44 replies to this topic

[Tom Hampton]

Yesterday was my first time in my own car on any R-compound tire (RA-1 takeoffs). It wasn't pretty:

• one 4-wheel off --- rear end tried to come around, saved it...realized I wasn't going to keep it on track, let it run straight into flat grassy area (outside of wagonwheel)
• one 2-wheel off (the front two on wrong side of the apex curbing) --- turned in too abruptly, broke rear end loose, slid sideways through apex CONE before car corrected back to straight (bigbend)
• one 180 degree spin --- missed heel-toe, broke rear end loose spun to outside of track. (horseshoe)
• one flat-spot --- got greedy on entry into turn 1. (rattlesnake entry)
• I had numerous near-misses that I did manage to save.

I'll post video after I've had a chance to edit the mistakes into a single video. Basically, both early morning sessions were like driving on ice, and I just didn't respect the situation enough (or understand it well enough to know the right approach).

Track: MSR-Cresson, 1.7, CCW
Conditions: 36F first session (55 by mid-afternoon), sunny and dry all day
Tires: RA-1s with only one groove still partially visible around "most" of the circumference. Unknown age or storage conditions. I can find out, I just didn't know to ask....or, appreciate its impact.
Driver: Its been 4 months since my last time at the track.

I HAVE driven on R888's before..on two rental cars without any issues...just not on my own car. Both times on R888's were in Texas SUMMER, however.

My preception (and it may only be that) is that there was no margin on the tire, one second it felt like it was there and the next NOT.

I did not fully appreciate the magnitude of impact that conditions (car, driver, tire, and weather) would have on the tire. I think I understand better how I should have handled the morning:

1. only taking what the tire would give me, and not attempting to stretch beyond that.
2. I need to be MUCH smoother with my hands, especially on entry.
3. Street tires can teach bad habits because their grip margin beyond optimal slip-angles is much flatter than R-compounds.

After the spin in Horseshoe, I left the track early...to think about what was happening and how to adjust. I'd lost traction in several different circumstances...but, all in situations of combined inputs (steering, brake, and/or gearing).

I went looking for some of the Apex owners/instructors, but couldn't find any. I knew Keith Verges was there, and would have been very keen to see what his thoughts were on how I should adjust. Alas, I was left to my own thoughts. So, I went back to simple: accelerate, brake, shift, turn. For the next session (number 3), I did zero trail braking, and zero shifting mid-turn. Things worked much better (it was also about 10 degrees warmer by this point). I took three careful progressive warm up laps.

I didn't flat-spot the tire until the middle of following session (number 4 on the day). I think that was a simple case of getting greedy. I didn't even know I'd locked the tire up, until I felt the vibration through the following turns.

I guess I'm looking for other lessons that I should learn from this...or, other commentary folks might have for the situation. Something like: "In that situation, I would have done X, Y, and Z." I know some feedback may be limited until you can see the video...but, I think I understand the specific mistakes I made in each loss of control....unless I'm wrong.

I'm fine with "you are a dumbass" criticism...just tell me what I should have known...and should know now. I want to learn as many lessons as I can from this experience. I have a nice reminder on the passenger door of just what I dumbass I was: the Apex cone from Bigbend left a nice imprint---scar number 1. I don't care about my paint, it won't be the last. But, I don't want to inflict on someone else's paint because I didn't learn something I could have.

[Tom Hampton]

If it matters here is the car setup. This setup was done based on street tires, before I had any R-compounds to play with. It was also done before I had the fat-cats. But, I adjusted the coilovers up 6 turns (all around) to put the RH back to approx. where the setup guy put it.

Camber: 2.8* front, 2.5* rear
Caster: setup guy didn't write it down...the caster cams are aproximately centered.
Ride height: 4 5/8ths all round (pinch weld at stock jack locations)
51% cross-weight
Rear Bar: full-soft
Front Bar: Medium
Front toe: 1/16th out
Rear toe: neutral

I have 99 hats + Fat Cats installed.

This is not to suggest that I think my problems had ANYTHING to do with setup.

[Johnny D]

Just so were on the same page...
Your tires were shaved, correct?
J~

[Tom Hampton]

Just so were on the same page...
Your tires were shaved, correct?
J~

Yes, these were race takeoffs from a national racer. I don't know what shave they started at new, but they were at or below 1/32 when he gave them to me.

