S197 Tire Fitment...

[rasalone]

Any reason why 19 vs 18? I always found that there are more tire options in 18. The 18s still fit over the Brembos if you get the right ones like from Vorshlag. Side note I am selling my 18x10 forgestar f14 wheels I got from Vorshlag.

 

[neema]

OD in 19" tires are a little more suitable (not sure what defines suitable, TBH) but plenty of folks run sub 26" OD tires on 18s, particularly on Hoosiers. Only 26" plus OD wide 18s are NT01s and R888s, RS4s, and 615s

305/30/19 is a pretty common size. Anyone know why Kumho V720s are so much cheaper than everything else?

 

[Coz]

Tire wear and temps are higher on the inside half of the tire compared to the outside, even with 2.6° camber.

What are your toe settings? 0 toe should result in minimal inside wear. Also, uneven temps may be due to improper pressure. If one side is higher then pressure is probably too low.

 

[neema]

What are your toe settings? 0 toe should result in minimal inside wear. Also, uneven temps may be due to improper pressure. If one side is higher then pressure is probably too low.

0 toe

(Sorry for continuing the thread jacking)

 

[modernbeat]

Any reason why 19 vs 18? I always found that there are more tire options in 18. The 18s still fit over the Brembos...

The reason to go to 19" wheels, is that you might want to do double duty on the tires and want something closer to stock height. And recently (in the last few years) more fast 19" tires have come out that are great for HPDE events, and casual TT events. There are more wheels that fit over the brakes, and the cost difference between the 19" and 18" street tires isn't too much over the life of the tires in the street tire category. Right now I have a lot of customers on the RS4 that are almost as fast as they were on more fragile street tires, yet they last for months instead of hours.

The wide tires in the 18" category has really turned to just competition tires. The absolute fastest of the street tires and the Hoosiers are just about the only tires in that diameter any more. For competition use, they are the hot ticket. And since they will be replaced frequently, the slightly less costly tire price is welcome. They are short, which helps us with aero and fitment, and you have to be a little more careful with brake and wheel fitment.

 

[blacksheep-1]

I hear this everywhere. Riddle me this:

My car has MM (looking) camber plates, Howe extended ball joints, and a MM K Member with raised LCA pickups. Max camber is 2.6°, ride height is low but not slammed (26.75" with a 26" OD tire) and control arms are level.

Tire wear and temps are higher on the inside half of the tire compared to the outside, even with 2.6° camber. Dare I say the camber curve is pretty effective and I don't need any more camber? Or am I being a weeny and there's actually more steering input that can be dialed in?

Well..it depends, more autocrosses are cut and thrust style of driving, roadracing is much different, IMO camber would help even more in an autocross environment, most guys around here are cutting into their strut towers to give even more camber. Don't worry so much about the tire temps being even across the width of the tire. as an example:

COTA/ Pirelli/ Mustang
214 198 206 199 199 212
195 208 206 199 208 181
vs
Daytona/ SCCA/Mustang
140 153 194 199 182 184
188 187 181 140 185 167
vs
Barber/Pirelli/Mustang
187 182 186 188 133 123
188 186 178 175 168 146

in the first example COTA is all pretty sweeping corners with an F1 rated asphalt, all fairly close together
in Example 2. it would appear that the car has too much camber, but we all know that's crap, because the car has to get through the banking, I'm sure, in the banking the outside of RF and inside of LF are heating up significantly more than is shown.
Example 3, at Barber is more of a cut and thrust track, so the numbers have all settled down, those numbers were also just 8 laps. 3 totally different tracks.
Here's an outstanding set of numbers..(the real pressure numbers are bogus, but they reflect how close they actually were since I guard those.) but the psi spread and the temps are legit.

 

[neema]

My mind is blown. All this time I thought the way to speed was spreading temp/wear across the tire.

Thanks for the info

 

[Coz]

Tyres must work differently than tires.

 

[TymeSlayer]

It's Tyre Tyme!

 

[s9669s]

For me...19's primarily because the car has 3.73's, and I want to preserve as much speed as possible at the top of 2nd until I swap the gears and diff some time down the road (autocross car, not track car).

Right now, I think my top candidate for rolling stock is 19x10.5 ET45 which I think should fit a 285/35 RE71R with no spacer (or may need 3-5mm). I think that allows me to grow to a 305/30-19 [Rival 1.5 or RE71R] when I am ready to do extended studs and bigger spacers, without having to buy another set of wheels.

Anyone have experience running 19x10.5 ET45 with either of these tires? How much spacer is needed?

[Suspension setup is Koni Sports, MM plates, and BMR Handling springs...]

 

[Champale]

Would depend on what wheel you are looking at. I run 20x10.5 ET45 at all 4 wheels with 285/35/20 PSS tires and had to use a 3mm spacer up front to clear the Brembos but I would guess you might not need a spacer with the regular brakes.

