The quest for wider wheels and tires, 295, 305 and beyond...

[Mash]

I absolutely understand this reality, never contradicted it, and am not sure why this is the singular focus of all the responses…

Anyone have actual inputs on my bolded question above?

Because you raised a suggestion that wider tires might require higher pressure and that negates benefits of wider tires. I mean, I don't know how else to read that, so I commented.

I alluded to it in the earlier comments that if one runs a wider tire, but has to bump up pressures to compensate for an under-supported sidewall (assuming appropriate camber), they lose the benefits of the wider tire.)​

I can't answer if wider wheels will be faster.

 

[Lindenwood]

Because you raised a suggestion that wider tires might require higher pressure and that negates benefits of wider tires. I mean, I don't know how else to read that, so I commented.

I alluded to it in the earlier comments that if one runs a wider tire, but has to bump up pressures to compensate for an under-supported sidewall (assuming appropriate camber), they lose the benefits of the wider tire.)​

I can't answer if wider wheels will be faster.

Sorry for the confusion. I was just acknowledging that if someone was seeing a lot of edge rollover because their wheels weren’t wide enough to properly support the tire at idea pressures, they might try to compensate with higher pressures which would unintentionally negate the benefits of the wider tire. Such things would certainly skew any conclusions we could make about wheel and tire width.

Thanks!

 

[The Other Dan]

I'll throw thus out fir the discussion...
Stock classes have max rim width criteria, so it's not uncommon to see them with comically wider tires than rims. I would think they've been there, done that, with finding what works and what doesn't over the decades (ES miata) The fact that the keep doing it indicates to me at least, that they are getting more speed/grip out of their tires the wider they go.
At some point they were right where we are now questioning stretch or pinch.

 

[Lindenwood]

That’s a fair point!

I am currently looking at my own acknowledged bias against the “…well we’ve always done it this way…” philosophy.

You might be on to something… maybe “less than ideal” is still “better than a 275” for us?

 

[Lindenwood]

Also, @dsgerbc , you mentioned camber and other adjustments. It’s certainly possible that a wider tire on the same wheel does require either a camber or pressure tweak to maintain the inherent performance gains of that wider tire! So, indeed, there are missing data in our quest for “the best wheel and tire combo.”

 

[Dallas J]

Some tires tolerate pinching better than others and usually it comes down to sidewall stiffness. Back in the day the A6 worked pinched but the A7 not as much. Similar thing with the Yokohama vs B-stone now.

I went against my better judgement and put a 275 on my 9" wheel and its been pretty dreadful. You can see the wear on the inner half where the inner wall buckles over. It has double the wear as the outside edge with -3.5f/-2.5r camber. Its possible I have too much camber, but shouldn't be that far from the ballpark.

Fingers crossed a set of 19x11s show up in the next 3 days before we leave to Crows Tour so I can test with an extra 2" of wheel.

FWIW, Dan and I traded cars for a run with my 275 a052/9" and his 295s RE71-rs/11" and tire grip difference was pretty dramatic. My car was better in other ways but peak grip on his tires felt much higher.

 

[dsgerbc]

It has double the wear as the outside edge with -3.5f/-2.5r

I think it could be camber. -3.5 degrees is too much for autox IMO, especially with more caster. I had tons of inner wear on 295 and 305-wide tires. I'm probably dialing it down to start the season.

 

[Dallas J]

If it is, its not by much. All the kits for TM3s are super soft and even with my current spring rates (800/1200) theres quite a bit of roll. Thats only 2.1hz/2.2hz. And tires alone need 1.5-2deg on their own.

My car also has more camber gain compared to stock upright TM3s. I havent done bracket testing yet, but will eventually try more and less back to back to confirm as Ive done with the Evo setup.

 

[Mash]

If it is, its not by much. All the kits for TM3s are super soft and even with my current spring rates (800/1200) theres quite a bit of roll. Thats only 2.1hz/2.2hz. And tires alone need 1.5-2deg on their own.

My car also has more camber gain compared to stock upright TM3s. I havent done bracket testing yet, but will eventually try more and less back to back to confirm as Ive done with the Evo setup.

