Track Tac

Rolling wheel measuring device at Amazon.

racer47 said:
Is there really an ideal stagger for a particular track? I used to race asphalt cars on a 3/8ths mile track. We ran roughly 2" of stagger depending on the weather. Asphalt sprint cars come to visit and they would run 4" plus on the same track. The radius of the turns didn't magically change when a sprint car rolled out of the pits.
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A prime example of forces applied through lateral transfer and the use of stagger to help control them. :)
 
racer47 said:
Is there really an ideal stagger for a particular track? I used to race asphalt cars on a 3/8ths mile track. We ran roughly 2" of stagger depending on the weather. Asphalt sprint cars come to visit and they would run 4" plus on the same track. The radius of the turns didn't magically change when a sprint car rolled out of the pits.
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IMHO:

Radius does effect stagger and in general a tighter radius will get additional stagger then a less tight radius. But IMHO, that's where generalities end and function and application begin. How much stagger works for you is dependent on the ability of what your racing to use stagger. A quick example is a winged sprint car as more ability to better use stagger then a late model and the ability of each is about the mechanical ability to apply weight to each rear tire when needed.

The reason stagger can give additional rotational effort from the axle with it's staggered tires, is because of the difference in surface speed between the two rear tires, available grip and how weight is applied to each rear tire.

I'll try to net it out speaking about the LR tire only. Somewhere on the track you must slow down and it's usually going into a corner. If your slowing down and you can push or hold the LR tire into the track, with it's slower surface speed then the RR tire, it will act as a brake or a rudder allowing the larger RR tire with it's faster surface speed to roll around it.

When even your asphalt car gets off the gas going into the corner, it instantly can apply weight to the LR. Then as soon as you accelerate weight and grip begins to leave the LR. You get your function out of stagger even though you only use 2"s of stagger, because of aero down force on your car preloading the LR while on the straight and the additional help when you let off. That's what slightly helps you into the start of the corner, along with your front tires.

The sprint with it's 4 inches of stagger... I have to stop because you did not say if they are winged sprints or not. If no wing they function exactly as your car and it's only their bigger tires with more grip that allow them to use more stagger then you. If there winged, then the wing will help them load the LR better and also help maintain the loading while slowing down and they are winged over. If you don't see them wing over, then there pretty much doing only what you do. Depending on the HP of the sprint and available grip, they may even setup to ride on the RR it all just depends on need.

I'll stop, either this made some sense to you and fit your question or it did not and if it don't fit, it is all just IMHO and ain't necessairly right anyway. ... :)
 
:)Take care Al. I know your just trying to help. I think everybody else knows too.
How about that picture. I'm riding an old rear engine antique just for novelty and fun.
I've thought about a big block hanging off the back and being able to carry the front wheels down the straight for crowd appeal but I'm getting old and tired. Bicycle, maybe. Unicycle, thats pushing it.:)__
 
M.D.racing said:
:)Take care Al. I know your just trying to help. I think everybody else knows too.
How about that picture. I'm riding an old rear engine antique just for novelty and fun.
I've thought about a big block hanging off the back and being able to carry the front wheels down the straight for crowd appeal but I'm getting old and tired. Bicycle, maybe. Unicycle, thats pushing it.:)__
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Actually, a Sauder, Kinser, and SAE are rear engine'd dirt karts that worked (some say still do) quite well on loose dirt tracks. But on "dirtphalt" like is run here in Fl. they're unfortunately out to lunch. Put a 135cc 2 stroke on any one of these karts and wheelies are a gimme. :)
 
Crazyboyracing7 said:
Al must be blown away with the amount of rear Stagger a dirt sprint car uses!
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Are you talking about a Sprint Car or a Sprint kart?

I get blown away by nothing. I do get curious. When I hear that the locals are running 2 inches of stagger and the visitors are running 4 inches of stagger, I wonder who is closer to the right stagger. I wonder why there is so much difference. I wonder; if they switched, would either go better, or would both go worse. I wonder what the difference is, between the two cars, that accounts for the huge difference in stagger. Could it be the difference in power between the two cars? I wonder what effect spinning both rear tires has on the selected stagger, or the fact that the car might be sideways with reverse steering. I would wonder how much caster they use and the amount of camber. I would wonder about the steering geometry. I would wonder about the weight distribution. So many questions, so little knowledge.

"Blown away", I don't think so. lol
 
Interestingly, when a dirt track slicks off and loses bite, you need less rear stagger in the car. The turn radius does not change, the tracking does not change, the horsepower does not change, the corner entry speed does not change, the caster, camber, etc does not change...but the available grip sure does. This is demonstrated very well with a winged sprint car when you might start the night with 15" stagger and end up the night with 10." Same radius corner, yet the stagger changes considerably.
Again, I feel that the turn radius is an important piece of data -- not discounting that whatsoever, but it certainly is not the only thing to consider when determining stagger.
 
The most important thing and consideration in dirt oval racing is, available grip.
Second are available forces out on the track.

The most important tool is having a driver and crew able to identify and fix on track problems.
And last if not first, a driver who knows how to race and able to use the equipment to it's potential.
 
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