Tyre wear diagnosis

[tinsfci]

Mr sprint tyres are developing a circumfrential wear patter on all 4 corners, which I presume is tyre pressure related, but I am unsure which way to move. Tyres are:
Right Front

Left Front

Right Rear

Left Rear

Cookie Monster practicing photo bombing


Tyres are 205/50-15 R888's on 6.5" wheels. The groove is toward the outside of the tyre on all 4 corners, camber is ~2 degrees on each corner. I do get wear on the outside of each tyre but I can't add much more camber as it is still a daily driver. The wear has been developing over quite a few events, Barbagallo is a Clockwise circuit and Collie is CCW, so at least the wear is even!

So, before reveal what tyre pressure I have been using, I would appreciate suggestions as to increasing or decreasing pressure, or what else to change...... over to the experts.

[project.r.racing]

look to me like it is rubbing on something. as it is more like a groove than uneven wear. and it is on all 4 tyres in the same place. do you run a super low suspension setup? if so it could be rubbing on something when turning corners when the chassis rolls in corners.

skinny wheel + wide tyres may mean alot more than average tyre flex. which pushes the contact surface of the tyre into funny shapes. maybe hitting/rubbing on something inside the wheel wells.

over pressure tyres = wear in middle. under pressure = wear on outside. you have none of those above. as the wear is 1/4 in on every tyre.

[wun911]

dude the dog licked the tires?

[bruce]

That is a cute dog? He looks Chinese?

[tinsfci]

dude the dog licked the tires?

The secret is out.... dog slobber makes great traction compund. He is a Chow Chow (9 weeks old), one of the very few animals on the planet with a blue tongue, and yup the breed is chinese, chows are thought to be one of the oldest breed of dog with a history going back 3000 years.

The tyres have been run mid 30 pounds hot, because I thought that I was getting the outer edge far too hot running lower pressures, blue on the outer edge after a sprint day. Alignment should be good, 2 deg camber, 4 deg caster and sod all toe at either end, hasn't been checked for a while so that may be something to look at. Suspension is tein ss, minimal lowering. The more I think about it, the more I say the pressure is too high and the lack of camber is the big issue.

I think I will try a few pounds lower hot and see what the outer edge looks like, I think I can flog this set for a couple more sprints before I bin them.

P

[Hellmun]

Well I havnt' change my alignments between my D03's and D01J's I'm currently running and I'm seeing similar with slightly more camber on my car. I noticed that Ian Vickers car does that on Toyo R888's which is in standard class and so did Irwin's car when he ran R888's . I doubt it's alignment related, more likely the tyres constuction.

[4sfed5]

it looks like not enough camber (edge wear) and over inflation (center wear) . The problems going to be exaggerated by the 6.5" wheels not being wide enough.the narrow wheel will "pull" the tyre face rounder. you really need a 7 or 7.5" wheel to be a good stable platform for the tyre to work on and respond to pressure and alignment changes. a 50 profile is still fairly tall in the sidewall and you will get movement of the tread face.
As a band aid for the short term id look at going for .5 more camber and back the pressures down about 3-5 psi. maybe add just a wee bit of toe in at the back..

long term the wider wheels will sort it out.

[Boags]

NMX516 and I both have the exact same groove. I run 205/50/15 on a 15x6.5 rim and he runs 195/50/15 on a 15x6 rim.

Rims being too skinny makes sense.

Solution - flip them round lots of times!

[Okibi]

..He is a Chow Chow (9 weeks old), one of the very few animals on the planet with a blue tongue...

Tries desperately not to make a smurfette joke

[NMX516]

What Boags said, except mine are actually 55 series. I think it is just a case of rotating as often as possible. I have this on my front left only, from two track days at QR. I start with 28psi cold in them.

I noticed quite a few sets of 888's showing these symptoms at Philip Island, but the consensus was to rotate them frequently to get the best wear. Manga_blue had done this and his seemed very consistently worn.

I think that area of the tyre is just to the inside of where there may be stiffer sidewall construction/support. Every 888 I've seen with this has the groove in exactly the same area, so I don't think it is really too much alignment related.

[Fatty]

yes i've just learnt that tyre rotation is important. i wore out my first set of r-specs prematurely (dunlop DZ03G) as i did not pay close enough attention to tyre wear. if i had spent some time swapping them around i would've probably got a couple more track days out of them. i've got a new set of 888's now so i'll be keeping a closer eye on them from now on.

[Steve - Toyo Tyres]

Hot pressures should be no more than 32psi.
A little more camber would help.
You will find the tyres will wear a little faster at the quarter point compared to the tread centre or shoulders. This relates to the fact that the the tread block is smallest at this part of the tread, therefore it has more movement & a faster wear rate.
The tread pattern is quite efficient at dispersing water considering considering the groove area is small.
Regular rotations will maximize tyre life regardless of the tyre brand or pattern. Most race tracks will work one tyre much hader than the other three.

[blackster]

Hot pressures should be no more than 32psi.
A little more camber would help.
You will find the tyres will wear a little faster at the quarter point compared to the tread centre or shoulders. This relates to the fact that the the tread block is smallest at this part of the tread, therefore it has more movement & a faster wear rate.
The tread pattern is quite efficient at dispersing water considering considering the groove area is small.
Regular rotations will maximize tyre life regardless of the tyre brand or pattern. Most race tracks will work one tyre much hader than the other three.

Welcome steve, nice to see a rep from a tyre company acutally on the forum. Perhaps you may be able to assist us with other enquires, eg group buys?

[Boags]

Thanks and welcome, Steve!

Great to have you on the forum; please stick around.

Cheers,
Boags

[tinsfci]

Cheers for all the replies, interesting to see others are having similar issues.

I have tried lower pressures, which to me seemed to result in too much heat and hence a blue edge on the tyre after events (which I presume is bad) and slower laptimes. Laptimes can be difficult to compare as I am only doing short sprints, not back to back testing.

Steve, does the target pressure change with wheel width? I have to say I have had a great run out of these tyres, they have now done at least a dozen sprints and hillclimb events and my best lap times at each event have been suprisingly consistent over more than a year. Trailering the car to events I reckon I can get still get a few more events out of them.

I think the cunning plan calls for slightly lower pressure, more frequent swaps of tyres on the wheels to even out the edge wear and a set of wider wheels when the budget co-ordinator will allow.

Thanks

Pete