Attempted Speedo fix for 315's gone awry

[SHyans]

Today I took my truck in and got the reflash for fuel mileage increase and also asked them to adjust my speedo for the 315's.

When they are done, the svc guy says my speedo adjustment was already done. Huh?!

Took it back to my diesel guy to reinstall my Juice and he double checks speedo fix and concurs... . Speedo fix already done. Huh?

I never had anyone do this fix before. I know Tire guy didn't do it.

What's up? Only thing I've done is input my tire size specs into the Juice for the speedo alert feature. Could that have done something to make it appear as if it was adjusted already. Don't think so.

What the hell is going on? I was hoping to get some increases on MPG with my hand calc readings with the speedo fix alone.

 

[bpenrod]

Did he (service guy) tell you what the setting was (is?)??

 

[SHyans]

Did he (service guy) tell you what the setting was (is?)??

No. I figured that with all my rantings about my poor mpg, and them telling me it's cuz of the bigger tires, they'd be paying attention to that and make sure the setting was correct.

If they did check but the setting was wrong, I'd expect a blunder from the dealer, but not from my diesel shop.

 

[BHolm]

Have you checked with a GPS to see if the speedo is right? That would be the first thing I did. Then you need to get a revs/mile number for the tires you have. If they are BFG's you can get the revs/mile number off thier website. This is the number that needs to be used when calibrating the speedo. I'm not sure how the dealer could have made a change without you giving them the correct number. Did they just guess? I'd bet the speedo is off. Show up with the number and watch them do it. It only takes 2 minutes.