Mark2002

iTrader: (2)

Attended my first HPDE this past weekend down at MotorSport Ranch in Cresson, TX. One word... AWESOME! I learned so much, and now I'm hungry for more! I have a question about my 3-week-old 245/50-R16 BFG g-Force Sport tires though.

The car I'm driving is my daily driver '02 Z28 (stock suspension, SFCs, STB). I had a "mild street performance" alignment done on it just before the event by PST at the track... don't remember the exact specs, but if I remember correctly I think the camber was set at about -1.5 (updated in post 5)... their reasoning for not going more than that was "it starts affecting braking" which seemed to make sense. The car seemed pretty well balanced... at least as balanced as a rookie can tell. Nothing felt like it wanted to break loose even though the car was 4-wheel skidding around some of the sweeping turns. I was told by my ride-along instructor that I was entering the corners a bit too fast and occasionally slightly early.

Here's a pic of my left front after the event (Saturday's runs were mostly on a wet track so its safe to say the vast majority of this wear came from the 4 sessions on Sunday). Although this is the worst tire, the wear is pretty typical for all 4.So my questions for the experienced folks out there...

1. Any reservations using these tires again at the track?
   
2. Since I know my technique wasn't perfect I'm wondering if this type of wear is mostly preventable. Does it look like the result of just poor technique, bad alignment, going too fast, a combination of all of these, or something else?

I don't want to cover up my mistakes with mods so my mods are limited to safety/durability items for now until I learn how to drive the car properly.

Thanks for any help!

Mark

mitchntx

iTrader: (14)

Mark,

I wish we could have met. It's always good to meet new folks.

1) I would have no reservations at all about using those tires again.

2) I would be suspect of -1.5* camber on a stock ride height F-car. That just never happens. Somewhere around -1* max is more like it.

If you instructor was telling you you were charging the turns, then you were definitely over-cooking the left front. MSR-C CW is mostly right-hand, sharp, off-camber turns. So any left front will take a beating. But charging them, like at Boot Hill (down hill on the back side) and entry and exit out of Rattle snake (by pit entrance and exit) compounds the problem.

Because I don't see any lip damage on the other tread blocks, I venture a guess it was under inflated as well. If the contact patch were sliding across the pavement anywhere close to even, you would see the leading edges of the tread blocks rolled up as well. I don;t see any of that.

I would add a 3 or 4 pounds of pressure, mark the sidewalls with a tire pencil and see how much it is rolling over. Adjust from there.

Not sure I will run again this year. But if you run in December, I'll stop by.

Mark2002

iTrader: (2)

Thanks for the reply Mitch. Exactly the type of info I'm looking for!

Excellent... I feel better now

Ok, I'll pull the alignment sheet when I get home tonight and post the actual numbers.

All tires checked between 30 & 31 psi cold the morning of the event. I'll plan on marking them next time, inflating to 34 psi, and go from there. I'll also plan to not charge the corners so hard

I plan to attend the Dec event but haven't registered yet. I'd love for you to stop by and give me some pointers!

mitchntx

iTrader: (14)

Your instructor can do much more than I can. Listen closely, have fun and you'll do great.

Mark2002

iTrader: (2)

Ok, got the alignment specs in front of me...

Camber: -.61*
Caster: +4.34
Toe: -0"03 (stated in inches instead of degrees)

mitchntx

iTrader: (14)

That's more like it.

The left front CCW at MSR-C won;t see NEAR the abuse it did going CW. But the right front will.

You have your cold pressures, add ~3 lbs to the front, chalk all four and see how it does.

2000Z28M6

iTrader: (13)

mark I used those tires before, for the street they were great. I have my reservations about them for the track. Although I was using them for AX they never offered any real grip. You might have better results since you were at a road course, but just know there are alot more grippier street tires.

Mark2002

iTrader: (2)

Thanks for the input. One of those endless quests I guess... to find "the best" tires. Any suggestions?? (keep in mind I'm not running a separate set of track tires)

It would be nice if we could try before we buy, but I doubt any manufacturer would adopt that strategy Until they do I guess we're left with reviews and such. These had decent reviews, and were available (my 1st choice: Eagle F1 GS-D3 were not). I can say one thing... these g-Force Sports are much grippier than the g-Force Super Sport A/S I had on it before!

2000Z28M6

iTrader: (13)

I was blown away with Firestone Wide Ovals. I never expected them to be so good. I'm sure the more pricey Eagle F1 GS-D3 are right on par with them too.

