February 7, 2018 at 2:42 pm #90990
Our front tires are showing wear on the inside edges and zero wear on the outside. Actually there is about 3/4” wide stripe that looks like it’s not even touching the track. We had the same thing last year on a different brand kart, but when I add positive camber the kart gets loose. But the coning goes away. I have showed it to a couple of local guys that are knowledgeable, and they say it’s normal to get coning. What doesn’t make sense to me is why give up the extra front grip by adding camber? Is it because cadet carts have narrow rear wheels compared to full size? I have tried tuning out the loose condition but it only gets a little better. My son still has to correct an oversteer condition several times in a corner. When I go back to neutral camber (1.5 degrees per side on the stand) the kart is pretty neutral. Am I missing something?
February 7, 2018 at 11:21 pm #91002
where did you set up your toe at?
How much caster do you have?
What air pressures are you running?
Do you have enough weight at the front of the kart?
What tires are you running?
Is this track smooth, or rough?
And does it do the same thing at any track? Or all tracks?
I’m assuming your seat position is correct, and your weight distribution too.
February 8, 2018 at 5:17 am #91003
Toe is 2mm out on stand.
Dont have any way to check caster.
Tires are evinco blue at 12f and 14r.
Kart scales with 42 percent front weight bias. Seat position per manufacturers recommendation.
We’ve been to several tracks both smooth and bumpy, same result.
February 8, 2018 at 7:48 am #91032
People often worry about tire wear when in reality it doesn’t really matter. What matters is the stopwatch, so I wouldn’t worry too much about it.
If you think the coning is excessive (more than your competitors’ tires) but you can’t get the kart to stop oversteering when you add camber, that sounds like a driving issue to me. It sounds like the kart might be understeering with negative camber which means it’s really stable, but you’re burning up the fronts. Your driver might be too harsh on the wheel and when you put front grip into the kart, he isn’t adapting his driving to the increase response in the front end. Something I would try would be to incrementally add small amounts of camber to the front over a practice day and see if he can adapt over the course of the day. You might find if he slows his hands down, he can run with that extra front grip and be faster.
Driver/Coach/Wrench : Innovative Performance/Exprit
Owner : Oktane Visual - www.oktanevisual.com
February 21, 2018 at 1:44 pm #91423
As TJ said use the watch. Evinco tires do tend to wear the way you describe due to the shoulder geometry. For a cadet running blues flip the tires after a full day at the track to reverse the inside and outside edges.
I assume you mean 1.5mm on the snipers and not 1.5 degrees. 1.5 degrees would be a massive amount of camber. If you due the math quickly and we assume that the snipers are 30 inches apart when doing an alignment 1.5 degrees would be 20mm. On the other hand 2mm on the snipers at the same distance between the snipers and you get .15 degrees.
Adding the positive camber to drive tire wear as you have tried will increase grip up front and throw off the front to rear balance in the kart (as you have found). Remember these karts are mostly designed in Italy and the euro run a narrower front tire. The rears are still the 4.6″ we run but the fronts are about an inch narrower. So when the kart is run with 4.6″ tires all around the cadets have a massive amount of front grip. Imagine driving a full size kart with 7.10″ tires in front. when my son was running a birel cadet we would typically run 2-4mm negative camber per side.
February 21, 2018 at 3:40 pm #91427
Thanks for the advice. Yes I meant 1.5mm still learning how to read these things. I like the idea of taking away the camber over a practice day and seeing how he does. I’ve told him from the beginning to be as smooth as possible on the wheel and always watch his hands closely when he drives and he is pretty good at keeping his steering inputs to a minimum. But I’m sure there’s room for improvement there.
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