Track Tac

Kart design?

alvin l nunley

alvin l nunley

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Does anybody have thoughts on current chassis design?

Why is it that tread widths have gotten wider and wider, but chassis widths have stayed pretty much the same? Can sticking that tire way out on those extended spindles be ideal? Has anybody tried a wider frame?

Back in the 70s, the rear tread width was, by rule, maximum of 40 inches. A 1 inch rear axle work just fine, as far as we could tell. Now you can have a maximum of 54 inches, 7 inches farther out on each side, so is it any wonder that they need the bigger diameter axle. I know part of it is because the tires are gripping much better than they did back in the 70s, but that's not all of it.

My Mayko frame was wider than other karts of the day, who will be the first to try a wider frame now? Does anybody have reasons why a wider frame would not wo
 
Skidude said:
I’m going to take a guess and say that the extended length of axle works like a stiff spring.
Click to expand...
Similar to this, sprint cars use torsion bars of various weights to help setups. You cant tell me that the top guys aren't playing with axle thicknesses to find the best mix of weight and spring.

Perhaps bumpy track, thicker wall, smooth track thin wall.
 
On a sprint kart...

Well, the actual track width has needed to get considerably wider as tires have gotten stickier. A kart will just bicycle otherwise.

Since a sprint kart runs no stagger, AND the tires are really sticky, AND the contact patches are further apart... long stub axles on the front spindles dramatically increase the scrub radius, which provides a lot more weight jacking -- Simply put: the combination of front end geometry and large scrub radius allows that inside rear to get unloaded with a relatively small amount of steering input (so the kart can "turn in" easily).

On the rear, most modern karts are probably using 50mm axles, so the axle is going to be stiffer than the chassis would be if brought out further. I'd also suspect the main rail width in the rear is influenced by where the engine needs to be.

PM
 
In the case of CIK homologated karts, max frame and track width are set in the regulations as well as wheelbase. I can't speak as to what drives those specific numbers though
 
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It's about how you present the forces to the tire.
Longer lever though when they operate their working ends move faster, they initially more slowly ease the tire into the track, better than shorter levers

So, it's short lever and bang and bicycle tending to keep it up because the working end moves slower or ease the tire into the track with a longer lever and the chassis away from the tire will return faster to the track once it gets moving.

A longer lever with stickier tires is a win-win.

Al it's exactly what John tried in vain to explain to you maybe 30 years ago now.

maybe? ... :)
 
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