[FTodaro]

How many Heat cycles were on those take offs? What cold and Hot pressures were you running and how far into the session were you before you get lose. I do not know enough about the track to comment on the set up but it does not look like its way off of a normal base line.

[Caveman-kwebb99]

what was your tire psi cold? what was your psi hot? what was your car setup? Those tires are usually bulletproof but 36 degree is cold cold! At mid ohio when its that cold I start psi at 34. come off track about 38-40, and then adjust accordingly for what i think the next session will have in store. If you go out on track betwwen 28-30psi you will never get grip in a 30 minute session. This is most likely a major contributor to your car control problems. Setup could be another huge problem. I do not know Cresson but if your car is set to say 50.0, I would imagine your car wouldnt be to far off.

[Johnny D]

Maybe too many heat cycles?
Maybe just the nut behind the wheel.
How were you tire pressures when you came in?
J~

[Caveman-kwebb99]

I bought my first SM straight from a Cresson member it was set to 50.4 -3.0 front -2.5 rear.

[Tom Hampton]

No idea on the number of heat cycles.

The guy who gave me the tires recommended 27psi cold, 35 psi hot. So, I started session 1 at 28psi. At the end of session, hot psi was 31 everywhere except RR (32psi). So, I bumped the cold pressures to 31psi for session 2. Session 2 ended at 35 psi. I didn't make any further pressure changes between sessions 2, 3, or 4.

I asked for a baseline setup with the expressed intent of not making any changes for a good long while. the only compromise was to back off on the camber/caster because he said the street radials would perform poorly any higher.

I completely agree with the nut behind the wheel. I'm trying to figure out what's wrong with that guy!

[Johnny D]

R888 are a different animal than RA1s IMO. Stiffer side walls (R888)
I'd run at 37 hot right off the track to start. But those tires may be junk.
Camber, you really have to get off the fence at some point, what do you want your car to be, street or track, IMO.
U ran clean laps last time, right?
U may have screwed your alignment up with the offs and spinning and that's giving you a hard time.
But I'd say it those tires or pressures.
J~

[Zauskycop]

1. Stiffen the front bar, and it will tighten help with the rear end moving
2. IMO, too low on the tire pressures. We have always gone for 38-39 psi hot, but then again, WE may be wrong.
3. Double check your rear toe...

At least to start...there are far better drivers than I who may have better ideas

[Jim Drago]

Tom
With only a 3-4lb growth in tire pressure, that pretty much tells me that the tires are completely wore out or you never used the tires at all? I normally see about 8 psi growth in tires if that helps any. Check the the DOT numbers on the sidewall. How old are the tires?


Jim

[Keith Novak]

My first thought would be those take-offs are trashed too but make sure to check your pressure gauge off another one. More than one person has chased horrible tire issues to find somewhere along the line, after being dropped for whatever reason the gauge they've been using is now 10psi off.

[LarryKing]

Is it possible that you have the ride height too low? Maybe you are hitting the bumpstops midturn - will make the car very loose. (The reasons I measure clearance between shock and bumpstop instead of ride height at the pinch welds.)

Kyle W. is right - if the ambient temp is 36*F you need to set cold pressures higher than 27-28 psi. If it were me I'd start 32 psi cold.

[Tom Hampton]

Johnny- I'm not on any fence. I've always planned to go full track setup. We're buying a towing rig in the spring. I'll still maintain my state inspection because quick test drives around the neighborhood are extremely useful.

I had the initial setup put on the car back when the only tires I had were street radials (July '11). These RA-1s were given to me, and this track day was a spur of the moment thing. So, I didn't have time to get back to the race shop and get the camber/caster maxed out. That said, I know others with 1.6 cars who have reported max camber similar to what I have now...and I have, at least, another 0.7* of play in my cam bolts (according to the setup guy). So, its not like 2.8* is a silly number for a race setup.

Yes, previous days at track were all clean except first ever session in any racecar, ever. I spun once that day. No spins or handling issues since that incident, both in my car and other rental cars in both directions around this track (never in the cold though).

