Weird Headshake

[RCinNC]

The story thus far....

I have a 2014 non ES Super Tenere with 96,200 miles on the odometer.

Within the past couple days, I noticed the bike was experiencing a headshake. By that, I mean that the handlebars would oscillate when I took my hands off the bars. Basically, if I accelerate up to around 50 mph, take my hands off the bars, and let the bike deccelerate on its own, the shake begins right at 39 mph. It continues to when the bike reaches around 31 mph, when the oscillation stops. Between 39 mph and 31 mph, the oscillation goes in a wave: it increases right up until halfway between 39 and 31, then begins to decrease until it stops at 31. It isn't noticeable below 31 mph, nor above 39. It's a very consistetent condition, and occurred on several different roads.

I readjusted the headset as per the service manual. There was no indication that the headset was loose when I pulled back and forth on the forks. but I did the adjustment anyway. I removed the front wheel and put it on my balancing stand to check the balance (it was good).

Two things I did notice when the wheel was on the stand were that there was a very slight runout on the wheel. I don't have a runout gauge, but just from visual observation I don't think the runout was more than 1/16". I also noticed that the tire had a very slight "hop" to one side. It didn't appear to be really significant, but it was noticeable.

I realigned the forks.

After all that, I took the bike for a road test. The issue persisted.

The front tire is a Shinko 705, that I installed on 04/15/23 at 95,810 miles. I honestly can't say if the problem was occurring before that tire change. My feeling is that I would have noticed this at some point prior to the recent tire change, but I can't say that for sure.

My gut feeling is that it's a tire issue or a wheel issue. I lean more towards a bad tire, mainly because the runout on the rim doesn't seem significant enough to cause a problem. Both would cost about the same to fix, but the wheel issue means taking the wheel to a shop an hour away to have it trued by someone. The tire I can change on my own.

Does anyone want to weigh in on which issue they think is more likely, or to suggest some other cause that I might be overlooking?

 

[Sierra1]

I've never used Shinkos, but I've had plenty of worn tires; Metzler Z6, BT-23/30, etc. They've all done what you're describing. I'm thinking headshake is a little strong, but it's as good a description as any. There was definitely "movement" at the speeds you're talking about. I just put it down to cupping. Of course, that only occurs on well-worn tires. When I got to the point where the tires were replaced, the "movement" went away until those tires got to being well-worn.

It would only happen when I released the bars and wouldn't be felt if I was holding onto them.

As an apples to oranges comparison, I know a guy that works at Discount Tires. He talks about how much variation between tire brands there is as far as wheel weights are concerned. He said Michelins needed the least amount of wheel weights, and Coopers needed the most. But he also said that occasionally there would be a Michelin that needed a bunch of wheel weights. I don't know where Shinko comes in quality wise, but I have noticed over the years that every time I got a new tire, there were always a different amount of those flat wheel weights used. Some times 2, sometimes 6. Once there were none, and I thought they forgot to balance it; they hadn't.

 

[RCinNC]

That's been my experience with Shinkos, as far as balancing. There isn't really a consistent amount of weight required to balance them from tire to tire. The current one has five, the previous one I believe had seven, and they've taken as little as three.

 

[cyclemike4]

The story thus far....

I have a 2014 non ES Super Tenere with 96,200 miles on the odometer.

Within the past couple days, I noticed the bike was experiencing a headshake. By that, I mean that the handlebars would oscillate when I took my hands off the bars. Basically, if I accelerate up to around 50 mph, take my hands off the bars, and let the bike deccelerate on its own, the shake begins right at 39 mph. It continues to when the bike reaches around 31 mph, when the oscillation stops. Between 39 mph and 31 mph, the oscillation goes in a wave: it increases right up until halfway between 39 and 31, then begins to decrease until it stops at 31. It isn't noticeable below 31 mph, nor above 39. It's a very consistetent condition, and occurred on several different roads.

I readjusted the headset as per the service manual. There was no indication that the headset was loose when I pulled back and forth on the forks. but I did the adjustment anyway. I removed the front wheel and put it on my balancing stand to check the balance (it was good).

Two things I did notice when the wheel was on the stand were that there was a very slight runout on the wheel. I don't have a runout gauge, but just from visual observation I don't think the runout was more than 1/16". I also noticed that the tire had a very slight "hop" to one side. It didn't appear to be really significant, but it was noticeable.

I realigned the forks.

After all that, I took the bike for a road test. The issue persisted.

The front tire is a Shinko 705, that I installed on 04/15/23 at 95,810 miles. I honestly can't say if the problem was occurring before that tire change. My feeling is that I would have noticed this at some point prior to the recent tire change, but I can't say that for sure.

My gut feeling is that it's a tire issue or a wheel issue. I lean more towards a bad tire, mainly because the runout on the rim doesn't seem significant enough to cause a problem. Both would cost about the same to fix, but the wheel issue means taking the wheel to a shop an hour away to have it trued by someone. The tire I can change on my own.

Does anyone want to weigh in on which issue they think is more likely, or to suggest some other cause that I might be overlooking?

I have ran two sets of shinko 705s on my bike. both did just what you are saying and continued to get worse as the miles accumulated on them. Of course I don't remember but I am thinking I had a couple thousand miles on them before it was really noticeable. I have talked to a feller who has them on a DR650 and he mentioned the same thing on that bike. I know some of the forum members here use those tires and have good luck with them. They are cheap I like that but other than that i was not impressed with them at all.

 

[RCinNC]

I've actually used them for years, and the fronts can definitely wear in a weird way, but in general I've liked them. This particular issue is something new for me (if in fact the tire is the cause of the problem).

