Hi -- I just bought a 2000 Ford Ranger XLT Supercab V6 4.0L 4x4 Off Road from Oregon and am getting ready to register it here in California. The previous owner put on very nice larger wheels and tires -- they are P255/70R18 (as opposed to the stock 16s). My question is: Do the larger tires/wheels affect the speedometer/odometer?

I feel like I'm going faster than the speedometer says. I took it into the dealer for another computer issue this morning (the airbag light was on, and since it was a safety issue everybody said the dealer was the only place). And I asked about the speedometer/odometer. They referrred me to a speedometer specialist -- they also said that when I get the truck inspected at the DMV it may not pass if the speedometer isn't properly calibrated.

The truck is new for me, so I'm only starting to get familiar with it. And I saw on the Ford Trucks forum that some speedometers/odometers are connected to the transmission rotation, whereas others are connected to the wheels. The transmission on this vehicle is stock. So could I be imagining having a problem I don't have?

I don't want to get hosed by a specialty speedometer place that will charge me $200 just to "inspect" something that doesn't need to be inspected. Can somebody give me guidance on what to do and where to go to get this looked at and/or adjusted for a reasonable price?

Thanks!
-maya

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