Does wheel width affect contact patch?

I'm due for some new tires on my car and really don't like the wheels I have. Also, the tires I want are not available in a size that will fit my wheels.

I'm thinking about a few things when considering which wheels to get. One idea that I have is to buy the narrowest wheel that will fit a staggered front/rear tire size set up. For example, just using arbitrary numbers:

For example, if I get a set of 18x9 wheels for all for corners, I was thinking about putting a narrower tire (say... 255) up front and a wider tire (say.. 275 out back... assuming it fits).

I want the wheels to be as light as possible (hence, narrowest wheel that will hold both sizes) and I want the handling benefits of a staggered set up.

But my question is:

Does wheel width affect the behavior of a tire, assuming that the tire fits that wheel under normal circumstances (not "stretched")? Would a 275 tire behave the same on a 9-inch wheel as it would on a 10-inch wheel (width)?

Short answer: yes it does. There is plenty info here only if you move you hand over to Search button. Getting the same rim width to run so different tire width makes no sense. As well as there is no need to do it. It's not like proper width rims aren't available.

You want to get a correct sized wheel to fit the tires - no way around it. There are ranges for each tire/wheel combo (285 for a 10-11" wheel) and you can use the range to make a decision but the performance difference via weight is going to be negligible from the ideal wheel size. I'm afraid that a 255 and 275 on the same wheel may be too great and the net effect of doing that will be that performance suffers.

Wheel width definitely has an affect on how the tire performs.

Contact patch size no. The area touching the road will be the same regardless if you put a 205 or a 255 tire on. The vehicle weight and tire pressure will affect the contact patch size. What wider tires will do is cause the tire to deform less meaning it will run cooler than a narrower tire as the contact patch shape is changed. The shape is more important than the size so in a nut shell, wider is better as that creates the shape that handles in dry conditions better than narrower and vice versa in the snow.

Whats the reason behind this? You sound anti-staggard, hehe. But seriously, why the same size all around?

Well, to be honest, I'm looking for tires for my car (not NSX). I posted here because I figured this group would have more to say about the topic than the other forum I'm on (they're more into drag racing). I want to have a staggered set up (it's what I have now, 17x8.5 and 17x9.5), but I'm also considering the possibility of just going with same size at all 4 corners (the car comes that way stock) so I could rotate them and stuff. If I had same sized wheels, I'd have a choice between staggered or not.

In any case, I figured if I could get a narrower wheel for the back, it might save me some money and some unsprung weight, so long as it doesn't hurt the performance of the tire. Sounds like its a no-go, though. Oh well.

Depends on a lot of factors. What car?

I agree with the above that the contact patch size will not change if the tire pressure and vehicle weight are the same, although the SHAPE will be different.

I suppose I should have phrased my topic title differently, now that I'm looking at it again. After reading about tire performance, I was stuck on the phrase "contact patch." What I should have asked is whether wheel width affects tire performance.

The car is a 98 Camaro. It makes 361 rwhp, in case that matters. 6-speed with 3.42 final drive.

I would like to get the Michelin Pilot Super Sports (or possibly the A/S 3s), but they are not available in any size that will fit my wheels. Closest size I can find is 275/35/18 for the back, and 255/40/18 for the fronts.

I typically shoot to have the tire tread width the same or slightly narrower than the wheel width. For most tires that equates to ~275 on a 10" wheel. Tire fitment does affect the feel and stability of the tire. Can you not fit the 275 up front? You can make any wheel stagger work by adjusting the springs/bars/alignment accordingly. Just depends on your constraints.

Stuntman, is that b/c of the propensity (IMHO) for a wider than wheel width tire to squirm (meaning movement across the width) a little at the limit.

I'm trying to decide if I should stay with my present 235/40-17 (8.5" wheel) and 285/30-18 (10.5" wheel) combo on Yokos or move to 245/40-17 and 295/30-18 on Hoosiers. Decisions decision.

Sorry for the thread derail naaman.

stuntman said:

I typically shoot to have the tire tread width the same or slightly narrower than the wheel width. For most tires that equates to ~275 on a 10" wheel. Tire fitment does affect the feel and stability of the tire. Can you not fit the 275 up front? You can make any wheel stagger work by adjusting the springs/bars/alignment accordingly. Just depends on your constraints.

