Adjust Speedo for tire change?

[nm50]

How do you adjust for speedo error due to tire size change? Can this be done with the Superchips tuner?

Thanks!

[trhland]

what size tire are you thinking of?

[nm50]

I was thinking of 265/75-16. I assume these will fit the stock rims.

[trhland]

what tire did it come with?

[nm50]

I thought it was a 245/75-16. Now I am unsure. This is the stock size that Discount Tire lists for the truck.

[trhland]

thats real small are you sure?they useally put 265s on stock f250s which is like a 30 inch tire.check it out for sure and let me know

[fordnut85]

HERE is a really good article on how to recalibrate it.

[trhland]

that only works on older trucks

[nm50]

Maybe a better question is how big can you reasonably go on the stock aluminum wheels?

[trhland]

my truck came with 275/70/r18s and i upgraded to a 285/70/r18 and i didnt bother with adjusting the speedo it may be off by like 1 .if you have a 16 inch rim you could go pretty big . if i was you i would go with a 305 tire its like a 33 inch. real nice size not to big . i couldnt go with that because they dont make them for the 18 inch rim .but the 285s nice