As for 305s on a 10.5 ET45 wheel, I tried 305/30/20 PSS and even 295/30/20 PSS and got rub. I even had 3mm shaved off the hub side of the wheel and still got rub. Now the PSS runs pretty wide and these tires would be 1/2" taller at the top side than the 305/30/19 but my car isn't exactly slammed - I think your BMRs might actually sit the car lower than mine is set up. If I were going to go with 10.5 wheel again, I would want ET50-52 for the back.

 

[DaveW]

For me...19's primarily because the car has 3.73's, and I want to preserve as much speed as possible at the top of 2nd until I swap the gears and diff some time down the road (autocross car, not track car).

Right now, I think my top candidate for rolling stock is 19x10.5 ET45 which I think should fit a 285/35 RE71R with no spacer (or may need 3-5mm). I think that allows me to grow to a 305/30-19 [Rival 1.5 or RE71R] when I am ready to do extended studs and bigger spacers, without having to buy another set of wheels.

Anyone have experience running 19x10.5 ET45 with either of these tires? How much spacer is needed?

[Suspension setup is Koni Sports, MM plates, and BMR Handling springs...]

I don't know if the new Rival is like this, but the RE71 does not like being squeezed on a wheel...so I am not 100% sure how well a 305 would work on a 10.5" wide wheel. It is not squeezed on an 11, but the people who have put them on 11.5 or 12 have reported good results.

DaveW

 

[blacksheep-1]

My mind is blown. All this time I thought the way to speed was spreading temp/wear across the tire.

Thanks for the info

That's a common misconception. all of these measurements are just another tool to work with, you can't hang your hat on them and say "only this way works"

 

[s9669s]

Would depend on what wheel you are looking at. I run 20x10.5 ET45 at all 4 wheels with 285/35/20 PSS tires and had to use a 3mm spacer up front to clear the Brembos but I would guess you might not need a spacer with the regular brakes.

As for 305s on a 10.5 ET45 wheel, I tried 305/30/20 PSS and even 295/30/20 PSS and got rub. I even had 3mm shaved off the hub side of the wheel and still got rub. Now the PSS runs pretty wide and these tires would be 1/2" taller at the top side than the 305/30/19 but my car isn't exactly slammed - I think your BMRs might actually sit the car lower than mine is set up. If I were going to go with 10.5 wheel again, I would want ET50-52 for the back.

Re: front clearance... In the front, what are you running for struts/springs? With the 3mm spacer, how is clearance to the strut body and sway bar endlink bolt? Are you able to run 295's/305's up front with just the 3mm spacer?

With 295's/305's, where is the rub? From your message, I want to assume rear fender lips (outer)? If so, that is a bit of a surprise given others running 315's on ET50, which should measure out about the same as a 305 on ET45 in terms of outboard clearance...except for the larger OD on your setup.

 

[Champale]

Hey s9669s - I have never run anything bigger than 285 up front with those wheels (285/30/20 and 285/35/20) so hard for me to comment. I am on KW V3 coilovers with MM cc plates at 1.8 degrees. I trimmed the upper swaybar bolt a long time ago when I was running 19x10 ET47 (LS rear wheels) up front with 285/35/19 RE-11s. I'd have to get under the car to tell you exactly how much clearance I have to the coilover but its not a whole lot if I recall.

Yeah I listened to all sorts of 'experts' on other forums who told me my rear tires wouldn't rub with that offset. False false false. Again the Pilot Super Sport is a very wide tire compared to others so take my info for whatever it's worth and these are 20s, so a taller overall tire (although a 305/30/20 is barely taller than OE 285/35/19). And yes, the outer edge of tire would rub at the top of the fender lip, as evidenced by shiny strip on sidewall where it met the tread and also there were rubber deposits on the top inner edge of the fender. I drive my cars pretty hard, no trackdays just lots of backroad corners, some with a lot of bumps and ripples that really test a suspension.

 

[s9669s]

Just to close the loop on this...

285/35-19 RE71's on 19x10.5 ET45 makes a nice square setup. I am running a 3mm spacer for strut clearance similar to Champale, but may be able to get away without it.

On a car that originally came on 18's (which may mean greater steering angle?), I am getting some fender liner rub on front, and at full lock the tire touches the frame rail (in front of the axle, both sides--no contact on the backside). I am not sure yet if the fender liner contact is only in parking situations, or in a loaded chassis plus steering input (autocross) condition.

No issues at all in the rear on 285's, but 305's may be close.

 

[KRyn]

@DaveW

They should fit. I am using 19x11 +50 wheels with a 25mm spacer in front. I have done this setup on another car too, Mine has JRi struts and the other has KW.

