Tire wear diagnosis

First off I tried to find it but couldn’t. I thought I saw previously a thread about diagnosing tire wear.
My daughter and I both race karts, a thing we can do together but I have a hard time getting feedback from her and allot of times I am guessing on chassis set up or changes. She is only in it for fun since she has way higher priorities as a newly turned 16 yr old( she is big into ag and livestock showing, 4H) but I still want to set her up for success.
Any one have any onsite into what the kart is telling me by the look of these tires. She is telling me the kart feels great. But I know she can go faster.
She ran her first race at Sr. Weight with
a kpv 3 pipe. These tires were one race old but I flipped them before she raced. They are Bridgestone YLC
Front right.


Front leftimage
The rears look good, same as mine. But my fronts are way smoother, no wrinkles or anything.

Sorry for the long post and thanks for any help.

There’s a thread, look up learning how to diagnose tires. That’s the thread you are looking for.

It looks like you are feathering the front tires meaning you have a “push” and are sliding the front tires. Try widening the front end a bit to get some more grip. Hopefully that helps you some.

What pressures are you running?

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Go out at 13 grows about 3-4 pounds

Looks like understeer or driving too hard into the corner. Wavy, longitudinal lines = understeer, but if they are concentrated on the inner shoulder of the tire, that to me says that the driver is driving in too hard and overworking the tires.

If it was her first race at senior weight, I can imagine that she wasn’t used to having to slow down that extra weight and could’ve been entering the corner too fast.

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Makes sense. Thanks. Next time out I’ll mess with track width and her driving.

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MG yellows. 9.5 psi, 45 F outside, 1mm toe out on each side when on the stand. I put 4 laps on these new tires in November 2018 before a crash ended my race. Hours later, I stored the tires indoors at 70 F in a dark closet.
The kart was setup the same as last year, except with wider front hubs (+20mm each side). Handling seemed good. I can’t see any issue with hubs or wheels being bent. After running 9 laps, I re-checked the toe and it was still 1mm out on each side. However,
RF tire:
20190216_150228
LF tire:
20190216_150219

Whoa, that’s gnarly.

Right front looks almost perfect. Left front looks like it was attacked by a rabid animal.

Did you check camber? The right front has even wear all the way across, the left front has barely used the outside edge of the tire, but has shredded inside edge. That seems odd. Even with a track that’s heavily biased toward one direction, I wouldn’t expect to see that.

Also, possible to get a durometer tool to check and compare hardness between the two?

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Holy mother of god! Somebody give that tire last rites.

When I put lasers on it to check toe, I also saw that the camber was equal on both sides. It’s just over 2 mm positive (one line on the sniper laser tool, not really sure what 2mm is in degrees) on both sides. It is for sure positive, not negative camber. I had been trying to run some positive camber to help with tire wear and I had been having no issue with it.

I really wasn’t driving very well, and after thinking about it more, I probably did not have a good feel for the balance of the kart. I’m starting to think it was understeering more than I realize. I’m not really sure how widening the front would make it understeer though.

Something that might be worth a try is swapping the front tires and seeing if that other tire gets chewed up on that side. If so, then you know it’s not a defective tire and it’s something in the chassis or something.

Otherwise, I’m a bit stumped on it.

is the frame straight? Any cracks?

I had a MG Yellow do that exact same thing last year. I chalked it up to a defective tire…nothing unusual about my setup either or weird tire pressure.

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First Kart for my son. Trying to learn some stuff :slightly_smiling_face:
Tires are bridgestone YLC inflated to 12psi. Got to 13psi after a 15 minute session.
image image image image

Fronts look fairly normal, no feathering to indicate understeer. Slight build-up on the outer edge of the one usually means that tire is dragging a little or being slightly overworked, but nothing too alarming. Could use a little more of the tire, the outer wear dot looks almost untouched. Looks like you’ve got neutral caster/camber pills in there, but a little positive camber might help increase the contact patch.

Rears look like they’ve got quite a bit of pick-up on them, so a bit hard to tell but otherwise look alright. What’s your rear track width? Just curious because it looks like the tires are quite far outside the pods.

Thanks for the feedback! The rears are 7.1x11-5

Sorry, I meant the overall track width, from one wheel face to the other.

What can you tell me about these? VEGA Blue. Cadet kart running at 230 lbs. These are about a year old. My son is 6 years old and only started to push hard enough for them to start wearing recently.
Left Front

Right Front

Left Rear

Right Rear

Thanks,
Brian

Looks pretty good/normal to me. Looks like the fastest corners on the track are probably left-handers? The left front isn’t rolling over much, as shown by the wear dots. Nothing too much to worry about.

Than for the reply TJ. What causes the tires to wear so much more on the inside? On the front I can understand it can be caused by camber. I’m an automotive mechanic and I have lots of alignment experience but unfortunately none of if helps here. No suspension and a solid rear axle… I gave a lot to learn about karts and appreciate any info you can provide.