Spinning My Wheels... (Yet Another Wheel Thread)

[Blufc3s]

Did you have any rubbing issues running the 215s on the 16x7 rota rb wheels? I bought identical wheels and would like to run the 215s, if they don't rub. Is your car stock height? I assume they're +4 offset.
Love the look on your car!
Thanks


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[charliekwin]

I put 225s on there and haven't had any problems rubbing. 215 should be fine too. 225 is a fair amount of tire, but options at my budget were better with that size. My car is on Vogtland springs, dropped about 1.25" all around.

[Blufc3s]

Thanks, this is very helpful as I have the vogtland lowering springs on my car. They only lowered it about 1" , but I suspect it's due to the original springs being a bit weak.


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[Jeff G 78]

Be careful as every car and every brand/model of tire is different.  Some cars don't rub and others rub badly.  Tires can vary greatly in size depending on the shape of the tire.  Some are trapezoidal and others are square.  The more trapezoidal the tire, the less chance of rubbing, but also the less tread on the road.  Tire widths are measured at the widest part of the sidewall, not at the tread and even then, there is no real standard.  Much like tread wear ratings don't mean much.

[Zed Head]

The above is true.  I had a set of 205-70-14's that rubbed on tight hard corners and the same size of a different brand didn't.  The car's lowered about an inch.

I think the 205 is the width of the tread.  Sidewall width isn't defined.

[Jeff G 78]

Other way around Zed.  205 would be the sidewall.  The tread width is always narrower, but some tires are much closer to the sidewall width than others.

[Rob1972]

11 minutes ago, Jeff G 78 said:

Other way around Zed.  205 would be the sidewall.  The tread width is always narrower, but some tires are much closer to the sidewall width than others.

Beg to differ:  In Zed's example 205/70/14 = 205mm tread width, 70% of the tread width is the sidewall height (called aspect ratio), with 14 inch wheel diameter.

[Jeff G 78]

Rob, I'm an automotive engineer.  Trust me on this.

[Jeff G 78]

Okay, to help people understand, I went to TireRack.com and copied the specs of two Hankook 225/50R16 tires and a General tire.  The first Hankook is a medium performance tire and the second is a max performance summer tire.  Note how different the tread widths are between the two tires.  Keep in mind, these are both by the same manufacturer and they still vary greatly.  The third tire is the same size, but a General.  Note again how different the section width and tread widths are.  Multiply section width by 25.4 to get the nominal tire width as advertized.  The General is small and the Hankooks are much bigger than nominal.

Edited April 30, 2017 by Jeff G 78
Added a 3rd tire to chart

[Zed Head]

Sorry about the misunderstanding on my part.  I had assumed what made sense to me, that width meant tread width.  The sidewall-to-sidewall width seems of little use, compared to tread width since rubber on the ground is the main purpose of being a tire.  Weird that this labeling scheme has lasted so long, it's a lot less meaningful than I thought.  There's no way to calculate tread width.  So thanks for the TireRack link, it has immense value now.

No offense I hope, if I add a few more references.

https://en.wikipedia.org/wiki/Tire_code

https://www.goodyearautoservice.com/en-US/tire-basics/tire-size

https://www.tirebuyer.com/education/understanding-tire-sizes-and-types

[Jeff G 78]

No worries Zed, just trying to help clear things up.

I deal with tire sizes every day and it's amazing how many variables there are just in sizing, let alone compounds and constructions.  Tire engineering is a black art for sure.

[SteveJ]

1 hour ago, Jeff G 78 said:

Okay, to help people understand, I went to TireRack.com and copied the specs of two Hankook 225/50R16 tires and a General tire.  The first Hankook is a medium performance tire and the second is a max performance summer tire.  Note how different the tread widths are between the two tires.  Keep in mind, these are both by the same manufacturer and they still vary greatly.  The third tire is the same size, but a General.  Note again how different the section width and tread widths are.  Multiply section width by 25.4 to get the nominal tire width as advertized.  The General is small and the Hankooks are much bigger than nominal.

I love coming to this site and learning what I thought I knew was wrong.  Thanks for taking the time to explain.