| fastwrx | 02-20-2005 11:52 PM |
Corded / Destroyed Dunlop SuperSport Race Tires today
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Hi all,
I tracked my STi today at Moroso. I'm used Dunlop SuperSport Race tires. Today was only the 2nd track day on them.
Tire pressures were 36 / 30 (front / back)... pretty much stock pressures. I check for how far they're rolling over after each session and found that these pressures worked pretty well.
Today's sessions were longer than usual... I ran about 45 minutes straight. This was the third session... and the car started feeling funny. In turns it felt almost as if I had a flat. On the straights, I could hear a buzzing sound, but the car tracked straight with no pulling to the side. Nevertheless, I decided to trust my instinct and pull into the pits. The front left tire was trashed! (Moroso runs counter-clockwise.) When I pulled into the paddock, the pressure in the front left tire was 47 psi!
Granted, I was driving harder than I've ever driven the car (Skippy school paid off!) and the sessions were longer than usual. But, this looks unusual to me.
Here are some pics:
[IMG]http://www.racingdentist.com/images/tires2005_0220aa.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220ab.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220ac.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220af.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220ah.jpg[/IMG]
I would love to hear from the experts here.
The right front was pretty worn on the outside, too... but not corded... still serviceable. The rears were fine.
Thanks!
Mike
I tracked my STi today at Moroso. I'm used Dunlop SuperSport Race tires. Today was only the 2nd track day on them.
Tire pressures were 36 / 30 (front / back)... pretty much stock pressures. I check for how far they're rolling over after each session and found that these pressures worked pretty well.
Today's sessions were longer than usual... I ran about 45 minutes straight. This was the third session... and the car started feeling funny. In turns it felt almost as if I had a flat. On the straights, I could hear a buzzing sound, but the car tracked straight with no pulling to the side. Nevertheless, I decided to trust my instinct and pull into the pits. The front left tire was trashed! (Moroso runs counter-clockwise.) When I pulled into the paddock, the pressure in the front left tire was 47 psi!
Granted, I was driving harder than I've ever driven the car (Skippy school paid off!) and the sessions were longer than usual. But, this looks unusual to me.
Here are some pics:
[IMG]http://www.racingdentist.com/images/tires2005_0220aa.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220ab.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220ac.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220af.jpg[/IMG]
[IMG]http://www.racingdentist.com/images/tires2005_0220ah.jpg[/IMG]
I would love to hear from the experts here.
The right front was pretty worn on the outside, too... but not corded... still serviceable. The rears were fine.
Thanks!
Mike
| Ruff | 02-21-2005 12:02 AM |
I'm no expert here, but how much negative camber were you running? Don't most R compounds require a good deal of negative camber? Is it possible you weren't running enough and the tire, in the corners, would be on the outer edges more then laying flat in the corners?
| fastwrx | 02-21-2005 12:04 AM |
Alignment is stock. No changes to camber.
Mike - not an expert, either
Mike - not an expert, either
| dwx | 02-21-2005 12:35 AM |
Yeah too much heat and not enough camber will destroy tires like that. Getting a good alignment and dialing in more front camber is just about the best thing you can do to the car handling wise.
| adhowe70 | 02-21-2005 01:02 AM |
Too much heat, too much air (caused by too much heat), and not enough camber (which seriously overheated the outside shoulder.) That is what's called a "blister" and you continued to drive on a few laps longer than you should have. Good call on bailing off the track.
I'd be curious to see what the tire temperatures were at, particularly on the shoulder.
I'd be curious to see what the tire temperatures were at, particularly on the shoulder.
| calworld | 02-21-2005 01:19 AM |
Sorry being off topic, but I am thinking about getting the SuperSport Race as well. What do you think of them on the track and on the street?
Thanks
Thanks
| RaceComp Engineering | 02-21-2005 01:20 AM |
I rqan those tires on my STI with 18x8 BBS RE, with a 245/35-18. They needed 45psi cold for track driving. So 36 yeah, I can see why they look like that. The other issue I take up with my students is this. You HAD to "feel" that car pushing all day. These cars talk to you and that tire went aloong for a ride.
just my .02 cents worth.
944 turbo guy
Myles
just my .02 cents worth.
944 turbo guy
Myles
| KoneKiller | 02-21-2005 02:21 AM |
I had the exact same problem after two autocrosses while running the pressures at 45. Not edge wear, but in the center third of the tread. I won't buy them again.
| fastwrx | 02-21-2005 06:42 AM |
Myles,
Yes... I did feel the car pushing as the day went on. But, I chalked that up to the general tendency of the car to push AND that I was driving so much harder than previously.
