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Z6 cupping

S

STAN

Guest
I have only 1700 miles on my R1200Rt. I have always kept a close eye on tire pressure. About 200 miles ago I started hearing tire noise while in turns. Sounded just like when my old Avons would start cupping around 6kmi. After CLOSE examination yesterday I see that my front Metzeler Z6 is starting to cup. This is a real disappointment. Has anyone had a similar problem, or does anyone have any comments? These are my first set of Metzs and will probably be my last. I'm leaving Monday the 17th for what will probably be a 3000+k trip. I have a feeling the tires (or at least the front one) will be scrap when I get back. The rear tire still looks great.
The fact these tires have absolutely no tread in the center of the tire does make me wonder about rainy conditions, but they have yet to be a problem in that department.
 
Try running 38-40 in the front. This will probably help. With all the big advantages of the telelever front end, this may be one disadvantage.
 
I'm on my third set of Z6's and have gotten close to 8k before changing them each time. The reason I've changed them without letting them run longer is each time I was setting out on a trip over 5,000 miles and wanted to leave home with new rubber. The front tire has had cupping, but only towards the end of the life and certainly not at 1700 miles. My 04 RT is heavier than a 1200RT and I've always run 40 front and 42 rear.

I've had a number of days caught in rain and give them high marks on wet pavement though I never push it when the ground is wet.

Is it possible you have a defective tire? It may be worth contacting Metzler just to see what they have to say.
 
I changed my first front Z6 after 12k miles a month ago. I keep pressure between 37 and 40 psi. My rear Z6 has close to 8k on it now. It seems like it can do another 2k or so, maybe, although it's getting pretty flat in the middle... The rear I try to keep between 40 and 42 psi. This on an R1100R.

A question about this rear Z6: Since there are no grooves in the middle, how do I know when the tire should be replaced? I did a lot of highway riding on this one, so there's plenty of thread left on the sides. Anyone with a suggestion? I don't want to ride until the carcas shows, but don't want to trash it too early either...
 
There are wear marks on the rear Z6. You have to look very closely to see them. There are three, I believe, bumps in the tread groove. Not sure how helpful they are but they are there.
 
DanGreene said:
There are wear marks on the rear Z6. You have to look very closely to see them. There are three, I believe, bumps in the tread groove. Not sure how helpful they are but they are there.
Click to expand...

OK, thanks! I'll look more carefully...
 
jacco said:
I changed my first front Z6 after 12k miles a month ago. I keep pressure between 37 and 40 psi. My rear Z6 has close to 8k on it now. It seems like it can do another 2k or so, maybe, although it's getting pretty flat in the middle... The rear I try to keep between 40 and 42 psi. This on an R1100R.

A question about this rear Z6: Since there are no grooves in the middle, how do I know when the tire should be replaced? I did a lot of highway riding on this one, so there's plenty of thread left on the sides. Anyone with a suggestion? I don't want to ride until the carcas shows, but don't want to trash it too early either...
Click to expand...

I've wondered about that non groove riding surface in the middle. Where does the water go without the grooves? I suspect acqua planing may be a problem. That said, I've put 2 four hour high speed rain trips - with the only problem being underwear laundering.
 
With cars its lateral wear points (excepting long storage flat spot). I wonder how a bike front wheel can get cupped also.
 
I believe it is under inflation at some point that is long enough to set a wear pattern. The ridder may increase the preasurer in an effort to prolong the life but the cupping wear pattern remains and continues throught the life of that particular tire.

Others may be able to confrim or correct this.
 
To find the location of the wear bars, look on the sidewall just next to where the tread begins. You should find some small triangles. At that location, in the tread grooves, will be the tread wear indicator.
 
manicmechanic said:
To find the location of the wear bars, look on the sidewall just next to where the tread begins. You should find some small triangles. At that location, in the tread grooves, will be the tread wear indicator.
Click to expand...

:thumb
Cool, thanks!
 