If I could afford it I would always roll on those 2 specific brand and models. They are the kind of tire you can drive to the track be somewhat competitive and then drive home

Arctic2002ss

I would suspect the tire pressure as well. I was running about 37lbs hot the last time I was there and it seemed to work well. I ran the KDW and it wore well. I gotta get out there with my current NT05. MSR Cresson (3.1) is a fun track. Who did you do your HPDE with? I run with TDE.

Mark2002

iTrader: (2)

Yep, same here... The Drivers Edge. I was originally holding out for Apex since it was suggested by a friend who had been to both. However, I was anxious and couldn't wait any longer for them to schedule an event.

Mark2002

iTrader: (2)

I understand how the tire marking method works for fine tuning air pressure... What I don't understand is where the right spot on the tire is that I should be shooting for. Where in the picture above would I want to see the mark rubbed off? I noticed a very small triangle at the very top of the picture (below the treadblock on the sidewall)... is this the scrub line? I'm guessing not since it doesn't look like I'm scrubbing that far on the sidewall and the suggestions have been I'm scrubbing too far already.

EchoMirage

iTrader: (3)

thats what the triangle is for. you dont want the tire to roll over any further past that. if the triangle suddenly disappears from wear, then your tires are under inflated, and possibly not enough camber.

if you do this often enough, it would be smart and safe to get another set of dedicated track rims/tires. you dont need 17x11 slicks. even another set of 16s with some kind of half decent summer performance tires will do while youre starting out, and most importantly save wear on your daily driver tires.

Mark2002

iTrader: (2)

Hmmm... Ok, interesting. Doesn't look like I'm quite rolling over that far. I'll still try a couple more pounds in the fronts and see if the wear at least evens up on the tires.

For anyone that's interested, I posted a video of some laps that resulted in the tire wear shown above over in this thread:

https://ls1tech.com/forums/road-raci...-1st-hpde.html

Thanks everyone for the responses!

SOMbitch

iTrader: (8)

Nitto NT05 is about as sticky as you can get w/o running an R compound...

01 ss vert

iTrader: (1)

From my experience in autocrossing, and one HPDE under my belt, those tires to me appear to be worn from over steering and not just roll over.

Let me explain. If it was just from roll over, I believe the corners (edge) of the tire would be come worn in a smooth, symmetric fashion. The photo in the first post appears that the rubber is 'chunked' out of the edge of the tire, and not smooth. I may be wrong, but that's my impression.

I did this a lot myself with R-comps on rough pavement when I first started. This was caused by going in too fast and the tires singing (scretching) during the turns. Essentially I was going in too fast and was trying to make the turns stick with wheel input vs the proper speed input. This would then cause me to exit the turn past the apex, and at a lower speed.

If you have ever heard 'slower is faster' this is a great example.

I have since learned to enter the turn slightly slower, that way I could hit the apex at the correct spot, and this technique allows me to accelerate out of the turn at a quicker rate. What this technique also allows is the tires to last longer. I don't have to fight the turn with steering input, and instead I can focus on braking/accelerating to keep my line vs adjusting the steering wheel which puts additional stress/wear into the tire, and unsettles the suspension.

Next time try braking slightly earlier to get the correct line for the turn/apex. Once you have the line, brake or accelerate accordingly without upsetting the suspension. If you go too fast, the tires will start slipping and this is what causes that wear.

In other words, to help save your tires more, adjust your line and then your throttle/brake vs moving the steering wheel more while already turning. In addition, I bet you will be faster and smoother at that.

I would like to hear others thoughts' on this suggestion.

Mark2002

iTrader: (2)

Sorry I missed this!

Yes, I believe this is a big part of it. My instructor and I talked about it quite a bit, and I was "over-driving" the car into the turns. Combined with that I was more often apexing early rather than later. Suffered a bit from the "I want to go fast" so I was trying to make things happen a little sooner than necessary. The result was not being able to get on the throttle as hard and as soon as optimum during the later part of the turn.

I quite ofter entered the 4-wheel skid where the tires were 'singing' especially around the long sweeping Big Bend turn. I never really had to correct with steering that much (got really good scores on "smoothness" ) just simply sliding the car smoothly on all fours through the turn.

I think my biggest problem was entering some of the tighter turns a bit too fast, to the point it felt like the car was understeering, when all that was happening was the tires were simply sliding until the speed bled off enough for them to actually turn me.

I definitely plan to brake more and concentrate on my turn entry more next time!

Thanks for the input!