Just a question. If this is true, without a doubt...then why does every single race car, including formula 1 who have wheel width limits run tread widths less than the wheel width?

then why does every single race car, including formula 1 who have wheel width limits run tread widths less than the wheel width?

Because they don't.

In classes that limit the wheel width more so than the tire width there is even a special construction tire made- the cantilever slick.

This tire is especially made to fit on a wheel narrower than the tire tread width, it reinforces and "cantilevers" the sidewall over the top of the wheel bead so the lower sidewall hinge point is outside the wheel bead.

In racing without budget constraints you will have the best suspension design allowed, the widest tire allowed and the widest wheel allowed.

If you are somehow limited by one of these (mac strut suspension in the FC case) then it does affect the others.

If you stretch a tire on a mac strut car setting up the static camber becomes much more critical since it is very easy to tilt the flat tread surface with body roll so it is no longer in contact with the track.

Tire manufactures have your back on this somewhat, most the fastest tires for production car based racing are soft sidewall rounded tread profile pillows of grip. Because most production cars do have crap mac strut suspension.
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I just went to 285/30-18 BFG R1S DOT tires on my 18x11 on the RX-8 and I joke that I put American tires on my car and now it drives like an American car. Its that bad!

I got spoiled by the awesome steering response and precision of the stiffer sidewall flat tread profile 295 R888 and even the 255 Maxxis RC-1 on 17x9.5.

But guess what, you learn to drive a wider line around the sloppy sloppy tires with more grip and it is a lot faster lap times.

And this is on an RX-8 with pretty damn good suspension.

Eggcellent.

Thank you. You are absolutely right. And now I have another data point... I ran 255 NT01s on a 9 inch rim and now run 275 RC1s on a 9.5 inch rim and GASP! It is faster and more consistent on the 275s. The tires are wider than the wheels.

I would like to try 10.5 inch wheels with these 275s and see what happens. Times may very well improve slightly, but the lesson here is RUN THE WIDEST TIRES YOU CAN.

but the lesson here is RUN THE WIDEST TIRES YOU CAN.

Well, if its for competition... like in this thread.

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Not related to this thread-

I would much rather have the tire that felt the best with the most feedback on the street.

That could be a wider tire like the stiffer sidewall flatter tread surface 295/30-18 R888 on 18x11 instead of grip pillow 285/30-18 BFG on the RX-8

or it could be narrower version of the exact same tire like when I went down from 275/40-17 NT01 to 255/40-17 NT01 on my 17x9.5 on the rear of my FC

or when I put the 255/40-17 RC-1 on the 17x9.5 up front on the RX-8 for better steering feel and the same 255 on the 17x8.5 on the rear

or how on my FD I preferred the steering feel of 265/35-18 Federal RS-R on 18x10.5 the most and then 265/35-18 Ventus TD on the 18x10.5 was still better than the 295/30-18 TDs on 18x11.

I think you just need to try a lot of set-ups and see what you prefer, and keep trying new things as your driving progresses since your preferences will evolve as well.

For competition, you just check the clock and make the decision.

Thanks alot guys, the input in this thread lead to my wheel setup that is to arrive next week.
Cosmis racing model 206 wheels, 18x11 et8
My learning tires will be federal rsr 285/30-18, racing tires probably hankook or yokohama,
Pics will follow :)

Cool thread!

Here's some more about the Super Motobei FC. I'm not sure the info is correct when it states the 295/30 18s are on 9.5" rims... Just going off the pics.

Super Motobei FC3S

aren't the 295 tires requires a 10" wide wheel to be safe? Most manufacturers list a minimum rim width of 10" for it.

by the way, the car shown on the link looks awesome. The Japanese makes their car look unique.

RX-mania
Quote:
Originally Posted by S2-13BT View Post
Cool thread!

Here's some more about the Super Motobei FC. I'm not sure the info is correct when it states the 295/30 18s are on 9.5" rims... Just going off the pics.

Super Motobei FC3S
aren't the 295 tires requires a 10" wide wheel to be safe? Most manufacturers list a minimum rim width of 10" for it.

by the way, the car shown on the link looks awesome. The Japanese makes their car look unique.

It only takes a glance at the pictures of this car to see the wheels are 18x10.5 and that was a typo.

This is what a 18x9.5 with a 295/30-18 looks like (R888 pictured, but I went from 295 ventus TD to 295 R888 and the width is pretty close, but the R888 is a more square profile tire).

https://cimg2.ibsrv.net/gimg/www.rx7...3566bed89a.jpg

I don't know how unsafe 1/2" muffin topped from manufacturer recommended widths is, but it would be slower and feel horrible.

feel horrible? yes... slower? probably not...

in autocross all the corvettes in SSR run 315 hoosiers on 18x9.5s because that's the fast setup...

I currently have 315 NT01s on 17x10s for street tires. looking this up, this is a hot setup for time trial mustangs who are limited on wheel width.

more tire is almost always better as far as time goes, but yes, it doesn't feel nearly as good and is probably a bit harder to drive.

that being said, if you can run a wider wheel, there is no reason not to, it's the best of both worlds. responsive and more grip which is why my current setup is 315 hoosiers on 18x12s

eage8


feel horrible? yes... slower? probably not...