Well, I'll up the front tire pressure from 36 to 40. I know when cupping starts it tends to get expotentialy worse with miles and there is no turning back. The good news is that they have barely just started to cup. I was alerted by the sound it was making. I'm suprised I could hear it at such a minor stage. No perceptable vibration yet. Hopefully the increased pressure will pull my fat out of the fire.
I have over 25 vehicles on my insurance list, including several 18 wheelers so I cannot tell you how many tires I have on the ground. I have a lot of tire experience. Cupping is a problem that can show up on trailer tires (especially lowbeds with elementary suspension systems) and I think it is usually started by an out of balance tire. As the cupping develops the tire gets even more out of balance and the problem gets worse fast.
My Kawasaki Concours hadcupping problems but usually around 6k. My R1100rt would start around 8k, but by then the tire was toast anyways. Thanks for all the insight, I'll be raiseing the pressure today.
 
M1ka said:
I believe it is under inflation at some point that is long enough to set a wear pattern. The ridder may increase the preasurer in an effort to prolong the life but the cupping wear pattern remains and continues throught the life of that particular tire.

Others may be able to confrim or correct this.
Click to expand...

My front Z6 has never been underinflated, I keep an eye on the pressure religiously. I run 40-42 lbs and at 7000 miles the front tire is starting to cup also. But not near as bad as the Dunlop I had previous to this tire.

I think I would blame the heavy weight of the bike on the cupping. But I really don't know either. I just know I've seen a ton of cupping tires on the front of RT's.
 
stan said:
I have only 1700 miles on my R1200Rt. I have always kept a close eye on tire pressure.
Click to expand...
You don't mention what tire pressure you keep your tires at. Forget the factory recommended pressures and run 38-40 front & 40-42 rear and things will be better. Please note that the lower number for the front corresponds to the lower number for the rear, etc.. Also, you need to know that the higher pressures will not fix the cupped front tire. Live with the present cupping until you replace the tire in 6-7K miles, or replace the tire if you have a mind to.

The fact these tires have absolutely no tread in the center of the tire does make me wonder about rainy conditions, but they have yet to be a problem in that department.
Click to expand...
The Z6 does quite well in the wet, so don't worry about the solid patch in the center.

Hope this helps! Safe riding!
 
I love the Z6's and consistently get around 12K miles out of a set on my '96 1100RS and they're exceptional in the wet

BUT

don't rely on the wear bars on the rear. On my first set I just started to touch the cord and still had, what appeared to be plenty of rubber before I got to the wear bars. That set had a lot of interstate miles on them so the rear was pretty flat. I contacted Metzeler and sent them pictures. I knew I had to be getting close, so it didn't come as a big surprise.

My recomendation to Metzeler was to put a couple of dimples in the center like they do on slicks.

I've just ordered my 3rd set in preparation for my ride to complete my quest to ride through all of the lower 48. 44 down :bolt 4 to go.

Next year, Alaska :clap
 
Ozonkiller said:
I love the Z6's and consistently get around 12K miles out of a set on my '96 1100RS and they're exceptional in the wet
Click to expand...
12K on a set of Z6's, WOW! The Z6 were my worst wearing tires to date on my RT, only getting 6K miles out of them. I do ride pretty agressively, but in comparison, the 880ME's from Metz gave me 10K out of the set and the ride handling was about equal to the Z6's. Really couldn't tell them apart. Sure didn't effect my riding style any.
 
I got 3K miles on an overinflated Z6 on my K75, with spirited driving. I no longer overinflated.

Under inflated tire edges wear quickly, over inflated tire centers wear quickly.

On front cupping: Perhaps the fork tubes are out of synch. No where is it written they have to wear evenly, we just assume it.
 
Under inflated tire edges wear quickly, over inflated tire centers wear quickly.
Click to expand...
That is why it is so important to keep tires properly inflated. ;)

On front cupping: Perhaps the fork tubes are out of synch. No where is it written they have to wear evenly, we just assume it.
Click to expand...
Fork tubes "out of synch" is a technical term I have never heard before. Can you explain what you mean by that term.
 
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