Got a track related question? I'll try to answer.

[CSG Mike]

Originally Posted by Pat

Here is my car as it sits now:
BFG R1-S tires at 35.5 psi hot
Stock suspension
DTC-60 pads
Togue Factory brake ducts
Motul RBF-600 brake fluid
Camber plates
2.6* of front camber
1.3* of rear camber
The car is pretty much stock other than that.
Yesterday I was at High Plains Raceway and noticed something funny with the tires. It was my first day on these tires. They are four years old and have been heat cycled by The Tire Rack. Before yesterday they had maybe one or two sessions on them. In the morning ambient temps were in the upper 40s. By the end of the afternoon it was around 70.
I experienced some graining with the front tires. Once the car had warmed up about three or four minutes and I started building some speed, the front tires would start to feel like they were driving on small gravel pieces. They would sound louder and rougher and I could feel it through the steering wheel.
When I brought the car in I could see a strip of clag all the way around the inner third of the tire, but the outer two thirds of the front tires looked perfect. The wear on the outer and inner shoulders looked right where they should be.
There were two turns where this behavior was especially noticeable (7 and 11). They are both very long turns. I would enter the turns with almost none of these bad feeling from the front tires, but as I would drive through each of these long turns, I could slowly feel them graining. By the end of each turn it feel fairly rough in the front end and the grip would slowly go away as I proceeded through each turn. By the end of these turns the car would be understeering.
It seems to me like these long sustained turns heated up the front tires past the point of where they should be. That said, these are pretty serious tires and I would not expect that type of driving to be a problem for them. Especially on my lowly car.
I don't have data acquisition available for review. If you need to see a video of my driving i can post one, but doubt it's necessary to figure out what's going on with the tires. I've been driving on tracks for 17 years and instructing for much of that.
FWIW, I spoke with a long-time national champion racer about this yesterday at the track and he couldn't figure it out.
What theories do you guys have for this kind of tire behavior? I'm kind of drawing a blank. My only theory is I need more camber up front, but honestly, I don't really think that's right.
TIA

Is your traction control on?

[DocWalt]

Originally Posted by CSG Mike

How much pad is left?

More than half. I have plans tonight, no time to pull the pads and measure. BTW what's full thickness on the pads anyway? I didn't measure beforehand

[Pat]

Originally Posted by CSG Mike

Is your traction control on?

No, I always do the pedal dance.

[DarkSunrise]

Originally Posted by CSG Mike

That's overheated pad. Time to step up

Thanks Mike. I haven't tried a ton of brands, but am happy with Carbotech so far - best track pads I've tried to date. Would you recommend XP12's next, or something more aggressive?

I was getting mild fade towards the end of 25 minutes sessions on XP10's, but nothing alarming. Ambient temps were 60 F. Tires next season will be cheap 2013-stock Rivals (non-S). I don't have any ducting, although I may try GT3-type vanes (not that I'm expecting any difference lol). Power is NA, not expecting to move to a SC anytime soon. TY!

[Pat]

Originally Posted by CSG Mike

Is your traction control on?

Added this to the original post:
I measured temperatures on the inner shoulder, center and outer shoulder of each tire at the end of a session. I came into hot pits quickly, stopped quickly and jumped out to measure as fast as I could using my cheap China Freight IR pyrometer. Each of the four tires varied less than ten degrees across the tread. IIRC most were about five degrees in variance.

[strat61caster]

Originally Posted by DocWalt

I agree that I need a bit more oversteer. As I got faster at the end of the weekend I was noticing more and more understeer. Very rarely did I get any oversteer, but it definitely went more neutral in the trigger with power. In the corkscrew it just plowed with more power. It's pretty obvious in my videos too, the tire squeal goes through the roof as the track falls away and I roll on the power.

Apologies if you mentioned it before but where's your alignment at? It blows my mind how much grip Toyobaru left on the table with how crappy their alignment is and how you have to spend a few hundred bucks if not a thousand+ to unlock it.

I finally unlocked full on oversteer a few weeks back by going up to over -3 degrees of camber up front, the rear was at -1 and -1.4. Endless grip up front, none in the rear in comparison, couldn't get the power down, backed off on the camber up front between runs and the balance came back. I know I'll get more grip with more camber in the rear which means I can use more camber up front.

My car came with -0.3 degrees up front from the factory

[CSG Mike]

Originally Posted by Pat

Added this to the original post:
I measured temperatures on the inner shoulder, center and outer shoulder of each tire at the end of a session. I came into hot pits quickly, stopped quickly and jumped out to measure as fast as I could using my cheap China Freight IR pyrometer. Each of the four tires varied less than ten degrees across the tread. IIRC most were about five degrees in variance.

Do you have a probe type? Surface temps unfortunately don't tell the real story

My instinct is that you're just slowly cooking the front tires and overheating them. Stock suspension has a pretty good understeer bias.