You think 295/30-18 on 18x9.5 is going to be faster than 295/30-18 on 18x10.5 or 18x11?


in autocross all the corvettes in SSR run 315 hoosiers on 18x9.5s because that's the fast setup...


Nope, they do it because they aren't allowed wider wheels in that class.

no, I was saying a 315 is going to be faster on a 9.5" wheel than a 285 on a 9.5" wheel

which is why I followed up with the corvette comment :) and why I run 18x12s

Gotcha.

Yeah, the context of my comment is we have lap times, dates, pictures and tire widths documented on the Super Motobei FC3s, but an article mistakenly listed the wheels as 18x9.5 when they are obviously 18x10.5

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RX-mania
Quote:
Originally Posted by S2-13BT View Post
Cool thread!

Here's some more about the Super Motobei FC. I'm not sure the info is correct when it states the 295/30 18s are on 9.5" rims... Just going off the pics.

Super Motobei FC3S
------
aren't the 295 tires requires a 10" wide wheel to be safe? Most manufacturers list a minimum rim width of 10" for it.

by the way, the car shown on the link looks awesome. The Japanese makes their car look unique.
------
It only takes a glance at the pictures of this car to see the wheels are 18x10.5 and that was a typo.

This is what a 18x9.5 with a 295/30-18 looks like (R888 pictured, but I went from 295 ventus TD to 295 R888 and the width is pretty close, but the R888 is a more square profile tire).

I don't know how unsafe 1/2" muffin topped from manufacturer recommended widths is, but it would be slower and feel horrible.

Just to toss it out there.

Factory rear E39 M5 wheels are 18x9.5 with 275/35/18 tires. Bunch of the bimmer guys who track their E39 M5's with OEM wheels run square 9.5's (square rear wheels) with 285/35/18 rubber all-round. Pretty common thing they do.

Not saying you should run 295's on 9.5's. But im not saying you cant either.

Now that RE71r's are available in 285/30/18 I am seriously considering just throwing them on all 4 corners of my FD..With 18x9.5 and 18x10 wheels. 275/35/18s were too tall for the front.

One thing I have noticed between bridgestone and other tire manufacturers is that re-11 and re-71's have the highest rating for turn in and steering response, they also have the least wide tire widths for their size amongst extreme sports tires. bridgestone I think figured out that most people put a tire on the recommended tire width and they set up the tire width to be square on that recommended tire width.

A 285 re-11 is only 10" tread width. An AD08R is 11" in the same size. I am willing to bet these two tires feel drastically different on a 10" wide wheel.

They are 2 completely different tires. Of course they will feel different.

Real racing ALWAYS has a rule set, and they ALL limit the tire and or wheel size. especially in F1.

So... Kinda to get back to the original question -

With the ronin widebody, coilovers and no spacers
Whats the widest wheel and tire and what offset?

incubuseva So... Kinda to get back to the original question -

With the ronin widebody, coilovers and no spacers
Whats the widest wheel and tire and what offset?

With a little futzing about with the front strut you should be able to run 18x12 -5 with a 305/30-18 up front for street (-1.5 to 2.5 degrees camber).

As Ronin site states with race camber (-3.5 to 5.5 degrees) and more futzing with the strut you should be able to fit 315/30-18 up front on something like 18x12 -15 offset.

Prepare for steering effort, monster spring rates and monster truck ride height to keep from rubbing the unibody with the top of the tire.

You can fit the same in the rear, which is nice so you can rotate.

If you wanted stagger you could squeeze 335/30-18 as the Ronin site says on something like a 18x13 +0 and moderate camber (-1.5 to -2 degrees).

If you want to go super conservative with no camber on the street 285/30-18 on 18x11 +0 will work front/rear and allow you to run a little lower (shorter tire).

I'm running square 18x12s with 315/30/18s all around. front -10 offset rear 0.

a lot of it depends on how your rear fenders are installed and your front strut ear length too. AkinaFC on norotors is already running 315/335s on 18x11/12s (335s won't fit on my car I tried) and is trying to get a a 335/345 setup working... but square 315s is the easy button...


https://cimg3.ibsrv.net/gimg/www.rx7...cb631b8632.jpg

If this forum had a like button, I would like eage8's post.

Ronin fits a 315/335 easily but make sure to fit the quarters with the wheels and tires you are wanting to run as it makes it waaaay easier in the end, this is also with Fortune coilovers. Dont know about other brands of suspension as I have not personally used them.
18x11 -6 et front and 18x12 +6 et rear with a 6mm spacer so effectively 0 in the rear, camber was about -2 front and almost 0 in the rear in the pic attached. The 335 front and 345 rear can be done and I will finish that fitment over the winter when I'm not racing :)
I wouldn't call it a monster truck fitment as it still takes two jacks or a ramp to get the car off the ground.

I love it when wheel and tire fitment threads turn into car porn.


https://cimg8.ibsrv.net/gimg/www.rx7...fbbd475732.jpg