pdpgps

iTrader: (1)

Hello all,

I recently acquired 18" f-sport wheels for my 2011 is250 AWD. These are the wheels that match the AWD systems. My question is does lexus reprogram the car computer to recognize 18" wheels when customers upgrade to f-sports?

Stock tire- 225/45/17
Fsport tire - 225/35/18

Online calculators tell me I'll be going "3%" faster because of the shorter tire. What tire sizes have you all gone with?

-Chris

gridlock13

iTrader: (1)

hey chris, the recommended tire size for 18x8 wheels is 225/40/18. there's no reprogramming to speed sensors when you switch wheels. the only reprogramming you'll have to do is to your TPMS sensors. have you tried this website to calculate tire sizes?

http://www.rimsntires.com/specs.jsp

GOTORacing

iTrader: (5)

gridlock13 is right. 225/40/18 is the tire size that best matches the original 17" wheels and tires. This will result in a very minimal change in overall diameter and will only result in .46% difference from stock.

Sango

iTrader: (10)

The Lexus vehicle does not have the ability to to reprogram the speed sensors.

The engineers at Lexus at programmed it such that the spedometer will always report accurate speed or above but never below your actual speed, assuming the proper tires are used.

This is what it would be.

pdpgps

iTrader: (1)

Thanks for the responses guys. It would seem that even with a 3% too fast difference, the changes in MPH are still within the acceptable range.

20 mph / 20.0 to 23.0 mph (new value 20.6mph)

40 mph / 40.0 to 43.5 mph (new value 41.2mph)

60 mph / 60.0 to 64.0 mph (new value 61.8mph)

80 mph / 80.0 to 84.5 mph (new value 82.4mph)

100 mph / 100.0 to 105.0 mph (new value 103.0mph)

120 mph / 120.0 to 125.5 mph

140 mph / 140.0 to 146.0 mph

160 mph / 160.0 to 166.5 mph

Sango

iTrader: (10)

Did you actually mean 225/40/18? This is because this would be the correct size equivalent. Then from 17" to 18", it will be 0.5% slower and 60mph (from 17") would be 60.3 mph (18").

pdpgps

iTrader: (1)

I did mean 225/35/18. The guy that sold me his f-sport wheels paired that tire set with the wheels.

I can either get a whole new set of tires or deal with what's on there.

Sango

iTrader: (10)

Oh I see. I thought it was acquired brand new and you were looking for tires and asking the question.

Hmm in that case, yeah probably do not want to spoil the tires which are on there and wait for them to wear off before getting the proper sized tire.