pretty much wanna know what the title says, i mean for handling and traction wise, not looks/fitment wise. Thanks!

 

Neither. It's best to first choose the rim diameter you would like, to then choose the proper tire size for your car using that diameter wheel, and to then choose wheels that are the best width for that tire size (in the middle of the range of approved rim widths).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxtasy &raquo;</TD></TR><TR><TD CLASS="quote">Neither. It's best to first choose the rim diameter you would like, to then choose the proper tire size for your car using that diameter wheel, and to then choose wheels that are the best width for that tire size (in the middle of the range of approved rim widths).
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Couldn't agree more!

 

255 is perfect for a 9" wheel.

 

So what would be the overall best choice of the tire width for a 18x9.5" rim? And is running 235's on a 9.5" rim kinda bad for performance? i see a lot of people doing this running stretched tires, they do this so they fit into their fender wells, but are they loosing performance?

 

wider tire=larger contact patch=more grip

so to answer your question of losing performance, yes they are losing performance as opposed to using a wider tire. for some, there is no choice but to run a stretched tire for it to fit in the wheel well.
i personally ran 275/35/18 on an 18x9.5 rim. the sidewall and the wheel lined up evenly. going with a 235 might work but it will be pretty stretched. id say also that 255 would be your best bet.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aleks77 &raquo;</TD></TR><TR><TD CLASS="quote">So what would be the overall best choice of the tire width for a 18x9.5" rim?</TD></TR></TABLE>

Your decision process is all backwards.

What kind of car do you have (model, year, version)?

How do you plan to use it (everyday driving, track driving, dragstrip, autocross, car shows)?

What do you care about - performance? bling?

What diameter wheels do you want? (18" is NOT usually the best for performance.)

THEN you can decide the best tire size, and THEN the best wheel width.

The way you're trying to decide on the wheel size first, you are almost surely going to end up with a LOW performance solution.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aleks77 &raquo;</TD></TR><TR><TD CLASS="quote">And is running 235's on a 9.5" rim kinda bad for performance?</TD></TR></TABLE>

Probably - and especially if that's not the best tire size for your car.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aleks77 &raquo;</TD></TR><TR><TD CLASS="quote">i see a lot of people doing this running stretched tires, they do this so they fit into their fender wells, but are they loosing performance?</TD></TR></TABLE>

Yes, they usually are. But again, it depends on the kind of car and how they are using it.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by junkspeedproject &raquo;</TD></TR><TR><TD CLASS="quote">wider tire=larger contact patch=more grip</TD></TR></TABLE>

Wrong. As long as the tires are inflated normally to support the weight of the car, the size of the contact patch depends on the weight of the car and the air pressure in the tires. If you have a 2640-pound car with 33 pounds per square inch inflation in the tires, the size of the four contact patches is 80 square inches - and that is true regardless of whether the tires are 175 mm treadwidth skinnies or 235 mm steamrollers.

A wider tire has a different shape contact patch, wider side to side and narrower front to back. This may help slightly in cornering. However, if you have larger diameter tires, that usually hurts acceleration. So larger tires do not necessarily provide better performance; it all depends on what you're looking for.

 

well the car is gonna be my 91 accord, with custom bodywork to flare out the fenders to fit 9.5" rims with as wide as a 255 tire. And extended wheel studs. The car is gonna be an all around car, but will be taken to track days and auto-x events. Im doing it for show and performance, i dont care much about loosing acceleration, as long as i gain cornering.

Is it stupid to go with a 18x.9.5" and 255mm tire, am i gonna see any real cornering gains over lets say a 15x7" with a 215mm tire?

 

The biggest factor in performance and traction is the kind (make and model) of tire, much more so than the tread width.

Your car came from the factory with 185/70-14 tires, unless it's an EX, in which case it came with 195/60-15 tires. For street use, the best matching sizes for your car are 205/50-16 with 16" wheels, 205/45-17 with 17" wheels, or 215/35-18 tires with 18" wheels.

