Tires for 19x9.5

[Lucky_13]

Hey Everyone,

I recently had a set of decently lightweight (Gram Lights) 19x9.5 +35's come into my possession, and I'm considering turning them into my track day wheels. I do about 1-2 events a month. What tire size would you all recommend? Considering 275/35/19 or 285/35/19 atm. I've driven a buddy's mustang on 275/40/19's on the same size/offset wheels (RTR), and the car felt lazy and doughy.

Other relevant bits:
Vorshlag Bilstein/P Springs/Camber Plates
Eibach adjustable sta-bars

Thanks in advance

 

[csamsh]

I think you're on the right track for 275/35 or 285/35.

I've never heard anybody say they liked their 40-series tires on track or at autox on an S197

 

[SlowJim]

18s will save you a ton of dough on tire costs.

 

[VTXFrank]

I think you're on the right track for 275/35 or 285/35.

I've never heard anybody say they liked their 40-series tires on track or at autox on an S197

Would have to agree. Also, the tire itself will make all the difference in the world. The BFG KDWII's I was rolling on only needed 36psi to stay sidewall strong. My new A/S tires need 40psi for the same stiffness. When it comes to auto-x racing, it's ALL about the sidewall stiffness once suspension concerns are equal, IMO.

 

[Jucostud]

275/35/19's. i wouldn't want bigger unless you had a 10".

 

[TGR96]

I have 285/40s Conti Extreme contract DWs on a 10" wide wheel, and the fit is perfect. Id say 275 on a 9.5 would be perfect as well.

 

[Norm Peterson]

Unless otherwise restricted by class rules, 9.5" wheels are really best reserved for 255's and 265's.

Given availability in the right offsets, I'd use 10's for 275's and 10.5's for 285's. And probably go half an inch wider before going half an inch narrower.

40 and even 45 profile tires don't have to be all that bad, but in most cases you do need to run them on wheel widths out around max-recommended. The mildly stretched sidewall contour that results tends to crutch the fact that the sidewalls are taller.


Norm

 

[sheizasosay]

9.5" wheels are really best reserved for 255's and 265's.

Given availability in the right offsets, I'd use 10's for 275's and 10.5's for 285's. And probably go half an inch wider before going half an inch narrower.



Norm

Why do all the major tire manufacturers recommend 9.5" for 275s? Considering "measuring rim width" is the "designed rim width" tire rack shows:

All these tires are either 275/35 or 275/40 18s and the measuring rim width is 9.5" regardless if it is 40 or 35 series tire.

Bridgestone RE-11 /Meas rim width- 9.5"
BFG Rival /Meas rim width- 9.5"
Dunlop ZII /Meas rim width- 9.5"
Hankook RS3 v2 /Meas rim width- 9.5"
Michelin PS2 /Meas rim width- 9.5"
Kumho Exsta XS /Meas rim width- 9.5"
Toyo R888 /Meas rim width- 9.5"

For 255s, the 9" rim is recommended. At 265, the 9.5" is recommended. 275's 9.5".

285s are all at 10" regardless if 30, 35 or 40 series tires.

Why are most of your wheel/tire combo recommendations a .5" larger than what the manufacturers make?

 

[moostang09]

I have RTR wheels which are 19x9.5 and I run 275/35/19 Nitto NT555. They have served their purpose for my use and I really enjoy them. They are a little "bouncy" sounding but any car with exhaust or a radio on will drowned that out. By bouncy I mean like a basketball..

I was going for 285 but couldn't find the ones I wanted/price range for my setup.

 

[Norm Peterson]

Why do all the major tire manufacturers recommend 9.5" for 275's? Considering "measuring rim width" is the "designed rim width" tire rack shows:

All these tires are either 275/35 or 275/40 18s and the measuring rim width is 9.5" regardless if it is 40 or 35 series tire.

Bridgestone RE-11 /Meas rim width- 9.5"
BFG Rival /Meas rim width- 9.5"
Dunlop ZII /Meas rim width- 9.5"
Hankook RS3 v2 /Meas rim width- 9.5"
Michelin PS2 /Meas rim width- 9.5"
Kumho Exsta XS /Meas rim width- 9.5"
Toyo R888 /Meas rim width- 9.5"

For 255's, the 9" rim is recommended. At 265, the 9.5" is recommended. 275's 9.5".

285 are all at 10" regardless if 30, 35 or 40 series tires.

Why are most of your wheel/tire combo recommendations a .5" larger than what the manufacturers make?

"Measuring width" may or may not be the design width, but even if it is, it is with some assumptions regarding a wide variety of tire characteristics that frequently work at cross purposes to one another. Which one(s) do you want to favor?

Because this is a corner-carving section and track time was specifically mentioned, it is reasonable to assume that people want a bigger slice of cornering attributes, and that any payback in terms of soft(er) ride quality and NVH is understood to be a secondary concern . . . at best.

In daily street driving, steering response is mainly what you'll notice as far as cornering performance metrics are concerned. The ride quality penalty really doesn't amount to much, so what sort of sense does it make to buy a tire for cornering purposes, and then turn around and compromise the very facet of its performance you're most likely to notice?



