Reason I'm considering this is because I need MORE tire, especially with my blower. I was thinking about replacing my wheels with either a 16x8 or 17x8, but then had this crazy idea that maybe this 235/40/17 RA-1 would fit on my 17x7 OZ sls.
Just for comparison, the 235/40/17 RA-1 has the same width as a 245/45/16, plus its lighter and has slightly better gearing.
I dont know what the sidewall stiffness is like on the RA-1's. If they are anything like Hoosiers or Kumho R Comps, I would say go for it. But if they are anything like street tires(which I hear they are) having that little rim to support the treadwidth may make them pretty sloppy. Hard to say, I guess try it out and see how it feels. You will definetely be able to get them on the wheel, but it may not be optimal.
You considering some track time? The tires should fit though.
Yeah... my Corvette buddy has been trying to get me out to Willow Springs. I'm kind of nervous to tell you the truth. I had a bad dream that I totalled my car on a track
...having that little rim to support the treadwidth may make them pretty sloppy...
I'll check into the sidewall strength, but as far as the amount of sidewall... I've been running on 215/40/17's for several years without a problem. The 235/40's would give me more protection.
So get this everyone...
I contacted Toyo and asked them for an opinion. Of course, the guy answering the phone was the person I had to talk to, rather than transfering me to tech support. This makes me question his knowledge. But oh well, FWIW, he told me that the reason they don't recommend a smaller width rim (ie. 7" rim on a 235 tire) is because of slippage. I said what??? He said that Toyo's testing showed that the tires can actually slip around the rim (the rim spins, but the tire stays put). He mentioned nothing about the sidewall.
I've never heard of a tire slipping around the rim before
Here's some more information on slipping. Might be a different type of tire slippage. And it's about motorcycles.
What causes tire tread wear?
Tire wear is caused by what is called "slippage." Slippage is what happens when the tire is rubbed against the pavement instead of simply rolling along it. It can be thought of as skidding at a micro level. Whenever you accelerate your bike during a sprint you are causing small amounts of slippage. When you turn around corners you are causing small amounts of slippage. Also, braking causes slippage. The harder the accelerations and the more you weigh, the greater the amount of tire that is rubbed away during slippage. Front tires wear so much longer than rear tires because they have much less weight on them (one third of your weight is on the front; two thirds on the rear) and because the don't have the drivetrain connected to them like with the rear tire.
^^^ Thats talking about the tire sliding instead of rolling, i.e. burnout or locking up the brakes, not about the tire slipping on the wheel. I would highly doubt a 235/40-17 would slip on a 17x7 wheel, and amongst all the racers I have run with, especially autoxers that run obscenely wide tires on stock wheels(i.e. 225's on stock 6" wide Miata wheels), I have never heard of that before.
just to bring it up, make sure there won't be any rubbing from the wider tire. to my knowledge people have only successfully run 235 tires on 48mm offset rims. you might need to make sure the 235s won't rub on what I'm asuming is probably a 42mm offset rim (your 17x7s).
...and amongst all the racers I have run with, especially autoxers that run obscenely wide tires on stock wheels(i.e. 225's on stock 6" wide Miata wheels), I have never heard of that before.
Me too. Neither have any of my racer buddies heard of this wheel slippage issue. This is why I'm always so damn skeptical when it comes to advice. Sad to think that we can't even trust a manufacturer's rep.
just to bring it up, make sure there won't be any rubbing from the wider tire. to my knowledge people have only successfully run 235 tires on 48mm offset rims. you might need to make sure the 235s won't rub on what I'm asuming is probably a 42mm offset rim (your 17x7s).
OZ sls 17x7 I think are 45mm.... but based upon my current setup, I don't think rubbing will be an issue. I have no problem rolling fenders if I have to. Small price to pay imo. But thanks for the heads up.
I'm still considering getting wider wheels though. I just don't like to mess around. I want to find one set of wheels that will fit the tire I want to run, and be done with it, ya know.
by the by, if you want some used 235/40/17 ra-1's, go to www.bimmerworld.com and get their take offs from their swc challenge car.
50/tire or 100/tire, depending on condition, and probably better suited for shakedowns and test fitting than a new 170 ra-1 that also needs to be shaved and heat cycled.
their 50 dollar variety is probably good for a couple of hpde's. maybe 4 tops, depending on conditions. i think the 100 dollar ones should be perfect for a chronic de'er.
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