Don't underestimate influence of low cg. Tire temps on the track say that -3.5f is too much for Model 3.

On my Evo with hard springs I needed 3.5 easily

 

[MasterC17]

FWIW I did some testing this weekend and concluded that -3.5F and -3R to be near ideal camber settings. Tire pressures at 38psi seemed to be about right.

 

[Dallas J]

FWIW I did some testing this weekend and concluded that -3.5F and -3R to be near ideal camber settings. Tire pressures at 38psi seemed to be about right.

Yep, this is what I would expect.

 

[The Other Dan]

FWIW I did some testing this weekend and concluded that -3.5F and -3R to be near ideal camber settings. Tire pressures at 38psi seemed to be about right.

Was that for track or autox?

 

[MasterC17]

Was that for track or autox?

Track

 

[Mash]

Track

Which tire wheel?

 

[MasterC17]

Which tire wheel?

MW03 19x10.5 - Kumho V730 275/35/19

 

[Lindenwood]

I'd simplify it to this. If you are repeatedly losing AutoX's by a tenth of a second, then get wider tires. If you are hoping they'll gain you a half second, you need to work on the driver.

Just to be clear, your understanding is still that 295s and 305s would be generally faster—even if [by a tenth]—on a 10.5” wheel than a 275?

@MasterC17 Given your experiences over the last few years, and your own comments on the subject, I’m hopeful you can find the time—and desire—to chime in. For some reason opening this discussion seems to have been unpopular, so hopefully I haven’t backed myself too far into an uncool corner for others to bother with non-dismissive response . More seriously, I certainly meant no disrespect if anyone associated my inquiry as implicitly condemning all those running wide tires on 10.5” wheels.

Thanks!

 

[MasterC17]

Just to be clear, your understanding is still that 295s and 305s would be generally faster—even if [by a tenth]—on a 10.5” wheel than a 275?

@MasterC17 Given your experiences over the last few years, and your own comments on the subject, I’m hopeful you can find the time—and desire—to chime in. For some reason opening this discussion seems to have been unpopular, so hopefully I haven’t backed myself too far into an uncool corner for others to bother with non-dismissive response . More seriously, I certainly meant no disrespect if anyone associated my inquiry as implicitly condemning all those running wide tires on 10.5” wheels.

Thanks!

IMO 305's on 10.5's don't provide enough sidewall support, and you would likely be faster on something like a 285. 305's on a 11, on the other hand, would be faster than a 285 on a 10.5. I think the Tire Rack tests illustrate this well. It's also somewhat dependent on the tire construction as well.

 

[Lindenwood]

IMO 305's on 10.5's don't provide enough sidewall support, and you would likely be faster on something like a 285. 305's on a 11, on the other hand, would be faster than a 285 on a 10.5. I think the Tire Rack tests illustrate this well. It's also somewhat dependent on the tire construction as well.

I am kind of back and forth between the 275/35R19 and 285/35R19 RE71RS. For the latter, I am looking at the much more limited 11” wheel options that are all generally heavier or more expensive than something like the Konig 19x10.5s.

If you were hypothetically stuck with a 10.5” wheel, would you go with this 285 Re71RS, or stick with 275? (Mostly for AutoX, with a few HPDEs).

Thank you!

 

[MasterC17]

I am kind of back and forth between the 275/35R19 and 285/35R19 RE71RS. For the latter, I am looking at the much more limited 11” wheel options that are all generally heavier or more expensive than something like the Konig 19x10.5s.

If you were hypothetically stuck with a 10.5” wheel, would you go with this 285 Re71RS, or stick with 275? (Mostly for AutoX).

Thank you!

Tread width is 10.5" for the 285 - should be fine on a 10.5" wheel, wouldn't go wider.

 

[Dallas J]

I am kind of back and forth between the 275/35R19 and 285/35R19 RE71RS. For the latter, I am looking at the much more limited 11” wheel options that are all generally heavier or more expensive than something like the Konig 19x10.5s.

If you were hypothetically stuck with a 10.5” wheel, would you go with this 285 Re71RS, or stick with 275? (Mostly for AutoX).

Thank you!

I would run the 275 because the 285 is even taller at 26.9in.