# A few questions about tires and wheels



## marden64 (Dec 1, 2013)

When you get a new set of wheels and are a different size from the stock ones, 16" to 18" does the speedometer show a different speed?? I heard someplace that it will show that you're going slower than you actually are. Looking at getting a new set, either DAI or Konig.

I noticed that a lot of people on here run a higher tire pressure then what's listed on the door. Wouldn't this contribute to a abnormal tire wear??


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## PanJet (Jun 18, 2013)

It's not so much the wheels that make the difference but the tires.

If you go from 16" wheels to 17" wheels, if you get the right tires there will be no (or very minimal) change in the actual circumference of your rolling surface. This is why the larger wheels have smaller tire sidewalls as more of the diameter is wheel.

The measurements of the tire are a formatted in an XXX/XXRXX pattern with the first three digits being the width of the tread in millimeters, the second pair of digits the height of the sidewall as a percentage of the tread width, and the final pair of digits being the rim size. For example, the stock wheels on a 1LT are 215/60-16 meaning the tread width is 215mm, the sidewall is 60% of 215 mm (approx 129 mm), and the wheel size is 16". The stock 18" wheels on the LTZ are 225/45-18; a much narrower sidewall (approx 101 mm).

Discount Tire has a nice calculator on their website that shows how close in size various tires are. Tire Dimensions Made Simple - Discount Tire

In the case above, there is only a 0.46 mph difference in speed between the two sizes of tires at 65 mph, which is negligible, although I believe the computer can be reprogrammed for different size wheels if needed.


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## marden64 (Dec 1, 2013)

Thanks PanJet


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## marden64 (Dec 1, 2013)

What about the TPMS. Will I need to buy new parts or can the factory ones be used?? Is there any problems in bypassing that all together??


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## Patman (May 7, 2011)

If you remove the TPMS from the wheels, you will have a light on on your dash. You should be able to take the TPMS from your stock wheels and have them installed on your new wheels or just buy another set of sensors. They are not that expensive A place called PartsGeek or Amazon has them @ $40 ea. Do a Google search on them. Depends on how often you will be changing the wheels as to whether you want a second set or not.


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## marden64 (Dec 1, 2013)

Thanks Pat. I was thinking of changing them in the late fall to the factory rims with winters on them and the new ones in the spring with the new rim.


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