Tires... what happened to them? Does it mean anything? What next?

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Danielle Gilbert
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Tires... what happened to them? Does it mean anything? What next?

Post by Danielle Gilbert »

I came out for the practice session on Saturday 12/2 and had a wonderful time! It was so much fun zooming around, but the best part was the incredible friendliness and helpfulness of everyone I met - thanks especially to Randy for being my mentor for the day. :) I'm really excited about coming out in January.

After I got home I took a look at my tires:

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Is that all rubber that got picked up from the track? Or is it rubber that melted off my tire? I tried to pick some of it off, but it's really stuck.

Is it normal?

How much use I am putting on these tires by using them for autocross? Someone guessed I'd only get two or three more events out of them... is that true?

The tires are Michelin Pilot Super Sports.
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Rick Brown
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Re: Tires... what happened to them? Does it mean anything? What next?

Post by Rick Brown »

That's mostly what's referred to as OPR - Other Peoples Rubber! Your tire wear looks pretty even to me. One of the other Vette people will have to chime in on expected tire life, but two or three events sounds low, although there is a big difference between 12+ runs at a practice and 4 on Sunday. Driving style has an effect also, smooth is tire friendly, too aggressive and/or drifting in corners increases wear and is generally not faster. Those who have ridden with you can give feedback in that area.

It was nice to meet you and definitely great to see you coming off course with that big smile after every run!
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Randy Gonzalez
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Re: Tires... what happened to them? Does it mean anything? What next?

Post by Randy Gonzalez »

FYI: Unfortunately, tires will probably be your biggest expense autocrossing. And, as you know, Corvette tires aren't cheap! But that being said, you'll be able to use your tires a heck of a lot more than 3 or 4 events.

As Rick said, the junk on your tires is OPR and nothing to be concerned about. Your driving style will have a significant impact on longevity. You were riding with a lot of fast people, so you were driving pretty aggressive by the end of the day ( :thumbup: ). Of course, that newly found aggression meant you were sometimes a bit too hot into some of the turns and plowing a bit (understeer) which is pretty hard on your front tires (i.e. they're turned sideways while the car is pushing forward just grinding at them). As you get your aggression dialed back appropriately, that radical wear will go away (and you'll be faster too!).

I drove on 2 separate set of PSS's when I first started. As we discussed, PSS's are sensitive to too much heat....if you let them get too hot, you'll have chunks falling out of the outer shoulders. My first set I didn't water at all (and I was the king of overcooking every corner and understeering like a fool). After one hot summer practice, I looked at my tires...and they were missing big 1/2 inch chunks in the shoulders....still plenty of tread...but chunks missing and exposed cords. So after getting the "get a tire sprayer" advice, I put on another set. Religiously keeping them cool did really help extend the second set (and of course having Tom Berry rolling his eyes and shaking his head after every lap that I over cooked everything may have helped a bit too!). Those PSS's lasted much longer than the first set (better driving on my part and better heat management as well). But....after 2 sets, I decided that the PSS's didn't have the "shoulders" for the excessive edge wear of autocross and started looking at other tires.

That being said, I wouldn't recommend buying tires any time soon. You've got a decent set of tires to start with, and working on your driving skills will yield far better return than throwing money at tires at this point. As I remember, my PSS's lasted over a year of autocrossing and daily driving (and I was autocrossing more than just SCCA events) each set. You're going to wear those tires for sure, but assuming you jumped in with both feet and start attending every event and practice I'd be surprised if you don't get at least a season or more out of them.

Real World Numbers: You drove my car with Rival-S all the way around (Rival S are one of the competitive street tires available in Vette sizes). The Rival-S is a softer tire than the PSS and you wouldn't expect them to last anywhere near as long as PSS. Those tires have about 220 laps on the rears and about 180 laps on the fronts (and maybe 6-7K daily driving miles). They are close to done (at least for competition)...but I'll probably use them at least a few more practice days. I tend to drive my tires till they are completely toast just to keep my budget down where I can. The tires were competitive till about 140 laps....and then slowly have fallen off a bit. That being said, I had some great results with those same tires this last weekend, so no need to scrap them quite yet!

Anyway, our tire gurus may chime in here with some additional thoughts for ya! :thumbup:
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Ed T
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Re: Tires... what happened to them? Does it mean anything? What next?

Post by Ed T »

Check out my brand new tires at Nationals with gobs of OPR on the inside edge after only the Test n Tune course. :D I had about 10x more after both days of competition.

