Installed 18's car sits high now - 986 Forum - The Community for Porsche Boxster & Cayman Owners

mioprimo · 07-30-2010, 03:06 PM

I put some Victor Turismo 18 inch rims on my 07 Boxster and now I feel like I am ridding very high. Also would like to lower the car some for better look. Is there any adjustments than can be made? Thanks Marty

Overdrive · 07-30-2010, 03:58 PM

Did you keep the overall diameter of the wheel and tire consistent with what was there with the original equipment? Having gone up a size you'll end up with tires with shorter sidewalls if you're keeping dimensions consistent.

This has probably been seen/used before by some people, but here's a little item that'll give you an idea of what I mean.

http://www.miata.net/garage/tirecalc.html

Put in your original tires' diemnsions and those of your new tires to see not only visually and numerically the difference but also how much % off your speedometer would be.

I'm just thinking that, if you're feeling physically higher up, as opposed to the car just looking kinda high due to the wheel change, that maybe you might not have gone with the right tire size. If you did go with what's supposed to be on the 18s from the factory, though (235/40-18 Front and 265/40-18 Rear), then the difference should be absolutely minimal (the new size is actually very slightly shorter in height).

I'm also assuming you went from a 17 to an 18, and not the other way around...

mioprimo · 07-30-2010, 05:26 PM

OD, I did go with the factory size 18's up from. 17's. The Victor Equipment tires are made just for Porsche. It's much easier to get into the car now so I know I am riding higher. I can send a picture if you like? M

husker boxster · 07-30-2010, 06:11 PM

I notice a difference in ride height when I go from my std 19s down to my 18" snows, so you're probably correct about riding higher when going from 17s to 18s. The 18s you now have should fill out the wheel opening better. Is it that big of a deal? It's not like you put a set of 22s on.

ekam · 07-30-2010, 06:49 PM

It's an optical illusion since the thicker tires on the 17"s hide the wheel gap better than 18"s.

blue2000s · 07-30-2010, 06:56 PM

Quote:

Originally Posted by husker boxster

I notice a difference in ride height when I go from my std 19s down to my 18" snows, so you're probably correct about riding higher when going from 17s to 18s. The 18s you now have should fill out the wheel opening better. Is it that big of a deal? It's not like you put a set of 22s on.

The rolling diameter should be the same when going to a plus sized wheel/tire. Lower profile tire side walls deflect less at the road at a given air pressure. So if you are doing it right, the larger tires should have a slightly smaller sized diameter. This makes them the same rolling diameter. So the larger profile wheel and tire combo should actually fill in the wheel well less than the smaller wheel.

It's probable that if the car is riding higher, the tires are the wrong size.

mioprimo · 07-30-2010, 07:20 PM

Looks pretty good I just need to get used to the new ride/feel. Fronts are 235/40's and rears are 265/40's.

Overdrive · 08-03-2010, 05:54 AM

Yes, it does look pretty good.

Just can't figure out that whole thing of you "feeling" higher, especially on spec tires....

tommy986 · 08-03-2010, 09:12 AM

OEM sizes are :
225/40-18 front
265/35-18 rear

The tires you put on are slightly taller.
The fronts are about 1/3 inch taller.
the rears by about 1 inch

ekam · 08-03-2010, 09:27 AM

Quote:

Originally Posted by tommy986

OEM sizes are :
225/40-18 front
265/35-18 rear

The tires you put on are slightly taller.
The fronts are about 1/3 inch taller.
the rears by about 1 inch

No these are 986 sizes... 987 tires are taller.

tommy986 · 08-03-2010, 09:34 AM

oops. sorry. disregard my post.

blue2000s · 08-03-2010, 09:37 AM

I assume the car had 17s originally? What size were they?

jmatta · 08-04-2010, 02:23 PM

All US cars come with an "off road" ride height mandated by the DOT. You would do yourself a favor to install a set of ROW or aftermarket springs to bring the height down. I dropped my '02 986 S by around 1.5" with H&R sport springs running 18s.

Quickurt · 08-04-2010, 02:36 PM

Those are stock size 987 - 18" tires.

Geez, I hope you don't drop a 3/4" socket on your garage floor!!! I've never seen expansion joints like that before!!

jaykay · 08-04-2010, 03:35 PM

Quote:

Originally Posted by jmatta

All US cars come with an "off road" ride height mandated by the DOT. You would do yourself a favor to install a set of ROW or aftermarket springs to bring the height down. I dropped my '02 986 S by around 1.5" with H&R sport springs running 18s.

Are you eating tires yet.....or were you able to keep the toe in within spec?