Front End Wobbles

[Boom King]

Wow, this thread is over 2 years old. Get this problem fixed KKim so we don't have to hear your old man whining anymore and so you can post another beautiful DIY !

I didn't read through this entire thread but I've heard things to check are tire pressure, alignment, wheel balance, spokes (does not apply here), and bearings. I've also heard that it can be caused by a rear tire that is worn or "squared". Best of luck.

[Rebel M9tn11]

I know this is olddd, and im on an 07, but I had similar problems from day 1... I did everything I could think of over the years and finally gave in and threw a gixxer stabalizer on it with a fork mount I machined up.. I don't know if the 08+'s have the room but its something to look into.. It is like a bandaid for the actual problem, but I found many handling benifets other then just the shake not being there anymore.
http://imageshack.us/photo/my-images/27/p8230025.jpg/

[CZroe]

Well, once again, changing tires cures the decel wobble for me. *shrug*

[Rebel M9tn11]

Mine would at speed as soon as the pressure on the bars went to light-none.
Knowing this from using choke for cruise control at 30mph and removing hands (hovering over bars) to check for wobble.. Sometimes it would go 1m without even a bit of shake.. Other times it would start its shake as I let off and try going into a slapper.
I can run no handed and go from line to line (leaning to stear) hard and it wont half the time.. Its completely random and I nor' anyone else has ever figured it out.

[Jinx250]

I've said it before and I'll say it again, it is absolutely not normal for a NInja 250 to have constant headshake. Sure, at certain speeds under specific cirucmstances and road conditions it's possible, but if you get it all the time, there is a problem that needs to be addressed. A steering stabilizer only masks the problem - it doesn't fix it. Just like shimming the needles.

[skateboarder1210]

Originally Posted by kkim

Wow... that's interesting. I'd be very interested to hear from others if this is a common occurrence with our bikes. I wouldn't think so... you may have the same problem I have, whatever it ends up being.

i had a pre gen that would wobble like that but my 2011 i can ride all day without hands, so definately could be the alignment of something

[ratlab]

mine went away with bt-003rs ,but i did racetech front and rear shock at same time-so i don"t know what was difference-but is dead stable at every speed now

[kkim]

thanks for that feedback, Reese.

[darrell85]

mine was doing the same thing untill i recently installed a new tire(by my self so i know its done right) it is usually caused from slight "cupping" on the tire tread due to hard front braking, and unbalanced tirescan also cause wobbling. it is much more noticable on our bikes because of the light weight and when we let off on the throttle the front end nosedives a little transfering more weight to the front end.

[Alex]

OK - another data point. I will not go so far as say the problem has been completely solved, but here goes. I just put on a brand-new set of Pirelli Sport Demons, replacing a very worn pair. The front was completely toast, with a V profile and nothing left on either side in terms of tread, though there was still a little left right in the middle. The rear was a little different, a bit flatspotted in the center, but still worn on the sides as well. The bike would have the decel wobble at almost any speed. Whether it was 60 mph or 30 mph, if I released pressure on the bar, it would start to wobble at an ever increasing amplitude until I grabbed the bar again. It was actually pretty bad toward the end.

I put on the new tires yesterday, the exact same model on both ends. But on today's ride, there was *zero* wobble. It didn't happen decelerating through 45 mph. It didn't happen at any other speed. I took my hands off the bars and coasted down a very large hill nearby, from 60 mph all the way down to just a few mph, and it was stable the whole way down. I'm a happy camper, and will be looking out for when it starts to reappear again on this set of tires.

[kkim]

Thanks, Alex... this gets more interesting the longer this thread lives on.

[Lowspeed Lowside]

Intriguing thread...

I don't think we can completely rule out that the kkim-wobble might be the result of torque-induced precession: when a spinning top slows down the amplitude and frequency of wobbles increases.

There are many sources of torque that have the effect of pushing the wheel to one side, such as a minute amounts of debris rattling a bearing ever so slightly. Now, when you take the wheel off and hold it horizontally and whack it a couple of times when changing the tire the piece of debris dislocates and the problem disappears!

This would easy to check: take the tire all the way off and put it back on as if it were a new one. If that solves the problem, it would save people experiencing wobbles a lot of cash, as it would prove that the new tires are not an essential part of the solution.