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I can fit 275 up front. Should be no problem. What I'm worried about is how it will change the behavior of the car on the road (don't care about track). I do like to carve out a canyon when I get the chance, and I like having sharp steering response. Everything I do to my car is to improve the responsiveness of the car to my inputs (steering, braking, acceleration). My short list of future mods includes stainless steel brake lines, tires, and some chassis stiffening/weight reduction (tubular subframe, torque arm, lower control arms, etc).

Ponyboy said:

Stuntman, is that b/c of the propensity (IMHO) for a wider than wheel width tire to squirm (meaning movement across the width) a little at the limit.

I'm trying to decide if I should stay with my present 235/40-17 (8.5" wheel) and 285/30-18 (10.5" wheel) combo on Yokos or move to 245/40-17 and 295/30-18 on Hoosiers. Decisions decision.

Sorry for the thread derail naaman.

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Not at all. The more info crammed into the thread, the better. Your question is right in line with what I'm trying to find out and is something that I would not have even known to ask.

IMO I think the 275 is a much better rear choice than a 255. Due to the camaros poor weight distribution, a 275 will perform better than a 255 up front to reduce understeer, and the benefit of being able to rotate the tires is huge. Their may be a minor reduction in steering feel bit the gain in front grip will far outweigh any losses on steering feel IMO.

Pony - yes when you have a tread width wider than the wheel width, the tires sidewall 'bulges' which leads to a less responsive tire since the tire needs to roll over and stretch the sidewall after a steering input while a smaller tire (on the same wheel) 'preloads' the sidewall with a slight stretch to improve response and peak grip.

stuntman said:

IMO I think the 275 is a much better rear choice than a 255. Due to the camaros poor weight distribution, a 275 will perform better than a 255 up front to reduce understeer, and the benefit of being able to rotate the tires is huge. Their may be a minor reduction in steering feel bit the gain in front grip will far outweigh any losses on steering feel IMO.

Pony - yes when you have a tread width wider than the wheel width, the tires sidewall 'bulges' which leads to a less responsive tire since the tire needs to roll over and stretch the sidewall after a steering input while a smaller tire (on the same wheel) 'preloads' the sidewall with a slight stretch to improve response and peak grip.

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Dude, priceless. Thank you. I feel better about trying the 275 square set up now. A little more expensive since I'll have to get bigger front wheels and all four tires in 275, but the ability to rotate ought to offset that in the long run.

Earlier you said that a "~275" would go with a 10" wheel. Is this based on a formula? For example, 275 mm is about 10.8 inches. Would the rule of thumb be to have the tire 1 inch wider than the rim? Or is it more like 11/10ths?

Go onto tire rack, look at the tire you want, look at the specific size then look at its "tread width". Tread widths vary greatly from the "275" description on the sidewall, even for the same model tire.

Okay, now I get it. Thank you, sir. Now I just have to figure out whether I can fit a 10" wheel up front. All the online tire dealers won't even allow me to choose a 10" tire for the front.

Looking at Michelin's website I came across this bit of info:

Michelin Wibsite said:

The rim width range is extremely important. This range represents proper rim widths that will assist the tire/wheel assembly in meeting its performance potential. To achieve the best balance between ride, handling and tread wear, select a rim width in the middle of the manufacturer’s range.

To improve cornering traction and steering response, choose a rim at or near the maximum recommended width. The wider the rim width, the straighter the sidewall and the quicker the steering response. Conversely, using a rim width at the low end of the range will cause the tire to balloon or curve out, slowing steering response.

Refer to our website for tire specifications.

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As I look at the specs for a 275/35/18 tire, I see that the maximum rim width for this size of the Super Sports is 11". It seems to be saying that the best handling/responsiveness will be achieved on a rim that is as close to 11" as I can fit on the car. I'm not sure I can fit 11" up front, though... not even sure if I can fit 10" up front, but I'm hoping I can, since wider seems to be better than narrower.