Sorry for such a mundane question in the face of all of the expertise on this board.

On an '01 with the Allison, I swapped the original 245's in favor of a set of 285-16's. I'm surprised they're not rubbing on the front but since they're not, I'm going to leave well enough alone there. I only want to correct the speedometer. What are my options?

The Predator will do it, but I have heard that the 01 speedo can't
be corrected. You might want to check your speedo accuracy with the
285s. I swapped the 245 for 275 and when I checked the speedo it was
ok. Don't know why, but it is very close. Maybe try a search in the forums for 01 speedo correction.

I swapped my 245's for 265's. The speedo is right on with my radar detector, which gives you your speed based off of satellite. Go figure.

1st of all you will not chip it....so at least we got that straight....
;)

tts will fix the speedo on an 01

With 285s you should be off by roughly 7.5%. That means your speedo says 60mph and your really going very close to 65mph.
The Predator works for 03 but not 01? Anyway the Predator is alot of bang for the buck IMHO.

01's have a speed limiter problem. Not a speedo adjustment problem. Any tuner that has those capabilities should work. You just won't be able to raise or get rid of the limiter.

I have some wore out 285's and my '02 is doing 63mph, as per, GPS, when the speedo says it's doing 60mph.

Sam