jcmeister

Hey guys,
I'm looking into upgrading my stock wheels for 20s, probably going fatter with 9s on the width just to give that nice stance. (I've always been kind of bugged by the fact that the skinny stock wheels make the whole car look uneven.. kinda like that gym guy that skips leg day) Anyway, not the point... I was just wondering if anyone here has experienced an issue with discrepancies on actual speed than what the speedometer says because of the new wheel size. And if so, is there a significant difference? A coworker of mine told me a story that he got pulled over for going over the speed limit but believed he was safe because his speedometer said so...

Also, for those who upgraded wheels, what did you guys do with the stock? Sell them? Any recommended websites besides craigslist?

Torii

larger wheels will effect speedometer and odometer

http://auto.howstuffworks.com/car-dr...eedometer4.htm

jcmeister

Right... so I guess my next question is does Lexus or the wheel shop (wherever you get the wheels done) offer the calibration?

GoHuskers

...wait...Large wheels vs. Large rims are slightly different.

if you keep the OVERALL circumference the same then there is no ill effect. The car will not know whether or not you got new larger rims because it takes the same amount of rotations for the same distance. +/- 3% is still in safe zone.

Wider tires look better, handle better, and slightly less fuel efficient but you need to pay to play, right?

what are you thinking about the upgrade? My next tires will be 255/55/18 on stock rims.

oldwineguy

Use this and it should let you know how much you will be off on different size tires and wheels. After you put the tire and wheel size it, then you have to re-input the MPH to get it to show you the difference. My stock tires were 225/60-18 and I switched to 255/45-20, so when my speedometer shows 65 mph, I am actually going 65.9 mph, barely 1 mph over. Keeping the new size within +/- 3% is a good rule.

http://www.americastire.com/learn/tire-size-calculator

chezgk

I'm running 255/55 on 18x9.5, which is supposedly 1.6% larger in circumference than the original 225/60 tires, and my GPS speed is still lower than my speedometer speed.

d8168055

I use this tire calculator. It also is more detailed in showing the clearance of suspension components/fender. The values are my "best estimate" based on rulers and plumb lines for the NX. It's hard to measure some areas under the fenderwell, but again, I think its best estimate based on crude tools.

https://www.wheel-size.com/calc/?whe...cl=82mm&sr=0mm

GoHuskers

This is AWESOME. Thanks for posting the links.

So the NX 18" wheels are 7.5" Wide with 35 Offsets. Does anyone know the specs for the GX460 wheels?