I agree—the internet is very good at perpetuating bad info. After seeing the triangle mark identified as pointers to the tread wear indicators on several manufacturer's and tire dealer's websites, I'm convinced: they're not scuff markers.

Interestingly, my misinformation came from a successful race car driver who's father was a famous Can-Am champion. So, I can't blame the internet on this blunder.

The trouble is it doesn’t matter because the marks are not “scuff indicators” ...so they DON’T show the “max sidewall rollover recommended by the manufacturer”.  So “going beyond the indicators” DOESN’T sacrifice grip.... 

You are correct, as I said before, chalk/shoe cleaner shows “how much” you’re running on the sidewall.... YOU have to decide how much is OK.  The manufacturer doesn’t provide any advice....

If you don’t believe me, read what Yokohama have to say..(Yokohama-on line.com - “Triangle marks on the sidewall show the tread groove position of the “tread wear indicators......” 

The reason I labour this point is that, while you can do and believe as you please, this is exactly how bad/false information is perpetuated.  Bad information is repeated until it becomes true (which of course, it never does, but the perception remains).

To work out the optimum pressure you do a couple of laps then measure the tread temperature across the  tread (inner shoulder, tread centreline and outer shoulder). The ideal is to get the same temp at each location.  Of course its not easy ...and there are other factors involved (ie correct toe etc) ...

Or , just keep experimenting ... that’s the fun bit .  You’ll know when you’ve got it right when your tyres end up dead..but evenly worn across the entire tread face.

And let us know what you find out...

Cheers, Ian

They point toward the tread, don't they? Close enough?

It matters because the scuff indicators (if in fact that’s what they are) are the max sidewall rollover recommended by the tire manufacturer. Go beyond the indicators and you’re sacrificing contact patch. A chalk line (or shoe polish) on the sidewall only indicates how much the sidewall is rolling over, not how much is too much.

I'm not sure it matters when auto crossing as a much younger man I'd see people using white shoe polish. Just a dab several places around each tire. A wet rag and it wipes right off. Steve (CTR)

True enough. Still, it's weird that there are different opinions on the subject. Seems like they're ether scuff indicators or they are not. To be fair, the majority of the tire manufacture and tire dealer sites say that they are pointers to the wear bars as you have stated—although mine do not line up with my wear bars. Go figure.

I suppose you have to believe it 'cos a Porsche guy said so.....

The wear bar indicators (little triangles) on my 008s are about an inch down the side of the tyre....  I'm sure Yokohama didn't intend them to be run that flat.

Just because they form a useful marker on a specific tyre doesn't mean that what the manufacturer intended...  or the logic works with other tyres.

Cheers, Ian 

I finally found a reference to scuff indicators on a Porsche forum. Seems like my driving instructor knew what he was talking about.

Scuff indicators are generally a chalk line drawn radially (rim to tread) on the tyre wall.  I’ve never had a good grip on how much of the chalk should be scrubbed off to indicate the optimal pressure.

I would leave the camber as is but I use more caster.... about 4 deg maybe.  Be warned though, this will increase steering weight.  Caster “turns” into increased camber on the outer wheel as lock is applied.  This gives more traction in a straight line and a more “upright” wheel (bettter grip) on the outside during cornering.

Cheers, Ian

Great explanation. I now see why we need to run a little toe out. Regarding the uneven wear on the tire in the pic, the defective tire is in the rear, but now that you mention it, the uneven wear pattern in the center of the tire (pic) does seem like a balance issue. The tires were dynamically balanced 5k miles ago but may now be a bit imbalanced I suppose. The one rear tire wouldn't balance correctly and so it was deemed defective. My original concern was the excessive wear on the outer circumference. I didn't even notice what appears to be a balance issue. 

After reading the comments below, I suspect the wear on the outside of the front tires is a result of not having enough toe-out, under-inflation and perhaps being too modest with my camber. For reasons I've already addressed I'll leave the pressure at 24 psi., but I'll follow factory specs on the toe (1.6 mm out) and add a bit more negative camber.

So... is there such a thing as scuff indicators? Internet search turned up nothing.

I'm amazed you are getting that many miles on a set of 032's..... you're not driving hard enough !  

44lb max pressure doesn't mean run them that high at all....wow.
I think the highest I've gone is 38 while experimenting in auto cross.  I run them about 28 for daily driving.......even wear, just wear very quickly

I don't know if there are specific scuff indicators on certain tires. (Curb rash becomes pretty apparent. If your tire is underinflated and you corner hard, the tire will tend to flex sideways, lift the lightly loaded side and roll onto the heavily loaded sidewall, or at least try to.

In the attached photo of one of my Mini tires, you can see the tread has a fairly sharp shoulder with the tread extending over onto the sidewall. If I saw that wearing, I'd be concerned! ( Couldn't get a good shot of any wear bars.)
In the attached photo of my daily driver's Hankook 4-season tire, you can see two wear indicators - a nice fat blocky one and below it a much smaller one. The smaller one is to show when the tire is too worn to be safe - if you're down to that, time to re-tire. The bigger one is the snow tread rating indicator. When you get down to it, the tire is no longer warranted for winter driving.

I see what looks to be uneven tire wear not due to over/under inflation or alignment.
The two blue-circled tread grooves are worn in different paces that seem pretty good in other grooves. That would suggest a tire defect or shimmy or severe unbalance.
You did say "My alignment guy says that it's a factory defect and it happens sometimes."
The areas with red squares appear to contain the tread wear ribs.

