Would someone have to realign the suspension if the wheel/tire size is upgraded...


example, an evo is lowered with springs then aligned on the stock enkei wheel/tire. would you have to realign if you upgrade to 18" wheel and 245/40 tires?

 

No. but I think that your speedo will be off.

 

I think your alignment will be off by a slight amount when you switch tire sizes, but if it was in spec prior to the new tires I wouldn't worry about it. The most important to have corrected is toe. That will wear down tires fast, but I believe changing tire sizes will not affect toe at all.

BTW, the best match to stock size tire is a 235/40-18.

 

I believe if your alignment is within spec range, you wouldn't have a problem. If your camber is super aggressive when u aligned with the 17"s then you might have a slight problem with rubbing, same with toe settings. IF you leave toe to zero, you should be cool.

I would recommend everyone to get an alignment, even if your car is kinda new. Mine i sless than 10K miles and got an alignment using some specs I found here... -1.5 fronts, -1.0 rears, 0 toe and the car drives awesome! Most of the understeer is gone, and the steering feels quicker, even with the a/s winter tires and 17 x 7.5 rims. Can't wait for the track day and going back to the stock rims and Advans.

 

u really dont have to worry about it.. but its small insurance for those new tires to get an alinghment..

 

can u fix it so that it reads the right speeD?

 

Do you feel any difference with the way the car drives after the wheel change?

Because after I changed tires (same size as stock but a diff brand) I noticed that the steering felt loose and didn't track right. Just the same as when lowering the vehicle, and the wheels toe out, that same loose steering feel.

So I got it re-aligned to tighten up the feel and reset everything back to the way I had it before the tire change. So if you feel any difference in steering feel or response I would suggest getting another alignment.


alby988: you can get the speedometer recalibrated to correct it, but I wouldn't think that it would be worth it. Because for every tenth of an inch that your tires vary from stock, equals 3 tenths of a mile per hour difference in your speedometer.

So if your tires were larger or smaller by 1/2 in. than stock, that would equal 1.5mph difference in your speedometer reading.

 

thanks for the responses

 

your speedometer wont be off, it'll be different because it takes a longer distance to complete one revolution of the tire, so doing the same rpm with your 17's and with your 18's, the eighteens will be causing your car to move faster. As for the suspension, it could possibly have a unwanted camber, but nothing you couldnt check yourself man. you'll know if you need one as soon as you jump behind the wheel.

 

Wait... your saying the 18" wheel with a bigger rotational diameter, and probably mass, will cause your car to move faster than a 17" wheel with a smaller diameter and maybe mass? I don't think that's right.

 

This is a useful link to tell how much your speedometer will be off...
http://www.powerdog.com/tiresize.cgi
Enter two tire sizes you are comparing and hit the 'compute size' button.
i.e.:
235/45R17
235/40R18

Typically within 5% will be fairly negligible where you won't have to manually adjust your speedometer.