First time using slicks. Any advice/warnings?

[bubela]

I have a pair of M/T 8.5x15 slicks on the back of my car. I have a 225/40/17 on the front. I drove them around on the street a tad to check for rubbing, and they are very squirrely.
This will be only my second time at the track. Is there anything I should know about before I just tear down the track?
Anyone recommend a psi I should run with a 2700 pound car/driver?
I figure I’d drive through the waterbox and drop the clutch in second to heat up the tires for a few seconds. Any “good” amount of time to do so? It’ll probably be about 70 degrees at the track on Saturday.

[Tony Soprano]

I usually do 5 sec burnouts when ive run on slicks for DR's. put it in second, rev it up dump it, and then count to five and smoke em. seems to be a good technique.

[davidtm5]

i usually do it it in first gear,until you hear the tire screetching & let go your line lock switch. 2 gear burn out might be too much may be baking the slick

[jfdmas]

edited, cause i didnt read.

[bubela]

Cool. I think I have 18 or 20 psi in there now. I'll be checking to make sure. So definitely not longer than 5 seconds (assuming I can for that long) The car does not have a line lock, so..
It was just a lot more squirly than my 255's are.. I'm trying to stay out of the wall, that's all! Didn't know if I had to worry or not with these.

[multiplex]

bob how fast have you had the car up to with them on?

on my car the back end definetly wanted to sway a little bit.. took a little getting used to

[bubela]

Probably around 70, not sure. I wasn't looking at the speedo cause it was a little scared and focusing on keeping it straight. It was a slightly pitched road though, so perhaps that effected things?

[MrBlonde]

Bad advice here.

You've got ET Drags, right? These are not drag radials they are slicks. That means bias ply rubber.

Tire pressure: Start at 18-20 psi and drop it by half a pound until your short times get worse. On heavy sedans with such small slicks you don;t want to run 8 psi like a dragster.

Burnout: Slicks require a good hard burnout the first pass followed by a light burnout each subsequent pass. Drop the clutch in third gear and let off when the tires haze in your mirrors.

Front runners: Do NOT run with radial front tires and slicks in the rear. The handling dynamics in the top end are dangerous. You need to get front runners to match your slicks, or keep your radial fronts and run drag radials in the rear. Don;t mix and match, it's dangerous. Yes people do it. Yes they don't always crash. No you don't want to try it. It's dangerous.

[multiplex]

hey bob - hit up jon, maybe he can let you use his front skinnies.. they should bolt up

[jfdmas]

WOW, im sorry. I saw mickey thompson and i automaticaly ASSumed radials. I run slicks as well and you need a good long 2nd gear burnout or even better a 3rd gear burnout. I run front radials to 45-50psi and i run the rears at around 15-17psi. Be VERY careful if you decide to do this. If you watch my vids you can see the car squating sideways and swaying. Yes its scary to get used to but you just need to keep the car straight and you will be fine.

If possible run bias ply up front but its not gunna completely eliminate the swaying.lol Just cant be afraid to stay in it.

[VETT ENV]

if u wheel hop at alllll! get out of it, and save the car for the next run... its not worth breaking something or sheering a bolt on the rearend

[bubela]

awh man.. am I gona have to save these slicks for a later date?!
I've barely driven the car on the road (not yet passed PA inspection) and here I am trying to use slicks on a car I've driven less than 100 miles! and my second time at the strip!!

So my fear is more at the beginning than at the end of the 1/4 mile? If I keep it straight through the first couple shifts, crossing the line is simple?

I guess I can try them the first run, then swap tires if I chicken out..

Jay, how fast did YOU get up to on these?

[MrBlonde]

awh man.. am I gona have to save these slicks for a later date?!
I've barely driven the car on the road (not yet passed PA inspection) and here I am trying to use slicks on a car I've driven less than 100 miles! and my second time at the strip!!

So my fear is more at the beginning than at the end of the 1/4 mile? If I keep it straight through the first couple shifts, crossing the line is simple?

I guess I can try them the first run, then swap tires if I chicken out..

Jay, how fast did YOU get up to on these?

Slicks can be scary at the top end of the track, they are not an issue at the start. You can't drive your car on a public road with slicks fitted. They don't do corners.

If you're a bit iffy about the first meeting, just get the car to half track and then short shift, getting the feel of the car under power with slicks on. Then in subsequent runs gradually build up top end speed and sneak up on a full power pass.

[jfdmas]

yep, I did just what kenny said. Take a few short easy passes till your comfortable with how things feel. then start pushing it. If your going to a track day you should have plenty of runs to get dialed in.

