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Old 02-15-2016, 11:03 AM   #1
Tectoniic
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Upsizing to 18s, Speedo changes

I know there is a ton of info on this but I'm not sure why this is so hard for me understand....

I'm looking to get a pair of summer wheels/tires and I would prefer an 18x8 wheel. I am trying to find tires that will make that as close as possible to the diameter of the stock wheels on the stock tires for the speedometer's sake. It looks like 225/40/18 is about the closest I can get. I would love to step up to a 235/40/18 purely for the look of it and for better grip with FI in the future but it seems to make the speedo variance too high as tire rack recommends not going over 3% difference with a 1% difference being ideal.

http://www.1010tires.com/Tools/Tire-...5R17/225-40R18

http://www.1010tires.com/Tools/Tire-...5R17/235-40R18

On the calculator it shows that my speed variance is 1.87% too slow for the 225 and 3.08% too slow for 235.

Stupid questions:

This means that my actual speed is 1.87% and 3.08% faster than what the speedo shows right?

The confusing part is both of the tire setups I am looking at have an overall larger diameter than stock which I thought would cause me to actually be slightly slower?

Would you recommend 225 or 235 in this case? Rubbing/scraping on stock suspension/height?

EDIT: Pilot super sports are the same price in 225 and 235 so that is not a factor.
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