For what it's worth, the following scientific paper has other explanations:

Study of stability of a two wheeled vehicle through experiments on the road and in laboratory

[CZroe]

Every time I have replaced my tires (4 times) the decel wobble has gone away but it always returns soon. All my takeoffs have been low-mileage take-off GT501 tires so I probably have less time than I would with a fresh set.

[scotty]

Just replaced my front tire today. I had a good shake at 50mph+ with the OEM tire on. Today I test road the bike up to speeds of 40mph, and all seemed fine. I will try and test mine tomorrow to the speeds I had an issue with the "shake". Maybe it's nothing more than an out of balanced tire?

[ratlab]

i finally got around to installing my woodcraft clip-ons and slingshot preload adjusters-i have the racetech kit in my forks and i cut the spacer about 5mm to make room for the preload adjuster-i also put new bt-003rs front tire on going from 120 to 110 and now the decel wobble has come back with a vengeance-i'm going to put the stock bar ends back in like kkim diy and see what happens-with 120 front and stock bars bike was dead solid-on the other hand bike handles way better with 110 front and clip-ons

[alex.s]

is it possible as the amount of rubber leaves the tire due to wear, the wheel weights become relatively too heavy and actually end up unbalancing the tire? has anyone ever weighed a tire before they put it on then after they took it off once it's worn down?

[scotty]

Originally Posted by alex.s

is it possible as the amount of rubber leaves the tire due to wear, the wheel weights become relatively too heavy and actually end up unbalancing the tire? has anyone ever weighed a tire before they put it on then after they took it off once it's worn down?

Yes, you should have your tires re-balanced from time to time. Same thing with cars. Every 5-6,000 miles you should do it.

My shaking is still there, even with the new tire, but I think I have an issue with something with my bike that is making my bike control badly.

[bluepoof]

Are you guys only noticing the wobble with your hands off the bars? My 2007 has a wobble right around 35mph -- doesn't seem to matter the road condition, nor whether I'm accelerating or decelerating, and I keep both hands on the bars. My tire pressure is fine and the tires themselves are in good shape.

I'm 90% ready to believe that I'm hallucinating problems where there really aren't any.

[Alex]

How many miles on the front tire?

[rockNroll]

Maybe it's geometry, and normal? Mine has the decel wobble in the 45mph-40mph area with hands off. It had it with the new stock tire and kept it with 003rs tires. It didn't seem to change. It doesn't feel like a vibration at all (like a balance issue). It feels like the wheel of a shopping cart, wobbling back n forth.

[gt_turbo]

my handle bars use to vibrate about 40-50 mph real bad. after getting brand new tires, it seems to have gone away. possibly old tires were either unbalanced or bad tire wear.

[bluepoof]

Originally Posted by Alex

How many miles on the front tire?

About 900.

[Alex]

Yup, that's a new tire. I had some small wobbles on our 2004 version even with a new tire, but they were minor compared to how it felt as the tires wore down.

[exploring/carolina]

Had head shake (wobble) on my 08 Vstrom with Conti Road Attack tires with 3000 miles.

Tightened the steering head bearings to Suzuki's spec, and still had the head shake between 40 to 50MPH.

Tried several different tire pressures, checked balance, and wheel run out. Balance was good, no difference with different pressures, and the wheel run out was within factory specs.

Installed a new Bridgestone tire & headshake "went away". Understand some riders have problems on the Vstrom using the Conti Road Attack front tire.

[bluepoof]

Originally Posted by Alex

Yup, that's a new tire. I had some small wobbles on our 2004 version even with a new tire, but they were minor compared to how it felt as the tires wore down.

I'm pretty convinced that I'm making up issues. It's only at exactly 35mph (give or take 2mph) so I think it's just One Of Those Things. I'm not really used to only riding <100 miles/week, so maybe it's just that I'm not really used to the bike yet.

[Jiggles]

Just noticed today on my brand new 2007 that the front will wobble when I take my hands off the bars. The faster I'm going the more it wobbles, but I don't feel a thing while my hands are on the bars, even at 90mph. I lifted the bike up onto the rearstand (goddamn that rearstand is awsm, stupid kawasaki for not putting it on the newgens) and spun the back tire. I could tell the tire was slightly misaligned.