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Danielle Gilbert
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Re: Tires... what happened to them? Does it mean anything? What next?

Post by Danielle Gilbert »

Thanks for the reassurance! I was worried about my possible longevity in this sport if a set of tires was good for only a couple outings.

What happens to the OPR, eventually? Does it fall off? Does it melt/merge into your tire? Does it just live there forever? I guess I'll find out...

Smooth is fast, yep, got that... now I need to figure out how to be smooth. I've been practicing at braking before turns and accelerating away (as much as I can on the street). I also have been doing a bunch of reading, but that doesn't help too much without seat time.

Any recommendations for the tire sprayer? One with a metal stem, right? Anything else?

Also, it sounds like you track the number of laps on your tires. What other data about your runs is important to keep?
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Re: Tires... what happened to them? Does it mean anything? What next?

Post by Ed T »

Danielle Gilbert wrote:Thanks for the reassurance! I was worried about my possible longevity in this sport if a set of tires was good for only a couple outings.

What happens to the OPR, eventually? Does it fall off? Does it melt/merge into your tire? Does it just live there forever? I guess I'll find out...

Smooth is fast, yep, got that... now I need to figure out how to be smooth. I've been practicing at braking before turns and accelerating away (as much as I can on the street). I also have been doing a bunch of reading, but that doesn't help too much without seat time.

Any recommendations for the tire sprayer? One with a metal stem, right? Anything else?

Also, it sounds like you track the number of laps on your tires. What other data about your runs is important to keep?
OPR eventually falls off with highway driving. What we did at the Nationals in Lincoln, Nebraska was that there is a wet skidpad set up for cars to do donuts in a controlled environment in order to scrub off the OPR very quickly. Some people use electric scrapers to scrape off the OPR between or after competition runs. But honestly, the OPR on your tires don't look very bad at all. They will fall off eventually after some driving.

Any tire sprayer would work, I picked up a $9 sprayer from Amazon and it's all plastic. The metal ones are nicer but I've had my sprayer hose+nozzle run over by other cars in grid before and it survived. :lol:

If you have an iPhone, I used an $8 app called TrackAddict as my datalogger. It's very easy to use and very affordable. If you come find me during one of the Saturday practice days, I can show you the app and even try running it in your car for a few runs.
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Randy Gonzalez
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Re: Tires... what happened to them? Does it mean anything? What next?

Post by Randy Gonzalez »

I don't know that there's any preferred water sprayer brand, but the metal stem is a good call. You'll have to decide between a 1 Gal and a 2 Gal sprayer. A one gallon sprayer is perfectly adequate for 95% of events (and much lighter, etc.). But, your car has wider tires, so on hot practice days in the summer, you may go through a lot of water (more than a gallon). 2 gallon sprayers hold plenty of water even for the hottest days and/or co-driving, but....a 2 gallon sprayer won't typically fit in your back hatch standing completely upright (mine doesn't). So, if you go with a 2 gallon sprayer, you'll have to lay it down in the back (mine's never leaked) or put it on the passenger seat floor (where it'll bump up against your glove box and scratch it if you don't put a towel over it). Matthew has ridden shotgun to many an event straddling the water sprayer! :lol:

That all being said, over they years, I've never had a problem borrowing a little water from someone when I've run out, and a 2 gallon sprayer might be a bit much to haul around every event. Kyoo (Q) has a 1 gallon sprayer and never seems to run out. I co-drive with my kid a lot, so my needs might be a little more than his. Sorry....don't mean to make a simple decision complicated...just some thoughts for you. You can pick up a sprayer at any Lowes or Home Depot (or wherever).

And don't forget to put your name on it. We have water sprayers left on-site at just about every event. We put them all in our "lost and found" (the passenger seat of the motorhome). Putting your name on it might get it back to you faster in the event that you do accidentally leave it in grid! :)
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Rick Brown
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Re: Tires... what happened to them? Does it mean anything? What next?

Post by Rick Brown »

Randy Gonzalez wrote: And don't forget to put your name on it. We have water sprayers left on-site at just about every event. We put them all in our "lost and found" (the passenger seat of the motorhome). Putting your name on it might get it back to you faster in the event that you do accidentally leave it in grid! :)
Lost and found stuff from the previous year is put out at the first event and is free on a first come-first serve basis. I think we have two or three now, you might find one there.
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