The problem you get into with larger wheels is that the very best tires aren't available in the sizes you need. For example, the Falken Azenis RT-615, which is maybe the best street tire around, doesn't come in anything smaller (for 18" wheels) than a 225/40-18, and that's too big for your car (almost 4 percent larger diameter than stock - and a larger diameter makes performance worse, not better). And you're talking 235 and 255 widths and that's WAY too big. That won't do anything for your performance - in fact, it will make it MUCH worse, for acceleration, and won't really help your cornering at all. Remember, part of performance in cornering is being able to accelerate out of a corner, and if your acceleration is worse, your lap times will be worse.

If this were my car, and I wanted to get the absolute best cornering with a street tire, I would get the Falken Azenis RT-615 in size 215/40-17 and mount them on 17x7.5 wheels. That will give you better cornering and grip than any street tire in any other size.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aleks77 &raquo;</TD></TR><TR><TD CLASS="quote">Is it stupid to go with a 18x.9.5" and 255mm tire</TD></TR></TABLE>

If you're expecting better performance - yes. If you're just doing it for show - go ahead.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aleks77 &raquo;</TD></TR><TR><TD CLASS="quote">am i gonna see any real cornering gains over lets say a 15x7" with a 215mm tire?</TD></TR></TABLE>

Maybe - but only because there aren't any good 215 mm tires in 15" sizes. Otherwise, no, no significant difference.

$.02

 

I don't understand why you would think 18 would give you better performance... they are going to be so heavy!

Agree with what the above person said!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaveSi677 &raquo;</TD></TR><TR><TD CLASS="quote">I don't understand why you would think 18 would give you better performance... they are going to be so heavy!

Agree with what the above person said!</TD></TR></TABLE>

especialy 18x9.5 on a 91 accord

ok i guess if you get some racing hart cp 035's or ce28's in that size and are running 600hp in your accord then you could probably pull it off and find some other nice tires but theyll cost $$$$$

 

im not really worried about acceleration, im in the process of dropping in my new fully built motor, and gonna go for about 430whp. The reason i want 18" rims is for show, but at the same time im tryin to get the most performance i can out of it. My accord is a base model coupe, it weighs more then EGs and EFs obviously but its not a boat, its at about 2750lbs without me. I currently have 225/40/18s on and it handles very well, the other reason i want a fatter tire is for traction with all that power from the turbo.

 

thats already a very very large tire for your car,


you know that with a high hp boosted car even with a really wide street tire your still gonna spin them if you drop the clutch at 8000 rpm....

its called learning how to drive... if that sounded harsh but its true, get some nice street tires and learn how to drive the car once its finished

 

i do admit i dont know how to drive a boosted car, is it really "bad" and horrible for performance to put on a 255mm with 18x9.5 rims that weigh 24lbs each, on a honda? I mean how much performance loss are we talkin about? compared to a lighter smaller diameter wheel?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aleks77 &raquo;</TD></TR><TR><TD CLASS="quote">i do admit i dont know how to drive a boosted car, is it really "bad" and horrible for performance to put on a 255mm with 18x9.5 rims that weigh 24lbs each, on a honda? I mean how much performance loss are we talkin about? compared to a lighter smaller diameter wheel?</TD></TR></TABLE>

Think of it like always being in the next gear higher than where you could be.

Oh, and they will probably rub, and throw off the accuracy of your speedometer and odometer.

But it sounds like you just have the idea in your head that you want to use the wrong size tires, no matter what anyone tells you. So go ahead and do that if you want. But don't ask people's advice, since you're just going to ignore it anyway.

 

what about the people below, they are running a "wrong size" tire too then? by the looks of it they seem to know what they are doing tho, and are performance oriented:


255/60/15


"in this pic, i have a 15x8.5 +19mm offset, soon i will be running a 15x11 -25mm offset" Next 2 pix are the same guy, not sure if they same car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aleks77 &raquo;</TD></TR><TR><TD CLASS="quote">what about the people below, they are running a "wrong size" tire too then? by the looks of it they seem to know what they are doing tho, and are performance oriented:</TD></TR></TABLE>

I've seen lots of people use the wrong size tire.

Also, the needs of autocrossing can be different from those of street use.

But you apparently already think you know everything, and you don't want to listen to advice from anyone else. Please stop wasting our time.