Front tire size,,,,,,

[72GSX]

I feel so dumb having to ask this question, but which way do I go to speed up my reaction times, taller front tires or shorter ones? I need new fronts on my car so I also want to help my slow reaction times. If its taller how tall of a tire will fit in a 72 skylark with stock springs? I think my old tires are about 25" tall. I am talking the narrow drag tires.

[paul c]

i never knew that front tire diameter made a difference with times :Do No: , i know that the width plays a part in overall drag.

[72GSX]

It has to do with the rollout distance of different sized tires but I am not sure if bigger = faster or smaller. Just letting air out or putting more in the same front tires can change reaction times.

[paul c]

well i can only imagine that a smaller diameter tire would quicken it up since it will take less time for it to rotate around once? good luck and fill me in if you find out the exact formula and reason. thanks, paul c.

[gmmopar]

I feel so dumb having to ask this question, but which way do I go to speed up my reaction times, taller front tires or shorter ones? I need new fronts on my car so I also want to help my slow reaction times. If its taller how tall of a tire will fit in a 72 skylark with stock springs? I think my old tires are about 25" tall. I am talking the narrow drag tires.
I believe that the taller tires are used to prevent redlighting, for they take longer to roll out of the beam. Therefor you can start rolling and still not break the beam.

[otter]

An old article from some magazine years ago had a "How to bracket race" guide and they mentioned roll-out and such. They mention that when you just barely break the beam you have a ways to go before the tire clears the beam all together. Some people practice by pulling into the beams and then lightly pump the brake pedal to make the car inch forward. It will depend on your brake system and how consistant your foot is but if you know that each pump on the pedal moves you 1.25" and you just mounted a tire that is 2.5" larger, then you could pump twice and already have a head start on your opponent at the finish lights. Depending on how far apart the stage and pre-stage beams are, you could possibly move 8" before worrying about redlighting. A larger tire will give you more room to bump forward to get a head start, or you could leave one light earlier on the tree. There are a lot of options or strategies on what tire is right for you.
A taller tire will rotate fewer times to go the same distance so it will last longer, it will also fill the wheel well better for looks, then again, a shorter tire will bring the front of the car down and look cool too.
I guess you pick whatever tires you like and then change your launch method to maximize results for you. Did I help or confuse?

[72GSX]

Yes I understand, We used to be able to deep stage to the point of the top bulb going out but they won't let us do that any more. I used to do this when it was on street tires years ago to get good lights.

I have tried bumping in extra after both lights are on but it is real hard to get consistant lights for me this way. If I bump in just till both lights are on and leave on the last yellow I can cut consistant lights but they are real slow, like .110- .120 on a tree where .000 is perfect. So I was wondering which way to go on tire size to speed up the reaction time without having to bump in after both lights are on. It must be I can't get it in the same spot all the time with the extra bumps in. When I move in deeper I end up with .070 lights to red lights.

Maybe its the car thats the problem and not me, when I play on a practice tree I am pretty good normaly. I also think the track rollout is part of my problem, When I go to a different track once in a while I have no problem cutting good lights, just my home track. Maybe I try harder at the other tracks because they are new to me and I get more adrenalin going than at the home track. So I don't know what the problem is but I am sick of loosing because of real bad reaction times. I wonder if they change the rollout during the year to throw off some of the better racers. One of the racers made a wheel to check the rollout distance of the track but they got upset and wouldn't let him check it anymore.

[Shayne Dillinge]

Tom,

If you're consistantly cutting lights in the .110 to .120 range that's perfect. That means that "YOU" are doing your job. Now all you need to do is dial in the "CARS" reaction time and you'll be going round after round. I'll just through out some ideas on how you can speed up a "CARS" r.t. and you can figure out if any can be applied to your car.

- Shorter front tire. But your already at 25".
- Stiffer rear sidewalls. There's quite a bit here. I use the M.T. 3055S which is a stiff sidewall tire for heavier cars. Also, running tubes will add additional stiffness.
- Running more initial timing. Or just locking out the dist.
- Raising your staging line RPM. This is huge. This is how I adjust my r.t. when I footbrake. If I was cutting .060 lights, I could raise my RPM's by 200 and change my r.t. to .030's.
- Do not ware sunglasses or use a dark shield.
- Tune the accel. pump cirrcuts on the carb.

I'm sure there are other ways to speed up the "CARS" r.t. but a least this is food for thought.

Good luck