perfect FD offset for 18x9.5 F/R?
 

would a +45 work?

or 9.5 +45 on rear and 8.5 +40 on front?

I was running 18x9.5 +50 SSR GT2s all around with 265/35r18 Kumho MXs. Suspension was Konii Yellows set on middle height and RSR race springs, and I had no issues whatsoever, didnt even have front fenders rolled at the time. I would think the +45 should work but I would roll the fenders to be safe.

I think it depends on wheel design to decide what is perfect for the fd. Of course there is a ball park figure, but then when you say perfect you mean flush right?

I am running 9.5 +45 all around no problems...

9.5 + 30

How high is your car from ground to top of the front fender?? 24in? 25? or higher?

I believe it was 23, not sure though and cant measure right now since the car is on jackstands....

Here you go guys. Work with me thru my thought process. It'll be fun.

"Remember that your 9.5" ideal offset will be determine by your tire size."

The THOUGHT PROCESS: begins.

For all intensive purposes people run a 18x10.0 +50 with a 285/30/18 all the time on basically stock fenders without any problems. From a front spacing aspect a 18x9.5 +45 is the same as the 10 +50. Therefore one would assume that a 285/30/18 on the 9.5 +45 would work the same. Unfortunately it's not always so. You're basically chopping a half inch off the back of the wheel, therefore pushing the centerline of the tire towards the direction of your fender. Hope that makes sense to y'all. Now for the rest.

Once you determine the size of tire you want to run you can look into the OD of that tire and determine your ground to fender clearance variable. Always take into account suspension travel under agressive loads to preserve your fenders.

You'll find these average OD's per tire size: These will vary between tire models but are good averages to work with.

Stock:
225/50/16 = 25"

--- Not Stock-------
285/30/18 = 24.8"

255/35/18 = 25.0"
295/30/18 = 25.0"

265/35/18 = 25.3"

You can do some interpolations and come up with a good ground clearance height based on the amount of suspension travel and alignment settings you have. The ideal tire sizes based on stock tire diamter are the 255/35/18mandn 295/30/18.

The 285/30/18 is more commonly found because that's about all the room you have with stock fenders are appropriate 10" offset wheels.

Now most tire manufacturers do not recommend a 285/30/18 on a 9.5" wide wheel. That doesn't mean it doesn't work as it's commonly seen, but it might mean that the tire will not work optimally. If you decide to run a 18x9.5 with a 285/30/18 you should look at the tire manufacturer specs to see if they endorse the fitment. Most do not, there are a few that do.

To answer the question with stock fenders the ideal offset would be a +50. If you mod your front fenders a little you should be able to do a +45 all day. Unmodded fenders without coilovers might require a 26.00" ride height. Most people want to run a ride height of about 25" to 25.5".

If you run a 265/35/18 and a 25.5" ride height i think that would be the money.

Now for guys would will really do a little bit of work and not worry about the appearance of the car can run the 10.5" +45 and 295/30/18. That would be a really great track setup.

for the staggered guy I would definitely do something like this:

18x9.0 +45 with 255/35/18
18x10.5 +45 with 295/30/18

Ok that's my info plug for tonight. Hope this helps put things in one place for reference. Even for myself. hehe.

Oh and remember the statements above are approximations made by me. In no way are they written in stone. There are tires out there you can run 285/30/18 9.5" +45 wheels on stock fenders and probably have no problems.

Please rely on your fellow board members like Kai above who is likely running that setup or other guys with real experience and ask them what tire brand and model they are running without problems.

Peace, Rishie

There is no way you can get those rims and tires to fit at that height. I am currently running 18x8.5+40 offset up front and it measures 23.25 from ground to fender with a 225/40/18, and they are slightly in the wheel well. I recently purchased 18x9.5+45 offset for all four corners with 275/35/18, they stick out about 7.5mm more then my current setup(front) so I will have to raise the car to accomadate. I figure 25in from ground to the fender should work, this will be my track set of wheels and will work perfect for rotating.


Hope this helps others out.

I am still waiting for my wheels from Rishie, bump for a good dealer.

For a 3rd gen the 275/35/18 is going to be way tooo tall of a tire.

You need to remain in a 255/35/18 or a 265/35/18 diameter. THe wheel well arch will not allow for the 275/35/18 on all four corners. I can't remember what we spoke about on the phone now Paul, but i would not have advised the 275/35/18 for the front.

Rishie

285/30/18 = 24.8"

So would you say I could go with this size on all four corners?

ARD T2 is this the same rishie who started out with Sean who had a road race protoge or something like that? If so whats up my freind bought rims when you first started out 98 neon and we put 18 on it when they really shouldnt have fit lol.

That is me. However Sean joined the company a few years after I had started it. WE setup Sean's MP3 for SoloII autox just to have fun, not to compete. You must have met us in the San Jose location. THat was our first commercial location, prior to that we were strictly mail order and online consultation.

Nice to hear from you.

Rishie

Paul, I'd say that the 285/30/18 would be the best route to go if you pick a tire that recommends this size on a 9.5" wide wheel. You might also need to roll your front fenders ever so slightly. You should be able to run a ride height of 25".

I think the 265/35/18 would actually be a better fitment without needing to roll fenders if you ran a ride height of about 25.5".

Rishie

I will be running either Hoosiers or Kumho 710's, I will have to find out who makes the best tire size to suit my application.

My experience with a 265/35-18 (Mich. PS2's) on a 18X9.5 +50 at 25.25" height (front): Fit great. The outside edge of the tire will rub the front of the wheel liner when turning. Eventially put 255/35-18 on the front and it will still rub slightly, but only on full lock turns.

I looked into running 255/35 front and 285/30 back (same rim all corners) but didn't find a tire manufacturer that made a 255/35-18 AND a 285/30-18 for a 9.5" rim. Currently have 265/35-18 rear.

For a track setup the 285/30/18 all around is perfect. On the street it will be darty, follow every/all crack and imperfection in the road.

The minimum rim width I believe is an 18x10 for this size tire. I'm running an 18x10.5 up front on this tire which works as well. You need to roll the front fender lips big time.

The 275/35/18 as suggested is way too tall to run up front. Out back it is fine.. I actually run this on my street tires (18x10 out back) and 18x9 with 255/35/18's up front. Gram Light 57Pro rims.

If you can have 2 sets of rims that is optimal. One set for the street and one set for the track with dedicated track DOT or true slicks.