TB2

iTrader: (1)

Had the car to the track couple weeks ago. First time with new wheels and skinnys up front. Car goes down the track nice and straight. No issues until I lift and apply the brakes in the shutdown. The car is all over the place. Weaving side to side as Im holdin on for dear life. Never had this issue when I was running 245/50-16 street tires up front. Car was only running mid 120's as I was having trans problems. Need to get this problem sorted out before I get back to the track with new trans. All the suspension is in good shape (was aligned) and the brakes are stock, but in good working order. Any ideas what to look into first?

Orr89RocZ

iTrader: (20)

How are your brakes and rotors? Is one caliper sticking causing it to pull to one side? Are rotors warped at all? How is the braking bias front to rear?

Shouldnt have any problems as long as brakes are functioning fine.

greezemonkey

iTrader: (14)

how mush psi in the front runners and what brand? what size ? and what are you running out back? this is at lapeer I`m assuming?

TB2

iTrader: (1)

Rotors are not warped, pads have maybe 300 miles. Its not pulling in just one direction which makes me think my problem is not front brakes. Bias is stock, but Im wondering if more rear brake may help.

M/T sportsman front runners. Im not at home to check, but Im pretty sure that I set them to 35psi. Not sure on size of fronts. Rears are E/T drag 28x10.5-15 stiff wall. And yes, Lapeer. My faverite place to test. Anything but flat and smooth.

DIGGLER

iTrader: (1)

may be worn out suspension parts in the front. i run factory brake bias and never had a problem running slicks/skinnies at around 140mph.

Orr89RocZ

iTrader: (20)

Maybe check the steering components, tie rod ends, suspension bushings. Does it have a front sway bar and rear sway bar?

Shagwell

I was running stock front brakes for a while, shutting down from 130mph in the 1/8 w/o any issues.

You might try lowering the front pressure down to 30, 35 might have them trying to sit on an overly small surface area.

What tire pressure out back? - Slicks do "grow" with speed; the softer they're set the more the grow & thus the more the "worm" when settling back down during shut-down.

How are the rear brake components? - Defintely need the rears to be functioning well with skinnies up front. If one side is grabbing more than the other or maybe has a spot where it's tighter it will drag the front end around.

GreggymacZ28

When i raced at lapeer all my car was running was 105 back then down the track, but i was scared to run even that at lapeer. After the traps the road is so bumpy, and there are so many cracks, it made me wonder how anyone going any faster could do it. I doubt thats your issue, but im sure it wasnt helping the situation.

TB2

iTrader: (1)

New ball joints and idler arm. Tie rods checked good.

No front sway bar. Rear is preloaded and I have an air bag on the right rear @ 15psi.

running about 13psi in the rears. Havn't checked the rear brakes. I geuss if the front is doing all the stopping it wouldn't be as noticable with the street tires as with the skinnys. Like I said, i had no issue when I was running my street tires. I will have to look at the rear brakes and make sure they are good and adjusted correctly.

Lapeer's track conditions are definetly an issue. But I figure if I can get it to go there, I can take it anywhere without issue. I also know there are guys running way faster than me at that track and make it work. Some on this board(greaze monkey)

hrspwr

iTrader: (3)

Had a friend that had an issue, but he fought the car all the way down the track.Turned out that the radial tires on the front and the slicks did not track well. He switched over to a bias ply tire on the front and the issue went away.

AlkyIROC

Too much preload is good for the launch but bad for downtrack and at the top end. Drop that pressure down under 10 psi and try again or reduce the amount of preload in the rear sway bar.

TB2

iTrader: (1)

Front runners and slicks are bias ply. Didnt have this issue with the stock radials on the front.

Possible. Maybe the problem is just amplified since I put the skinnys up front. Because I ran with more air than that in the bag with no issue before I put the skinnys on.

As soon as I get the trans done Im going to check the rear brakes. Does it make sense that if the rear brakes are bad and Im shutting down with just the fronts that it would slow down much more controllable with the wide stock tires than the skinnys?

Orr89RocZ

iTrader: (20)

Yes wider tires have more rotating mass and thus same brake pressure applied will stop a skinny tire quicker than fat front meat. I was able to lock my front brakes at 30 mph with skinnies but couldnt dream of doing that with my big fat 18"'s up front. So the brakes could grab one side and pull it one way

greezemonkey

iTrader: (14)

100% what **** said....30 psi should be the MAX on the front runner. When the weight transfers to the front on the shutdown you want the front tires to "spread" so there is more rubber meeting the road for braking. Try using all the shut down too, it`s long so you can go easy on the binders. You do have to have Big Brass Nuts to run there, I`m not saying it`s smart or am I proud of it because it`s more stupid than anything but- I`ve been 163MPH there and never even needed to throw the laundry. I will admit though at that speed THERE, you get your adrenaline really pumping.

Shagwell

Most skinny wheels/tires are only rated for around 30psi anyway. The wheels often have warning stickers on them when new stating that, and the weight load we put on the little tires dictates a lower pressure to keep them within their weight per pressure rating.

The rear brakes definitely play a much larger roll on a car with skinnies vs a car with a full street width tire up front. - Many altereds & most dragsters don't even have front brakes.




The only time I don't throw the laundry is when running 1/8 on a 1/4 track. - "Live by it or die by it" has been etched in my head for years watching my ol man race; if you "only throw it when you need it" by the time you realize you need it it's far too late for it to help ya.

1gary

I am going to use the analogy the same as a snow tire.A taller skinny tire provides more traction because it has to make more revolutions to start it than a shorter wider tire and for the matter a taller skinny tire takes more revolutions to stop it.The slicks tire pressure along with this is changing the bias front to back.You put in a adjustor front to back and play with those pressures might help.

Our racing policy with our driver is a chute gets pulled on every run.The 1/8 mile times are in the mid 4's@ 150 with a relatively short shut-down area.No front brakes.There is a delay from the pilot to full bloom and he has to be prepared to deal with that.BUT once it hits,it stops fairly quickly.