I had no handling issues in the 4th session (after all spins), while still on the RA-1s. Further, after switching back to the street radials I was turning laps 2 seconds faster than previous PR at this track. I realize something could still be bent. I'm planning on getting the setup maxed out later this month, then I'll leave it alone for the rest of the year. If anything is bent it will show up then.

Tracy-

I did think about the front bar. But, I was (and am still) reluctant to make setup changes to correct a handling "preception", possible driver error, or temporary condition. If the setup is one that has worked on this and other cars...then it seems more likely that it is *not the car*, but the driver. Better for me to learn to drive the setup. Besides, the setup worked fine once the day progressed and I made the adjustments described above. I didn't have any issues in the 4th session until I flat-spotted the RF---completely unrelated to the previous extremely loose condition. My intention is to drive every track in Texas with a baseline setup before I begin to tweak for track specifics or daily conditions. I figure until I'm good enough of a driver to maximize a baseline setup at every track...tweaking is only likely to cause me to chase my own tail.

Jim- I didn't get many clean laps in the first two sessions. Even when I wasn't spinning I was busy saving it. Perhaps, I would have gotten more growth if I'd been more steady and progressively worked up to harder laps. Every "incident" is followed by a slow lap back to the pits for an explanation and inspection. So, lots of time for the tires to cool back off before returning to "pace". In retrospect, I'm pretty sure I should have backed off more, and just tried to drive more clean laps to get more heat into the tires. At the time, I didn't understand what was going on...and, thought it was "just me" driving poorly.

Obviously, some of it was...and depending on your perspective, most of it was. Even if it was "the tires" I'm still the one who needs to recognize that fact...and drive accordingly. I don't like grass in my car...or looking into the windshield of the car "behind" me. Clearly the green blur is the wrong place to be.

I don't know the age of the tires, I'll check the DOT numbers when I get home. I'd guess they are from 2011. They have been in my unheated garage since September---not ideal, I know. I don't know how they were stored before that.

So, the consensus seems to be that the primary failure was the tires:
1. Old, possibly worn out tires.
2. Pressures too low...start higher (at hot pressure) in super cold weather...and, remove air from there.

Am I missing anything about how the driver (me) should have handled the situation? Cold, or worn out tires isn't an excuse for getting backwards. What is the proper procedure to get heat into the tires..if you find yourself stuck in the car and can't just pull in to adjust?

Mr. Moose (aka Bulkwinkle)- Yes, its possible. The shock-bumpstop clearance on the RF is only 1/2"-5/8", it is 3/4" on all other corners. That's one of my questions for the setup guy, when I go back. He measures the pinch welds, but I measured the shock-bumpstop before/after I switched to the fat-cats. But, without a level spot, scales, or even a camber/caster/toe guages I didn't want to monkey with it myself.

Again, however, I note that after the first three sessions I didn't have any further loose handling issues. I drove as hard as I could all afternoon, without the car ever coming out from underneath me...over drove several corners, sure...but, never lost or almost lost control. I set a new PR (on street tires) and the car never felt "squirrely" (no pun intented to Mrs. Squirrel).

[MPR22]

Tom,

A few observations:
RA-1's at 37 degrees are slippery little animals until they reach better tempertures and pressures. Probably should have started at a higher pressure for the first session and then adjusted from there.

Not knowing the number of heat cycles, I would say the tires were done if they were down to 1/32, unless the orginal owner started with 2/32 and even then it would be more heat cycle/driver dependent. If those were CNJ's takeoffs from TWS last May, the tires are cooked.

I have been practicing on my old tires this last month. Having one tire go off makes the world of difference in how the car works. Practicing on bad tires will only lead to the types of questions you are asking now. You are too close to the start of the NASA season to not have a good set of 3/32 or 4/32 RA-1s. If you plan on attending the first race at MSR Houston you are going to want the 4/32 with a couple of heat cycles on them. I am assuming you are running the HPDE route to your license. If you are racing you will want 3/32's, the track likes a thinner tire for outright speed.

Practice how you will race. Running out on different equipment with different setups will net you marginal results. It might teach you some car control playing catch that spinning car game, but it won't teach you what the car should feel like when it is right.

Just starting season 3 and I have learned all the hard lesson about skimping on tires. If your tires aren't up to the task all the setup changes and mad driving skills won't help.