I did look at the tires between sessions, and I didn't see any hints of what was to come during the third session.
It seems you guys are saying that in addition to negative camber, I should have been running a HIGHER tire pressure than 36 psi cold?
Thanks for the input!
Mike
Yes... I did feel the car pushing as the day went on. But, I chalked that up to the general tendency of the car to push AND that I was driving so much harder than previously.
I did look at the tires between sessions, and I didn't see any hints of what was to come during the third session.
It seems you guys are saying that in addition to negative camber, I should have been running a HIGHER tire pressure than 36 psi cold?
Thanks for the input!
Mike
| RaceComp Engineering | 02-21-2005 08:01 AM |
[QUOTE=fastwrx]Myles,
Yes... I did feel the car pushing as the day went on. But, I chalked that up to the general tendency of the car to push AND that I was driving so much harder than previously.
I did look at the tires between sessions, and I didn't see any hints of what was to come during the third session.
It seems you guys are saying that in addition to negative camber, I should have been running a HIGHER tire pressure than 36 psi cold?
Thanks for the input!
Mike[/QUOTE]
Mike I was prob harder on you than I or anyone should have been. I apologize if it came off so " its your fault-ish"....If it was fine 1st and 2nd sessions and then blam, chunked in the third session, then its a tire issue.
I also think these tires would benefit from being shaved at purchase.
I do think a higher cold pressure would have helped,..but how much , we dont know.
Myles
Yes... I did feel the car pushing as the day went on. But, I chalked that up to the general tendency of the car to push AND that I was driving so much harder than previously.
I did look at the tires between sessions, and I didn't see any hints of what was to come during the third session.
It seems you guys are saying that in addition to negative camber, I should have been running a HIGHER tire pressure than 36 psi cold?
Thanks for the input!
Mike[/QUOTE]
Mike I was prob harder on you than I or anyone should have been. I apologize if it came off so " its your fault-ish"....If it was fine 1st and 2nd sessions and then blam, chunked in the third session, then its a tire issue.
I also think these tires would benefit from being shaved at purchase.
I do think a higher cold pressure would have helped,..but how much , we dont know.
Myles
| fastwrx | 02-21-2005 09:11 AM |
Myles,
I didn't take it personally. :) You are right... I was just 'splainin' myself. Someone else at the track suggested shaving the tire, too. I'm getting conflicting comments about the tire pressure, though. Some say it was too high... Some say not high enough. But, I think shaving the tire plus some negative camber would probably make a big difference.
Maybe I shouldn't drive so hard??? ;)
Mike
I didn't take it personally. :) You are right... I was just 'splainin' myself. Someone else at the track suggested shaving the tire, too. I'm getting conflicting comments about the tire pressure, though. Some say it was too high... Some say not high enough. But, I think shaving the tire plus some negative camber would probably make a big difference.
Maybe I shouldn't drive so hard??? ;)
Mike
| mav1c | 02-21-2005 09:26 AM |
Definitely an issue of not enough camber and overheating. I run -2 front camber, and that's still not quite enough, but I don't want to run any more on the street. I've heard that the sidewalls on the Dunlops are fairly soft, which may have been a contributing factor. I was thinking about trying these tires, but after seeing this....I think not. I would suggest Toyo RA-1's for your next track tire, but make sure you get some camber plates and dial in some more front camber first.
| kfoote | 02-21-2005 11:11 AM |
[QUOTE=RaceComp Engineering]..."....If it was fine 1st and 2nd sessions and then blam, chunked in the third session, then its a tire issue.
I also think these tires would benefit from being shaved at purchase.
I do think a higher cold pressure would have helped,..but how much , we dont know.
Myles [/QUOTE]
To me, this looks like exterme chunking rather than blistering or normal wear. Basically, I'd reccommend a better DOT track tire. IMO, shvaing would have helped, but may not have completely solved the problem. Moroso is fairly abrasive, and exceptionally hard on the LF tire on a car that understeers, due to several long right hand corners.
I also think these tires would benefit from being shaved at purchase.
I do think a higher cold pressure would have helped,..but how much , we dont know.
