Ford spedo calibration

[jbiersba]

I know i've read on this site before what the max tire size the ford factory computer is capable of being adjusted to, but I can't seem to find it.

Recently switched from he stock 33.3 inch tires to a set of 35's. It has affected my spedo a bit.

Truck is going in for service next tuesday, wondering if I should bother to ask the service guys to try and adjust the computer?

Thanks

[po-po 5.0]

I've been told 35 is the max a dealer can calibrate for.

[jbiersba]

that would work for me.

[Dusten]

yep, 35" is the max

[greasyF250]

Originally Posted by jbiersba

I know i've read on this site before what the max tire size the ford factory computer is capable of being adjusted to, but I can't seem to find it.

Recently switched from he stock 33.3 inch tires to a set of 35's. It has affected my spedo a bit.

Truck is going in for service next tuesday, wondering if I should bother to ask the service guys to try and adjust the computer?

Thanks

try this link Speedometer Calibration??? - Ford Truck Enthusiasts Forums It worked for my 95 f150

[Pahrump]

Originally Posted by greasyF250

try this link Speedometer Calibration??? - Ford Truck Enthusiasts Forums It worked for my 95 f150

Wont work on these 08...nothing will at the moment.

However as said above, I think the dealer can get it close for 35's...but thats it.

[jbiersba]

excellent, I go in Tuesday....
Venturi install, oil change, 30K maint., re-calibrate the spedo (hopefully), and apparently there is a software update available ( I had heard that it was suspended, but dealer says there is one available).

If unable to adjust the spedo, i'll post here.

Thanks

[Mercury]

Originally Posted by Pahrump

Wont work on these 08...nothing will at the moment.

However as said above, I think the dealer can get it close for 35's...but thats it.

I do not visit all the forums as often as I should, but yes there is a inline device that will work on the 08 F250, as a matter of fact there are many on F450's from 2008

as for programmers, i do not know of any, but for inline devices....

speed wizard by merlin controls I would think the truspeed would work as well but I hear people say no it don't....

kenny

[jbiersba]

update:

Picked up the truck yesterday afternoon. Turns out I had to pay 51 bucks and change (after tax) to have them re-calibrate the cpu to take into account the new tires.

Prior to the change, my speed was off by about 2.5 MPH at 60MPH (calculated by GPS). After the adjustment, I am still of by at least 1.5MPH or more. SO, in my opinion, his is very little improvement for my 50 bucks. Had I known that this adjustment would only bring my spedo 1MPH closer to being accurate, I probably wouldn't have spent the money.

For future reference here's the tech write-up indicating what the lower limit of the module is in our '08 vehicles:

26210 TIRE SIZE REPROGRAMMING PROGRAMMED TIRE RPM TO 596, THE LOWEST ALLOWABLE BY MODULE

For reference, my 35's say that the revs per mile is 593. Close, but no cigar

Jay

[Mercury]

Originally Posted by jbiersba

update:

Picked up the truck yesterday afternoon. Turns out I had to pay 51 bucks and change (after tax) to have them re-calibrate the cpu to take into account the new tires.

Prior to the change, my speed was off by about 2.5 MPH at 60MPH (calculated by GPS). After the adjustment, I am still of by at least 1.5MPH or more. SO, in my opinion, his is very little improvement for my 50 bucks. Had I known that this adjustment would only bring my spedo 1MPH closer to being accurate, I probably wouldn't have spent the money.

For future reference here's the tech write-up indicating what the lower limit of the module is in our '08 vehicles:

26210 TIRE SIZE REPROGRAMMING PROGRAMMED TIRE RPM TO 596, THE LOWEST ALLOWABLE BY MODULE

For reference, my 35's say that the revs per mile is 593. Close, but no cigar

Jay

I hate to see when people spend good hard earned money and do not get what they should in return...

Cant you fight the dealer to put it back to normal then?

have you tried an inline device?

kenny