Sam Khoury

I was just wondering if 245/45R18 tires on 18x9 will fit in the front wheel well of my 2002 GS300. I'm getting those wheels that I posted in another thread and the paperwork inside the wheels says that the largest tire size is 245/45R18. I'm leaning towards 245/40R18 but I'd like as much sidewall height as I can get since I'll be driving in NYC a lot and I don' t have to tell you how smooth the streets are. I spoke to Tirerack and the guy I spoke to saw something in their database about that tire size rubbing on the GS. I don't want to modify the wheel well or flare the fenders.

GS4Will

too tall..asking for suspension problem in the future.

jeffandi

I get confused. How is a 245/45/18 on an 18" wheel too tall and a 245/35/20 on a 20" wheel ok? By my calculations, they are about the same:

245(mm) * 2 * 0.45(aspect ratio) * 1(inch) / 25.4(mm) + 18(in) =

26.7(in) diameter

245(mm) * 2 * 0.35(aspect ratio) * 1(inch) / 25.4(mm) + 20(in) =

26.75(in) diameter

Just wondering. Is something wrong with my math?

Jeff

GS4Will

Jeff..

your math is correct...

with 20s, the tyre sizes/selections are limited to 245/35/20. yes, it is ~1" taller than 25.5-25.75" that we are looking for, stock wise. the 1" translates to over 3% difference.

with 18s, there are more choices, and 245/40 would be a better one. not sure about 245/45/18's selections. but manaray and i have mentioned here on the same idea for 245/40/19. it would work, just not ideal. i read one guy could not fine one(if any) good 245/35/19 tyre.

without sounding contradicting "catch 22", i have seen too tall tyres resulted in suspension problem, and tireack's guide lines also make the limit at 3%, so i usually like to stay close to stock as possible. heck, i plan to run 19s in the near future, and would like more side walls. BUT, to look good, there are things you need to give up, and i am not just talking about the $$$.

jeffandi

Will,

Yeah, I hear you. Right now I'm thinking about 19's with the oversized aspect ratio for several reasons. First is to keep my ride at it's current comfort/harshness level. Right now I have 245/40/18 front and 275/35/18 in back. I figure if I go with 19's and keep the same aspect ratio as the 18's, hopefully my ride comfort won't suffer. I have the Bilstein PSS and don't want to get any harsher than that. Second is to close the fender gap without lowering my car any furthur. Actually, the oversized 19's shouls add a 1/2 inch to my ride height so I might get a Greddy front lip spoiler.

Damn you Club Lexus.....Mods are all I think about now.....

Jeff

Sam Khoury

Thanks guys. I'm going with Michelin Pilot Sport All Season 245/40R18 all the way around so that I can stay below the recommended maximum tire size for the wheels.

Jeff, I'm in the same boat. I'm only thinking about what I can do to my car.

SoCalSC4

The 245/45-18 will indeed work on an 18x9 if you use the correct offset- a +37 to +42 is about all the range you'll have.

If you hit a pothole hard enough to twang a wheel with a 245/40-18, most likely a 245/45-18 wouldn't save you. The lower aspect ratio tires have more reinforcement in the sidewalls than the higher profile tires. This makes for a slightly stiffer ride, but helps protect the wheels from impact damage.

Anopther thing nobody brought up: the change in gearing by going to a 1" taller tire. Off-the-line accelleration will suffer slightly, not the end of the world.

I'd go 245/40-18... the 245/45-18s will look like "buffalo tires."