tire size help...
 

what is the tire size for the stock 2004 rx8 rims???:banghead:

225/45/18 is stock. Most people go 245/40/18 when they change their tires though.. I'll probably be going that.

y do people change the tires? what is the difference? I am a new rx8 owner, so im new to all of this stuff. Last car was a maxima.

Wider tires (245 vs. 225) give the car more grip on the road and, ostensibly, better handling.

will the tires fit on the stock rims? or would i have to buy a new set?

245's will fit fine on the OEM 18 x 8 rims. I have 245 Blizzaks on mine for the winter.

funny you say that diesel. im a new 8 owner as well and my last car was a maxima :mdrmed:

colnago, Would you recommend the 245's over going stock width?

I'm not Colnago, but I would recommend the 245's over the 225's. I currently run 275's. Not that they are needed, but I really like the way the look and the overall cost difference is not that much.

a 245/40R18 mounted on a stock 18x8 wheel will have a marginally larger contact patch than the stock size 225/45R18 mounted on the same 18x8 wheel.

The extra contact patch of the 245 isn't fully utilized on the 8" wheel since you generally want the wheel width to equal the tire contact area. A 8" wheel is 203.2 mm wide, where a typical 245/40R18 tire will have a 220 mm wide contact patch.

Is a 245/40 on a 8" wheel better than a 225/45 on a 8" wheel? Short answer is yes, but only marginally. Would a 245/40 on a 8.5" or 9" be better from an all out grip standpoint?.....yes.

R U running 275/35s on all 4 tires - do they wear quicker in the center or rub the fenders?

Yes, I have them on all four corners. The wear is even all the way around. I run 39 PSI on all of them and there is no rubbing at all. Keep in mind that there are no suspension modifications on my car either. If your car has been lowered it may rub the fronts for sure. The back seems like it would be really close. I have close to 25k on these, so I'm getting ready to replace them in the next 5. I will be going back with the same setup.

You might want to add what wheels you are on (width and offset). I hope you are not running 275/35 on stock 8" wide wheels.

They are stock wheels. I have been running them for years with no problem. The next set I buy will be my third. If there is some theoretical reason why they won't fit or they might fail, I think it's been pretty much debunked.

Just because something is possible, doesn't make it a good idea or a benefit.

There are people who run SCCA Solo stock class that mount a 285 slick on the stock 8", and see benefits....but that isn't what you are doing is it?

What 275 section tires are they? Are they R compound racing tires with extremely stiff sidewalls? If they aren't, then you are not getting anymore contact patch than if you were running a 225 or 245. Your turn in response will also suffer as the sidewalls are not properly supported. A 275 needs a 9" wheel minimum, preferably a 9.5".

Is your car going to explode by running a 275 on a 8" wheel..........of course not, but you aren't actually achieving any benefit by having it there. You are actually hurting your performance more than helping.

Lol, Wow you really missed the part where I said "Not that they are needed, but I really like the way the look and the overall cost difference is not that much."

Do you think I am not aware of that BS you just wrote and has been posted on just about every car forum across the internet? The guy asked me a question, I answered him. The fact is they fit, and they fit fine on the stock rim. So what if I get a little crappier fuel economy or I have past the point of diminishing returns as far as traction is concerned. My car handles fine and has given me zero problems. Furthermore it's not like I suggested he run out and buy 275's Bottom line here is that if you choose not to run that size tire on an 8 inch rim, then don't. If others want to take your advice and not run them that's fine as well. I happen to be satisfied with my setup and as it turns out, that's all that matters. Why is that? Oh yea, it's my car.

sorry if you took offense to my questioning, but it seemed to me that you were suggesting that others also run a 275 on a 8" wheel......in which I disagree with as stated above.

I did not take offense to your statements. I was taken aback by those statements when I made it clear that my setup was purely for aesthetics. I disagree with people putting 22, 24 and 26 inch rims on their cars, but I don't shove it down their throat about how stupid it looks (to me). There may be some adverse effects of doing that as well, but that's not the point. If everyone agreed with me, that would be awesome, but as it turns out they don't, oh well. I guess I'll just have to deal with it.

Different sized tyres
 

I have 225/45 on my fronts and then 245/45 on the rears. Is this ok? Or is could this be the reason my DSC light keeps coming on? Also they are all different loads and speeds.

It's ok for the car. But it will upset your handling to have a staggered setup. And yes, that is why your light keeps coming up. It's trying to get 2 different readings.
My advice is to go same width and hight all around.

question!!
 

So i just bought 18x9.5 +22 wheels. what would your guys advice for tire size be? 245/40? I'm also lowered on coils! thanks

So would a 225/40/18 tyre be a suitable replacement for the 225/45/18 standard??

No. It depends on a specific tire brands specs, but generally;

The overall diameter of the 225/40-18 is 25.1


The overall diameter of the 225/45-18 is 25.9

In general, keep the overall diameter of the new tires within 3% of the OEM tires.