It’s a ratio. If you go from 32” to 33”, your tire diameter changed 1/32, or ~3%, so your speedometer will be off the same ~3%. If you change from 32” to 35”, it’ll be more like 10%. And as you go to bigger tires, the speedometer will read slower than actual speed.

Kevin

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