Myles [/QUOTE]
To me, this looks like exterme chunking rather than blistering or normal wear. Basically, I'd reccommend a better DOT track tire. IMO, shvaing would have helped, but may not have completely solved the problem. Moroso is fairly abrasive, and exceptionally hard on the LF tire on a car that understeers, due to several long right hand corners.
| HoRo1 | 02-21-2005 11:19 AM |
I use RA-1s and find that 30-32lbs cold will result in 40lbs when hot, so I would start with my tyres (front and rear) at 30 lbs cold, do a session, let them get hot and see where you are at the end of the first session.
I have NEVER used the tyre that you are talking about but it seems to me that;
1) there is a lot of tread visible in those photos. I would strongly recommend shaving any R-compound that is going to be used in the dry.
2) I think that you need more negative camber at the front. I run -4
3) we've never met, but maybe your driving style is a little too aggressive - throwing the car into corners where a gentler touch might work better.
4) you should check pressures after every track session so that you have some idea about which tyres are getting pounded hardest. Obviously 47 lbs is far too high.
You're lucky that tyre didn't fail catastrophically at the track. A little care and you'll be fine next time.
I have NEVER used the tyre that you are talking about but it seems to me that;
1) there is a lot of tread visible in those photos. I would strongly recommend shaving any R-compound that is going to be used in the dry.
2) I think that you need more negative camber at the front. I run -4
3) we've never met, but maybe your driving style is a little too aggressive - throwing the car into corners where a gentler touch might work better.
4) you should check pressures after every track session so that you have some idea about which tyres are getting pounded hardest. Obviously 47 lbs is far too high.
You're lucky that tyre didn't fail catastrophically at the track. A little care and you'll be fine next time.
| adhowe70 | 02-21-2005 12:32 PM |
Like any community, we have a broad spectrum of people in this forum. Not everyone has a lot of track experience and a lot of people are hitting the track for the very first time. Here's some information to help the folks that are newer to the track scene:
Shave tires that are going to be run in the dry. This will decrease the amount of tread deformation (or squirm) that is seen when cornering. Less tread deformation equates to better feel AND less heat generation in the tread of the tire. Some tires don't need to be shaved, but the vast majority are molded for wet conditions, not dry.
Until you have a good cold pressure, religiously check hot pressures and tire temperatures when you come in off the track. By using a pyrometer and checking inside, middle and outside of the tire, you'll be able to set a good hot pressure. After you have that, a little more work will net you a good cold pressure.
You have to take care of your tires and brakes. The same principle applies to both parts of the car. Your tires work best at a given temperature. Above that temperature, grip decreases and blistering and chunking increases. When you run hard every lap, things get hot and don't necesdsarily work as well. Pay diligent attention to the car's attitude when driving it. Notice if the level of grip is dropping off or if the brakes smell bad or if the pedal is getting long. If this happens, back it off for a lap or two and let things cool down.
Continued hard driving will make the problem worse. In other words, a pushy car will push more. A loose car will be come more tail happy. Understeer or oversteer indicates that a particular end of the car is being overworked. For a car that understeers, the front end is being overworked. Continuing to force the issue will only make the condition worse.
Take notes. If the car does something you don't like, write it down. Describe the problem and the circumstances when the problem is noticed. Note the circumstances from a few laps before the problem started as well. This will help you fix the problem.
Have fun! Obviously. But there's more that goes into this. Take all the necessary precautions up front. You're probably not having fun if, at the lunch break, your tires look like the pictures above. So, remember what it takes to keep your car under you and happy. This will tend to increase your track time (and fun!) and decrease your chances of having a VERY bad day.
Andy H.
Shave tires that are going to be run in the dry. This will decrease the amount of tread deformation (or squirm) that is seen when cornering. Less tread deformation equates to better feel AND less heat generation in the tread of the tire. Some tires don't need to be shaved, but the vast majority are molded for wet conditions, not dry.
Until you have a good cold pressure, religiously check hot pressures and tire temperatures when you come in off the track. By using a pyrometer and checking inside, middle and outside of the tire, you'll be able to set a good hot pressure. After you have that, a little more work will net you a good cold pressure.
You have to take care of your tires and brakes. The same principle applies to both parts of the car. Your tires work best at a given temperature. Above that temperature, grip decreases and blistering and chunking increases. When you run hard every lap, things get hot and don't necesdsarily work as well. Pay diligent attention to the car's attitude when driving it. Notice if the level of grip is dropping off or if the brakes smell bad or if the pedal is getting long. If this happens, back it off for a lap or two and let things cool down.
