Speed Change

Hi everybody. I've finally joined the world of Chevy trucks. I had previously owned an '01 4x4 Blazer, but it just wasnt the same. Anywho, last night I bought my first truck, and first anything really, atleast on my own. Its a 2003 regular cab 4x4 with about 4 inches lift and bigger tires, but I'm not sure how much bigger. Now to my question. I know changing the size of tires can throw off the speedometer, but I don't know how much. Does anyone have a rough estimate on how much. I had heard mine will be off by as much as 10-15 mph, but that seems alittle outrageous. So, any help will be appreciated. And don't worry, I'll post a picture or two when I get a chance.

Phil D.

Welcome to a better world!!! I don't know exactly how much it changes it, but it can be easily recalibrated through the on-board computer (plug-in should be just under your dash just to the left of the steering column). You can either have the dealer reset it (and I don't have any idea what might cost), or a hand-held performance tuner, such as Hypertune can do it, or if you really jump on board, Mr. Nelson can do it with a lot of other neat stuff with one of his tunes. However it's done, it should be easy to correct. Also, the size of the tire should be on the side of the tire. Again.....Welcome aboard!!!
:thumbsup:

http://4wheeldrive.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.onlineconversion .com%2Fbigger_tires.htm

There's another one I believe on Tire Rack, but I couldn't find it.

In the Discount tire site they have a speed calculator also.

Here's another. I saved it in my favorites.

http://www.net-comber.com/tirecalc.html