Front End Wobbles

[backinthesaddleagain]

still happens when coming down from 50 to 40 mph with hands off bars, and new rear tire. perhaps with more adjustable suspension this could be solved. reason i think this is some of us have the shake others don't. there are various sized riders here, height and weigh, as well as some might sit more forward while others don't. i find if i sit back more it happens less.

look at a full on race bike. the seating position is set and the suspension is dialed in. getting it right can be like jetting as you keep adjusting until it gets better and then you go a bit too far and have to back it off a couple, with the added complexity that an adjustment on the rear can impact the front, or vice versa. my thought therefore is maybe, maybe some more rebound damping in the shock, or a stiffer fork spring would reduce headshake.

[TheDuck]

Originally Posted by fjyang

I installed a fork brace on my bike and at first I just clamp on the brace with the bike on its side stand and go riding, I notice the bike starts to wobble around 80mph and at fast corners the front end just feel twitchy at certain lean angels.

Mine did that too when I properly adjusted the preload on the front end for my weight. While it felt more solid most of the time at about 80mph in a sweeper the front end felt like the triples were mounted in playdoh. I didn't notice any different in wobble at low speeds though. I've since gone back to factory configuration and while there is definately a lot more sag it feels better at higher speeds, though not as tight when throwing a 90 degree right turn around town.

[CZroe]

Mine spontaneously started doing this back in November (1.3yo, 10K mi at the time).

[CZroe]

I've mentioned this elsewhere but I should add it to this thread: Mine did not do this for the first year but spontaneously started doing it after a year and a few months. I did have a tire change a month prior, but I can't say if it started then. I can say that I didn't notice despite frequently releasing the bars when I stop before and after the tire change.

A bike that didn't do it now does. Take that FWIW.

[Anthony_marr]

Here is my "theory":

When the bike is running on a perfectly flat and smooth road surface, this would not happen, but if the road is uneven, e.g. grooved, the front wheel maybe slightly deflected to one side or the other. When the front wheel is deflected, say, to the right, this would cause the body of the bike to lean slightly to the left. This would cause the front wheel to reorient to the left, which would then cause the body of the bike to lean slightly to the right, which will cause the front wheel to reorient to the right... Thus, the oscillation.

[CZroe]

Originally Posted by Anthony_marr

Here is my "theory":

When the bike is running on a perfectly flat and smooth road surface, this would not happen, but if the road is uneven, e.g. grooved, the front wheel maybe slightly deflected to one side or the other. When the front wheel is deflected, say, to the right, this would cause the body of the bike to lean slightly to the left. This would cause the front wheel to reorient to the left, which would then cause the body of the bike to lean slightly to the right, which will cause the front wheel to reorient to the right... Thus, the oscillation.

That would apply to all of the same design, but some bikes that didn't do it now do.

[Samer]

I routinely slow down with no handlebars and never experienced a wobble. My bike is still young at 1300 miles. Hope that doesn't change

[TheDuck]

The annoying shimmy of the front end when removing my hands has GONE AWAY!

I'm sure it had more to do with the new BT45 tires that I just had changed than the ZX6R rear shock swap, but its something to ponder.

[Ninja North]

K Kim - I hope you have found a solution by now. If not, I've heard someone had solved this problem and solved it by checking / tightening the steering stem.

[backinthesaddleagain]

Mine still does it slightly from 50 down to 40. I have tried various air pressure, having steering stem re-torqued, rear wheel alignment. I am betting a new front tire will be the cure. The tire looks fine to the naked eye, but that doesn't really mean anything.

[deezyellownutz]

Wow... interesting issue. I did notice that when I rode my 250 home that the handle bars were light as a feather compared to my zx10 so I never really trusted them to let either one go... lol From my experience putting around testing the suspension after I lowered it, the front end is extremely sensitive. Not sure if its from the combination of lowering it and me being on it or what. I just exercised caution. This was the reason I did the GPR damper for the wife as I didn't want any surprises. I did notice the bolt holding the triple tree was VERY easy to loosen and that my fork nut (no jokes now..) was loose... (lol) I had to take all that apart to install the GPR bracket and put it all back together and it was better.

[sktrs_kpr]

Mine has been doing this for a while, and I just did a bunch of suspension work that i hoped would help: R6 rear shock, ex500 springs, new chain/sprockets/complete swingarm cleaning/greasing, front end 'alignment' as per the wiki, etc.


It still does it. I'm inclined to think its the crappy front tire I have on there now but i'm not sure. Most of the time I only notice it when im slowing down around 40 or so hands off the bars, but the other day i was pushing it pretty hard through some twistiest and in one of them at around 60mph or so i was leaning almost far enough for my boots to start dragging and suddenly the front end went all sloppy, scared the crap out of me! I then slowly pushed it harder and harder through a few more turns and noticed it a few more times, although not quite as bad.