Continued hard driving will make the problem worse. In other words, a pushy car will push more. A loose car will be come more tail happy. Understeer or oversteer indicates that a particular end of the car is being overworked. For a car that understeers, the front end is being overworked. Continuing to force the issue will only make the condition worse.
Take notes. If the car does something you don't like, write it down. Describe the problem and the circumstances when the problem is noticed. Note the circumstances from a few laps before the problem started as well. This will help you fix the problem.
Have fun! Obviously. But there's more that goes into this. Take all the necessary precautions up front. You're probably not having fun if, at the lunch break, your tires look like the pictures above. So, remember what it takes to keep your car under you and happy. This will tend to increase your track time (and fun!) and decrease your chances of having a VERY bad day.
Andy H.
| slowstangguy | 02-21-2005 12:52 PM |
i did the same exact thing at moroso on my toyo ra1's, only made it thru the second session on the 2nd day and the front right showed chord. same tire pressures too. the car was understeering pretty bad. the stock alignment definately had alot to do with it. with it being an awd car the front tires are doing alot more work as opposed to a rwd. getting this car to rotate well can be difficult especially during turn 3 and 4 when double apexing. besides getting some negative camber in the front, getting a rear swaybar say 22mm would really help those front tires out and help get rid of that understeer when you need the car to rotate.
| slowstangguy | 02-21-2005 03:02 PM |
fastwrx i was curious about getting the dunlops in the future. what kind of lap times were you able to pull on them? on the toyos i was able to pull 1:43's but i've only taken this car out twice since i got it so still need to learn its quirks alittle more(and not run into tire problems) i know dunlops aren't the stickiest tires but for the price might be the way to go till i have my tire problem solved for sure.
| fastwrx | 02-21-2005 05:48 PM |
slowstangguy,
Just timed a couple of laps by reviewing video in my 3rd session (with an apparent serious tire problem), and I was a consistent 1:50. Not impressive, I guess... but, I consider myself a fairly conservative driver.
Getting the track tires shaved makes sense to me.
I have also been considering getting Cobb's front & rear sway bar kit.
My only dilemma is whether to spend more money on the STi, as I wonder how much I'll be tracking it once I get my Lotus Elise... due within the next couple of months! :)
Mike
Just timed a couple of laps by reviewing video in my 3rd session (with an apparent serious tire problem), and I was a consistent 1:50. Not impressive, I guess... but, I consider myself a fairly conservative driver.
Getting the track tires shaved makes sense to me.
I have also been considering getting Cobb's front & rear sway bar kit.
My only dilemma is whether to spend more money on the STi, as I wonder how much I'll be tracking it once I get my Lotus Elise... due within the next couple of months! :)
Mike
| fastwrx | 02-21-2005 05:56 PM |
Incidentally, here is a link to a quick video I made using a Canon Digital Elph mounted on the rear window. (You can see my "cone cam" mounted on the windshield.) This was in the first 15 minutes of the third session (about 45 minutes) where the tire went bad.
[URL=http://www.racingdentist.com/images/Videos/Moroso%20Feb%202005.wmv]Linky to video[/URL]
Mike
[URL=http://www.racingdentist.com/images/Videos/Moroso%20Feb%202005.wmv]Linky to video[/URL]
Mike
| majmun | 02-21-2005 05:58 PM |
Bummer man. I liked the vid though.
| slowstangguy | 02-21-2005 07:41 PM |
well now that a lotus is in the picture i wouldn't bother investing in the sti, the lotus is gonna be so much fun (slightly jealous over here)(actually really jealous):)
| fastwrx | 02-21-2005 08:33 PM |
The funny thing is even though I'm getting the Elise, I'm still in love with my STi (and keeping it, of course!). I just can't be a one-car man! ;) So, I think I'll STILL end up putting money into the STi. I don't think I can help it! It's a disease, and I don't want the cure!
BTW, since I missed the last session of the track day, I was able to snag a ride as a passenger in another car on my "short list"... a Radical! WOW! What a ride! I've gotsta get me one of them! :D
So... two cars down... three to go... Radical, Noble M12 GTO (or M400), and Ferrari 430. Just bought the property behind my house, so I can build my dream garage! :banana: It's going to take a few years to create my dream stable of cars, though. Gotta have goals, though!
