Dirty Howie

Some of you already have given me input

These tires were almost new when I got them. I put 3 or maybe 4 (can't remember right now) track days on them. The fronts have worn much worse that the rears. I was running 28-30 cold and they were heating up to 37-38. I did rotate the front wheels to balance the wear I was seeing on the outside (mostly drivers front ... WSIR) after last track day. I have used several different tires before but all even the Nitto R2 had tread across the whole tire, not just two grooves down the middle. So I didn't realize how thin the rubber actually is on these tires

Here are pictures that pretty much show how there is NO wear on the inside, the center grooves are still deep, but the outside couple of inches is severely beveled and some chording is present.

My questions are:
1. would you drive to the track and do a full day on this tire
2. what camber setting will help prevent this (I will be flipping tires next set before this happens again)
3. would lower tire pressure help

Any other comments .... Thanks








DH

tmak26b

Lower tire pressure would wear them out even faster. It looks like you just dont have enough camber

gonzalezfj

Your pictures are typical of a camber-challenged car. Hoosier recommends 2 to 3 degrees of negative camber, especially in the front.

I run -2.7 front, -1.7 rear camber, and reverse the tires on the rim at about half life. From the look of your tires, I would guess you are running about -1 degrees of camber. Also, you don't know what was done to those tires before you got them.

I can run the whole season on two sets of new A6s. You should be able to run pretty much all season (6 to 8 events) on a new set of R6 if you do the above.

YMMV

Frank Gonzalez

linutux

From https://www.hoosiertire.com/Tctips.htm

fatbillybob

Howie,

Your tire is done. That is cord showing you need new tires. I have similar issues and have some suspicions that I have not tested out yet. First the vettes are set up to understeer for safety and or naturally do that because they are nose heavy. My thinking is that weight on the front kills those tires as does chassis understeer causing you to have to throttle steer to get the car to turn or back off the gas to get ti pointed and then on the throttle. So weight kills the tires and understeer kills the tires. static Camber may not be a problem. Dynamic decambering may be the problem compensated for by lots of static camber. I'm running -2 which is about as much as I can get on stock camber cams and very mild lowering. The very soft rubber bushings in the control arms move and allow decambering upon corning. Somewhere one of the T1 racers has video footage of the massive movement of the control arms in the bushings. It is down right freightening. I'm limited by scca rules but you are not. You may experiment with urethane or poly bushings and if your alignment stays true you may not need as much camber becasue now you are not getting control arm travel. I do not know waht the C6Z has for swaybars but on the newer T1 swaybars there are 3 adjustments. Increasing bar rate may help induce more oversteer into the chassis and help take some pressure off the front tires. All I can play with is static camber and rear swaybar. See what adjustments you can play with or toys you can buy to control how your suspension works. Finally, we all know what hoosier says about tire pressures and you are correct for what hoosier says. However, Hoosier does not explain how the T1 racers are totally misusing the A6 tire and getting better than R6 performance. Anyway, lots of guys and maybe you do not have the tire properly matched to the rim width. This can change the even operating temp of the tire when hoosier's pressure recs are followed. So consider using a pyrometer in the hot pits and adjust pressures starting from the hoosier rec hot pressures. That way you will dial in the real hot pressure your car and your driving style wants to see. Then you have optimized your tires at this time. When you drive the car now you can eval for over/understeer and then maybe adjust swaybars or consider messing with camber or bushings. Personally, if you are not limited by rules I say get some good bushings first otherwise the static camber will not mean very much because your control arms will be moving all over the place.

CHJ In Virginia

1) That tire is toast
2) Hoosier recommends a lot of camber - have your alignment guy turn in as much as you can get with the stock equipment. Also check the toe which can eat a tire in a similar fashion. There have been many posts about overall specs on alignment for track days and tire longevity.
3) I start at 26-28 PSI front and 1-2 more in the rear depending on ambient temps and track temp. Hotter days - 90 degree day at VIR in August = lower initial starting PSI than a 50 Degree day in March.
You did not say what size rims and what size tires -- too large a tire on a rim can also cause edge damage.

the blur

More AIR.
your not racing, so you have nothing to lose by running higher pressures.

yes, I know you took 2 seconds off your lap times by running lower pressures, but it cost you $1200 worth of rubber

