What size will i need?
 

As you guys know i go myself a set of GXP wheels for my car but now i need to know what size rubber i will need to prechase for them because i know from my old test fit i did last year the stock GXP tire size is to tall and would through off my speedo. So what do i need?

my current tires; 225/60R16
GXP tire size; 235/50R18

I would also like to know what tires you guys would recomend, I am a very aggressive driver and i like to drive fast (never hit my limiter but i would like to (128mph))

your speedo will be off no matter what.

how do you figure?, as long as i get a tire thats total hight is the same as my current size (low profile tire) it would be fine

but with the fact that you are going from a 16" to a 18", you might be able to get a tire with a small enough side wall, but i dont know if i would. remember what happened to handdrummans rims?

Plus it would make ride=shit.

if you use the tires you listed Pete....your speedo will read 60 mph when you are actually traveling 61.4 mph

those were just for referance so you know what sizes are on both factory rim, i need to know what size tire i will need to get accurate readings on the speedo, i know the number i put there wouldnt be what i needed :roll:

your NEVER GOING TO GET IT PERFECT, the stock GXP size will be as close as is possible, the gxp will only be off by 3.28% which is very low, and as your tires wear they are in a constant state of change, a brand new tire will read a couple % off of what a bald tire will read on the speedo.

Also, differnt manufacturers of tires will make a difference, a dunlop 225/60/16 may be 1/4inch different diameter than a michelin 225/60/16

ok..... if you go with a

225/50/18 you speedo will be .5 slower
235/50/15 your speedo will read 1.4 mph slower


that is the closest you can get....i would not recommend the 225 tho because they will not look right on the rim....a 1.4 mph is nothing to be worried about

OK.....I'm running 225/45/18, and u could go a bit taller and
i would suggest too because of my rim issues!!

Ya i dont want that, i saw how much is sucked for you and how easy it happend, i will see if i can maybe get a tire with a slightly stiffer side wall (maybe a runflat?) and they will also have to have the curb protector (extra rubber sticking out to help agains curb rash)

according to what I found the gxp stock size is only 1/100 of an inch shorter than the tires you are currently running so they should fit. This linl may help u

http://www.csgnetwork.com/tireinfo4calc.html

Edit just typ in both sizes and bam staight across comparison :D

keep in mind that these cars usually read about 1mph or 2mph FAST anyway. Both my cars read 75 when it is 73 . verified with a GPS. HUD was only 1mph faster.

For those who haven't seen what happned to my rims.....

Attachment 66583

Both drivers side front & rear..... :evil:

i dont follow why did that happen

Well if u were reading the topic (j/k) we were discussing tire sizes on "18's and know that either peter needs to go w/a harder sidewall or taller sidewall so when he hits a "car sized pothole" above doen't happen to his!!