But, unfortunately, there is no single universal answer. I had a set of Vorshlag fitment Forgestars that required a spacer in the front to clear my particular strut setup at the time..not Vorshlag's fault, just a stack up of what I had on my car at the time.

Spacers are no issue, especially when it is a matter of when, not if, the stock front hubs will fail and the Ford Racing ones are so cheap with the long studs in them already.

DaveW

Dave I enjoy doing a couple of track days a year as well as a number of auto-x events. Currently I am only planning to modify my Boss with a set of MM camber plates, I am trying to decide between 18x10, 18x11 or a 19x11 setup.

From my research and thinking on the matter, the 18x10 seems to be the most ideal setup. My thoughts are to run RS4s (285/35 or 295/40) for triple duty: street driving (very minimal during summer), auto-x and track days. I can't think of any other decently priced tire that can perform all three duties that would actually take advantage of a 11" rim.

A 19x11 would allow the car to have a higher top speed in 2nd which would be a benefit for auto-x, but I feel the increased cost and weight outweigh the gearing advantage. The only other net benefit to going with a 19" is the car will not have the 4x4 look as the rims/tires will fill the wheel wells better as I don't plan on coilovers or lowering springs anytime soon. Also, fitting anything larger than a 305 becomes a challenge without suspension modification how much more grip will a 305 have vs a 295?

Open to all suggestions and thoughts.

 

[Bill Pemberton]

Once a driver starts thinking about another set of rims I immediately want to suggest keeping their old rims and use the new rims/tires to the maximum effect. You have the tires and wheels to drive around on, but once you want to go to the track or autocross, you can now open yourself to a World of choices. Your rims on the Stang are paid for, likely the rubber on them , and often they are in good shape for just cruising. Now you have the chance to get your new rims/tires and you can be way more decisive about maximum stick at the track/autocross. For example, a set of 18x11s ( Apex) , with a set of BFG Rival S 1.5s in 315/18s means a mean mother running in a CAM Class, auto crossing. Solid tire for the track, or heck, wing it for 315/18 gforce R1s and more stick on a road course. Sure there are other choices , but this is a solid example, because three tires in the back seat, and one in the trunk is super easy with the Mustang --- jack, tools, and even duffel bag with clothes and more is a cinch.

Common practice seems to be to sell the old rims ( they bring squat) and if the rubber is still on said , it is a giveaway. Keeping them makes so much sense and was super common with a bunch of folks years back. Something to consider????

 

[KRyn]

Once a driver starts thinking about another set of rims I immediately want to suggest keeping their old rims and use the new rims/tires to the maximum effect. You have the tires and wheels to drive around on, but once you want to go to the track or autocross, you can now open yourself to a World of choices. Your rims on the Stang are paid for, likely the rubber on them , and often they are in good shape for just cruising. Now you have the chance to get your new rims/tires and you can be way more decisive about maximum stick at the track/autocross. For example, a set of 18x11s ( Apex) , with a set of BFG Rival S 1.5s in 315/18s means a mean mother running in a CAM Class, auto crossing. Solid tire for the track, or heck, wing it for 315/18 gforce R1s and more stick on a road course. Sure there are other choices , but this is a solid example, because three tires in the back seat, and one in the trunk is super easy with the Mustang --- jack, tools, and even duffel bag with clothes and more is a cinch.

Common practice seems to be to sell the old rims ( they bring squat) and if the rubber is still on said , it is a giveaway. Keeping them makes so much sense and was super common with a bunch of folks years back. Something to consider????

Bill thanks for the response.

This is a good suggestion. My Boss is a recent acquisition and the owner before me must have been a bit of an enthusiast as he put a set of PS4S tires on the car. I could keep the stock rims / tires and use them exclusively for auto-x and daily driving. Once the current tires are shot I will replace them with a set of RE71Rs.

Picking up a set of 18x11s with a more track oriented tire that will perform better and last longer makes sense. Most of the time when I attend track days I am joined by a few friends who tow their vehicles and would have space for my extra rims, tires and a few tools.

Guess I will have to research budget friendly track tires that can take advantage of a 18x11.

 

[Bill Pemberton]

Depends on whether you want to go with sticky rubber ( Hoosier R7s, BFG gforceR1s, Toyo RRs) or DOT 200 Treadwear rubber like RE71Rs, BFG Rival S 1.5, Falken RT6715Ks. REs are not in the wider sizes though Rivals and Falkens are. The Falkens will not be as fast but they should last longer.
But..........one more alternative is to buy some used Pirelli slicks at usedracingtires.com or some other company that sells the tires off the World Challenge racers or other Pro Series ( hence other slicks like Michelin ,etc. )

I put three tires ( with Tire Rack tire covers on the rubber ) and one tire in the trunk ( when I had my first Boss) , so even if your friends don't go to the track with you , you have an alternative --- though friends are a big plus if they have trailer/!