street tires at the track - any tips?

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360duster

360duster

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Hi Guys,

next weekend i´ll go to the racetrack for the first time with my new engine. Since i don´t have some better suited tires for now i have to use the street tires 225/70-15 that i already have (they are near new).

Is it recommended to lower the air pressure also with street tires? Do a little, big or no burnout with street tires?

I´m new to this, been once to the track with my valiant - with the slant six.....now it´s a 408 with some serious torque. I know that´s not the best combination, just want to have some fun, hope for some 12 sec. runs. Rear is 3.73 with suregrip.

Thanks for info!

Michael
 
Hi there sweet engine you have there, here are a few things to think about:

* Your street tires will be just fine, no need for a burnout, heating up street tires isn't a good thing.

* If you feel the need to burn with your street tires, one small one is fine to clean them off when you get to the track.

* In general don't do high RPM neutral drops, or 1st gear hammering to 2nd burnouts if you have an automatic. Always start in selected 2nd or D, so it shifts out of 1st early.
It is killer on the overrunning sprag in the back of the transmission, especially when the tires are spinning free, and then they suddenly grip. KA-BOOM!


As far as PSI in the tire, experimentation comes into play for the best combination. Here are a few ideas to get the party started:


* Take it to a empty parking lot with a full tire and deflate 5-10 PSI at a time and lay into it, repeat, see what you come up with.

* 20PSI comes to mind as a balance between too full and too flat.

* I've found that, the best traction comes when the contact patch of the tire is the widest, and deflated to the point right before it starts to cup up in the middle.



Hope this helps,

Stay safe and have fun! :burnout:
 
PoisonDart74 said:
* I've found that, the best traction comes when the contact patch of the tire is the widest, and deflated to the point right before it starts to cup up in the middle.
Stay safe and have fun! :burnout:
Click to expand...

Key words right there. Too many people put wide tires on the narrow wheels and then gripe because the loose traction when doing a run.
 
Oklacarcollecto said:
Key words right there. Too many people put wide tires on the narrow wheels and then gripe because the loose traction when doing a run.
Click to expand...

This is true, its amazing how much you can utilize a smaller width tire when you get down to it.
 
you want the tire to have full contact with pavement, stiff wall street tires went under inflated the center will not make contact ...so watch out how much air you take out of the tire...

also...you will need practice leaving the starting line at part throttle to walk the car off the starting like....
 
And don't drive through the waterbox, go around it. Even if you do a decent burnout to get the water off the tires, the tread throws water up into your fender wells, then drips back down on your tires while your staged at the line.
 
Watch the car in front of you and line up in there tracks, especially if it's running slicks.....may leave a little fresh warm rubber for you.

Could also pull a little timing out of it to soften the bottom end.

A decent launch will probably be futile, but good luck and have fun:D.


P.S. Even if it's working for you be careful not to let "too" much air out of the tires. That car is easily capible of running 110-115mph in the quarter mile, even with those tires. Slowing and stopping with the pressure down really low can get a little squirrely.
 
to help figure out when you have full contact between tread/ground use chalk. draw a line across the tread and move the car. scrubs off the center you are over inflated....
 
Thank you guys for all your advice, i appreciate it...:newb:

I have 4 days left to check everything, so there´s time to find the "biggest footprint" pressure. At the track i´ll make a run with and one with out burnout - will make a "logbook" to write down the changes and then i can see what happens to the ET / 60 ft. times. The front tires are already at 40 psi.

Thanks again!
 
Street tires with a medium to large burnout = more tire spin off the line. Some have a happy spot but most just go around water box back up and clean tires off (spin a little) and be ready to pedal with a 408 . Have fun! Should be a blast for you!!
 
All good advise here. Just stay out of the water box and play with the air pressure.
 
A tip not many people know.Find out if your track has a concrete,or pavement launchpad.Fine out,then,find a similar spot.THEN,LAY WATER DOWN.Launch the car ,as if yoh would on the track.If this is truly a new combo,this will show with tire speed(slowly), how the car will work with the new mill.Sounds far fetched,but it works.....
 
Abodybomber said:
A tip not many people know.Find out if your track has a concrete,or pavement launchpad.Fine out,then,find a similar spot.THEN,LAY WATER DOWN.Launch the car ,as if yoh would on the track.If this is truly a new combo,this will show with tire speed(slowly), how the car will work with the new mill.Sounds far fetched,but it works.....
Click to expand...
Nothing like a little out of the way street testing, i did it constantly. Even had a special 2 mile loop from my house and back that included a interstate on ramp that was straight and about a quarter mile long. Adjust timing, run the loop. Play with jetting, run the loop. Was a Sunday morning ritual for me.....lol. That was in the 70s and with traffic and development now days i'd never get away with it.:D
 
Ricky ,still have mine.Lost my hobby shop,not my connects....
 
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