Track Tac

What Part of the tire??

L

LooksLikeFun

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I was told something that the more I think about it the more I second guess what I was told can someone Confirm this or is it Wrong?

On a Clay 1/8 mile oval when in the turns does the inside of the tire get used or the outside of the tire? I'm talking external inside and outside on lefts and rights. I was told the inside of the tire takes the beating not the outside,but it seems like the outside would be taking the beating, so would it be the Left side's inside would be taking the beating and the right side's outside taking the beating?
 
Outside of your left side tires will generally show more wear, and the inside of your Right sides.

Now, wear somewhere else will generally show a condition, like excessive wear on the outside shoulder of the Right Rear usually means you're rolling the Right Rear over, same goes for Right front.

The reason these particular sides are used more is due to Camber and stagger, think of how your camber is set, and then think of the stagger effect.


To elaborate more, you're using a very minimal amount of the right sides in the straights to increase roll speed. But, in the turns with camber gain and weight transfer, you're increasing footprint of the tire for cornering grip. With the camber and stagger effects you're effectively running on the inside of the Right sides, and outside of the Left side tires down the straights. When loading the tires through the corners you're effectively trying to use more or less of the footprint of the tires as needed to create just enough grip to get through the corners, but not too much to slow you down.
 
At least that's what I think, no one has said that I'm wrong yet. Or maybe they're all sitting back saying "you keep thinking that and we'll keep winning." Lol, I don't know!
 
Inside of rf and outside of lf. Due to camber. That's why it's good to flip the rf every couple races or every race. Or get outlaw wheels that are flip able
 
It is not due to camber. How many of you have camber in your RR? Yet it still wears on the inside of the tire. The reason for these wear patterns is due to the fact we race in circles. There is a pulling force towards the outside of the LR and a pushing force towards the inside of the RR. Its all based on how the kart moves around the track. If we went the opposite way, the outside of the RR would wear and the inside of the LR. Set a kart down with the toe lock in and roll it. You will see where the tires contact the ground without lateral loading. Once we turn and put lateral force on the tires, this area changes.
 
Krug2k said:
It is not due to camber. How many of you have camber in your RR? Yet it still wears on the inside of the tire. The reason for these wear patterns is due to the fact we race in circles. There is a pulling force towards the outside of the LR and a pushing force towards the inside of the RR. Its all based on how the kart moves around the track. If we went the opposite way, the outside of the RR would wear and the inside of the LR. Set a kart down with the toe lock in and roll it. You will see where the tires contact the ground without lateral loading. Once we turn and put lateral force on the tires, this area changes.
Click to expand...

Anyone with any stagger has a camber effect.
 
And going down the straights with negative camber on the rf it's gonna wear the inside of tire faster then the outside. Normally the straights are longer then the turns. So it don't flatten out but in the corners for it to wear the outside of rf
 
With 1.5" of stagger the camber in the rear is less than 1 degree.. close to .85, In this case I would consider that to be negligible..

Can post equations if you would like.

I return to what I said before, roll the kart and you can see where the tire is touching by what part of the tires pick up dust. Put positive 1 in the RF and you will still wear the inside of the tire. Trust me, I've done it.

The wear is all about slip angles and lateral forces.
 
Turn the steering wheel to the left. Just look at the right front wheel. You can see that it is laid over, caused by the stagger, and the inside edge is on the ground. Look at the left front wheel. You can see that that it is laid over and the outside edges is on the ground. The edges that are on the ground are taking the brunt of the force required to turn the kart to the left. This is where the wear occurs The outside tire, on an LTO, is taking more force than the inside tire. The outside tire also has more camber and thus the inside edge of the tire takes even more abuse. Now kingpin inclinations negates some of this, but not much.

Now look at the rear tires. In most cases, the wheel is wider than the tread width. This means that the sidewalls are at an angle. In a left-hand turn, as the wheel tries to go to the right from the centrifugal force, and the tread tries to stay in place, the angle of the outside sidewall increases and the angle of the inside sidewall decreases, effectively pulling the outside edge of tread up and pushing the inside edge of the tread down. So the inside edge gets more wear. Plus add to that the stagger. Just the opposite for the left-hand tire.

From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
 
Al, I like the way you explained the dynamic load on the tires. I hit on that a little, but the way you talked about it even made it click a little better for me.
 
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