ST4 Tire tutorial

[esr]

Can someone give a general classification of the most common tires for ST4

 

Thanks

[esr]

I am told that te Hoosier r6 or r7 can't remember which one is the way to go(written down at work)

A BFg r1 would be a bit slower but last longer.

 

 

uote="esr"]Can someone give a general classification of the most common tires for ST4

 

Thanks

[djqd36]

Most common tire is going to be a Hoosier R7, possibly an A7 although this will depended heavily on the cars ability to get close to the weight/power ratio.

[Greg G.]

Can someone give a general classification of the most common tires for ST4

 

Thanks

I would think that we will see R7, RR, R1, RS, Z214 (C71), RC-1, and TD as the most common, with the Autocross tires for those that are under powered (A7, R1S, RS AC, Z214 (C91).

[flier129]

Greg, could you confirm something for us all. Under 7.3.1 - 4)Maximum tire size in ST4 is 275mm. Under ST 7.4.2 Modification Factors - Size 275 to 250 (DOT-approved) = +0.3 . So does this mean ALL ST4 cars get that +0.3?

[Greg G.]

Greg, could you confirm something for us all. Under 7.3.1 - 4)Maximum tire size in ST4 is 275mm. Under ST 7.4.2 Modification Factors - Size 275 to 250 (DOT-approved) = +0.3 . So does this mean ALL ST4 cars get that +0.3?

No, it means that all ST4 cars get the +0.3 or the +0.7 for 245mm or smaller tires.

[JHo]

Greg, could you confirm something for us all. Under 7.3.1 - 4)Maximum tire size in ST4 is 275mm. Under ST 7.4.2 Modification Factors - Size 275 to 250 (DOT-approved) = +0.3 . So does this mean ALL ST4 cars get that +0.3?

No, it means that all ST4 cars get the +0.3 or the +0.7 for 245mm or smaller tires.

 

If that's the case, why is the base ratio not 12.3:1? These two tire rules functionally make the ST4 base ration 11.7:1 and pushes us closer to ST3.

[Greg G.]

Greg, could you confirm something for us all. Under 7.3.1 - 4)Maximum tire size in ST4 is 275mm. Under ST 7.4.2 Modification Factors - Size 275 to 250 (DOT-approved) = +0.3 . So does this mean ALL ST4 cars get that +0.3?

No, it means that all ST4 cars get the +0.3 or the +0.7 for 245mm or smaller tires.

 

If that's the case, why is the base ratio not 12.3:1? These two tire rules functionally make the ST4 base ration 11.7:1 and pushes us closer to ST3.

Really? And by your logic then, since many (if not most) ST3 cars are on 275's, then ST3 is functionally 9.7:1.

It makes it easier to move from one class to the other if the tire size Mod Factors are the same.

[JHo]

Really? And by your logic then, since many (if not most) ST3 cars are on 275's, then ST3 is functionally 9.7:1.

It makes it easier to move from one class to the other if the tire size Mod Factors are the same.

 

There is a difference between people choosing to run a 275 to get a break on the power to weight and people being forced to run a 275 by rule. I know it's in the minority but there are several people in my region who have expressed an interest in running wider than 275 in ST4 but can't.

[esr]

In my opinion the Toyo proxes rr 275 or an even harder tire should put you at 12:1.

Any one wanting to go much faster than this should and can probably afford st3.

It seems to me that at this rate you guys will kill st3.

St4 needs to be a good bit slower than st4

Looks like we have a bunch of st3 rejects wanting to go to st4 and not wanting to start fresh. This is a bad way to create something that will grow.

 

 

 

Really? And by your logic then, since many (if not most) ST3 cars are on 275's, then ST3 is functionally 9.7:1.

It makes it easier to move from one class to the other if the tire size Mod Factors are the same.

 

There is a difference between people choosing to run a 275 to get a break on the power to weight and people being forced to run a 275 by rule. I know it's in the minority but there are several people in my region who have expressed an interest in running wider than 275 in ST4 but can't.

[esr]

Having a class in a grass roots series at the lowest levels of racing where you have to run a Hoosier tire at 400 plus dollars each seems very short sighted!

 

 

 

quote="esr"]In my opinion the Toyo proxes rr 275 or an even harder tire should put you at 12:1.

Any one wanting to go much faster than this should and can probably afford st3.

It seems to me that at this rate you guys will kill st3.

St4 needs to be a good bit slower than st4

Looks like we have a bunch of st3 rejects wanting to go to st4 and not wanting to start fresh. This is a bad way to create something that will grow.

 

 

 

Really? And by your logic then, since many (if not most) ST3 cars are on 275's, then ST3 is functionally 9.7:1.

It makes it easier to move from one class to the other if the tire size Mod Factors are the same.

 

There is a difference between people choosing to run a 275 to get a break on the power to weight and people being forced to run a 275 by rule. I know it's in the minority but there are several people in my region who have expressed an interest in running wider than 275 in ST4 but can't.

[Roninph3]

Having a class in a grass roots series at the lowest levels of racing where you have to run a Hoosier tire at 400 plus dollars each seems very short sighted!

 

 

 

quote="esr"]In my opinion the Toyo proxes rr 275 or an even harder tire should put you at 12:1.

Any one wanting to go much faster than this should and can probably afford st3.

It seems to me that at this rate you guys will kill st3.

