[HighlandPete]

Originally Posted by weehe126

Man this is special. How can anyone think this is cause by rubbing. He installed spacers, moving the tire FARTHER away from anything it could rub. Alignment/toe issue, end of story. Probably was warn before he even bought the car.

Agree on it not being a rub issue, that's the first shout with most folks, when seeing this type of wear.

Although alignment can be involved, (not always outside BMW spec'), I still hold the view it is a type of wear when RFT's are run at too low a pressure. Often the user has lowered the pressure to try and get a better ride quality. Experience teaches us the RFT doesn't work like conventional tires. We may need to 'increase' the pressure to get the best ride quality, ride the crown of the tire, not the sidewalls.

[oVeRdOsE.]

Originally Posted by type-dRew

One thing is for sure, nearly any time there is odd tire wear, 99% of the time it will be toe related.

toe angle

inb4 OP post his alignment sheet : toe angle bad .

bmw oem camber is very hard on square wear when toe is bad.

[Tambohamilton]

Originally Posted by oVeRdOsE.

bmw oem camber is very hard on square wear when toe is bad.

That seems weird. What do you mean?

[iqraceworks]

A close of picture of the side of that tire showing that worn area would help.....

[type-dRew]

Originally Posted by Tambohamilton

That seems weird. What do you mean?

He means BMW uses aggressive camber, which when toe is in spec is good for handling and shouldn't affect wear.

When toe is out, its going to wear hard and fast.

[iqraceworks]

Originally Posted by type-dRew

He means BMW uses aggressive camber, which when toe is in spec is good for handling and shouldn't affect wear.

When toe is out, its going to wear hard and fast.

BMW uses agressive camber? I though the reason guys went with the M3 front suspension parts and/or the adjustable camber plates was because BMW didn't use agressive camber.....and adding camber really AIDS in the handling. ??

[Antetokounmpo]

Originally Posted by iqraceworks

BMW uses agressive camber? I though the reason guys went with the M3 front suspension parts and/or the adjustable camber plates was because BMW didn't use agressive camber.....and adding camber really AIDS in the handling. ??

In the rear they do. Front is too low IMO. You need a ton of front negative camber on a Machphearson strut car to maintain a good contact patch under hard cornering.

[feuer]

Originally Posted by HighlandPete

I agree with your reasoning, and there will be a difference.

Issue with the wear pattern on the OP's tires, that stepped wear can be the same on a standard set up and on the rear. Also a scrub issue typically has a different wear pattern.

Here is some photos:255/35 developed cupping on the inside 225/40 is wearing evenly but a lot more. Tire pressure has been 35psi on both. I understand that there is a difference in rubber compound too. From my experience if alignment is off adding spacers (or lower offset wheels) would make tire wear worse because is changing the contact patch and the scrub radius. I run toe out...

[iqraceworks]

Ok...that's not as sharp of an edge as I first thought. Like everyone else....I'm saying allignment/tire pressure issue.....for sure.

Also....unless you are tracking the car and want a little more twitchy type steering, why are you running toe out????? And how much toe out are you running?

[Antetokounmpo]

Originally Posted by iqraceworks

Ok...that's not as sharp of an edge as I first thought. Like everyone else....I'm saying allignment/tire pressure issue.....for sure.

Also....unless you are tracking the car and want a little more twitchy type steering, why are you running toe out????? And how much toe out are you running?

feuer is one of the few legit track junkies on here, that's why

[Emilime75]

Originally Posted by feuer

Here is some photos:255/35 developed cupping on the inside 225/40 is wearing evenly but a lot more. Tire pressure has been 35psi on both. I understand that there is a difference in rubber compound too. From my experience if alignment is off adding spacers (or lower offset wheels) would make tire wear worse because is changing the contact patch and the scrub radius. I run toe out...

How does it change the contact patch. I understand the scrub radius change, but not the contact patch...no angles are being changed when adding spacers, or lower offset wheels.

In theory, unless the suspension is at zero degrees camber, the car will sit slightly lower if camber is negative, and slightly higher if camber is positive, as the spacer pushes the wheel/tire outward at an angle in relation to zero. But, that angle does not change.

[nsjames]

well I can't say that I've ever ran runflats long enough to observe the wear.

so maybe they do wear 90 degree angles into tread.

it's still very very odd.

[Tambohamilton]

Originally Posted by type-dRew

He means BMW uses aggressive camber, which when toe is in spec is good for handling and shouldn't affect wear.

When toe is out, its going to wear hard and fast.

Actually, adding a little toe out with factory camber tends to even out the wear across the tyre - they normally wear the outer edge faster, due to insufficient negative camber...which also hinders performance.

For tyre wear in a straight line, negative camber and positive toe (in the correct proportions) give neutral tyre wear, or positive camber and negative toe.

[feuer]

Originally Posted by Emilime75

How does it change the contact patch. I understand the scrub radius change, but not the contact patch...no angles are being changed when adding spacers, or lower offset wheels.

In theory, unless the suspension is at zero degrees camber, the car will sit slightly lower if camber is negative, and slightly higher if camber is positive, as the spacer pushes the wheel/tire outward at an angle in relation to zero. But, that angle does not change.

It doesn't make the contact patch smaller or larger, is changing where the contact patch is, and because when you turn steering wheels left-right they don't just pivot around fixed point, they move in line shaped like arc. If the contact patch was moved inward being affected that way by the change of scrub it will wear out the tire more on the inside. Also, just going forward will cause the wheels to toe out more if they are further apart vs being close together. Remember, all of the suspension parts have a give including the tires. Bushings, tie rods, tires all deflect and will deflect more when tires are further apart. This is why you as a driver feel immediate difference in steering input when adding spacers. It becomes firmer. It will also cause the wheels to tramlining.

[Meeni]

There was a recall on the Turanza RFT that are OE on many e9x. These tires dry rot very quickly, to the point that they were considered defective in a class action. From the low-res pictures, it looks like the thread is delaminating from the carcass of the tire. Not a bad idea to check alignment anyway, but you may just be looking at the tire disintegrating for no other reason that its a piece of junk to start with, it is dry rotted to death, and maybe someone drove on the RFT under inflated without paying attention.

[feuer]

Originally Posted by iqraceworks

Ok...that's not as sharp of an edge as I first thought. Like everyone else....I'm saying allignment/tire pressure issue.....for sure.

Also....unless you are tracking the car and want a little more twitchy type steering, why are you running toe out????? And how much toe out are you running?

I never said isn't alignment issue. It is. Probably tire pressure too. I run 0.05 on street and 0.12 to 0.18 (I do my own and just put the car on alignment rack to check). Long time ago I came across TCKline alignment spec for e90 that suggested up to 0.15 to out.

Originally Posted by Antetokounmpo

feuer is one of the few legit track junkies on here, that's why

I missed a lot in 2019, was difficult year, hopefully will have plenty of track days in 2020

[Airjaff]

Okay so, had a major headache with these tyres. So the reason for this horrible wear was, running the tyres on low pressure and the tyres being pretty old. These tyres were run flats! Avoid run flats! I thought the tyre pressure monitor would tell me that the tyres are down in pressure, but I found out it doesn't work that way. Apparently if both tyres are relatively losing pressure at the same time, you will not get a warning!