Learning how to diagnose tires

tires_tyres

(Greg Meller) #21

Sorry, i have no input. Just flagging this thread for later referal.


(TJ Koyen) #22

Nope, you’re always going to wear the inner edge more than the outer.

That tire wear actually looks pretty good.


(James McMahon) #23

Yeah those are pretty good to me, minimal graining. Nice texture.

Wear on the inside is normal, which I know sounds crazy on a solid rear axle, but it’s due to how the inside rear tire unloads. As it does so, the contact patch moves towards the inner edge of the tire.


(Ben Marshall) #24

Ok. Cheers guys.
I found this photo below.
It has nice wear from inner to outer.
Is this just because of the tyre construction?


(TJ Koyen) #25

Not sure what compound specifically that LeCont is, but yes different compounds/brands will wear differently depending on the construction of the sidewall, how soft the tire is, what pressures you’re running etc.

What tire and pressure are you running in your photo?


(Andy Kutscher) #26

Thoughts on these?

Bridgestone YLC, relatively low grip track - 3 race weekends relegating these to practice tires now. I believe I have too much static camber in the front but would appreciate opinions


(TJ Koyen) #27

Slight graining, meaning lack of grip, but they look pretty good. The front wear pattern is totally fine. The kart will always wear the inside shoulder harder due to the geometry of the front end.


(James McMahon) #28

Yeah they look pretty good to me. Inside rear is a little hot, but sometimes they are fast when they get that way. You could be “binding” a little on the exit of turns. You could try narrowing or softening the rear very slightly, and see if the kart comes out of the turn a little faster.

Camber wear on front is nominal.


(Noah Stark) #29

How about these? Haha


(Jason Allan) #30

Looks good to me!! Throw them on again and have a real try!:upside_down_face:


(Greg Meller) #31

What about these ones, what can you gents tell me… first ever drive/practice

Arriw X5 CIK x30r Medium. 10:88. Tightish 408m track, Unknown age Dunlop DFM’s (KA control prime). 3 x 8m practice sessions totalling 59 laps and a big spin to finish the day. 26C ambient.

Cold startIng:
LF = 9psi RF = 10psi
Rears = 10 psi

(Lines in rr are not from the track)


(Jason Allan) #32

The top photo looks like there is a tyre fault, but could just be the photo.
I run my DFM’s at (Cold) 10 psi and aim for a 2 psi increase to hot. Mainly to keep tyre life as long as possible.
I have heard of people running them at up to 15 psi cold, but when I try to run a higher pressure I end up destroying tyres.
The tracks I race on in WA are highly abrasive and I am KA3 Heavy. so take that into consideration.otherwise they look OK to me,


(Greg Meller) #33

Cheers,

The top photo, the middle lines? They were rub marks from when the kart was slid onto the back of a trailer over a metal lip. Didnt damage the tyre but left a superficial mark. :+1:

Glad to hear they look ok. I thought they looked ok too but dont really know what i’m not seeing either. A little negative camber and widening the rear track width has been done since based on setup suggestions from the guys who race Cairns frequently.


(Brian Janty) #34

Ever seen wear like this? Any thoughts would be appreciated. Bridgestone YNB tires on a Komsic M6 Stock Honda Shifter. This was only occurring on the left rear (clockwise track) all the other tires were worn consistently and show a smooth surface on the tire. Kart became un-driveable with a noticeable tire shake in cornering and under hard acceleration, almost like the tire surface was bunching up.

Pre-race PSI - 11, Post Race PSI - 15


(Eric Gunderson) #35

Looks like the tire is flat out way too hot! 11 cold to 15 hot is a 4 psi increase, which is a pretty large pressure build. Typically a pattern like this is not as spread out on the tire, and more localized on the inside edge, with a series of lines at about a 45 degree angle to the direction of tire rotation, usually .5-1" in length at most, and that suggests the inside of the tire is working too hard and getting too hot. This is even more dramatic than that, which if on a shifter makes sense, but again is pretty severe.


(Don Westlie) #36

Don’t have a pic with me but thought I would ask while in my head…

At the Brickyard and never ran YLC before. The rear tires wore the inside almost like a front does with the negative camber. Is that a case of too wide or too narrow in the rear?


(TJ Koyen) #37

I would try a longer hub, maybe even just on that side. I’ve seen this kind of wear on the rears before with short or long hubs. If it’s on the inside shoulder, my gut feeling is that the flex on the axle is causing the tire to squat on the inside while cornering.


(Mags Jim) #38


(Eric Gunderson) #39

How old are the tires? One of them on the outer edge seems to be cracked, which is usually a sign of the rubber losing much of its oil or binding agent, which happens over time…

Also, what are the dimensions on these tires? If they are standard 4.5x10-5 and 7.1x10-5 they look fairly rounded…


(Nicholas Bushnell) #40

MG yellows 9 psi, thoughts?