PontiacBonnevilleClub.com

I had posted a pic of these wheels once before, and I have been eyeballing them ever since...


A few night ago I noticed the price had come down on eBay and the listing included an "or best offer" button.
I offered a bid of $325 and the seller took it! I was floored really, but still pretty stoked about the deal. Now the issue is to decide on the proper tire size. The new wheels are 18x8.5, 38mm offset.
Am I correct that the stock size wheel/tire for the GXP was 18x8- 235/50R-18?

I did a little digging on bigwheels.net and came up with some size comparisons I've seen mentioned here.

stock size I have now,
235/55/17 - 690mm diameter

sizes I've seen listed here;
245/50/17 - 677mm
255/50/17 - 687mm
255/45/18 - 687mm (I was told to avoid these for low sidewall height)
235/50/18 - 692mm
245/50/18 - 702mm (I can get a set of these for a good price but I fear they are too tall)

i CANT wait to see those on the car...OMFG

top notch as always

Although I like the Sawblades your car has now, I think these will look good... Can't wait to see them mounted...

I'm concerned the 8.5 rim width may be too wide for the 235/50 tire. I dont want it to look like its riding on balloons!LOL

I had 245/45/18s on my GP on 18x9 wheels and those sidewalls were a bit bowed out, but that size tire is far too short for the Bonnie.

I'd probably go with 245/50's, but your speedometer will be off slightly. I'm gonna hold judgement on the wheels until you mount them.

Also in to see these on your car!! I think It'll look great

Bigwheels.net fitment guide says the 245/50s do not fit. I took a flashlight to the front wheel wells and the clearance between the tire and the strut spring pad is pretty darn close. I dont know if it will accept another 5mm of tire height. If it does, you'll be able to measure clearance with a feeler gauge! LOL

The set of 245/50s on eBay I was looking at is a bargain, but I'm chicken to buy them without being absolutely sure they will fit on the car.

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

paul (2000silverbullet) and Jim (Gumball) both run wider then stock tires, maybe one of them will chime in. I have seen wheels like that years ago on a bonne and I liked them. cant wait to see the finished product


EDIT: FWIW the gxp is an 18x8 wheel and it runs the 235 50 18s, that's also the size I run on my 18x7's

I'm guessing the 8.5 width is not going to work... thats a whole inch wider than stock.

Yeah, they may be too wide. It all depends on the offset and backspacing though.

I'll do a dry fit when I get them to be sure. The 18x9s I had on the GP were 38mm offset and posed no clearance problems, but they were right out even with the fender lip. as seen here with 1.0 lowering springs. the tires were 245/45/18



bigwheels.net lists 8.5 as the max width the Bonnie will accept, and they list quite a few wheels in 8 and 8.5 with 40-42mm offset. Hopefully the 38mm will buy the space I need without going outside the fender.

The wheels arrived today but since I had to work tonight they are still in the boxes. Hopefully weather will be decent tomorrow and I can do a dry-fit and get some measurements for clearance. Then I can determine which size tire to go with, and thanks to "wake" for the link to the tire calculator that gives some specific dimensions to work with.

I checked on a couple of other tire sites and the max recommended rim width for the 235/50/18 is 8.5in, so I should be able to fall back on that size if need be. I hoping the 245/50s will skate by but only the measuring tape will tell for sure.

Ghosthawk wrote:The wheels arrived today but since I had to work tonight they are still in the boxes. Hopefully weather will be decent tomorrow and I can do a dry-fit and get some measurements for clearance. Then I can determine which size tire to go with, and thanks to "wake" for the link to the tire calculator that gives some specific dimensions to work with.

I checked on a couple of other tire sites and the max recommended rim width for the 235/50/18 is 8.5in, so I should be able to fall back on that size if need be. I hoping the 245/50s will skate by but only the measuring tape will tell for sure.

I sure hope the rims and tire size you want fit. The tire size you want is what I would go with if I could. I love those rims! They look very similar to the CTS-V rims. Can't wait to see how they look on the 'Ghosthawk'!!! - BC

A spacer will probably solve quite a few problems. I rea

255/45 wont have crazy small sidewalls, they'll be VERY close to your stock size. Tire calculator says you'll speedo will read .5% fast. So you'll be slightly smaller than OEM (good with 255's) and have tons of rubber... A small spacer to get it away from the strut, and if you rub, some fender rolling..

On page one of this thread....

viewtopic.php?f=9&t=23385

ZLTFUL posted pics of his car with 255/45s and they look lost in the wheel wells. According to the measuring specs they are only 3mm shorter than my stock 235/55/17s, but it sure doesnt look that way in his posted pic!

Reminds me of the short set Harofreak had many years ago. I spotted his car at a pizza joint near campus one day after seeing photos but not IRL yet.

*dang* it looked bad.

I did the dry fit today and things are looking good

There are no clearance issues with the rim itself. I did a full lock-to-lock turn of the front wheels and there is no contact (of course after the tires are installed, but we'll see)

This image isnt the best with the car jacked and no tire, but I love the look already, and once my new rotors and painted calipers are in place they should show off nicely!


I really love the lip on the front side, and after some measuring, I think the 235/50/18 is going to have to be the tire of choice. I dont see any way the taller 245/50 will clear the spring pad.


The last shot shows the rim right at the fenderline, pretty much where the wheels were on my GP, and I like the "filled out" appearance once the tires are on. With 8.5 listed as the max recommended rim width for that size tire, I'm sure the sidewall will be either straight or slightly bowed out. Sounds good to me


I checked with my local tire dealer and the best price he can offer on the 235s is $700-800 installed. He told me it would be about $80 to install I set I buy myself, so I've been doing some eBay surfing and came across a brand called Milestar...anybody heard of these? They are distributed by Tireco in CA, but I've never seen them before.

Don't cheap out on tires... You're 95% of the way there, cheap tires will spoil ride, handling, acceleration and braking...

Bit of advice, stay away from the BFG G-force kdws line. I bought them with my then new wheels. that had to be the hardest to balance, worse riding tires I have ever owned. IF and when I buy new tires I will probably get Michelin Pilot sport a/s plus tires, a bit pricey but a pretty good tire