I've also noticed that while in a turn the bike wants to go back to a vertical position. I'm guessing this also has to do with the misalignment. Currently my handlebars are both bent, could this be contributing at all?

[cuong-nutz]

Is your bike used? Most likely your bike has been dropped a few times. In some cases your front forks will twist inside the triples causing a misalignment. Worse case scenario is that your lower triple will get bent. Ask me how I know. I replaced my bent triple and it fixed the wobbly problem Now I just got to realign the front end since I have the steering turned to the left slightly to go straight.

[Jiggles]

Originally Posted by cuong-nutz

Is your bike used? Most likely your bike has been dropped a few times. In some cases your front forks will twist inside the triples causing a misalignment. Worse case scenario is that your lower triple will get bent. Ask me how I know. I replaced my bent triple and it fixed the wobbly problem Now I just got to realign the front end since I have the steering turned to the left slightly to go straight.

Yea its been dropped quite a few times. When we tear it apart on Monday I'll check out the forks. Bike also needs a new front tire which I think is contributing to the problem.

[Domagoj]

Originally Posted by cuong-nutz

Is your bike used? Most likely your bike has been dropped a few times. In some cases your front forks will twist inside the triples causing a misalignment. Worse case scenario is that your lower triple will get bent. Ask me how I know. I replaced my bent triple and it fixed the wobbly problem Now I just got to realign the front end since I have the steering turned to the left slightly to go straight.

How do you measure this? A small deformation of lower triple will result in a not so small misalignment at the front wheel. Is there any way to estimate this by checking the wheel itself? I'm thinking that large dicrepancy is easier to detect than a small one, right?

cuong-nutz:
Thank you. After more than a year here I still seem to be stupid enough to not check the diy thread before asking dumb questions...

[cuong-nutz]

There's a DYI thread about line your forks. You can use two flat straight edges and put one atop your top triple and one on top of the lowers and eyeball to see if they are parallel and level. Usually you can just kind of tell by pointing the front wheel straight and you look down the sides and seeing what's off.

[leed]

I did a brief search through this thread, and didn't see anything.. But you may find this interesting. There is a theory I read some time ago, about the front end wobble on bikes like ours. And when I say 'like ours,' I really mean bikes with only one disc in the front.

The idea is that since we only have one disc, off to the side, instead of in the center of the rim, you get uneven wear on the tire under any form of braking from the front. Technically, you have more friction on the right side of the tire than the left. This may explain why a lot of people are losing the wobble with fresh tires. It only shows up at a given speed with our tire size due to harmonic vibration without dampening (gets bigger, blah blah blah) caused by the unevenness of the tire.

It has been mentioned that a lot of larger bikes don't have this issue with front end wobble at moderate speeds (40-55ish), so it seems plausible.

[Alex]

That has been debunked. The tire has no idea which side it's being braked from, from its perspective the rim it's mounted to is providing the force (which the disk is mounted to).

[Jiggles]

Got a new front tire and it pretty much fixed the wobble. Front end will still wobble if I hit some bumpy rode but I can now show off and stretch my arms while at speed .

My mechanic also said that a front end wobble is more likely on the pregens than the newgens because of the difference in tire size. 16in vs. 17in.

[alex.s]

I welded my stem bearings... no more wobble.

[Greyfox]

Hi guys.

What usually causes the front wheel to wobble?

My Ninja's front wheel sometimes wobbles / shakes when I take my hands off the handlebars. It does not do this all the time though

My tire pressure is perfect.

Wheel balancing?

Bearings?

Any of you guys had this problem before?

[alex.s]

maybe you shouldnt take your hands off the bars?

[hoodadooda]

Although I don't take my hands off the bars, I do keep a lighter grip on them. I have felt the steering want to wobble around 45-35 mph on decel and it definitely comes from the front being improperly balanced in my case. The damn weight they used to balance the wheel&tire came off! Luckily it didn't hit the bike...

[alex.s]

if you take the wheel into cyclegear they will balance it for you for free

[SlowBoyRacing]

Are the weights still on the wheel?

[NDspd]

Yeah mine always does a head shake decelerating from 50-40mph. What's causing this?