Anyway to re-calibrate Speedo? 2010 T&C
 

So about 6 months ago I had brand new tires put on my wifes van. 3 months ago we were using a Garmin GPS that displays speed and we realized the speed on the garmin was far less then the van showed (72 on van is actually 65) and my wife then told me she had been feeling like traffic was zipping by her. Turns out the tires that were put on the van are the wrong size. 225/55/17 instead of 225/65/17. Long store short the guy who put the tires on is a good friend, actually one of my best friends and he made a mistake on the tire size. He says the problem is fixable with a "starscan" dodge/chrysler computer but ive had no luck getting anyone to preform the fix. The dealerships just tell me to buy the right size tires, ive called a few nationwide tire shops, no luck.

Anyone have any ideas BESIDES buy the right size tires? These tires cost me like $800 and I just dont have that kind of money to buy another set. And every-time we drive the van were racking up miles against our extended service plan.

Incase it helps at all im located in St Louis Missouri.


Thanks!

Well if it comes to the crunch and you can't get your speedo re-calibrated you only need to buy tyres for the front wheels.

If it were me (and I don't like wasting money either) I'd make up a little conversion chart and put it close to the speedo, and make key speeds like 30mph, 70mph, etc. a little bigger. Even I can't think of a trick/dodge/wangle to accommodate over-size tyres and that effect on the speedo.

Leedsman.

Called around today and got a local Dealership to fix the problem. I got a appointment next week. He said they will flash the computer and change the tire size. I guess its not that weird of a thing to do as he said its common in trucks/cars, no idea why other dealers would tell me there is no fix. Not so much in vans and hes not 100% sure my tire size will be available as they wont know until they get it hooked up.

We know its off by 4-5mph in the 60-70 indicated range so a conversion chart is a good idea but not needed. My main concern is the fact were racking up miles were not actually using and its eating away our warranty. Hopefully ill be able to report back in a week that the issue has been resolved.

Thanks for the advice/info!

Thanks for the feedback. Let us know if the dealer is able to change the settings.

I can't think why you were told by a dealer that it was impossible to reset the all electronic digital speedo either, because on first principles, it's just a matter of counting pulses into a register, then a small program to convert. Having alternatives in the program will be dead easy for the original programmer. As your man said, it will be a common requirement for many road vehicles, esp. a big manufacturer like Chrysler. Lets hope your program has suitable alternatives already installed for the tyre size you've bought. After all, the Windows operating systems seem to already have just about every driver there has ever been produced for any peripheral you could possibly buy, so that approach will have almost certainly percolated down to the simple programs for vehicles.

Leedsman.

Hi, KidHauler! If the dealer isn't able to help, try your local Autozone, or better still look up custom wheel and tire shops in your area. These guys are dealing with larger wheel/tire combo's all the time so should be able to recalibrate your speedo easily and cheaply!