Lowering the car but turning the control arm?

[96Formula6sp]

A 10"-11" wheel is about perfect width for a 275 width tire. A 9" wouldn't support the sidewall as well, so you'd lose a little time there. Since you know Miatas, you likely know 949Racing. They did some back to back testing on track with same tires (225/45-15) and gained a second a lap going from an 8" wheel to a 9" wheel. Same tires, same track, same day, same car. The 9" wheel gave a very slight stretch, which gives the best sidewall support.

Yep...for reference 15x6 and a 15x9 with a 225/45/15 looks like this

 

[Rennkafer]

The experience of the testers is not in contention by me. It's more like why the Eiffel tower has a widening angled base vs a straight vertical tower analogy. I also have no idea how "stretch" properly applies here as a positive in this context. Significant stretch is rather uncommon aspect for a tire.
Enlighten me.

If you do the math on a 225 width tire and a 9" wheel you'll see it's not a significant stretch at just over 1/8". You get a similar amount with an 11" wheel and a 275 section tire.

 

[j-c-c-62]

Yep...for reference 15x6 and a 15x9 with a 225/45/15 looks like this

View attachment 1627585

Those are two different size tires

If you do the math on a 225 width tire and a 9" wheel you'll see it's not a significant stretch at just over 1/8". You get a similar amount with an 11" wheel and a 275 section tire.

Granted, but how many here are running 12" wheels with 295, or 13" with 315? or even have the room to even with mini tubbing?
It is interesting however finding reduced lap times in simply running wider rims, but wonder it that might also be simply due to wider track, roll center improvements, etc?

 

[Rennkafer]

Those are two different size tires

Granted, but how many here are running 12" wheels with 295, or 13" with 315? or even have the room to even with mini tubbing?
It is interesting however finding reduced lap times in simply running wider rims, but wonder it that might also be simply due to wider track, roll center improvements, etc?

They're not, what you do see is a bunch of people with 275's and 295's crammed onto 8" wheels. Very few people understand how much they hurt performance by doing it, and like you've pointed out in other threads, they just do whatever the crowd is doing without understanding any of it.

 

[96Formula6sp]

Those are two different size tires

Granted, but how many here are running 12" wheels with 295, or 13" with 315? or even have the room to even with mini tubbing?
It is interesting however finding reduced lap times in simply running wider rims, but wonder it that might also be simply due to wider track, roll center improvements, etc?

They were not. Both were the 225/45/15 rs4 Hankook. Its amazing what rim width can do. Why we are wanting to at least run a 9 inch wheel but would prefer a 10 or more to get some more with advantage. Shoot in Maita land a 205 was fastest on an 15x8 inch wheel and a 225 was fastest on the 15x9 inch. Some of the fast guys started running the 245 option on some 15x10. My daily driver c5 has a 275 on a 10.5 and its just starting to stretch. The rear is almost pinched with a 295 on the same 10.5.

Granted a wider tire is not always better. You need the power to turn that tire and you want it to be working right. Loads of stuff matters in your choices. But sometimes if your only running an 8 inch wheel you might be faster on a 255/265 tire vs a 285/295.

 

[j-c-c-62]

They were not. Both were the 225/45/15 rs4 Hankook. Its amazing what rim width can do. Why we are wanting to at least run a 9 inch wheel but would prefer a 10 or more to get some more with advantage. Shoot in Maita land a 205 was fastest on an 15x8 inch wheel and a 225 was fastest on the 15x9 inch. Some of the fast guys started running the 245 option on some 15x10. My daily driver c5 has a 275 on a 10.5 and its just starting to stretch. The rear is almost pinched with a 295 on the same 10.5.

Granted a wider tire is not always better. You need the power to turn that tire and you want it to be working right. Loads of stuff matters in your choices. But sometimes if your only running an 8 inch wheel you might be faster on a 255/265 tire vs a 285/295.

Really?
Because the top side above the large center grooves looks exactly the same width, but the bottom width visually looks much different.
Explain how any rim can "stretch" only one side of a tire.
The center rib/grooves also do not appear the same size.

 

[96Formula6sp]

Really?
Because the top side above the large center grooves looks exactly the same width, but the bottom width visually looks much different.
Explain how any rim can "stretch" only one side of a tire.
The center rib/grooves also do not appear the same size.

So on those the tire on the left was mine. It was on a stock 15x6 inch wheel. if you look at it its very pinched in. Really the 225 is not recommended on a 6 inch wheel. But my tire was sitting on the tire. Buddies 15x9 is on the right. As you can see in the side wall its stretched. His was sitting on the rim as the rubber was not touching the ground. If you look at mine some of the tread is rolled over to the inside.

 

[j-c-c-62]

So on those the tire on the left was mine. It was on a stock 15x6 inch wheel. if you look at it its very pinched in. Really the 225 is not recommended on a 6 inch wheel. But my tire was sitting on the tire. Buddies 15x9 is on the right. As you can see in the side wall its stretched. His was sitting on the rim as the rubber was not touching the ground. If you look at mine some of the tread is rolled over to the inside.

Your explanation above does not match what my eyes see. Again, and mainly, why would only one side, the lower side on the narrow rim, "roll under" and plainly in my eyes, be narrower?
The only explanation here might be, camera distortion, but that would have other telltale signs, that I do not see.
And again, the tire does not stretch, its inherent dimensions stay relatively the same, the tire changes shape from being inflated, balloons stretch and change dimensions.
If you truly believe a tire "stretches", then so does a scuba air tank when inflated.