[bubela]

Just: "take it easy".. Something I'm not use to doing, but I'll try.

Thank you for the advice guys.

[///M3 CRAZY]

i was running slicks with radial fronts and they get pretty scary at the top end the first few times. first don't correct too much, second if it gets scary get out of it but just like in a turn do not let all the way off let off the throttle but don't shut it down, and third start high pressure and work your way down. it will sway!

[StreuB1]

like kenny said.....u want to run bias ply with bias ply. reason is that when the rear sways and you correct with the fronts, you wont get IMMEDIATE response....there is a delay. that delay is the sidewall flexing, which is what you want. when the rear begins to sway left you want the front to sway right and the same with the opposite direction. you dont turn corners with these things at all. thats the main thing to remember. when you correct on a drag strip, radials turn and bias plys correct. it is VERY easy to over correct when you have radials in front. also, the taller your side wall the more sway youll have, the lower the tire pressure you will run and the more radials will be dangerous.

also be aware that radials hop and bias plys shake....though bias plys will hop....more so JUMP. they feel nothing alike. wheel hop feels like yer in a pin ball machine but tire shake feels like the world is coming to an end....it will rock your world and shake yer melon good if you get it bad enough...this is due to the side walls ability to wrinkle and store/release energy. if you experience tire shake, DO NOT try and drive out of it. Shut it down.

[StreuB1]

For reference....if some out there believe the interweb and think shake and hop are the same. Here is a video shot at 500 frames per second of a chassis car launching and experiencing tire shake. Youll naturally want to watch the right tire due to lighting but focus on the left about 5-10 seconds after launch through to the camera panning upwards. You see the beginnings of shake on the right tire but the left goes into a hard shake which transitions into extreme hop.

http://videos.streetfire.net/video/Lindberg-bros-Tire-shake_188537.htm

[bubela]

I want to thank Mr. Blonde and jfdmas for their wise advise. Definitely think twice before running a radial tire up front and non-radial Slicks in the rear. Here's why:

I'm not sure what happened really, as it all happened Really fast. I watched the video of my run, and it looks like there was a tiny bit of smoke from the tires; it looks like I start floating to the right; I must have overcompensated because then from the right lane I go sideways (90 degrees) and head for the left wall; then do a 180 and head for the right wall; before I know it I'm straight again.

Before all this, the tires felt great. I had 20 psi in them, cold. So who knows what they were after a (3rd gear!) warm up and zip down the track? My 60 foot was 2.2: .3 better than before, but still I was not modulating the clutch correctly. I felt fine through the first 3 gears, going straight and feeling safe. I'm not sure exactly, but I think it was the top of 4th that I lost control.


When I pulled back into the pit it was clear the expansion tank and fender had streaks of coolant, and could have dumped a "fair" amount of coolant onto the track.


p.s.
for all those guys that say driving in a straight line is easy, and doing a race track is where the "real skill" is needed.. Have apparently not tried the 1/4 mile.

My car is capable of so much more than I am able of piloting it.

[bubela]

Just a reminder, Mr. Blondes exact words were:

"Front runners: Do NOT run with radial front tires and slicks in the rear. The handling dynamics in the top end are dangerous. You need to get front runners to match your slicks, or keep your radial fronts and run drag radials in the rear. Don;t mix and match, it's dangerous. Yes people do it. Yes they don't always crash. No you don't want to try it. It's dangerous."

[jfdmas]

Just a reminder, Mr. Blondes exact words were:

"Front runners: Do NOT run with radial front tires and slicks in the rear. The handling dynamics in the top end are dangerous. You need to get front runners to match your slicks, or keep your radial fronts and run drag radials in the rear. Don;t mix and match, it's dangerous. Yes people do it. Yes they don't always crash. No you don't want to try it. It's dangerous."


if you leaked any kinda of liquid onto your rear slicks then it def wouldnt of mattered if you had front runners or not. Same thing happened to bmwsob earlier this year when he ran his 10.2 but the only difference was he actually did kiss the wall and he was runnin front bias ply. Slicks + any kinda liquid is scary.

[MrBlonde]

When you are running bias ply (front runners and slicks) you will find the car can wander in the top end. This might require a little concentration but it's nothing compared to the problems you'll get when you mix and match.

It's the differential in the turning capabilities of radials vs bias ply that causes the misbalance issues.

[multiplex]

yeah its a good possibility the tire got wet.. leak was on the drivers side. which would make the car go left - which it did.

i'm kinda glad i didn't witness the event :eyecrazy, i must have been busy getting my record setting time slip :D