Bonneville America Forums Forums Technical Forums General Tech Front end wobble!

This may sound strange but when letting go of the handlebars with both hands at say 50mph my bike starts to shake or wobble at the front as it slows down..it then stops the more it slows down 30mph ish.
Is this an out of balance front wheel or is just the geometry of the bike(BA). Its not a vibration and its only when you have no hands on the bars at approx 45mph.
Anyone else experience this?
Stephen

Yes. Solution: Don't let go of the handlebars.

Maybe a worn/underinflated front tire, or worn/dented steering-head bearings. The old Windjammer fairings could cause a wobble, don't know if a handlebar-mounted screen would or not.

Warped brake rotor anyone? Or just an out of balance tire?

I would try having the front tire re-Balanced first.

Mine has done this since new, worse w/low F tire pressure.
My solution? Hold on!

Mine has also done this since new. I've brought to several dealers and they insist theat everything is ok. One suggested that it's my windshield causing the wobble. I just hold on and don't worry about it.

Possible reasons:
Bad tire
Wheel assy out of balance
Wheel bearings
Headset bearings loose or bad
Wheel out of true (bent or spokes out of adjust)

Experienced that before and a new tyre cured it. Just recently was experiencing it again. The tyre was worn again and I assumed that was the cause. I suppose it is the cause, but after replacement, I still have a very slight oscillation. Here's my theory - The original Metz was a 'LAZAR' the last two where the upgraded version - 'LAZAR TECH'. The tyre is much the same with upgraded compounds I believe. The original suggested PSI was 36 which I maintained. The Metz site fitment chart indicates 40psi. I am going to up the pressure before I get permanent cupping and see if the vibes subside. If there's any marked change I'll post. May not occur till the week end.

Mine has done that for 5 years, with two sets of tires. I know my Avon Venoms are good tires. I disassembled and greased and adjusted the head bearings. I have installed Progressive fork springs and 440 shocks (but not for that reason). No change on the handlebar shake at about 40 mph. It only needs one hand on the handlebar to control it, so it is not that bad, just unusal/spooky. So, like someone said, don't let go of the handlebars.

ok i would look at your rear wheel....that can make your front end wobble also if it's not lined up or balanced it will make your front end act up

BIKER

Wendys bike has been doing that lately her front tire has an uneven wear pattern but can't find a cause. Wheel is true / balanced,rear wheel is aligned,head and wheel bearings are OK,rotor might be slightly warped but not enough to cause anything like that. I think it's the stock Bridgestone tire.My Speedmaster I can let go of the bars as long as it will roll I even go down long windy hills no hands just leaning to turn the corners. Stock Metz Laser on it still with almost 13,000 miles on it. Just ordered a new tire yesterday for it Michlin stock size for $90 will have to see if it cures the problem.

good source for tires by the way:
http://www.ridedirect.com/?utm_source=go...tor+Cycle+Tires

Mine was doing that. Turned out is was a bad tire. Dealer replaced under warranty no out of pocket to me.

I think Freedom had this problem and had it somewhat fixed with heavier fork oil. Probably didn't remove the cause, just help alleviate the symptoms somewhat.

My Avons helped a little. The stock Bridgestones were terrible. Maybe the Metzler Lazer is better thatn the Avons???

Mine does it too. Not so much at 80 MPH and above, (I gotta throttle lock) but also at around 50 & below. Perhaps the extreme wheel caster / fork angle is a factor?

From looking at everyone's responses, it seems this is more a problem on BA's, not Speedys. Maybe the extra weight of the second rotor has something to do with it? Changing the harmonic?

I was thinking it might have to do with that and the spoked wheel as opposed to the mag.

EDIT: Wendys tire is worn enough to need replacing anyway so not doing it just to get rid of the wobble. In her case being inexperienced I might though.

It's done it on my bike a couple of times, usually around 45 mph when I let go of the handlebars. The fix was always new tires, but I never bought tires just to get rid of the wobble. Always waited till the tread was worn. I used the FJ solution in the meantime.

OK, so now I'm obsessed. Been ISO wobble since I read this thread... It seems that when my bike is cold, there's a bit of a wobble on the front end (like going over small bumps, not side to side, very minor really)- but then when my bike warms up, I don't seem to notice it.

?

I'm getting ready to go ride- I'll watch for it again.

That could be a front tire slightly out of round, or having ridges/lips that actually change the local radius of the tire. My wobble is side-to-side, not up-and-down.

What is the "FJ"solution...can't work that one out! Must be US slang.

Solution is...Don't let go of the handlebars!

If the only time you experience a wobble or head shake, side to side movement of the front end, is when you you let go of the handlebars, then don't let go of the grips. Shouldn't be riding like that anyway, it's dangerous.

But if you're picky about it, then buy new tires(tyres for the Brit translation).

"FJ" meant post by FriarJohn, earlier in this thread.

New tires doesn't always do it. I always have the wobble. But I don't have to clutch the bars to stop it. Most of the time I can just rest one hand on a grip (I have a throttle rocker) and it stops. But I am trying to get out of the one-hand habit.

My speedy with 3500 miles on it does it holding the bars lightly with or without the shield on.

mike

Seems I remember a long time ago (more than 40 yrs) some Triumphs had a steering damper (like ashock absorber)on the left side, from the frame to the left side of the lower triple tree.

mine also aqiured this freaky wobble at around 45mph a long time ago. i went thru the usual things that have been mentioned here, but to no avail. then i changed the fork oil. problem cured. but wait, i trailered my bike to the Ga. rally and the wobble has been back ever since. i am thinkin it has something to do with the forks,ie; oil, or springs being weak?? something there, more than anywhere else. after what someone has said here about how it got better after changeing springs i am thinkin new springs and a higher grade fork oil will probably cure this problem. my 72's front end is shot, the gaiters rotted away yrs ago and so i have very little oil in the forks and the wobble i get on her is intense at around 50mph. i am leaning more and more toward weak springs and light oil as being the problem. i think i am gonna change to a heavier oil first to see if anything changes and then decide on the springs. i have to wonder about the people that have noticed this from the first, if they trailered their bike home when they bought it or rode it home??? i rode my bike home when i bought it and never noticed the wobble untill the first time i had to trailer it. but didnt put the 2 together untill this time to Ga.

Quote:

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Experienced that before and a new tyre cured it. Just recently was experiencing it again. The tyre was worn again and I assumed that was the cause. I suppose it is the cause, but after replacement, I still have a very slight oscillation. Here's my theory - The original Metz was a 'LAZAR' the last two where the upgraded version - 'LAZAR TECH'. The tyre is much the same with upgraded compounds I believe. The original suggested PSI was 36 which I maintained. The Metz site fitment chart indicates 40psi. I am going to up the pressure before I get permanent cupping and see if the vibes subside. If there's any marked change I'll post. May not occur till the week end.

---

Stephen'

I finally got to play with the pressure and take a good ride. I raised the pressure from the 36PSI Triumph recommendation on the neck and manual to the Metzler recommended 40 PSI from the Fitment Chart on their web site. The wobble ia ALL BUT gone. There is the most slight wobble at about 43 - 45 mph. So, it seems two factors are at play - Tyre wear (i.e., cupping - Mostly due to low pressure flex and wear), and inflation (which seems to have from the 36 PSI of the original ME-33 Lazer to the Lazertech replacement. Anyway, thats my story - and I'm stickin' to it.