Wheel width: Is wider always better?

In reply to Andy Hollis :

Appreciate the response. 

I understand that on a flat smooth race track the 9's would be faster but would they be faster on a potholed, uneven, undulating British B-road too?

Would the 9's give more warning before grip breaks away and inspire more confidence going into turns than the 8's or less? Would 9's be better for tyre wear/longevity? 

Psst, look for another wheel comparison test soon. 

We run 4.5" wheels with 5" tires in front and and 5.5" tires in the rear in Formula Vee and still manage 1.5Gs; who needs wide wheels?  In our case, the width is specified by the rule book, but folks who have experimented with wider wheels and tires find out they're slower around the track.  Probably mostly aero, but also rolling resistance and weight aren't helping anything.

Berck said:

We run 4.5" wheels with 5" tires in front and and 5.5" tires in the rear in Formula Vee and still manage 1.5Gs; who needs wide wheels?  In our case, the width is specified by the rule book, but folks who have experimented with wider wheels and tires find out they're slower around the track.  Probably mostly aero, but also rolling resistance and weight aren't helping anything.

An open wheel race car is a great comparison to a street car on 200TW tires. 

Yesterday I managed to bend both of my rims on the passenger side from a kerb I didn't see, so now I'm going to have to buy new rims.

I remembered seeing this post and so now I'm replacing them I'm wondering what width to try. I want to order right this time. I have the option of 8.5, 9 or 9.5 inches wide to pick from. 

I currently have 17x8 flow formed wheels running Goodyear asm 6 tyres @ 245/40/17 on a bmw 135i coupe. It's running about 400 to the wheels at the moment and that may increase. It's having a wide body conversion soon so I can fit wider tyres but It's really only for fast road purposes (which are mostly potholed, lumpy bumpy undulating British country roads.) rather than track so I'm thinking that staying at 17 inches with bigger sidewalls with spacers is best rather than going for 18s and even wider tyres as a fast daily but would really love to hear some thoughts on my thinking as it may be flawed in reality and what width/size would be best for my needs. 

In reply to Confusedtuning :

For street driven cars curbs are why I like a wider tire on a narrower wheel.  My gram lights got curb damage at 3 mph thanks to trying to miss a pothole that would eat my Civic in a parking lot.  If I had a wider tire it'd have saved the wheel.

Andy, I know you're the master of all things FWD Honda, so I figured I would ask for your recommendation:

I'll be competing in a local PWR based autoX class next year in my Integra GS-R. The car weighs around 2600 lbs, is making 160whp and is using a B16b gearbox. I'm limited to 200tw tires that are no wider than 225.

I'll be running 15x9 wheels up front and 15x8 wheels in the rear (thank you Flyin' Miata!). 

I've decided I want to run A052's, but am torn between 205/50's and 225/50's up front (A052's don't come in 225/45's unfortunately). With the 205's I think I hit the rev limiter in 2nd gear around 59-60mph, with the 225's I think that would go up to 62-63mph. Is it worth the extra tire height and weight to run the wider 225/50's on a 9 inch wheel?

I know you ran 205/50’s on a 9 inch wheel on your CRX on track, but I wasn't sure how applicable that was to autoX? 

In reply to roninsoldier83 :

Replied in your other thread.

In reply to Andy Hollis :

"I know you ran 205/50’s on a 9 inch wheel on your CRX on track, but I wasn't sure how applicable that was to autoX?"

I'd like to see a picture of a 205/50 on a 9" wheel. 

In reply to Confusedtuning :

I run a 17x9" et 52 on my 135i hybrid street/track car with stock fenders (Apex wheel, highly recommend! Great figment guides on their website too!). Currently run a 255 width but considering going down to 245 based on this article. Tried several tires (615k+, RT660 twice) but going back to RS4

using the 0.5" tread width less than wheel width would actually mean 235 for an RS4!

Smaller diameter is better for weight and ride comfort, just make sure it clears the brakes. Eventually the sidewall height will add some flex/squirm but usually not noticeable unless it's a hardcore track build with super stiff suspension 

In reply to Keith Tanner :

Keith has touched on an interesting aspect, everyday ride comfort. It is important. To take it a step further one needs to become specific. Let us consider a Miata. Going from the factory 195/50 on 15x6 factory wheels to 175/55 on the same wheels, there is on average an approx. weight saving of about 2.4lbs per tire. At the same time overall diameter is reduced from 22.7" to 22.6". Now, if the wheel is also changed to a wider aftermarket 15x7 weighing 9.65lbs, instead of the factory 13.1 lbs, there is a further weight reduction of 3.45lbs, raising the total weight saving to 5.85lbs per corner! This is an appreciable saving. Reducing unsprung mass improves ride comfort. Stretching a tire has the opposite effect. A 7" wide wheel measures 177.8mm compared to the tyre's tread width of 175mm. How is ride comfort affected? Perhaps this is better known to those with related experience like Keith.

AGGELIAFOROS said:

In reply to Keith Tanner :

Keith has touched on an interesting aspect, everyday ride comfort. It is important. To take it a step further one needs to become specific. Let us consider a Miata. Going from the factory 195/50 on 15x6 factory wheels to 175/55 on the same wheels, there is on average an approx. weight saving of about 2.4lbs per tire. At the same time overall diameter is reduced from 22.7" to 22.6". Now, if the wheel is also changed to a wider aftermarket 15x7 weighing 9.65lbs, instead of the factory 13.1 lbs, there is a further weight reduction of 3.45lbs, raising the total weight saving to 5.85lbs per corner! This is an appreciable saving. Reducing unsprung mass improves ride comfort. Stretching a tire has the opposite effect. A 7" wide wheel measures 177.8mm compared to the tyre's tread width of 175mm. How is ride comfort affected? Perhaps this is better known to those with related experience like Keith.

 

I have found two main contributors to ride comfort: tire model and sidewall height (aspect ratio)...both for the same reason.

A tire is a spring.  A stiffer sidewall produces a higher spring rate, and most UHP tires have much stiffer sidewalls than typical all-seasons.  And 200tw tires designed for motorsports tend to have the stiffest of all.

Aspect ratio does the same.  Shorter sidewalls are more responsive, but also have less "spring" travel.  So they hit the "bumpstops" sooner.  Think of potholes and +1/+2 fitments.

Another factor, though less important, is the tread compound and depth.  Tread squirm is bad for performance, but good for ride quality.  Each tread block is a mini-spring, and softer rubber has a lower spring rate.  So does a taller piece of that same rubber.

And finally...air pressure.  Again using the spring analogy, more air means higher spring rate.  Less is softer.

For our Triple Threat ND Miata project, long road trips are taken with a set of stock BBS 17x7's with full-tread Conti ECS in stock size of 205/45-17, aired to 28psi.  The ride is waaaaay more comfortable than any of our track fitments (typically 245/40-17 4/32nds 200tw on 9's).  Plus they double as our track wets for deep standing water.

My 245s are done on my 9s.  Maybe I should consider going to 225s next year on my turbo fwd for the front.