St4 needs to be a good bit slower than st4

Looks like we have a bunch of st3 rejects wanting to go to st4 and not wanting to start fresh. This is a bad way to create something that will grow.

 

 

 

Really? And by your logic then, since many (if not most) ST3 cars are on 275's, then ST3 is functionally 9.7:1.

It makes it easier to move from one class to the other if the tire size Mod Factors are the same.

 

There is a difference between people choosing to run a 275 to get a break on the power to weight and people being forced to run a 275 by rule. I know it's in the minority but there are several people in my region who have expressed an interest in running wider than 275 in ST4 but can't.

 

 

I agree here as well....I'd rather have an ST4 restriction to hard tires like Nitto NT01 (Shaving allowed) being the stickiest possible rubber for ST4, or possibly Toyo RR. This would make more sense than the aero rules as stated and would level the playing field a bit. At this rate I don't care how your car is configured otherwise, you WILL be 2-3 seconds a lap slower if you are not running the widest allowable hoosiers for your car. ST$ is not going to cost me a penny less than running ST3. Actually more after I replace my fenders, LOL!

[Brian L.]

Having a class in a grass roots series at the lowest levels of racing where you have to run a Hoosier tire at 400 plus dollars each seems very short sighted!

 

 

 

quote="esr"]In my opinion the Toyo proxes rr 275 or an even harder tire should put you at 12:1.

Any one wanting to go much faster than this should and can probably afford st3.

It seems to me that at this rate you guys will kill st3.

St4 needs to be a good bit slower than st4

Looks like we have a bunch of st3 rejects wanting to go to st4 and not wanting to start fresh. This is a bad way to create something that will grow.

 

 

 

Really? And by your logic then, since many (if not most) ST3 cars are on 275's, then ST3 is functionally 9.7:1.

It makes it easier to move from one class to the other if the tire size Mod Factors are the same.

 

There is a difference between people choosing to run a 275 to get a break on the power to weight and people being forced to run a 275 by rule. I know it's in the minority but there are several people in my region who have expressed an interest in running wider than 275 in ST4 but can't.

 

ST is by no means the "lowest level of racing" in regards to cost. It is by no means the least expensive class in NASA, and it doesn't claim to be. This isn't a spec class, and no one wants a spec tire. These are fairly high HP cars with decent aero and the flexibility in the rules to highly develop the chassis. If you can afford to build a car for ST, I would be very surprised if you can't afford the difference between Hoosiers or other semi slick tires and a set Toyo's.

 

Your statement about ST3 rejects is also quite out of place. There are a ton of people who are building fresh cars for ST4, or modifying existing ST3 cars because ST4 will be a less expense class. Not sure how this makes them rejects...

 

 

Oh yeah, Hoosier are NOT $400 + a tire, have you actually looked at prices?

[Brian L.]

 

I agree here as well....I'd rather have an ST4 restriction to hard tires like Nitto NT01 (Shaving allowed) being the stickiest possible rubber for ST4, or possibly Toyo RR. This would make more sense than the aero rules as stated and would level the playing field a bit. At this rate I don't care how your car is configured otherwise, you WILL be 2-3 seconds a lap slower if you are not running the widest allowable hoosiers for your car. ST$ is not going to cost me a penny less than running ST3. Actually more after I replace my fenders, LOL!

 

If ST4 isn't going to cost you less than ST3, you weren't taking full advantage of the ST3 rules .

 

ST4 will be much less expensive than ST3. Less power = a lot of stock motor's will be able to make power to weight. Less tire, the top ST3 guys in Norcal were on 295's. Less aero = less test time costs. No non production mods, the winning ST3 car's for the last couple of years have all done major chassis fab and had to take non prod points. No sequentials, penalties for A7's, etc. etc.

[Roninph3]

Brian,

 

My car was OBVIOUSLY not maximized to ST3 rules...I was talking about the fact that specific to MY level of Prep it was going to cost as much. It's an entry level ST class. I'd gladly race on Nitto...matters little. My car is competitive for ST4. My car was at 12:1 in ST3. So no more whining from me! Looking forward to April and Thill. Can't come out in March, but itching to go!!

[esr]

How will an autox tire hold up (A7,C91) in a 3100lbs car?

Will go the full weekend?

Summer?

Anyone with first hand experience?

 

Can someone give a general classification of the most common tires for ST4

 

Thanks

I would think that we will see R7, RR, R1, RS, Z214 (C71), RC-1, and TD as the most common, with the Autocross tires for those that are under powered (A7, R1S, RS AC, Z214 (C91).

[brkntrxn]

How will an autox tire hold up (A7,C91) in a 3100lbs car?

Will go the full weekend?

Summer?

Anyone with first hand experience?

 

Can someone give a general classification of the most common tires for ST4

 

Thanks

I would think that we will see R7, RR, R1, RS, Z214 (C71), RC-1, and TD as the most common, with the Autocross tires for those that are under powered (A7, R1S, RS AC, Z214 (C91).

 

 

Start paying attention to the tires on the ST3, ST2, ST1 podium cars and you will see.

[scotts300]

 

 

Start paying attention to the tires on the ST3, ST2, ST1 podium cars and you will see.

 

HoHoHo. . .

 

Which reminds me of the Green Giant vegetable commercials from the 90s "Ho-ho-ho, Green Giant"

[mmmbrap]

So am I understanding correctly that the R7 is neither a +0.5 nor a -1.0 tire? What about the TOYO RR  or NT01?