Sidney004

Dismount and flip the tires after two or three events in addition to the rotation. Though I do not recommend it, I flipped tires with this amount of cording to the non wearing inside with no ill effects.

vms4evr

I've got -2.0 front and -1.4 rear camber. I run R6s and don't have that problem. The edge rounds and you do need to flip them after a couple of weekends. I start with 34/30 for pressure. Then bleed off if they get to 40lbs.

sperkins

I wouldn't trust that tire at 50mph, much less at 150mph.

fatbillybob

you were lucky...don't do it. flipping is fine but not using a corded tire. 3 weeks ago I blew my second tire on track and nearly took out half a dozen cars. Fortunately there was not even a scratch not because of my skill but because of the other racers around moving off in all directions. Then there was the time I blew my first tire only to spin and nearly hit a wall. Again...no problems. I got lucky twice. I have corded many many tires too and corded tires just are not fast or fun...they are just "done".

Dirty Howie

Carl

Thanks for all your input and insight. But I made a decision when I bought this car ........ its staying stock. So I will not mess with the suspension, I haven't even lowered this thing. I would go to the MAX stock spec on camber or any other alignment component. The tires are on stock OEM wheels. AND its my daily driver ........ getting near 22K miles in less than one year ...... so I have to consider tire wear on my street tires too. Maybe I have chosen the wrong tire. I might need to switch to the Pilot Sport Cup which may not be too expensive if the Hoosiers are going to last half as long!!!!!!


DH

Dirty Howie

Car has the stock alignment so I have no idea what the Toe is any more than the Camber ..... thanks for that tip.

The Hoosiers are exact size as stock and are mounted on stock OEM wheels ........ 275x35x18 and 325x30x19.


DH

Dirty Howie

I'm starting at 30 cold which is the same or more than everyone else I have checked with and have seen the pressure consistantly at 38.

Tire says MAX is 40


DH

Dirty Howie

It bums me out but I guess I will follow the consensus and trash the tire


DH

gonzalezfj

There is no way around it, Howie. The corded tires are toast. Period.

It is very difficult, if not impossible to set a street-driven Corvette for use at the track. The alignment requirements are too different.

If you run an unknown alignment, especially if it started as a street alignment, you are not giving your tires a chance to survive at the track. I don't care what tires you run (Hoosier, GY, PS2 or whatever) you will need more negative camber at the track than you need on the street.

Now is the time to face what you really want your car to do: street or serious track car, and set it up accordingly.

If you must have a dual-purpose car, you can probably get away with around -2 degrees of camber up front and about -1.5 in the rear. This will not kill your street tires, while giving your rack tires a chance to survive.

You WILL need to flip the tires on the wheels to use both edges before you cord them. Most HPDE Vette drivers do this.

While it is true that the OEM bushings deflect considerably under load, you don't need hard bushings to enjoy your car at the track.

By the way, Hoosiers (both A6s and R6s) come fromt he factory with little "dimples" on the tread that allow you to see how much tread rubber is left around the periphery of the tire. Use them to decide when to flip the tire.

Best of luck on your track adventures,
Frank Gonzalez

Olitho

Kumho V710s are much more resilient and durable to shoulder cording than the Hoosier R series.

While Frank is right that it is hard to compromise between your two purposed Howie, the V710 is a much better choice in this compromise. It will be a faster tire in my opinion than the Hoosier R6 overall, wear better for your purposes. It will be just as fast as the A6 on the first four to five laps as the A6 and then be within 1/2 second per lap after that. ...at least that is my experience.

The bottom line is that while I prefer the A6, for your purposes I think the V710 will last at least twice as long, be more resistant to shoulder cording and cost about $100 less per set.

Bill Dearborn

I can buy used 710s (with 3 to 4 heat cycles) and get almost a season of HPDEs and autocrossing out of them. Much better wear than Hoosiers. The older Hoosiers were really bad at wearing out the edges and the newer ones although better are still not the tire to use if you are interested in tire life.

Bill

flink

So do Hoosier Cup tires, and Nitto NT-01's.

How do you read them? For example, is the tire toast when the indicator is
completely worn away, or when it is 2/3rds gone, or...?

gonzalezfj

When the dimples are gone you are essentially out of tread. The smart thing to do is to flip the tire on the rim when the dimples on the outboard edge are about half depth compared to the inboard edge. This gives you maximum tire life.

Frank Gonzalez