Race Tracking Your Supra - Information exchange

[kungfujedis]

Teach me to read this tire wear. I'm stock, so camber is what it is for now. PSI too high, I'm guessing? I kept lowering it session after session. Total wear is from 5 days of HPDE. I swapped opposite corners each day. Kumho v730.

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[Traxion]

Teach me to read this tire wear. I'm stock, so camber is what it is for now. PSI too high, I'm guessing? I kept lowering it session after session. Total wear is from 5 days of HPDE. I swapped opposite corners each day. Kumho v730.

Show us a side view so we can see how far down the sidewall it's been worn. With stock camber I adjust my PSI based on that. What PSI are you running?

I'm running the same ones on my front and tend to start at 26-28 PSI on an ambient temp day around 70-80 degrees which puts my hotlap around 30-32 before ballooning on the later laps which I don't really care about since they're not really ever going to be PBs anyway.

 

[Rocksandblues]

Doesn’t look terrible. Yes a side view would help. Can see signs of lack of camber. Rotation is probably helping that.

 

[kungfujedis]

Thanks for the help!

Side views below. I was starting around.....32 cold at the beginning, and then about 29 'warm' right before going out for a session by the end. I should have kept better notes. I keep the display on pressure/temps, too bad i deleted my go pro footage already.

 

[Traxion]

Thanks for the help!

Side views below. I was starting around.....32 cold at the beginning, and then about 29 'warm' right before going out for a session by the end. I should have kept better notes. I keep the display on pressure/temps, too bad i deleted my go pro footage already.

The wear pattern is right on the top of the triangle and the two little dots that are to the right and left are nubs instead of still being pokey so you're just about right. Nothing more you can do besides add camber eventually so keep doing what you're doing. You could try dropping 1-2 more PSI but honestly it probably won't make much of a difference and seat time and track/weather conditions will make more of a difference over 1-2 PSI.

 

[nibble]

Teach me to read this tire wear. I'm stock, so camber is what it is for now. PSI too high, I'm guessing? I kept lowering it session after session. Total wear is from 5 days of HPDE. I swapped opposite corners each day. Kumho v730.

This is typical characteristic of v730. On my race car, even with -4.0 camber, there were no groove left outside after a day of driving. there were plenty of groove inside so it was a mystery. However, after looking at every car that uses v730, it yielded same pattern. smooth outside, no wear inside no matter what camber or car. increasing pressure helps a little but not whole lot of difference. the running theory at the moment is because side wall flexes so tire is skewed to outward hence increasing pressure helps side wall to stay in shape just a little bit. v730 is good tire for money and I will use it again for my race car, btw.

 

[kungfujedis]

Thanks for the analysis, much appreciated!

 

[Rensuhlo]

 

[Traxion]

Just finished mine off this past weekend so for reference, here are my fronts after 8 track days (4 sessions per day) and I'll need to replace them before next event since one is now corded. Plenty of inside tread depth left.

 

[Rocksandblues]

Did you rotate them at all? ^^^

 

[FLtrackdays]

Anyone have issues with the muffler section of their aftermarket exhaust "shifting" while running the car on the track?

I was a little too aggressive over the kerbs on the esses in Button willow (#14 CCW) and the car hopped up quite a bit. After the session, I did a quick walk around on the car and noticed that the exhaust-tip had a little bit of melted plastic from the stock diffuser. Centering myself behind the car -- I can see the exhaust slightly "shifted" to the left a bit.

Everything was bolted down pretty tightly, when I installed the DP and HKS exhaust so it can't be a mounting issue. The only thing I can think of is that the rubber hangers still have a little bit of WD40 on them from when I removed the stock exhaust....

This happen to anyone else?

Nope ?‍ Not me

Teach me to read this tire wear. I'm stock, so camber is what it is for now. PSI too high, I'm guessing? I kept lowering it session after session. Total wear is from 5 days of HPDE. I swapped opposite corners each day. Kumho v730.

More negative camber.
*(side note: bleed tire pressure down -36psi or less- as the day goes on when driving HPDE. And…. don’t ? lower the car until you get rub ?)*

 

[razorlab]

This is typical characteristic of v730. On my race car, even with -4.0 camber, there were no groove left outside after a day of driving. there were plenty of groove inside so it was a mystery. However, after looking at every car that uses v730, it yielded same pattern. smooth outside, no wear inside no matter what camber or car. increasing pressure helps a little but not whole lot of difference. the running theory at the moment is because side wall flexes so tire is skewed to outward hence increasing pressure helps side wall to stay in shape just a little bit. v730 is good tire for money and I will use it again for my race car, btw.

It’s actually how the v730 is molded. If you look at a brand new one, the outside half has grooves that are molded about half way deep compared to the deeper inside grooves. This is so the outside wears to a slick faster. Still way more tread to go after the grooves go away. People, like yourself, commonly think it’s a camber issue, when it’s actually the tire design.

“Mystery” solved.

 

[Traxion]

Did you rotate them at all? ^^^

Yes I rotated them after every two sessions. Only time I didn't was this last weekend when they put 1 early session and the next 2 sessions only had a 20 minute break between them. At the end of the day it had very slight chunking but no cords, so for Sunday I put that tire on the passenger side since it was a clockwise track. Checked the tires after every session there on out and didn't hit cords until the last session.

 

[Traxion]

I threw down a new PB of 1:37.67 at Road Atlanta with the only change being new PMu Club Racer pads. I'm totally in love with them. Decent street bite and once they're hot on track man do they stick. I definitely could have done later braking and more trail braking with them. I'll need a few more events under my belt with them to get used to their bite and modulating off the brake with them. Now that I'm also done with my 265/V730s I'll finally be able to go to 275/RE71RS on the front and gain a little more pace. The only down side is there's a 2.5-3 month break until my next track event due to NASA's summer break so I'll be a little rusty getting back into form.

 

[Rocksandblues]

I bet Nasa isn't the only group to run Atlanta?

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