Head shake/tank slap?

[Lester532]

I put 12,500 miles on the front Avon with dyna beads with zero abnormal wear. Smooth as silk up to 125 mph. that's with my windshield starts to shake. And I've been running a Riken Raptor for 15,000 miles with dyna beads with zero abnormal wear.
3 oz in the front and 4 oz in the back.

I doubt the sudden on set of a high speed wobble is caused by tire balance. Look some where else.

Wheel Installation
Wheel Bearing
Bad tire
Head Stock Bearings

Is the problem repeatable ? And I understand if you didn't try it more than once.

 

[CWCobra]

Where did you get the beads if you don't mind me asking???

I will need some not to long from now.

Local shop by my house sells them. Aslo widely available over internet
CW

 

[CWCobra]

I put 12,500 miles on the front Avon with dyna beads with zero abnormal wear. Smooth as silk up to 125 mph. that's with my windshield starts to shake. And I've been running a Riken Raptor for 15,000 miles with dyna beads with zero abnormal wear.
3 oz in the front and 4 oz in the back.

I doubt the sudden on set of a high speed wobble is caused by tire balance. Look some where else.

Wheel Installation
Wheel Bearing
Bad tire
Head Stock Bearings

Is the problem repeatable ? And I understand if you didn't try it more than once.

Double checked my balancing, and my installation today. All OK. Air pressure OK too. Still had the shake today: 88 mph. Pretty darned scary, that's for sure!!!

I've ruled out all but possible bad tire. I'm thinking either my Shinko is bad, or the General Altimax is bad. At this point I think I'll put my old front tire back on, and see what happens. Only cost is my time.

One other thought: wonder if front wheel is directional? I know the tire is, but I don't know about the wheel itself. I have to admit that after I got the front wheel off to install the new Shinko, I forgot which side was left vs. right. But I noted a small arrow that I assumed indicated direction of rotation, so I reinstalled accordingly.

Have to travel over next couple of weeks, but will post again when I can get back to it, and have some results..

CW

 

[HellFire]

I've had no tire shake even with an oversize windscreen up to 150mph. Steering wobble at high speed would be caused by side to side (dynamic) imbalance and I just don't see how loose beads inside a tire carcass can fix that.

I've tried to deduce how they expect a mass of round weights to migrate to the lightest area inside a rolling tire, I don't. The centrifugal force wouldn't necessarily cause that to happen. I've been through John Bean technician classes for their wheel service equipment and balancing was one of those topics covered. I guess I'd have to see it actually work on a balancer to believe the beads moving around can properly balance a tire.

Three ounces of beads is alot of weight, especially when you move it to the outermost part of the tire. The centrifugal forces make the G's on them quite high and would multiply the faster you go. I can see how a ring of mass evenly distributed inside might overcome an imbalance in feel, but the imbalance would still be there. Maybe they just count on them that way.

 

[Molinoman]

Is there any disclaimer by Dynabeads that they do not recommend/are not responsible for speeds in excess of 80 mph (just picking a speed out of thin air here).

It may be under "normal" speeds dynabeads work fine but at higher speeds maybe they change in "behavior" and have an adverse effect on the bike.

I know some have said they have been well over 100 mph with no problems but you may have everything working right.

Tires, steering head bearings, different tires...etc my cause different effects on the bike.

Dennis

 

[Lester532]

[YT]eq263AYgyYg[/YT]

 

[HellFire]

20 grams is .7 ounces right?
So they are indeed using more weight in beads than the tire is out of balance. That is something to think about as well. Would that difference have to increase geometrically as the initial counter weight, speed and overall mass increases? Wow, now my head hurts again.

 

[UNCLE JESSE]

I took my CT to bike shop and they balanced it the old fashion way stick on weights no shake at all running a 404 on front stick on weights.

 

[CWCobra]

Most of my riding buds don't even bother to balance their tires. One road racer gets up to 150mph from time to time, and never balances his tires.

I hate to say it, but I'm beginning to think I wasted a bunch of money on crap tires. shoulda bought Avons from the start and avoided all this dark side/shinko stuff. Might be 4 times as expensive, and get 1/5 the mileage, but at least I could go 90 if I wanted to!!!!

 

[GPMAZ]

If you're looking for the best handling tire for the R3T I'd recommend the Avons, although I haven't tried the Dunlops. The Metzlers will give you more miles but the Avons handle better.