[CSG Mike]

Originally Posted by strat61caster

Apologies if you mentioned it before but where's your alignment at? It blows my mind how much grip Toyobaru left on the table with how crappy their alignment is and how you have to spend a few hundred bucks if not a thousand+ to unlock it.

I finally unlocked full on oversteer a few weeks back by going up to over -3 degrees of camber up front, the rear was at -1 and -1.4. Endless grip up front, none in the rear in comparison, couldn't get the power down, backed off on the camber up front between runs and the balance came back. I know I'll get more grip with more camber in the rear which means I can use more camber up front.

My car came with -0.3 degrees up front from the factory

Because 99% of the owners will never actually drive the car hard, and only a small (single digit) percentage will ever even attempt to experience the cornering ability.

[CSG Mike]

Originally Posted by DarkSunrise

Thanks Mike. I haven't tried a ton of brands, but am happy with Carbotech so far - best track pads I've tried to date. Would you recommend XP12's next, or something more aggressive?

I was getting mild fade towards the end of 25 minutes sessions on XP10's, but nothing alarming. Ambient temps were 60 F. Tires next season will be cheap 2013-stock Rivals (non-S). I don't have any ducting, although I may try GT3-type vanes (not that I'm expecting any difference lol). Power is NA, not expecting to move to a SC anytime soon. TY!

Try the XP12. Ducting will be good as well.

[MaximeT]

I got a tyre wear question.

Do you think you'll get more track miles out of an Hankook RS3 or out of the F200 hard race slick ?

Dunno the rating of the F200, but Michelin slicks are rated at 200km in race condition. That's the manufacturer specification and not the actual maximum mileage the tire can do.

I can get 500 km out of a rear set of a048r on the Lotus (same rear weight and power as the 86) with an enjoyable pace.

Would you use 215 or 235mm wide slicks (race size, not road size) with a Jackson Racing supercharger ?
I can't try both because one need 8" wheel and the other 9". So I need to purchase the right size wheel.

I may try different road going track tires, but race slick are 1300-1500€ a set out there. I can't afford to burn them in less than 400km.


The goal is to drive track days and no actual races. The tire will obviously be competitive for something like 20-50km

The wheels gonna be 949 6ul provided by CSG

A big thanks

Edit : my driving style is nice on tires.

[Pat]

Originally Posted by CSG Mike

Do you have a probe type? Surface temps unfortunately don't tell the real story

My instinct is that you're just slowly cooking the front tires and overheating them. Stock suspension has a pretty good understeer bias.

Thanks for sharing your thoughts, Mike. I don't have a probe type pyrometer, unfortunately. Everything I've read about these tires says they love heat. Considering it didn't get over ~73 that day, and I have a lightweight, low-power car, I'm surprised that is your best guess. Don't get me wrong, it certainly could be the issue. Do you have much first-hand experience with these tires? They don't really work with the same setup as A6s.

[strat61caster]

Originally Posted by CSG Mike

Because 99% of the owners will never actually drive the car hard, and only a small (single digit) percentage will ever even attempt to experience the cornering ability.

Oh, well aware of WHY, (don't forget tire wear, those Mac struts are not forgiving) I just never expected the magnitude of improvement out of something which should be relatively simple concept of "point the tires in the right direction" with no reduction in street mannerisms.

Watching family members struggle with similar problems on their cars (not all cars are fortunate enough to have half a dozen camber plate options within a year of release, or quality continued support decades later), I'm going to be much more diligent in researching my future sporting vehicles.

[DocWalt]

Originally Posted by strat61caster

Apologies if you mentioned it before but where's your alignment at? It blows my mind how much grip Toyobaru left on the table with how crappy their alignment is and how you have to spend a few hundred bucks if not a thousand+ to unlock it.

I finally unlocked full on oversteer a few weeks back by going up to over -3 degrees of camber up front, the rear was at -1 and -1.4. Endless grip up front, none in the rear in comparison, couldn't get the power down, backed off on the camber up front between runs and the balance came back. I know I'll get more grip with more camber in the rear which means I can use more camber up front.

My car came with -0.3 degrees up front from the factory

Stock never even touched from the factory. Paint marks still aligned on the tie rods even, lol. I know I need more camber. That's how I got my GTI to turn well, more front camber.

[CSG Mike]

Originally Posted by strat61caster

Oh, well aware of WHY, (don't forget tire wear, those Mac struts are not forgiving) I just never expected the magnitude of improvement out of something which should be relatively simple concept of "point the tires in the right direction" with no reduction in street mannerisms.

Watching family members struggle with similar problems on their cars (not all cars are fortunate enough to have half a dozen camber plate options within a year of release, or quality continued support decades later), I'm going to be much more diligent in researching my future sporting vehicles.

This applies to pretty much any production car though...