You are aware that Ford has put 235/50's on 18 x 8.5's for the OE 18" GT package, and that 255/45's on 18 x 9.5" was the front fitment for the GT500? Both of those are max-recommended-width fitments . . .


Norm

 

[Sky Render]

Bah, I just cram the widest tire I can afford onto my wheels.

 

[sheizasosay]

"Measuring width" may or may not be the design width, but even if it is, it is with some assumptions regarding a wide variety of tire characteristics that frequently work at cross purposes to one another. Which one(s) do you want to favor?

"Measuring Rim width" according to Tire Rack is: " the industry standardized rim width upon which the tire must be mounted in order to confirm it meets its dimensional targets. Because the width of the rim will influence the width of the tire, a standard rim width for every tire size is assigned and must be used. This standardized measuring rim width allows all of the tires produced around the world to meet the same dimensional standards and therefore, be equivalent with regards to their physical size. The measuring rim width is sometimes referred to as the tire's "design rim width." And the characteristics that *I* would favor, are a balance of how much money I have vs what gets me around the track fastest.

Because this is a corner-carving section and track time was specifically mentioned, it is reasonable to assume that people want a bigger slice of cornering attributes, and that any payback in terms of soft(er) ride quality and NVH is understood to be a secondary concern . . . at best.

I agree, which is why I questioned your recommendation to use a smaller tire than what is recommended by all of the tire companies.

In daily street driving, steering response is mainly what you'll notice as far as cornering performance metrics are concerned. The ride quality penalty really doesn't amount to much, so what sort of sense does it make to buy a tire for cornering purposes, and then turn around and compromise the very facet of its performance you're most likely to notice?

I am not talking about ride quality. I am talking about using a tire on a rim with the recommended sizes. I think your point is that a car with a wider rim on a given tire will generally be a better performer than that same tire on a smaller rim. I agree. A 275 35 18 mounted on a 9.5" wheel vs a 275 35 18 mounted on a 10" wheel would prove your point and your point.

But really what this is all about is you are *basically* saying 265 18 on a 9.5" wheel is better than a 275 18 on a 9.5". Because you do not recommend that tire on that rim. I shouldn't assume. Is that what you are saying?

You are aware that Ford has put 235/50's on 18 x 8.5's for the OE 18" GT package, and that 255/45's on 18 x 9.5" was the front fitment for the GT500? Both of those are max-recommended-width fitments . . .


Norm

No. I didn't know. I purchased a Roush that had 18x10s(et45mm) that weighed 34lbs a rim. I took those off for a lighter smaller 18x9.5 running the same 275 width. So I never had OEM wheels on and to be honest, I really do not keep up with what size wheels/rims/tires come on factory cars.

 

[Norm Peterson]

I agree, which is why I questioned your recommendation to use a smaller tire than what is recommended by all of the tire companies.

As far as I know, the tire companies only recommend a min to max range, rather than any specific width inside that range.

Any recommendation to use the "measuring width" wheel implies that the average mix of tire properties/qualities is "good enough", and that having nothing in particular favored is OK.

Forget any tire size recommendations made by the tire resellers, as those suggestions are there mainly for the appearance-oriented buyer and generally won't have cornering performance in mind. Certainly not autocross or track level cornering or even the half lateral g stuff that isn't much removed from normal street driving.

But really what this is all about is you are *basically* saying 265 18 on a 9.5" wheel is better than a 275 18 on a 9.5".

That is one of the things I am saying.

Because you do not recommend that tire on that rim. I shouldn't assume. Is that what you are saying?

I'm assuming that you're referring to 275's on 9.5". Until people in this kind of thread start specifically asking for more than just the one wheel width recommendation per tire size, one width suggestion per tire size is all they're likely to get from me or most anybody else.

With the overall experience I've had with 255/45's on 9.5" wheels (which I really feel should have been the GT's 18" OE fitment to begin with), it's really hard for me to recommend running 20mm more tire on the same width wheel - that's approaching a whole inch and is nearly 8% in terms of nominal tire dimensions. If appearance is the only thing that matters to any given individual with a tire/wheel quesiton, then it doesn't matter (and I generally stay out of those discussions entirely).

That said, I'd probably make a specific exception if this was a drag racing related question. A little extra vertical compliance is probably a good thing there, and lateral consequences are somewhat less important.


Norm

 

[Sky Render]

I autocrossed on 255s mounted on 8" wheels for more than two years.

 

[2008 V6]

Basic rule – Tread width of ½” larger than rim width maximum for best utilization of a high performance street tire. This is not optimum. Section widths vary from manufacture to manufacturer. A larger tread width will work, just not as well. I am using a 10.2” tread with on a 9.5” rim.

 

[Norm Peterson]

I autocrossed on 255s mounted on 8" wheels for more than two years.

Stock (street) category autocross is a piss-poor basis for judging proper wheel to tire widths. Wheel width is limited to OE, while tire sizes are limited only by what you can squeeze on and expect to hold air.

