Front end wobble on 800gs

Discussion in 'Parallel Universe' started by Moab, Jul 14, 2010.

  1. Moab

    Moab Been here awhile

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    Breaking in my new 800 gs, love the zippiness and agility of the bike, just one issue for me...when I get to 70mph or above my front wheel starts moving side to side, not drastic but enough to make me wonder.

    Have nobbies on, and i am coming from an 1150 gs and klr 650 that never had this wobble (and i think that the front tire is similar on the klr?)

    anyway, I cant tell if this is the wind buffeting me and me causing it? or is this an issue I need to see the dealer about? or do i just need to get used to it cause its inherent on this bike.

    :ear
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  2. WoodWorks

    WoodWorks House Ape

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    I only get the wobble with some knobbies. Never happened with the Battlewings nor the Heidenaus, but now that I have the Mefo on the front (don't like that tire at all :puke1), I get a mild wobble at higher speeds. You may want to see if there's any difference when you swap out your tires.

    David
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  3. GrizGirl

    GrizGirl Long timer

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    I was just writing up some thoughts on the 800 after going 4700 miles over every imaginable road surface in 9 days of driving. The front end with knobbies and highway driving became an issue on the trip. It is unstable. Above 90 mph it is downright dangerous. Yes, at highway speeds with knobbies you will feel the frontend wobble. I felt it with the battlewings as well but it was not as pronounced as when I went to TKC-80's.

    Up to 85 I just had to get used to the wobble. It never affected cornering or my ability to maintain control of the bike. You start going faster than that and you have some issues. Just be aware and watch your speed, particularly when you are passing at interstate speeds. More details will be in a post I'm working on.

    Cathy

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  4. Moab

    Moab Been here awhile

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    I am using the tkc's.......send me a link to your post when complete, id like to read it.
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  5. Maniac28

    Maniac28 Been here awhile

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    I am having the same issue since switching the battlewing front tire to the TKC. Grizgirl, I read your other post and agree about the issues with the bike that you address. However, I know there is no perfect bike. Everything is a compromise I suppose.
    #5
  6. WoodWorks

    WoodWorks House Ape

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    Exactly. I came from the big Boxer twin, and have ridden it up to Prudhoe and back. But given the choice, and after 24K miles on the F800, I'd take it for any "Adventure" ride over the Boxer any day. Having wrestled that pig over too many difficult surfaces, I'll gladly put up with the lack of range and high-speed cruising shortcomings of the F800. I can carry extra gas when necessary, and keep it under 90 mph easier than I can reduce the weight of the Boxer. But ain't it grand that we have other choices?

    David
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  7. Ducksbane

    Ducksbane Quaaack!!!

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    I would like to make two observations about F800GS instability.

    First when I first got the bike I noticed that there was a lot of movement from the windblast from passing semi trailers. I needed a better windscreen for comfort and ended up with a Calsci. (If I was doing it now I would probably get a Wunderlich ergo vario screen because of its adjustability.) One of the first things I noticed was much more stabilty in wind and windblast.

    The second thing is the tyres. The most instability I noticed was with a front Dunlop 606 knobby and a badly worn rear TKC80. It was bad enough to be a constant worry in the back of your mind. I then replaced the worn TKC with a Heidenau K60 ... much better, much more stable. Soon the front Dunlop wore out and I replaced it with another Heidenau K60. On the road the K60's are very good, good grip and very stable up to at least 180Km/hr. However I don't like the front K60 on loose surfaces like mud and sand, so I would probably not buy another one. I will probably try and run a front TKC and a rear K60.

    Bottom line ... Knobbies are less stable at high speeds and get worse when they are worn. I think the rear K60 would be more stable than the TKC, and I think a good windscreen can probably increase stabilty as well as comfort. YMMV (as you yanks say!) :lol3

    I would seriously consider a Rally-moto steering damper, if it wasn't for the price ... I imagine that it would be a big help in most conditions.
    #7
  8. supertorro

    supertorro Adventurer

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    yep, had the same front end wobble when I changed from the stock tyres to 50/50 tyres. front was a heidenau k60 and rear was metzler sahara enduro.
    really bad wobble at speed. I found the only way to cure it was to adjust the rebound on the rear, and that seemed to make it behave a little better.

    since i've replaced the metzler with a heidenau the problem seems to have gone away some, so I can run the rebound more where I prefer

    my 0.02
    #8
  9. The Griz

    The Griz Long timer

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    +100 Great post.
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  10. Nacho911

    Nacho911 Been here awhile

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    Hows your air pressures. Lots to be said about increase and decrease pressures on and off road with those tires. Look in other threads on the TKC's.

