Different tire size on an '09 GT?

[shemp]

I am due for some new skins, and wondering if anyone runs a different size than stock, and if so what are your thoughts.Stock size is 215/45R18. The guy at Discount tire says 235/40R18's are "approved" (I assume that means they have confirmed no clearance issues). I was considering changing to 225/45R18 which would be slightly larger diameter, but would only throw the speedo off by less than 1mph at 60mph which I can live with. I have always thougth the car rides way too stiff for it's sporting credentials (or lack thereof). These Michigan roads are pulverizing the poor car. I figured the larger diameter will provide a little extra sidewall, and soften the ride up a tad. As far as the tires themselves, I got 40K out of the stock Goodyears, which is pretty good. I was not a fan of the tires though, and I'm glad they are almost gone. The car is really loud on the freeway, and I'm hoping it's the tires. I'm considering Conti Extreme Contact DWS's or Yokohama YK580's as replacements. Your thoughts on those?Thanks in advance for your feedback.

[trb]

I just put some 235/40/18s on my 2010 several weeks ago. No issues with fitment except I notice the drivers side wheel does lightly rub the fender liner when I back out of my driveway and turn the wheel left. But I think it is because the fender liner is not 100% secure, the prior owner had some custom lighting on the car and they removed the fender liners to route the wiring. I need to put it up on a lift and fix them.The 225/45/18s look to be about 1/2" taller and of course slightly wider. That should be OK.No experience with either of those tires either. I went with Bridgestone Potenza RE760s based on my tire store friend's recommendation. He has them on 3 of his personal cars.And FWIW, I took the car on a 400 mile trip right after the new tires, and using my GPS, the speedo reads 3 mph fast at 60! The difference should only be about a 1/2 mph fast, but I don't know why it is off more.

[shemp]

Great feedback, thanks for the reply, trb. I'll have to look into the Potenza's.In my experience stock speedos are off a few mph, usually on the fast side. That's one of the reasons an extra 1mph off won't bother me.

[shemp]

BTW, do you have any pics of the 235's on your stock wheels? I'm curious how the extra width looks. Thanks!

[trb]

Not yet. I've been too busy to even wash the car since then! I'll take some tomorrow if the rain clears up, it is almost like a tropical storm here in Houston today! The Potenzas did very well in the wet, even through the curb deep flooding I hit going a bit too fast! Very little drag down as I hit the flooded areas of the road compared to my other cars & tires.Once I get the 17" wheels for my son's 06 Vibe, I'm mounting the 245/45/17 Potenzas from my Mustang on it. So far they've been good tires with over 20K miles on them, and they look to have a good 25K left. I think those are going to look great on it. I really like having a little meat that sticks out past the rim on my cars.

[shemp]

....so just to close out this post, I intended to be the guinnea-pig and try the 225/45R18 tires on my car, but that size of the tire I wanted was on a long backorder. Since winter is here, and my original skins were pretty bald, I couldn't wait for them, so I ended up going with the Continental Extreme Contact DWS in 235/40R18 size. I have to say that they look really good on the car. IMHO the stock donuts were a little narrow for the stock wheels. I was worried that these would be too wide. I wouldn't go much wider with this wheel width, but I think they look pretty good. I haven't noticed any rubbing at extreme wheel lock either, so they appear to clear everything.I am very happy with the tires. They are much quieter than the stockers, which should be expected for new tires compared to old, but a relief just the same. Those old tires were obnoxiously LOUD on the freeway. Hopefully when these wear down they do not get as loud as the factory shoes were.My one point of displeasure about the experience was that the installer appears to have used a die-grinder to remove the wheel weight tape residue, and in the process also removed a few square inches of paint off the inside of the wheel. With the large openings in these wheels, it is very noticable. The store is working on getting a few stock wheel replacements... we will see how that goes.

[trb]

Great to hear you got some and like them. I did take a pic of mine, just didn't get a chance to load it earlier, but here it is. I would like a bit more meat on mine if I could, but at least with these tires I don't have to worry about scraping the curb if I am slowly pulling into a parking place.Good luck with them!

Attached files

[shemp]

Those look pretty sweet, trb. I'll try to get a pic of mine next time I get the road-schmutz washed off my car. Thanks for the feedback!

[shemp]

Well it's winter here in Michigan, so it's impossible to keep the car clean, but here is a couple pics of the 235/40R18 Conti DWS's on stock wheels for anyone who might be wondering how they fit.

[vibenvy]

Quote, originally posted by shemp »Well it's winter here in Michigan, so it's impossible to keep the car clean, but here is a couple pics of the 235/40R18 Conti DWS's on stock wheels for anyone who might be wondering how they fit.Looks good !

[Kincaid]

I would have guessed that 10mm would have been more noticeable. Looks great!

[shemp]

I agree kincaid, and thanks. I was afraid 10mm would be too much and they might look stoopid, but IMHO they don't look bad. I don't think I would go any wider on this width rim though. Speaking of which, does anyone know how wide these stocker rims are?

[trb]

I believe they are 18x7 wheels.

[shemp]

Wow, that is narrow. I have been scoping out aftermarket wheels, and most 18" rims i have seen seem to be either 7.5" or 8" wide. Thanks trb.

[vibenvy]

Quote, originally posted by trb »I believe they are 18x7 wheels.They are indeed 18x7...

[shemp]

Thanks J! Does anyone happen to know the weight of the stockers?

[vibenvy]

Quote, originally posted by shemp »Thanks J!Any time !