Ultimately, you end up with people running tires for which the minimum recommended wheel width is well over an inch wider than the OE wheel width that you're stuck with. Think 295/xx on 8.5" wheels (but please don't run that combination anywhere except at an autocross event).


FWIW, every car of mine that has ever been autocrossed has run on wheels at least an inch wider than the originals and which weren't any narrower than 1/2" below max recommended for the tires fitted to them. The more heavily modified cars have ended up with wheels 2.5" to 3" wider than the original wheels they came with, and a couple of times that's stepped half an inch past max recommended for a subsequent set of tires.


2008 V6 - the first guideline I ever heard was to choose a wheel width from 1" smaller than the tire's measured tread width to 1" more than the tire's tread width. That was 40+ years ago, and my point is that there's no reason to turn your nose up at wheel widths greater than the measured tread widths of the tires you intend to fit to them.


Norm

 

[2008 V6]

2008 V6 - the first guideline I ever heard was to choose a wheel width from 1" smaller than the tire's measured tread width to 1" more than the tire's tread width. That was 40+ years ago, and my point is that there's no reason to turn your nose up at wheel widths greater than the measured tread widths of the tires you intend to fit to them.


Norm

I agree – Bigger or smaller will work especially if you have to work with specific rules for your class.

 

[Pentalab]

A 275 on a 10" rim has an effective width of 280mm. Same 275 on a 9" rim has an effective width of only 270mm. I recently swapped my 255-45-18's for some spare 275-40-18's. This was on the front 9" rims. The former 255's on the same 9" rim had an effective width of 260mm. So I only gained 10mm with the swap. I'm not impressed so far. It did reduce my stagger from 25mm..down to 15mm. Understeer is slightly less, but the turn in is worse.

Last year I swapped the rear 275's on 10" rims for 285's. I gained 5mm, and not 10mm. (275's were put in storage for a year... hence the spare 275's. The entire experiment was a waste of time imo, I should have left it alone. As is, I had to increase front tire pressure a bit )

Nitto sez you can put their 275 on anything from 9-11" rims. It would be interesting to see a 275 on a 11" rim..which should have an effective width of 290 mm.

That measuring rim width is what is used to determine the published overall diam + width. Measuring rim width may well not be optimum in most cases.
.5" to 1" greater (at least for 40/45 series) is more optimum.

 

[sheizasosay]

A 275 on a 10" rim has an effective width of 280mm. Same 275 on a 9" rim has an effective width of only 270mm. I recently swapped my 255-45-18's for some spare 275-40-18's. This was on the front 9" rims. The former 255's on the same 9" rim had an effective width of 260mm. So I only gained 10mm with the swap. I'm not impressed so far. It did reduce my stagger from 25mm..down to 15mm. Understeer is slightly less, but the turn in is worse.

Last year I swapped the rear 275's on 10" rims for 285's. I gained 5mm, and not 10mm. (275's were put in storage for a year... hence the spare 275's. The entire experiment was a waste of time imo, I should have left it alone. As is, I had to increase front tire pressure a bit )

Nitto sez you can put their 275 on anything from 9-11" rims. It would be interesting to see a 275 on a 11" rim..which should have an effective width of 290 mm.

That measuring rim width is what is used to determine the published overall diam + width. Measuring rim width may well not be optimum in most cases.
.5" to 1" greater (at least for 40/45 series) is more optimum.

The reason why your tires did not measure appropriately is because they were not on the recommended rim. The reason they have a "measuring rim width" is to set a standard that says "your 275 will be a 275 if you mount it on X rim".

FYI, not all the tires are the same size. A 275 is not 275mm always and it can vary by more than 10mm.

 

[2008 V6]

Not trying to be rude so take it that way BUT
– Who gives a waxed albino’s whiteish ass about section width unless your rubbing or on too small or large a rim. Tread width is what contacts the surface and keeps your car glued to the ground. The sidewall is going to float all over the place trying to keep the tread in contact with whatever surface it’s on. The more you bulge the tire on a small rim the more it floats. Just like a taller profile tire.
Too wide a rim stretching that tire out trying to look like a ricer - There is no give and the tire will break LOOSE unpredictably. So it’s a balancing act on how you want the car to behave – Just like setting up you suspension.
I personally am using a 265-40-18 tire - tread width 10.2 on a 9.5” rim. Not anywhere near optimum for fast lap times BUT my coordination, timing, balls, stamina and skill seem to have disappeared (Well lets say they aren’t what I remember them to be) so I’m trying to learn how to drive again. My rim / tire combo is very predictable combination and learning tool. Sure, I can run better, wider tires and/ or slicks on my boat and go a FCK of a lot faster but when I am maxed out at in turn (Having a blast) it’s easily controllable lower speed where as if I were on wider / better tires that would Jump to much higher speeds with less communication on breakaway. Much larger Pucker factor for my current skill set.
I still stand by my basic rule set - Tread width ½” wider than rim width max for best communication on a high performance street tire.