I hope putting a better front tire on will solve the issue... i don't think theres much else for me to try.

[CZroe]

Originally Posted by TheDuck

The annoying shimmy of the front end when removing my hands has GONE AWAY!

I'm sure it had more to do with the new BT45 tires that I just had changed than the ZX6R rear shock swap, but its something to ponder.

Yep. New to me take-off GT501 tires fixed mine.

[Ninja North]

So what front tyre did you change to - that solved your wobbles. Thanks. I am on 110 pirelli sport demon - and I have the problem.

[TheDuck]

Originally Posted by Ninja North

So what front tyre did you change to - that solved your wobbles. Thanks. I am on 110 pirelli sport demon - and I have the problem.

BT45, same as factory size. I'll have to look up the numbers to be any more exact.

[Momaru]

Originally Posted by Ninja North

So what front tyre did you change to - that solved your wobbles. Thanks. I am on 110 pirelli sport demon - and I have the problem.

FWIW I'm on the Pirelli Sport Demons 110/130 front/back and don't have any wobble issues. Did the "look ma, no hands" on the highway once to make sure I wasn't damping it out without noticing.

[Alex]

Originally Posted by Momaru

Did the "look ma, no hands" on the highway once to make sure I wasn't damping it out without noticing.

It's not just no hands at highway speeds, do the same no hands routine while letting the bike decelerate down from highway speeds to 40 mph or so...

[250fan]

Mine will also wobble a little from 46-40 on deceleration only.....doesn't seem like its too big of a deal. It only will wobble with "no hands" on the bars.....didn't notice until I tried it after reading this thread.....Maybe it has something to do with more weight on the front while decelerating.

[kkim]

...but not all 250 ninjas do this.

[Ninja North]

I have 110 front, 140 back, and lowered the front end by ~ 20 mm. But I can't be sure when the problem started

[ninja250]

Mine was doing it BARELY before the clip ons.
I could barely notice it. You have to be trained well to notice it without clip ons. It is extremely minute.

It does it much more with clip ons.

Dunno if it does it with my new tires, I'll check. FWIW I'm on a bent frame now and wasn't before.

It did it when the frame was straight with stock handlebars too anyways, but like I said, barely even noticeable. Seriously.

My steering stem nut is properly adjusted.

This "wobble" does not seem to induce tank slappers. It goes right away after a little shimmy.
Only happens with no hands on the bars when decelerating at certain speeds. In a couple different gears.

[Momaru]

Originally Posted by Alex

It's not just no hands at highway speeds, do the same no hands routine while letting the bike decelerate down from highway speeds to 40 mph or so...

So, checked this again today as you suggested, on decel from highway speeds to 40-ish. It does wobble between ~48 and 40 (indicated) if I go hands-free, checked and consistent across 2nd, 3rd and 4th gears. Don't feel it a bit with my hands even just resting on the bars, so not concerned. Thanks for correcting me though Alex.

Not sure if it did before I switched to clipons, but it's so minor now I'm not gonna bother with it. I am using the stock bar ends, so that may play into it somewhat.

I must admit this is the first thread I haven't at least mostly read through before replying. Bad habit to start.

[Alex]

No worries, Paul! Both of our ninjettes have done it, I have a hunch it may have something to do with rider weight and particular tire construction, but like you and others have mentioned, it really isn't a big deal in the scheme of things.

[kkim]

It is for me... I still have this problem. Will be changing front tire in the next few weeks.

My main concern is in a turn at that speed zone. I throttle into the turn, cut the throttle and as the bike is leaned over and decelerating, I can feel the front end wobble even with my hands on the bars. It's very slight, but very disconcerting in the middle of a turn while you're apexing.

On a straight with my hands off the bars, the bike will oscillate so bad, I know if I let it continue the bike would headshake itself into a highside.

I'm truly hoping changing out the front tire will cure or at least lessen the wobbles.

[Verus Cidere]

Hey Kim, I actually managed to fix this problem on my bike! I used to have it pretty bad, just like you. It would go off even with my hands on the bars. I recently replaced my front brake rotor and my headshake is almost completely gone! There's still a very slight shake, but it's nowhere near as bad as it was. You might check that after your tire.

[kkim]

hmmm... wouldn't a warped rotor show up during braking? or are you saying, even though your rotor wasn't warped, it helped?

