Instability at high speed...

[offcamber]

I've noticed that at speeds 80MPH and up the bike starts to feel unstable...almost like wind buffeting. A slight wobble/vibration in the handle bars. Its enough that I don't feel comfortable maintaining that speed for a long time. This is relativly knew as I just started noticing it. I don't normally ride at those speeds but occasional I'll sprint to get ahead of traffic on the interstate (some speed limits are as high as 75). I am wonder if this is a result of the K60 scout tires. I never expereince it with the battlewings. However recenty I have upgraded the rear shock to an Ohlins and softened the front stock suspension a little. Assuming its not the tires or the suspension what else should I be checking to make sure something isn't bent or loose. I havent' had any accidents other than a low speed drop....barley moving. I may restiffen the front shocks and re-balance the tires.

 

[satdishes]

At the upper end I get some wobble, but only when the hard bags are on. I am talking speeds of 100 plus, never as low as 80.

Sent from my SM-N910V using Tapatalk

 

[Dogdaze]

I believe the S10 geometry is set up well for higher speed cruising. So if wobble or instability is occurring I would first suspect the tyres, could be the rear as much as the front. Also the less road biased tyres will also affect the high speed handling, ie; 80/20, 50/50 etc. It is a process of elimination, check tyres, head bearing for play and then suspension, although suspension should not really cause this under normal circumstances.
I have stock suspension, road biased tyres and regularly ride at 85mph maintained speeds and on occasion when conditions allow, ahem, over 120mph..

 

[offcamber]

I am really thinking its the tires. I noticed it last year coming back from ME when I was having trouble keeping up with my buddy doing 85. In the past with the battlewings I could cruise all day at 85, the bike was very comfortable at those speeds. I really like the long life and off-road handling of the K60s but I may have to go to a more road bias tire on the next set.

 

[greg the pole]

Depending on how old the tires are, I would point the fingers at them (cupped, squared off etc..).
I had a big issue with a k60 rear that I installed on my bike. At first I thought it was my rear wheel, it turned out that the tire was out of round.

This also maybe a long shot, but how are your steering head bearings?

 

[sail2xxs]

Although I guess it is possible that it is the tires, after checking steering head bearings, I would look at the rear suspension settings. In 2009 I had a KLR 650 for a while. The bike was fine at all speeds it was capable of until I changed out the tires, rear shock, and re-worked the front suspension all on the same day. After that, the bike developed a serious wobble above 60 mph. After a frustrating process of elimination, it turned out to be the rebound and damping setting on the rear shock. It took several evenings of tinkering and testing different settings before I found the right one. After that, the bike was stable even at 85 (going downhill in Vermont) .

Good luck,

Chris

 

[offcamber]

I haven't checked anything yet....the tires have about 6K miles on them....they look great I don't see any cupping...a lot of tread left. Pressure is 35 PSI front 40 rear. The reason I'm leaning towards the tires is all other changes were made after I noticed the issue last year. I really hope its not dampening on the rear because its a PIA on the Ohlins when its installed. This hasn't been a major issue since just don't hit those speeds often and even when I do it doesn't feel that bad just not as solid as it should be (was).

 

[yz454]

I also would go for rebound adjustment .

 

[Madhatter]

to much rear preload will make it wobble, back it off.... i have hiedanaus no issues at 110 mph... you already said your soft in front...back off rear you will be fine... i find this bike to be very stable...... i weigh 250 lbs and the preload indicator is not even at half way mark .

 

[Maxified]

... i have hiedanaus no issues at 110 mph... i find this bike to be very stable...... i weigh 250 lbs and the preload indicator is not even at half way mark .

Firmly planted, stable with K60's straight & flat or long sweepers @ $1.10. A bit north 250 with OEM shock & HyperPro spring, front full stock...

 

[offcamber]

So I made some suspension adjustments. Firmed up the front preload as well as the dampening both compression and rebound. I also increased the rear preload bit. Took it for a test ride and basically no change. As soon as I hit 85 (actual speed, about 91 indicated) I start to get the a shake. Its not a wobble in the bars its more of a shutter. The bike really doesn't seem unstable its just vibrating. I am almost convinces its tire balance and here's why, The vibrations seem vertical, up and down, and the fact that its very speed specific. That 85MH is the limit....stay below it, no issue as soon as you hit it vibration. The other reason is...and this is where you are going to say....."well duh of course it probably balance" I changed the valves to metal ones and added the Garmin TPMS. This had to add significant weight and yet like a idiot I didn't think to rebalanced the wheels. I was careful not to rotate the tires on the rims to keep the original locations.

So hopefully this week I can get the wheels off and balance them.

Will update when I know more.

 

[shrekonwheels]

to much rear preload will make it wobble, back it off.... i have hiedanaus no issues at 110 mph... you already said your soft in front...back off rear you will be fine... i find this bike to be very stable...... i weigh 250 lbs and the preload indicator is not even at half way mark .

This

 

[offcamber]

As I said its not really a wobble more of a vibration.shutter. After I re-balance the wheels I'll revisit suspension.

