U7137 Tire Size

[Black05Hemi]

How come the tuner won't save the tire size info when entering 275/60/17, but it will save it when I enter 29"? My speedometer is off, because my actual tire height is 28.75", which cannot be entered...It's either 28.5" or 29"

Thanks

[johan]

Well the tire size in the pcm is just a number, we have no way of determining the actual tire size from that one value, we can calculate the tire height from that value but not the tire size.
So whenever you go into tire size we will display a default value.

[whitehemi]

David I used the actual measurements in inches and the speedometer is right on.

[need-a-cage]

You can adjust tire size in the quick adjust menu right?

If you adjust the size, does the LTFT get cleared when you update it or does the quick adjust leave the LTFT alone and NOT do a full reflash?

I want to adjust it at the track when I put some tiny drag radials on it but I don't want it to reset the LTFT.

Thanks

[mikel]

Tire size will not reset the trims.

[Black05Hemi]

Lonnie, the measurment in inches is 28.75, which cannot be set with the Predator...It's either 28.5 or 29

[DiabloFan]

1/4" increments would be nice. My choices seem to be 3mph over or 3 mph under.

[mikel]

.5" should not equate to 3 MPH by any means....should be less than 1 MPH.

[whitehemi]

Lonnie, the measurment in inches is 28.75, which cannot be set with the Predator...It's either 28.5 or 29

Then either get 29 in tires. LOL Or set it to 29 in and be fine..... lol

My tires are 31.5in and I set mine to 31in I just check the speedo on one of those traps, it was right on....