    Ride safe
    #10
  11. SCVGS

    SCVGS Adventurer

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    Relax your grip on the bars and dont pull with your arms to compensate for the wind hitting your chest. Knobbies dont make good street tires and vise versa.
    #11
  12. Dolly Sod

    Dolly Sod I want to do right, but not right now

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    Have you tried adjusting the height of the forks in the triple trees? Raising the forks in the trees often alleviates a high speed weave in other bikes.
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  13. geno_rocket

    geno_rocket Been here awhile

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    I am running the H60s and sure enough, I noticed the front end wobble around 60mph when riding on a highway surface with rain grooves. it gets pretty pronouced if the surface is cut concrete, but have experienced it on asphalt as well. On smooth asphalt there does not seem to be an issue, but I have not gone much higher than 80mph. I have a grooved patch of concrete interstate right near my house that is a wake up call on every ride out of town.

    I am guessing it is a combination of telescopic front forks, a big front diameter wheel and the knobbies. I would venture the big R bikes with their different suspension have a very different critical mass. A while back I had a CBX with a larger front diameter wheel and it would wobble and shake on the same cut concrete grooves - giving a real thrill. :eek1
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  14. Catskill

    Catskill tree hugger

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    Street tires here, no wobbling going on at high speeds.
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  15. Ducksbane

    Ducksbane Quaaack!!!

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    Geno_Rocket ... I think you should check your rear ride height ... Much as I dislike the front K60 on loose surfaces I have Never had any instabilty on a firm surface.
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  16. Dolly Sod

    Dolly Sod I want to do right, but not right now

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    That's a good point. The OP said nothing about verifying correct sag for the suspension. Sag is the first place I'd look then if it keeps weaving I'd lower raise the forks in the triple tree 5mm and see if that makes a difference.
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  17. geno_rocket

    geno_rocket Been here awhile

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    I would be concerned and check the ride height if the wobble occured anywhere else except this spot on the interstate. That mixture of rain grooved asphalt and concrete is the only place where I have the issue, but it is a big issue there, so I am chalking it up to the tires. When I get away from this one stretch of highway (I-64 east and west at the I-270 interchange in STL for anyone so interested) then I have no problems. Just a perfect mixture of traffic speed, wheel diameter, tire tread, and suspension mass to make the bike squirrely on those grooves.

    Heck, the rain grooves on the highway at that location would probably be considered ruts in some locations. Now that I think about it, that is why I took the BMW adventure riding school - to learn how to ride those things! :lol3

    Ducksbane, as you suggest, rear ride height should not be overlooked. I read back through the posts and none of the original posters mentioned whether the wobbles occur when the bike is fully loaded or not. Assuming the rear ride height is at the lower limit of specifications, and the front is at the upper limit and you are riding the bike fully loaded with gear - the net result can be a significant unloading of the front end and resulting instability at speed. I have the preload cranked up pretty high as I am a big boy, so I discounted that point in my situation. All that said, this weekend, when riding over my favorite highway interchange with fully loaded bags, I felt there was a bit more wobble, but I knew why and expected it - the load I was carrying unweighted the front end a bit more.

    Okay, at the risk of extending this thread even more, does anyone know how much difference the diameter of knobbies (any type) are from the OEM tire? That difference in diameter could upset the ride height and potentially bring on a wobble. Now a F8 is not a racebike, but racers are concerned with such things. What the heck, the post is only two pages long right now.....
    #17
  18. Moab

    Moab Been here awhile

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    Thanks for all the comments, they have certainly got me testi g different theories.... I have experimented since my original post and I am absolutely convinced of a couple things, first of all the wind can be a significant factor in wobble, as u are buffeted back and forth...that in combination of a death grip when it happens only exacerbates the problem.

    Have gotten to a point where I can duplicate the wobble every time, and while the knobbies make the problem worse, I think wind buffet and loose clothing combined with gripping too hard plays an equal part.

    I can almost always decrease the wobble down to almost nill with some simple adjustments.....

    May not work for everyone but in my case it sure did.

    Thanks all
    :clap
    #18
  19. WOLVERINE

    WOLVERINE Keep her pinned!

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    I put my stock Anakee's back on to compare....Let's just say the wobble(Squirrelliness) has gone away and all I can say is 180KPH is no problem and stable!:D
    #19
  20. upweekis

    upweekis Long timer

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    21 inch front wheel, Knobby tires and 80+mph on pavement, and people think the front end shouldn't wobble?
    #20