I see a lot of posts about people who have stepped up the size of their tires and am just wondering if anyone has gone as far as calibrating their spedometer to reflect the new tire size? Can any tire shop do this? Is it expensive? Thanks in advance. I am a relative noob and have found this forum extremely informative.

 

Tacoma Speedometer & Instrument sold me an adapter for my mechanical speedometer. I doubt that a tire shop is equipped to handle recalibration.

 

I ran a mechanical converter on my '85 for a while. It was about $90 as I recall. I know run the proper gears for the tire size and the stock reading is close enough. You could try Dakota Digital, they may a programmable calibration box for electronic VSS type speedos.

 

For what it is worth...

I went up almost 2" in tire size from my originals, and was concerned about accurate readings on my speedo.

I am a member of AAA. They often have a roving speedometer check station that will show up at various locations and give free speedo check. Well, I waited in line and my truck went through. They measured my speedo at within regular limits. The biggest variation was 2.5 mph @ 40. Measured at 5 mph intervals it was around 2 mph off from 30-45 mph. From 50-75mph there was less than a 1mph difference between the reading and actual speed.

Testing was free and it is nice to know where you stand.
I love the Auto Club!

 

Depending on the year of your vehicle you will either have a speedo gear or it will be electronically controlled. I have a 2003 Tacoma and mine is electronic. No speedo shop will be able to correct this type. I installed a Dakota Digital device to reset my speedo and checked it with a GPS unit. Now its dead on after my gear change and my upgrade in tire size.