Generally, over-inflation results in wear in the middle of the tread. Underinflation does the opposite - results in wear along the outer portions of the tread, both edges of the same tire. Too much toe-in would result in wear on the outboard edge of both front tires at the same time. Too little toe-in (or too much toe-out) would cause both front tires to wear on their inboard edges.

The toe-in/toe-out issue is straightforward if you think about it. On a rear-wheel drive car, the front wheels are pushed along the road. The drag would tend to flex an axle outward, but since the suspension is too resistant, the tires flex instead. If they were aligned straight (zero toe) the flex of the tire would result in their inboard edges wearing faster. So they are toed in to compensate. On a front-wheel drive car, the opposite occurs. the front tires are pulling the car along and tend to flex inward. They are toed out to compensate. Rear wheels are affected similarly. On a rigid axle rear drive, there is no opportunity for alignment. With independent suspension comes the ability to compensate for wear forces.

The original alignment specs for the Mini were to optimize tire wear. That's why there's so little adjustment in the factory standard suspension - toe in/out... that's it. Notice how the factory spec shows positive camber front and back, modest toe out at the front and modest toe in at the back. Front wheels also have a castor setting because they do the steering. When people discovered Minis could handle well, they started tweaking the alignment to improve cornering ability. The compromise of improved handling is increased tire wear.

I've had very limited track experence—certainly not enough to experiment and refine my suspension settings. Most of what I know I've cobbled together from books, bench racing and forums such as this. I appreciate getting tips from those of you who know what you're talking about.

Hmm.. pointers to the wear bar indicators? They don't seem to line-up with my wear bars, which are scattered over most of the circumference of the tire. My racing school instructor dropped my tire pressure to 24 psi. after a couple of laps and pointed out the so-called scuff indicators. I thought 24 psi. was crazy low myself, but it worked well on the track and the ride home was so pleasant I decided to keep it at 24 psi. So, is there such a thing as scuff indicators? 

I replaced my worn tie-rod bushings with new poly bushings last night. I've been chasing a front end clunk and thought the bushings might be the culprit. As I was tightening the nut on the rod ends it occurred to me that I was changing the toe angle depending on how much torque I was applying as I was squishing the bushings into place. So, tonight I'll get the alignment plates out and set the toe with a bit of toe-out per spec.  I might add another degree of negative camber if the new tires begin to show wear on the outside. Perhaps the new toe-in setting will take care of the uneven wear, but I'm reluctant to increase the tire pressure; it sure rides sweet @ 24 psi.

Currently at 2° positive.

So, what in the group's opinion would be an ideal front & rear alignment set-up for a fast road car driven (almost daily) on highway and twisty mountain roads with an occasional autocross and track-day thrown in? All of my suspension components are adjustable including the rear swaybar. Thanks!

Yes it is unusual or at least it was back when Mini's were first made maybe newer vehicles with fwd now as apposed to rwd which was the norm here for a long time. AFAIK Mini's have always been set up with toe out and an alignment may confirm that your 0 setting just may not be that anymore.
Just a thought haven't you done a fair amount of front end work on the Mini and was it re aligned afterwards, if not that may be where the discrepancy (if there is one) is.
Your 24 lbs of pressure would seem too low to me i too like Ian run around 30 in the fronts so this could also be a factor to the tires scrubbing the outer edges off.

I’m running 24 psi. Sidewall sez 44 max. Overinflation? I don’t think so. 

What pressure are you running ?

Those photos show classic overinflation.

I think you've got the wrong end of the stick with a few of your suppositions there....

Tyres don't (not the ones I've seen) have a "recommended tyre pressure...  They have a "maximum" inflation pressure ..that you shouldn't exceed.  But optimum pressure depends more on the weight placed on the tyre - which is why you run the front at higher pressure than the rear...  Car manufacturers know what their cars weigh so they provide the recommended pressures; not the tyre maker.

My 008s are stamped with a max recommended pressure of 44psi at the max load rating (roughly 2 x a Mini weight).  But I would never run them that hard.  I find around 30 is good (at the front) although when hillclimbing I bump them up a bit (say +4psi).  This probably reduced overall grip but it feels better in the transitions..... (IMHO  I run the backs about 4 or so psi less.

"I know the pressure isn't too low as the scuff indicators haven't come into play (see pic)"

Uuumm these are not scuff indicators.  They are wear bar indicators.  They show where the tread depth bars run across the tread face ...

My reading of your tyre photos is that the pressures are not bad ..if a little high ..which is reflected in the increased wear in the centre of the tread face.

I agree with the other statements regarding toe out.  Minis like front toe out.... Again the wear patterns indicate that you don't have enough.  I would suggest that with proper alignment you shouldn't see any significant wear with the limited camber you're running. (I don't with the same camber settings).

What sort of caster settings are you running?

Cheers, Ian

I did notice that toe-out is recommended for the Mini. Isn't toe-out unusual? I always thought that toe-in provides straight line stability, like snow-plowing on skis, and toe-out was never recommended. Is the Mini's FWD and suspension geometry that much different than standard autos?

I would not think it would change things. You could loosen up the tie rod ends and adjust them a few flats of the 3/4" nut on each side remembering how many flats you changed it in case you need to change it back, if you see no difference then get an alignment to correct specs.