[tLinder]

Tom,

A few observations:
RA-1's at 37 degrees are slippery little animals until they reach better temperatures and pressures. Probably should have started at a higher pressure for the first session and then adjusted from there.

Not knowing the number of heat cycles, I would say the tires were done if they were down to 1/32, unless the orginal owner started with 2/32 and even then it would be more heat cycle/driver dependent. If those were CNJ's takeoffs from TWS last May, the tires are cooked.

I have been practicing on my old tires this last month. Having one tire go off makes the world of difference in how the car works. Practicing on bad tires will only lead to the types of questions you are asking now. You are too close to the start of the NASA season to not have a good set of 3/32 or 4/32 RA-1s. If you plan on attending the first race at MSR Houston you are going to want the 4/32 with a couple of heat cycles on them. I am assuming you are running the HPDE route to your license. If you are racing you will want 3/32's, the track likes a thinner tire for outright speed.

Practice how you will race. Running out on different equipment with different setups will net you marginal results. It might teach you some car control playing catch that spinning car game, but it won't teach you what the car should feel like when it is right.

Just starting season 3 and I have learned all the hard lesson about skimping on tires. If your tires aren't up to the task all the setup changes and mad driving skills won't help.

+1 on Mr Ross' inputs.

But you are right, "Cold, or worn out tires isn't an excuse for getting backwards" (I'll give you my Excuse List if you need it ). Part of the challenge is adjusting to the cards you have, ie worn out tires.

MSRC is a low grip track and @ 37°F you'd probably need 2-3 laps to get the tires up to temp. Sometimes that can be a challenge and since the tires never reached that 37-39 psi hot indicates the tires weren't being worked hard enough. I'll be conservative on entrance and aggressive on exit with the throttle trying make the car under-steer to get heat in the front tires. Sounds like you got "flustered" early on and never re-gained full confidence in yourself or the car. I've been there myself. Make sure nothing is majorly wrong with car, get some 4/32" RA-1s and get back on the horse!

[davew]

My 2 cents;

Check the DOT codes on the tires, 3 heat cycle 7 year old tires are junk.

You want 37-39 psi hot on RA1s. Adjust the pressure accordingly

37* is nippley. Car will make great power and the power will overcome the handling brought on by the cold. 37* and sunny is track record conditions.

Only experienced Miata drivers should trail brake. Take that out of you vocabulary for a year or 2

Unless unavoidable, never shift in a turn.

Put some rake in the car by raising the rear 1/8"

Put a slight amount of rear toe in. Stabelizes the car under hard braking and puts the power down better in mid corner.

Front bar soft, rear bar middle/middle

With this this setup, you can get within a second of the best the car can do. Probably faster than the driver!!!!

If the car still does not feel right, blame the tires. Get a new set and see if the car behaves its self.

If that does not work, have an experienced Spec Miata driver, drive the car. Take what he says to heart.

Going a year without doing an allignment is just foolish. The car will change and you won't know what is going on. I recomend every 3-4 track days if you are in the least wanting to go fast. Every week if you want to think about the front. Every session or 2 if you expect to be up front. More often if you regularly drive off track or pound the curbs or if the track is bumpy.

Dave

Dave

[Johnny D]

Further, after switching back to the street radials I was turning laps 2 seconds faster than previous PR at this track.

This should be telling you something.
J~

[Tom Hampton]

Going a year without doing an allignment is just foolish. The car will change and you won't know what is going on. I recomend every 3-4 track days if you are in the least wanting to go fast. Every week if you want to think about the front. Every session or 2 if you expect to be up front. More often if you regularly drive off track or pound the curbs or if the track is bumpy.

Dave

Thanks, Dave.

Maybe I mis-spoke? I didn't mean a year without an alignment. I understand that bumps, and excursions like yesterday, and plain ole time will cause things to change.

I meant making changes to the alignment specs (per track, per weather conditions, etc). I intended to put and maintain a baseline setup on the car, without attempting to tweak the setup for tracks or conditions...until I was within that 1-2 second window. Exception wet conditions, where I think the recommendation is to drop the rear bar. The current setup was put on by the race shop when I asked for a " stable baseline setup". You are the second person to recommend some rear toe-in. I'll take your advice when I go back.