I have 18" wheels and in order to keep away from competition tires, I am limited to either a 27" tall or a 26.14" tall tire in the rear. Any preference to which one you would go with? One is a bit taller and the other a bit shorter than the manufacturer suggested (although both are a good bit shorter than I believe the original used).
Rear tire size opinion.
- Thread starter darrinps
- Start date
I hear you. Was wanting to go wider but to do so would mean going shorter as I'd need to drop the aspect ratio.
It was either the 285/40/18 = 27" or the 295/35/18 = 26.14"
I believe that comes out at 25.66 which is a bit shorter than I typically see by about 3/4". Hmm...I guess that's only 3/8" on top and on bottom so not too much of a difference. The way I calculate it that would be a sidewall height of about 4.3285".
My options would have a side wall of:
285/40 sidewall = 4.5
295/35 sidewall = 4.05
So yours would be in the middle of those two. If you get a chance, could you post a side photo of your car's back end please? I'd like to see how it looks. I agree with too low a profile tire looking odd but I sure would like to run the wider rubber too.
I used a 295/50/15 on the rear of my CAV, which is roughly a 26.6 rear....thought that roughly 27 inch wheel filled the well nicely and looked fairly original. Soft ride with the 50 series tire obviously.....
i use 315/45r17 rear
245/45r17 front but i changed to 225/45r17 front because of clearance problem.
245/45r17 front but i changed to 225/45r17 front because of clearance problem.
Howard Jones
Supporter
I have 245.40.17 on the front 8X17 wheels and 315.35.17 on 10.5x17 rears. Perfect fit and good grip, pretty easy to get good front to rear balance on track.
Not many tires left that will match these two sizes. If I was buying a set now I would get
http://www.tirerack.com/tires/tires...44WR7EXS&vehicleSearch=false&fromCompare1=yes
Not many tires left that will match these two sizes. If I was buying a set now I would get
http://www.tirerack.com/tires/tires...44WR7EXS&vehicleSearch=false&fromCompare1=yes
Wow, thanks for all of the replies guys!
OK, so it seems we have a:
Short size of 315/35/17 = 25.7"
Tall size of 315/45/17 = 28.2"
That's quite a bit of difference.
My manufacturer and I think CAV and ERA suggest about 26.6 or so. Looks like the 295/35/18 on the short end all the way up to a 295/40/18 (Falken Axzenis comes in that size) on the tall size will be well in between the extremes that people are running and working well with.
OK, so it seems we have a:
Short size of 315/35/17 = 25.7"
Tall size of 315/45/17 = 28.2"
That's quite a bit of difference.
My manufacturer and I think CAV and ERA suggest about 26.6 or so. Looks like the 295/35/18 on the short end all the way up to a 295/40/18 (Falken Axzenis comes in that size) on the tall size will be well in between the extremes that people are running and working well with.
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Howard Jones
Supporter
Howard Jones
Supporter
I think you PM'ed me about tire size. On my car, a GTD standard rear body width, I can't fit anything taller than 24.6 inches tall and 8.8 wide on the front. At least with the wheels I have on the car.
At the rear the 315.35.17s are 25.7 tall and 11.5 wide. I would handle another 3/4 inch wider and maybe a inch taller but the balance of the car would need to be completely retuned without changing the front tire width.
The performance is very sensitive to ride height. raising the car up a inch to get wider tires under it would make it slower IMHO. I run mine at 3.75 at the front and 4.25 at the rear. That's as low as I can go with the setup I have and not bottom it at several places at a couple of track I go to.
I do intend to return the car to a pure streetcar this year and will raise it up a 1/2 inch or so at both ends. 4.25 and 4.75.
At the rear the 315.35.17s are 25.7 tall and 11.5 wide. I would handle another 3/4 inch wider and maybe a inch taller but the balance of the car would need to be completely retuned without changing the front tire width.
The performance is very sensitive to ride height. raising the car up a inch to get wider tires under it would make it slower IMHO. I run mine at 3.75 at the front and 4.25 at the rear. That's as low as I can go with the setup I have and not bottom it at several places at a couple of track I go to.
I do intend to return the car to a pure streetcar this year and will raise it up a 1/2 inch or so at both ends. 4.25 and 4.75.
That 24.6" tall up front worries me as the shortest tire I see available for my wheels is 25.39. So, that's .395" per "side" difference. Hopefully that won't be an issue. I'll order in a 235/40/18 and verify as soon as I make sure the rears are good. In reality though, even if the 235/40/18 is a bit too tall, that's the shortest one I can go with without going to a different brand of tire as my wheel is too wide for a 225 (and I really don't want to go that narrow anyway).
Sounds like my 305/35/18 rear should be no problem though. I have a tire coming in today and my wheels should be in Friday or so. I'll mount it and test it out and if all goes well I'll order another.
Thanks!
Sounds like my 305/35/18 rear should be no problem though. I have a tire coming in today and my wheels should be in Friday or so. I'll mount it and test it out and if all goes well I'll order another.
Thanks!
Howard Jones
Supporter
You may not have a problem. Each manufacture's car will be different in many ways. The spot where my car limits tire diameter may and surely will be much different than other types. Unless you have a GTD, you didn't say what kind of car you have.
The way to check this is to remove the spring/shock and put the tire back on. Place the jack so that it does not interfere with tire movement lock to lock and up and down. This is usually at the center of the nose on a cross chassis tube.
Return the car to normal ride height on the jack, with the tire/wheel on and spring/shock off.
Now turn the steering wheel lock to lock and raise and lower the car with the jack to simulate full suspension movement up and down and full left and right turns. If it doesn't rub you are good to go.
The way to check this is to remove the spring/shock and put the tire back on. Place the jack so that it does not interfere with tire movement lock to lock and up and down. This is usually at the center of the nose on a cross chassis tube.
Return the car to normal ride height on the jack, with the tire/wheel on and spring/shock off.
Now turn the steering wheel lock to lock and raise and lower the car with the jack to simulate full suspension movement up and down and full left and right turns. If it doesn't rub you are good to go.
I didn't have any problem at all with the 235 and I think the 245 will fit and actually look better with my wheels (9.5" wide). Probably just get two of those in and try to sell the 235 one I mounted. I am ordering a shorter rotor hat though to set them in 3/4" as they do sit out a bit too wide. Not sure why I originally got such a tall hat but glad I did now as this is an easy adjustment.
Thanks for your help.
Thanks for your help.