[Verus Cidere]

My rotor was definitely warped. The weird thing was, it didn't show up nearly as much in regular braking as it did in the headshake. I felt a slight pulse when braking, but it was so slight I couldn't feel it unless I was really feeling for it. When we took it off, my mechanic said it was pretty bad and said it would be better if I just trashed the thing rather than keeping it as a spare. I'm not sure exactly how it works, but it fixed the problem.

[ninja250]

You can feel a slightly bent rotor as a pulse in the brake lever as feedback from the brake fluid when you squeeze the lever.

(Ask me how I know)

I don't think the front end wobbles described here are caused by the rotor, as I also just replaced my rotor and front rim and tires and still have a wobble.

It seems to have a lot to do with the weight of the handlebars to me, but I can't be sure.
The stock bars were very heavy, even without the bar ends.
Those were the first and only things I changed to get the wobbles to be pronounced on the bike. (Although they were barely detectable and there before the clip ons too!)

FWIW, I'm using the clips with the included plastic weightless bar ends.

[Verus Cidere]

How strange. Yeah, like I said, I felt the pulse before I replaced the rotor, and I could tell it was warped after I took it off. But I know for a fact (having a couple of butt-hole puckering situations) that I had some nasty headshake before the rotor change, and after it was changed the problem was about 95% fixed. There's still a very slight shake, but it's not nearly as bad as it was.

[backinthesaddleagain]

Kelly, New front tire cured my headshake. Smooth so far.

[kkim]

thanks for the feedback, Greg.

I changed out a worn rear tire a few weeks ago and that did not cure the problem. Hopefully when I get around to changing the front tire, too, the problem will disappear like yours has. Congrats.... it must be nice to ride w/o having to worry about the wobble cropping up at an inopportune moment.

which front tire did you install?

[TheDuck]

Originally Posted by kkim

thanks for the feedback, Greg.

I changed out a worn rear tire a few weeks ago and that did not cure the problem. Hopefully when I get around to changing the front tire, too, the problem will disappear like yours has. Congrats.... it must be nice to ride w/o having to worry about the wobble cropping up at an inopportune moment.

which front tire did you install?

Worn front tire replacement fixed mine, too.

[kkim]

thanks, duck. I've had this wobble ever since changing to the bt040s. After reading of the wobbles disappearing after a tire change on your bikes, I think I just got a bum tire.

[TheDuck]

Originally Posted by kkim

thanks, duck. I've had this wobble ever since changing to the bt040s. After reading of the wobbles disappearing after a tire change on your bikes, I think I just got a bum tire.

Make a front tire blow video and post it, lol.

[g21-30]

Originally Posted by TheDuck

Make a front tire blow video and post it, lol.

Duckman, you know those green bikes can't go that fast! kkim would need to put it on a BLACK bike for that!

[pedaltothemetal]

Use sensitive static balancer instead of stock axle to balance front tire!
Saw your DYI tire change and maybe it will help!
Also check out of round and wobble if you have a magnetic base to use
a dial indicator.
Seems you already thought of everything and just a few more ideas if you haven't already tried it!
Good luck!
So far I haven't had this problem and with stock tires, or the new 120/70 BT45
I just installed with tire irons! I do a lot of long rides and every chance to coast to a stop
coast to shake off the fatigue on my arms. So far so good with no wobble!

[bobguy]

i get the wobble too, but my tires are veeery worn. I'm about to try some brand new sport demons this week. I'll see if it still wobbles after the new tires.

[backinthesaddleagain]

I replaced the IRC with BT45. The IRC looked good to the naked eye, and felt smooth to the hand, but maybe just a hair out of round??

[backinthesaddleagain]

Originally Posted by kkim

thanks for the feedback, Greg.

I changed out a worn rear tire a few weeks ago and that did not cure the problem. Hopefully when I get around to changing the front tire, too, the problem will disappear like yours has. Congrats.... it must be nice to ride w/o having to worry about the wobble cropping up at an inopportune moment.

which front tire did you install?

Thanks Kelly. BT45, to match the BT45 on the rear. Definitely feels good to not have that wobble.

[kkim]

Originally Posted by pedaltothemetal

Use sensitive static balancer instead of stock axle to balance front tire!
Saw your DYI tire change and maybe it will help!
Also check out of round and wobble if you have a magnetic base to use
a dial indicator.
Seems you already thought of everything and just a few more ideas if you haven't already tried it!
Good luck!
So far I haven't had this problem and with stock tires, or the new 120/70 BT45
I just installed with tire irons! I do a lot of long rides and every chance to coast to a stop
coast to shake off the fatigue on my arms. So far so good with no wobble!

Thanks for the ideas, Leo. If the problem ends up being an unbalanced front wheel, you can be sure I'll be ordering a static balancer. At this point, I really feel it's the tire, though, and will explore that when I get around to changing the front... er, soon.