Mike
BTW, since I missed the last session of the track day, I was able to snag a ride as a passenger in another car on my "short list"... a Radical! WOW! What a ride! I've gotsta get me one of them! :D
So... two cars down... three to go... Radical, Noble M12 GTO (or M400), and Ferrari 430. Just bought the property behind my house, so I can build my dream garage! :banana: It's going to take a few years to create my dream stable of cars, though. Gotta have goals, though!
Mike
| KoneKiller | 02-22-2005 08:50 AM |
Again, this is autocross experience here, not track time (the miata is for track, the subie for autocross)....
I had the Dunlosts shaved to 4/32, heat cycled, ran around 45 psi in them and still had them chunk the outside of the middle tread block in very short order. We even spent time trying to figure out if they were making contact with something in the fender well... it looked like a lathe had cute a 1 inch striple out of the tire about 3 inches in.
baaaaad tires.
I had the Dunlosts shaved to 4/32, heat cycled, ran around 45 psi in them and still had them chunk the outside of the middle tread block in very short order. We even spent time trying to figure out if they were making contact with something in the fender well... it looked like a lathe had cute a 1 inch striple out of the tire about 3 inches in.
baaaaad tires.
| fastwrx | 02-22-2005 09:52 AM |
Interesting, konekiller. I wondered the same thing... was the tire rubbing something?? Couldn't find evidence of that. And, you're right... it looks like it was cut by a lathe. The destruction was so sharply defined... the border between the destroyed area and the good area is so sharp.
This wasn't my first track experience. I've run Toyo Proxes RA-1s and Falken Azeni Sports previously... at the same pressures... with ZERO chunking or cording. The only thing different during this particular track day was the sessions were twice as long as usual (1 hour, although I ran about 45 minutes each time), and I was driving harder than I've ever driven (fresh out of Skip Barber's 2-day Advanced Racing School last December).
Nevertheless, adjusting the camber and shaving future R-compounded tires makes sense... if for no other reason my improving driving skills. But, I don't think I'll get the Dunlops again. Back to the Toyos for me, I think! :)
Mike
This wasn't my first track experience. I've run Toyo Proxes RA-1s and Falken Azeni Sports previously... at the same pressures... with ZERO chunking or cording. The only thing different during this particular track day was the sessions were twice as long as usual (1 hour, although I ran about 45 minutes each time), and I was driving harder than I've ever driven (fresh out of Skip Barber's 2-day Advanced Racing School last December).
Nevertheless, adjusting the camber and shaving future R-compounded tires makes sense... if for no other reason my improving driving skills. But, I don't think I'll get the Dunlops again. Back to the Toyos for me, I think! :)
Mike
| slowstangguy | 02-22-2005 10:04 AM |
hey fastwrx what track did you do skippy school at? and they still running the neon motors with the nonsynchromesh tranny's?
| fastwrx | 02-22-2005 11:17 AM |
I did the 3-day racing school at Sebring in the Formula Dodge cars with Neon engines and non-synchro'ed tranny.
The 2-day advanced school uses Formula Dodge R/T 2000 cars. They have wings (aero) and use a sequential shifter (which was GREAT!).
Mike
The 2-day advanced school uses Formula Dodge R/T 2000 cars. They have wings (aero) and use a sequential shifter (which was GREAT!).
Mike
| ToddStratton | 02-22-2005 03:03 PM |
I've got a set of these Dunlops I'm ready to use, but now I'm going to watch them carefully...I've seen them on a number of cars here and they usually look like they are wearing okay (evenly).
TRS
TRS
| slowstangguy | 02-22-2005 03:22 PM |
ah i did the 3 day at sebring probably about 5 years ago. didn't do the 2 day. i bet those r/t 2000's must have been a nice step up from the formula dodges. working with that sequential shifter must have been nice. at the 3 day they took way too much time teaching some people how to shift with them(got to love the double clutch heal toe action for the down shifts). hey did you do the short course or full course at the 2 day?
| fastwrx | 02-22-2005 03:44 PM |
The 3-day course at Sebring was on an improvised course that used the front straight but then turned RIGHT behind the grandstand onto a marked course (with cones) and back onto the front straight (using turn 17).
Yes... the R/T 2000 was a LOT more fun. After using the sequential shifter, my STi seemed archaic! Whattaya mean I gotta use the clutch??? ;)
Mike
Yes... the R/T 2000 was a LOT more fun. After using the sequential shifter, my STi seemed archaic! Whattaya mean I gotta use the clutch??? ;)
Mike
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