Tire Size / Recalibration Input Wanted

[Heart2]

I want to replace the 255s on my BB (when it gets here) with 275s. Is there a minimum size difference that requires recalibration? The 255R75/17s are practically the same diameter as the 275R70/17s (1/10 of an inch bigger). At 65mph, the difference is only .2 mph faster. I have never swapped tires on previous vehicles, so I really don't know what the standard is (if there is one).

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[Coloradonatives]

That is a minuscule difference- I certainly would not pay for a recalibration. It can be done if, and when, the time comes for other changes need to be made.

 

[babraunagel]

I want to replace the 255s on my BB (when it gets here) with 275s. Is there a minimum size difference that requires recalibration? The 255R75/17s are practically the same diameter as the 275R70/17s (1/10 of an inch bigger). At 65mph, the difference is only .2 mph faster. I have never swapped tires on previous vehicles, so I really don't know what the standard is (if there is one).

Yep, that's a pretty small difference. You can make the change yourself using the free FORscan software if you want.

 

[BudgetBronco]

I agree, not worth reprogramming for a less than 1% change. That is probably within the +/- accuracy of the speedo to accurately measure speed.

A 5% change might be worth it

A 10% change, yes I would use Forscan and make the update

 

[Steve62]

I want to replace the 255s on my BB (when it gets here) with 275s. Is there a minimum size difference that requires recalibration? The 255R75/17s are practically the same diameter as the 275R70/17s (1/10 of an inch bigger). At 65mph, the difference is only .2 mph faster. I have never swapped tires on previous vehicles, so I really don't know what the standard is (if there is one).

The attached link will give you an idea of how tire changes affect calibrations. It's pretty interesting. For example I have a BB too and am thinking about adding Sasquatch rims with 35" tires. According to the speed calibration window on this link, if I didn't recalibrate and my speedometer still thought I was using 32" tires, when it registered 60mph, i'd actually be going 64mph. The odometer would be off too.


https://tiresize.com/calculator/

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