SCT, Tire Size & Speedo Adjustments?

**robertcarmel** · #1 (**permalink**) 04-13-2009, 06:52 AM

There is a place for Tire size selection in the SCT. If you enter other than stock does the computer make adjustments to the speedometer for the difference in diameter?

**Dave** · #2 (**permalink**) 04-13-2009, 07:01 AM

It just adjusts the tire size for shifting. Doesnt do anything for the speedo

**robertcarmel** · #3 (**permalink**) 04-13-2009, 07:10 AM

I thought so, but I wasn't sure

Davey~do · #4 (**permalink**) 04-13-2009, 08:58 AM

Quote:

Originally Posted by robertcarmel

There is a place for Tire size selection in the SCT. If you enter other than stock does the computer make adjustments to the speedometer for the difference in diameter?

Seems pretty obvious that it would have this ability, but, for whatever reason it doesn't

**colberjs** · #5 (**permalink**) 04-13-2009, 09:27 AM

Quote:

Originally Posted by Dave

It just adjusts the tire size for shifting. Doesnt do anything for the speedo

Really? I thought for sure it adjusted the speedo. How do you do that?

**stroken04** · #6 (**permalink**) 04-13-2009, 09:30 AM

You need a "truspeed" (I think thats what its called) to adjust the speedo

**Dave** · #7 (**permalink**) 04-13-2009, 09:31 AM

Quote:

Originally Posted by stroken04

You need a "truspeed" (I think thats what its called) to adjust the speedo

You need a superlift truspeed, Auto engineuity, The TS Respeed. Or ford can flash it for up to 35s

Davey~do · #8 (**permalink**) 04-13-2009, 09:39 AM

Quote:

Originally Posted by Dave

You need a superlift truspeed, Auto engineuity, The TS Respeed. Or ford can flash it for up to 35s

The dealership can flash it, but when I asked about it before I bought my X3 (thinking I could adjust the speedo with that

) they could not (or would not) guarantee the accuracy. Nor would they reflash till it was correct without charging for any subsequent reflashes. So be aware of that.

**Rob** · #9 (**permalink**) 04-13-2009, 09:40 AM

Is it only the X3 that has the tire size adjustment option? I have the Xcal2 and haven't seen that option. Can it be written into the tune?? I know on DJ's tunes I can adjust my shift points but on erics I can not.

**Dave** · #10 (**permalink**) 04-13-2009, 09:43 AM

Quote:

Originally Posted by Rwalker

Is it only the X3 that has the tire size adjustment option? I have the Xcal2 and haven't seen that option. Can it be written into the tune?? I know on DJ's tunes I can adjust my shift points but on erics I can not.

Rob the Xcal 2 has it. When you go to custom tune it. When it asks to change additional parameters say yes. Then what you are looking for is revs per mile

Use this tire calculator to figure your revs per mile Tire Size Calculator

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