metzeler z6 (st1100)

[astrogt]

metzeler z6 is now available in the correct size front AND rear for the ST1100....

[jams]

Thanks for the info. Will have to check this out when I require a set of tires.

[Darth Vader]

I had the Metzler Z6 tires put on last weekend and am experiencing a problem. When I reach 80-85 mph the bike has a side to side wobble. This does not go away the faster I go. The best way to describe it would be the feeling you get when you ride over the metal grates on bridges. At lower speeds, it rides fine. Cornering is ok, I don't feel like the bike is going to slip out from under me. But then again, I haven't cornered anything going 85 mph (YET :D ) First things first, the tires are broken in (250 miles since mounting) properly. Second, I have the recommended tire pressure (36 F 42 R). The tires were balanced and sat overnite before I did any riding. Any thoughts? Is the ST1100 made to have bias-ply instead of radials? I'm going to play with the suspension to see if that does anything. Other than that, I'm at a dead end. Help me ST Owners, you're my only hope!

[astrogt]

hey darth vader, try adjusting tire pressure to 34 front 36 rear (cold) and see if that helps. keep us posted.......clay

[CarSalesman]

The ST1100 does not "like" bias ply more than radial. I prefer radial, having used both. I suspect one or your tires is not balanced correctly. How where they balanced?

[Darth Vader]

Clay, I'm going to lower the psi to 34/36. Did you get those numbers from a Metzler brochure? I happened to pick one up at a MC show last month and read that recommendation last night.

How where they balanced? Well, I had them mounted at a Honda dealership; so whatever machine they use. I was with the mechanic while he was mounting the tires; he showed me how to properly remove the wheels. I have the stick on weights.

I should be taking her out tommorow morning. I'll give you guys an update...

[astrogt]

i got those figures from the my-mc discussion forum st1100. there is an ongoing thread titled (more tire talk) concerning the z6 radials. i am going to try the z6 tires next so please let me know if the tire pressure helps.....clay

[Darth Vader]

Clay, I have a funny feeling that the recommended psi from Metzler may fix the wobble-problem. After I had the tires installed I was running 40F and 42R. Then I dropped it down to Honda's recommendation 36/42. I felt an increase in stability after that (but still has a wobble). That being said, 34/36 may be the answer. Also, the Metzler numbers are the minimum pressures recommended. I always ride solo and when I take a trip I don't load the bike down, so, it makes sense. I was just disappointed to go from worn Bridgestones to new Z6s to find a wobble.

More to come, I'm doing some more research...

[number9]

I run the Z6 on my ST1100. Have been through 2 fronts and 3 rears. I run the 170/60 rear because the 160/70 wasn't out yet.

I have run pressures from 36 to 42 rear and not had a wobble. I am currently at 40f/42r and don't have any wobbles, but I have never had any wobbles with these tires. I have run (many sets of) Metzeler M1's on my R6 for a few years and now the Z6 on the ST and have never had a problem with a Metzeler tire.

This brings to mind an issue that someone on my-mc had once. How old is your bike and have you ever checked the steering head bearings? The guy I remember having an issue like this was he had put on some lighter handling tires and had a wobble. If I remember right, he had recently put in tapered steering head berings and had them a touch too tight which caused him to always be lightly fighting (and not realizing it) the handlebars and the result was his bike had a wobble. If your steering head bearings are stock and have lots of miles without service they could very well be flat spotted and the change to a lighter handling tire could magnify this issue to the point you'd have a wobble.

[astrogt]

number 9 has made a very good suggestion. i would be willing to wager that your steering head bearings need attention. jack up the front of your bike and SLOWLY turn the handlebars from side to side. you will be able to feel a flat spot or a catch in the side to side motion. stwannabe just had his head bearings replaced at 23,000 miles......... good luck

[Darth Vader]

Hmmmm, I must check the stearing head bearings this weekend. I have 37k miles on the bike and it's 12 years old. If I end up feeling a flat spot then do I just replace the bearing or is their more involved? BTW, I adjusted the tire pressure to 34/36 and the wobble went down even more, but is still present. Guess I gotta get my hands dirty this weekend! :woo
Thanks guys, I'll keep you updated

[number9]

Well, what's the report?

[Darth Vader]

Well, I believe my stearing head bearing is bad. I put my bike on the centerstand and had my wife push down on the back, thus lifting the front wheel. I slowly turned it left to right and it seemed to gravitate toward the center (in line with the rear wheel). I hope to have it looked at and possibly worked on this week. I'll give another update soon...

[number9]

If you have to replace them, going with tapered roller bearings is the upgrade of choice. CBR Bearing is the source of choice, although AllBalls sells them as well.

http://www.cbrbearing.com/

http://www.my-mc.com/messages/1/51784.html

[Darth Vader]

Thanks for those links Number9. Unfortunately I already ordered the parts at work today. It seems that the tapered bearing is the way to go, a bit more expensive, but probably worth it. Perhaps next time, as I'm sure there will be a next time :eek:

[Darth Vader]

All is good and well with my Z6s now! The culprit was in fact the stearing head bearing, it had a flat spot. The bike no longer wobbles and feels super smooth. Thanks everyone for your help! :bow1:

[saaz]

Good to hear. As with No9 I used a set of Z6s (120 front, 170 rear) and had no issues with wobble etc etc, and I ran 40 front/42 rear. Only got 10,000kms out of them mind. My bike is a 96 police model with upgraded suspension and notchy head bearing. Afters years with taper bearings in the GS1000 with no issues, they definitely are the longer term option

[Jim Davis]

This brings to mind an issue that someone on my-mc had once. How old is your bike and have you ever checked the steering head bearings? The guy I remember having an issue like this was he had put on some lighter handling tires and had a wobble. If I remember right, he had recently put in tapered steering head berings and had them a touch too tight which caused him to always be lightly fighting (and not realizing it) the handlebars and the result was his bike had a wobble. If your steering head bearings are stock and have lots of miles without service they could very well be flat spotted and the change to a lighter handling tire could magnify this issue to the point you'd have a wobble.

I'm wondering if anyone adjusts the steering bearings on their ST, or do people just wait until they get hammered and need replacing. Adjustment soon after buying a new bike is a necessity and I doubt many dealers actually do this.

Also, after replacing steering head bearings, they must be readjusted after a few hundred miles or even less.

I would suggest that all owners adjust their steering bearings at least every 10,000 miles or so. That way you'll get maximum life out of them, in fact you may never have to replace them.

I hope this helps someone, nobody mentioned adjusting, just replacing.