Metzeler Z6 tire uneven wear problems

[gazkid]

Hi,

I bought my '02 K1200RS this past March w/ 18 000 KM on it. It now has 26 000 km - it's been lots of fun. I'm careful w/ tire pressure, making sure to keep the recommended 36 & 42 psi, front & rear. After returning home form a trip w/ my wife this Saturday I noticed cupping on the left side of my rear tire. It's like there's a bald spot left of the center section of the tire (see picture). I don't know how much wear is on the tire as I'm not the original owner. 3 questions:

1) Should I replace w/ another set of new Z6s?
2) What can cause such uneven wear?
3) How much mileage can I expect out of a new set of tires?

Thanks!

Paul

[gazkid]

Here's a another picture of the rear tire wear. Paul

[lostboy]

This is typical of the Z6. Try a set of Michelin Pitot Roads.

[gazkid]

Thanks

[bikerfish1100]

too much riding at 0 lean angle.

[gazkid]

Not sure how that works seeing as I've still got lots of tread down the center? It's the left shoulder area that's worn out.

[GregFeeler]

I've run a number of sets of Z6's on my K1200RS and found that I get the best wear and performance by running 40 pounds pressure on the front tire and 42 on the back. The wear pattern you are seeing I've seen from a variety of different brands of tires: Pilot Roads, Metzelers, and others. From what I've been able to determine it's because high performance tires have a narrow center belt necessary to prevent the tire caucus from expanding at speed. The rest of the tread area is softer and not constrained by this belt, so it expands around either side of the center belt at higher speeds. Naturally, that protruding area quickly wears down and looks like what you see when the tire is at rest. The best solution I've found is to run somewhat higher pressures to stiffen the tire and reduce this effect.

[bikerfish1100]

Not sure how that works seeing as I've still got lots of tread down the center? It's the left shoulder area that's worn out.

center looks flat. no?

[58058D]

I agree the center looks flat, but the tread depth is greater than just off center. It could be that the prior owner rode a LOT on mild curvy roads but did not get fully leaned over, just stayed over a bit, but all the time? This is also indicative of a tire run for some time underinflated for the load. I see Gregg is a fan of the higher front pressure, but in my experience on my '00, that prevents my tires from coming up to temp and I don't develop the grip I desire. I just put on a set of Z6s for the first time, only have 800 on them, so no comparo on that tire.
I would put on a new set of tires, make and model to your preference and riding style. I have had great luck with the Pilot Road, BT 010/020 (f/r) combo, Pilot Power, Pirrelli Strada, etc - (hate the BT 020 front, D220 Front, Z1 front, etc. Their tread patterns cause lots of tire whine and wear Very unevenly - cupping- on my bike as set up.)

[gazkid]

Thanks for the feedback guys! The center of the tire does show wear, but nothing like the left side - there's about a 1 inch strip where there's no tread left what-so-ever. I knew the tire wasn't new when I bought the bike, I just couldn't figure out how you get a concave wear on one side. It just didn't make sense.

I do ride at high speeds quite regularly - 135 to 140 km/hr, but only when I'm solo. When my wife and I tour the speeds are usually around 110 km/hr. I do a lot of back roads, including dirt roads and tar over gravel.

As for leaning, I love twisty roads and let's just say that others have noticed how my tires show use right up to within 1/4 inch from the very edge.

I bought the Pilot Road 2, but unfortunately the front tire is BO so I was only able to replace the rear. I don't like riding on two different tires but for a few weeks I have no choice.

Paul

[NCStephen]

Your tire is worn way past where the TWI bars would show replacement is needed. The wear is typical and you have maybe 300 miles or less before metal is showing. Change it NOW

The same question came up in another forum and I ended up showing the wear life of a Z6 that I put on in May and wore out by the end of August. Here is the link. It would be easiest to join that forum to see the pics. About the time that a TWI bar wears to the surface Metzler recommends the tire for replacement. That was at 8600 miles on this tire for me about 9500 miles on the last one. I would guess that was about 600 -800 miles ago on your tire.

http://www.i-bmw.com/showthread.php?t=21972

As for the wear pattern to the left of center, that is a bit more characteristic of the bike that the brand of tire. It usually shows up when you are in the last part of the life of the tire. I tend to carry my daily odds and ins, water bottle, rainsuit, pump, lunch in the left bag with the right one empty. That seems to balance the bike for a very straight run rather than a drift to the right (which makes you lean a little to the left). This helped even the tire wearout on both the front and rear.
I hope this helps!

NCS

[gazkid]

Thanks. Yes I have replaced the rear tire and I am aware that it's not safe. I had been watching the tire, know that it was not new, but everything seemed fine. My wife and I went on a couple longer rides (1000 KM) and it's like the tire suddenly wore out. I was just having a hard time wrapping my head around why, especially the left of center bit. But after looking at your pictures and others, it's clear that I'm not the only one who's encountered this and it's more about the bike and loading than it is about the brand of tires.