 

[EricV]

What ever you decide to try next, don't shotgun the bike. Do one thing, go ride. Do another thing, go ride. Don't make multiple changes, like adjusting both ends of the suspension, when testing or you won't know what fixes it, and sometimes will cancel out the fix, because you also adjusted something else.

I've done a lot of high speed riding on the K60s in many different levels of wear. I've not noticed the instability you mention. I have noticed various quirks of tire wear. The front K60s, for me, wear down evenly to a point, then wear past the high points on one side, making the bike left or right biased, then continue to wear and even out again, only to then wear more and become biased to the other side for a while before evening out again. It appears to simply be a facet of the tread design and my riding style. I'm used to it and it doesn't bother me. I do have a much heavier rear spring on the stock shock to handle the heavy load of my fat ass at 260# and fully rally trim with fuel cell and water, etc.

After the local shop removed my engine for warranty repair of a CCT event, I have noticed more vibes at any speed over 75. A tad annoying since we have legal 80 mph limits on I-15 in UT, NV, ID & MT. Even with road based tires, (Metzler Anakee 3s currently), it still occurs, so it's not just tires. I have run mostly K60s over the bike's life so far, though tried a PR3 Trail set, (disappointing wear). I should probably re-torque the engine mounting bolts in the correct sequence. The local shop couldn't even be bothered to put all the bolts back in, or route hoses and wire correctly. But that's a different matter.

 

[shrekonwheels]

As I said its not really a wobble more of a vibration.shutter. After I re-balance the wheels I'll revisit suspension.

Do not waste your time, Poorly balanced tires will bounce, not force the head shake.

BTW Incorrect spoke adjustment possibly could.

As noticed, one thing at a time but I suspect it is suspension set up. Go to a local track day and somneone there can help you set up your suspension properly. If done right it is an amazing thing, if done wrong, well it sucks

 

[offcamber]

So I went for a longer ride today, on the back roads I noticed the suspension seemed harsh on the cracked roads around here......when I got to my half way point for lunch I checked the tire pressure. Both on the TPMS and a handheld gauge. Both tires were about 4-5 PSI over what they were when I started. Obviously this was caused by the tires warming up, I never thought it would add that much. Starting pressure was, 32 front 40 rear. When I checked it the front was 36 and rear was 45. While they were still warm I dropped the front back down to 32 and the rear t0 38. As expected this mad a big difference in handling and ride. I ended up on the interstate and figured I'd see if the pressure changed changed anything......it did! The shudder didn't start until 92 actual speed 99 indicated. On top of that it wasn't nearly as noticeable. In fact it could have been wind buffeting causing what I was feeling.

Next step is to reset the suspension to where it was and keep an eye on the pressure to see if it comes back.

All that said I still think it will be a good idea to balance the wheels.


Eric you are 100% correct, I have bad habit of making multiple changes and I know its a bad practice....

 

[Scott Williams]

Go back to the Battlewings, my friend.....and your problem is solved.

 

[TwoLukes]

OffCamber, On occasion, I take my S-10 a little faster than the limit. It's a long haul to CA from Vegas and BEGS you to exceed the posted.Coming back yesterday from a trip to San Diego, I held $1.00 for a long time and for fun took it to $1.20. . . With full set of Jesse's and running H-60's. Rock solid, no shimmy, no wobble, smooth. . . I have the stock settings on my 2012 suspension with a heavier spring as the only change . . Don't know if this really helps you but FYI . . . ;-)

 

[VictoryHammer2006]

So I went for a longer ride today, on the back roads I noticed the suspension seemed harsh on the cracked roads around here......when I got to my half way point for lunch I checked the tire pressure. Both on the TPMS and a handheld gauge. Both tires were about 4-5 PSI over what they were when I started. Obviously this was caused by the tires warming up, I never thought it would add that much. Starting pressure was, 32 front 40 rear. When I checked it the front was 36 and rear was 45. While they were still warm I dropped the front back down to 32 and the rear t0 38. As expected this mad a big difference in handling and ride. I ended up on the interstate and figured I'd see if the pressure changed changed anything......it did! The shudder didn't start until 92 actual speed 99 indicated. On top of that it wasn't nearly as noticeable. In fact it could have been wind buffeting causing what I was feeling.

Next step is to reset the suspension to where it was and keep an eye on the pressure to see if it comes back.

All that said I still think it will be a good idea to balance the wheels.


Eric you are 100% correct, I have bad habit of making multiple changes and I know its a bad practice....

changed my tires, now I have the same problem you described. /: went from stock Metz to Mitas. Love the new tires up until 80mph then it blows

 

[bigbob]

I have the Mitas E-07 on my 2014 ES and they are rock solid for me. Run 40 cold PSI front and rear. Sunday on the way back from Romney consistently ran 80 mph and hit a high of 103 per the gps log. Never did wobble at all.

(Saw an Amtrak train and wanted a closer look at the last vintage car. Those trains move!)