 

[cyclemike4]

Speaking of balancing the shinko's. I had one front that didn't need any weights. the other needed just a little but on both front tires if I ran long fast interstate runs something would change in the tires and I would have to balance them again. I would not loose any weights or have other kind of issue. they would start hopping and feeling bad. The rear Shinko I never had issues with till they got a flat spot in the center of the tire then turn in was a bit crazy feeling. it would walk up on a knob then fall off on a knob and the back of the bike felt like it was walking side to side all the way around the corner. They stayed balanced well and smooth otherwise.

 

[cyclemike4]

To be perfectly fair though i have had two Mitas tires on the front of my bike that were no good as well so expensive doesn't always mean better. I think the Mita's tires were stored wrong or something. I could see the tread walking left and right on the bike and balancing them was out of the question. I ran one a while and sent it back put the second one on and it did the same thing. Just ordered a different tire and smooth as silk. I still have that other Mitas tire in my shop. Guess I can use it if I have to but not planning on it. Still the same thing. Did the head shake kind of thing on the bars.

 

[~TABASCO~]

IMOP......... Probably a tire 'issue'..... I was a proponent of Shinkos until I ran into an issue year before last. And then a friend ran into a big (rear) tire issue when it started to come apart on the way home. Ive personally moved on from that brand....

I would try another tire.................

******************* Eye ball the steering top nut as well, make sure that is torqued to the proper TQ (with lock tight) Ive seen a loose one give head shake.

 

[RCinNC]

I torqued it to 94 foot pounds when I did the headset adjustment this morning. I torqued it to 94 foot pounds during my previous headset service back in July 2022 and it was still tight this morning when I started working on the bike, so I know that particular thing wasn't causing any issues..

 

[Rex.C]

I had exactly the same problems with a 705. The head shake developed on a long trip. I went through the same process, including new steering head bearings. I also had grip issues with the rear 705, wheelspin on smooth, wet tar. Changed both tires to Michelin adventures. Both problems went away.

 

[Tenman]

I had the same problem with a cupped Heidenau k60.

 

[thughes317]

Ran several sets of 705's, they work until they don't. Last set I put on did exactly as you describe only with an additional twist: right hand sweepers were fine, left hand sweepers induced a scarey oscillation in the bars. Never will buy another set of Shinkos again.

 

[RCinNC]

You know, I think I noticed that too, that there was a bias where turns felt a little worse on one side than the other. I thought it might have been my imagination.

 

[Sierra1]

I don't think you have enough miles on this pair, but as the rear tire becomes more squared off, left/right transitions become "different". Not as smooth, more on/off without as much middle ground.

 

[RCinNC]

Verdict is in...it's the tire.

I took the new one off and remounted the old one, and the oscillation disappears. The one I just took off is being replaced under warranty.

 

[Cycledude]

I’ve heard enough bad stuff about Shinkos that I have never even considered buying any.

 

[RCinNC]

My personal experiences with them have been positive. I checked my records and found that I've installed 23 front and rear Shinko 705's on my Super 10 in the nine years I've owned it, and this is the first one that has ever had an issue. I've found them to be pretty competent with regard to handling, and their longevity is acceptable to me. My rear tires last anywhere from 4000 to 5500 miles and the fronts usually around 8000, and that's with a ton of two-up riding. That's about the same longevity I got from the more expensive Battlewings I originally used.

I've heard complaints about the tread block separation, but this has never occurred in any of my tires (and I think many of those reports concerned the bias ply 705, and not the radial that I've always used).

My only real complaint about them is that the front tires can sometimes cup in a really weird way, which forces me to toss them before their full lifespan.

I'm sure they aren't in the same class as Pilot Roads or Anakees, but I can go through two or three rear tires in a year and maybe one or two fronts; money-wise, that can really add up. I've found that the Shinkos offer an economical alternative that meet my needs, so I keep rolling with them. Though maybe I'll treat myself to a set of A41's once I burn through this next set of Shinkos.

 

[Fennellg]

Tires can be weird, seen it be a wheel bearing going. Unfortunately you just have to shotgun the problem till it resolves. Good job figure it out eliminating one variable at time.

 

[RCinNC]

Another chapter in the story....

I had the tire replaced under warranty, and got a new Shinko 705. When I mounted that one, the handlebar oscillation was back, in the same speed range as the original new Shinko. I went through all the same steps as before: rechecked the headset adjustment, the fork alignment, the wheel balance, the front wheel bearings. All of them were still good.

The two Shinkos don't have the same date code. One was manufactured in the 17th week of 2022 and the other during the second week of 2023. The original Shinko that was on the bike when I first began this process (that didn't cause the oscillation issue) was made during the 47th week of 2020.

I borrowed a Michelin Anakee 3 from a friend of mine and put that on the Super Tenere, and the oscillation was gone; steady as a rock while riding no-hands, all the way down through the speed range where the oscillation was present with both Shinkos.

I don't know how the tire manufacturing business works, but my layman's opinion is that something in the manufacturing process must have changed sometime since the 47th week of 2020. I don't know, maybe it's a manufacturing hangover from the pandemic. It's kind of disappointing. I've used these tires for years; prior to this, I'd installed six of the front tires on my bike and had always found them to be a decent all around tire at a good price. The front tires tended to cup in a weird way once they got up in miles, but I could live with that quirk as it just made for a lumpier ride. The handlebar oscillation isn't acceptable though, so it looks like it's time to move on to another tire, at least in the front.

Right now I'm waiting to hear back from the seller about how to proceed with another warranty return. On the plus side, since I mounted, balanced, and dismounted three Shinkos and an Anakee all in the space of about a week, I've had a chance to further hone my tire changing skill set.