I did exactly this the other day. At 32psi-35psi (my usually street pressure), my tires cup badly and I get dark lines on both sides of the tread patterns. At 40psi (higher than I've ever put them at either the street or the strip), they leave a nice consistent strip. I have high-performance summer tires with very stiff sidewalls (Eagle F1 GS-D3s).

Here's what I know -- I've tried all of the things you said (and several other things), and I have not yet done better than a 2.2 60'. I've been trying since I bought the car in 2005, which is admittedly not very long. I'm young and by all accounts pretty new to this. That said, I probably have ~50 passes under my belt, and that's worth something.

Having recently discovered the tread cupping issue, I'm chomping at the bit to go drag racing again this year and see what I can do with a higher pressure.

Yup. Somewhere I have a similarly strage slip -- I think it said I ran a 13.5 @ 133mph in the quarter.

 

The slip is wrong.

 

It's true, I've seen a guy trap 672 MPH in the 1/4 in a close to stock civic LOL.

 

Sure that wasnt 67.2 mph hehehe

Alot has been said and a lot of it is true. Definately dont take what you read on the internet as law, learn for yourself cause in the end they are your times not ours.

Street tires can hook better if you drop the pressure, but there is certainly a limit to it. There construction keeps them from being effective at low pressures like you would run a DR. 20psi on a street tire is very low and I dont recomend it. The tread pattern test is the best way to find that perfect tire pressure, on that day. Plain and simple take the collective advice and do it for yourself, and find your tire pressure sweet spot.

As far as the spinning issue goes I wonder if your differential isnt to blame, worn clutches, lack of additive, or just malfunctioning all together. Thats my guess, and I dont think your LSD comes into play much when going into 2nd, but if it is not working properly then it might be the culpret.

We are so blessed to have so many experiance racers among us here. What is it that Regan said..."Trust, then Verify" good advice if you ask me.

 

The MPH is indeed off. My point was that spinning does sometimes make you rMPH read more.

 

I still say that's BS, and am waiting to be proven wrong.

 

What kind of proof do you want exactly? I'm not tryin to make it seem like just because it has happened to a handful of people that its completely true, but I don't know any other way to prove it.

 

Show me a timeslip with a crappy 60' and a better MPH than another timeslip from the similar car/driver/conditions, in which everything went well on the timeslip with the good ET, and the timing equipment did not fault.

 

Im sorry but i don't understand what you mean. I have plenty of slips from the same day, but no others where I spun and made the MPH read excessively high.

 

You say that spinning can/will result in a higher trap speed. Show me a good timeslip where you didn't spin so that I can see what your usual ET/trap speed is, and show me a timeslip with a crappy 60' (one where you spun) and a higher trap speed than the first slip.

 

I have seen many timeslips where a small amount of spin at the launch results in a higher wheelspeed when it hooks. This sometimes results in a slightly higher top end while sacrificing ET.

Notice I said "slight" amount of wheelspin. As with most factors, it is difficult to quantify and "prove" but it does seem to be a generally common condition. However excessive wheelspin will hurt both ET and trap.

 

Okay, I'll give you that -- we know for a fact that tires produce the most forward motion when they slip just a little.

However, that situation should give you a good 60' time too. What I'm talking about is excessive spinning that hurts your 60' but improves your trap speed, and that's a myth.

 

Okay, back on to my subject.....sorry for not responding. I'm a busy guy.

Tires are Kumho Ecsta Supras 275/40r17s. Tires are at 32psi or so.

The track I race at is Firebird International Raceway in AZ. It is notorious for lousy track prep. Always has been. But it's all I got. Speedworld is a better track, but it's more expensive and 75 miles away.

With that said, I could practice and practice but the track is horrible and I want some good tires to practice with and I thought what better tires than some M/T Streets.

Now, my question is why would getting DRs be bad w/o practice, when I can just practice with good tires at a track? Runners don't practice laps in flip-flops do they, so why should I?

 

Cause if you can run as fast in flip flops then you can run faster in cleats... Michael Jordan didn't start shooting hoops in Air Jordans.

We are saying DRs with give you more traction, but your still not launching correctly. Learn to launch then put DRs on. Not to mention if it is mechanical then the artifical improvment with the gained traction will mask the problem, and you will never even know better.

 

But...........................if the problem isn't anything more than trying to use the wrong tire for the job (ie. street tires at the track) then starting with track tires for the track may well solve the issue.
Street tires suck at the track.
Track tires suck on the street.