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@vespasfw3 avatar
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UTC quote
I know, a tired old topic sliced and diced years ago. I remember Jess pronouncing the wobble on deceleration as a known issue.

However, I posted a video today in response to an inquiry from someone who just bought a "new", low mileage used Vespa GTS (their first one but having had many other Vespa scooters over the years) and was dismayed by the front end wobble and thought something was terribly wrong.

In my video it's probably apparent that I feel it's no big deal. If I never took my hands off the bars I would not even know the thing wobbled. But showing it on video seems to be a bit unsettling to some and I thought I would touch base here regarding whether wobble on later models was solved and whether it persists.

My tires are relatively new, some tires seem to wobble less, steering head bearings ok, lug nuts tight, shock in good shape. But man oh man the wobble looks wild.

Any up-to-date experience beyond my 2006 GTS would be appreciated! Thanks!!

https://youtu.be/ungnOD14YUg
@grouper avatar
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UTC quote
Thanks for posting the video. I've never seen the wobble before.
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UTC quote
Nice video and interesting to see. I have experienced wobble on motorcycles, but not on the Vespa.

There are different causes for wobble, for example getting the front wheel off the ground even if briefly and not having the wheel straight when it connects with the road again, or other issues that are connected to driver input. One potential easy fix: a soft suspension can play a role, most aftermarket suspensions would be able to address that.
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UTC quote
I was riding with friends a couple of weeks ago, and one caught site of Gigi's wobble. He was appalled. The first month of the wobble was frightening, but I got used to it quickly. Razz emoticon

With less than 5000 miles on her clock, Gigi's wobble appeared suddenly and happens with both hands on the bars. She got new tires about 1000 miles previous to its appearence. I've since adjusted the suspension, tire pressure, checked balance, varified bar end weight, modified seating positions, and had the bearings looked at. The tires have about 7000 miles on them, and I'm waiting to see if the issue disappears when they're replaced.
OP
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UTC quote
grouper wrote:
Thanks for posting the video. I've never seen the wobble before.
Yeah, I had never seen a video of it either so I figured what the heck...
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Molto Verboso
2018 GTS 300 Touring Rosso Vignola, 2020 BV 350 Matte Green, 1956 VL3
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@lebo avatar
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UTC quote
Very good video illustrating the GTS wobble. Thanks for posting. FYI my BV350 does it also.
I have the exact jacket you're wearing in the video & really like it. Ciao
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UTC quote
giallo wrote:
Nice video and interesting to see. I have experienced wobble on motorcycles, but not on the Vespa.

There are different causes for wobble, for example getting the front wheel off the ground even if briefly and not having the wheel straight when it connects with the road again, or other issues that are connected to driver input. One potential easy fix: a soft suspension can play a role, most aftermarket suspensions would be able to address that.
I've not experienced deceleration wobble on motorcycles but have experienced mild "wobble" or tank slap under power. Tucking down and changing the air flow stopped it. But it was very slight. I think the GTS issue is something different. But what do I know. I've ignored it for over a decade. Just light I ignore the engine fault light that's been on since 2009...
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UTC quote
Lebo wrote:
Very good video illustrating the GTS wobble. Thanks for posting. FYI my BV350 does it also.
I have the exact jacket you're wearing in the video & really like it. Ciao
Thanks. You have wobble on the BV350. Geez. I hadn't heard that.

The KLIM jacket is great. I was able to get a good deal at Revzilla.
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UTC quote
Guzzi Gal wrote:
I was riding with friends a couple of weeks ago, and one caught site of Gigi's wobble. He was appalled. The first month of the wobble was frightening, but I got used to it quickly. Razz emoticon

With less than 5000 miles on her clock, Gigi's wobble appeared suddenly and happens with both hands on the bars. She got new tires about 1000 miles previous to its appearence. I've since adjusted the suspension, tire pressure, checked balance, varified bar end weight, modified seating positions, and had the bearings looked at. The tires have about 7000 miles on them, and I'm waiting to see if the issue disappears when they're replaced.
Wow -- wobble with both hands on the bars. That would be a little annoying but at least it's only happening as you decelerate right?

I've been dealing with it for so long that it has become invisible.
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UTC quote
VESPAsfw3 wrote:
Wow -- wobble with both hands on the bars. That would be a little annoying but at least it's only happening as you decelerate right?

I've been dealing with it for so long that it has become invisible.
Yes, only upon deceleration. I regularly ride one handed at various speeds, but never when slowing.
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UTC quote
Nice video. We have an 18 and a 20 GTS and no wobble on either one. Only bike I remember owning with any head shake / wobble issues was an early 80's Kawasaki KZ440 with an aftermarket windshield.
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UTC quote
VESPAsfw3 wrote:
Just like I ignore the engine fault light that's been on since 2009...
ROFL emoticon My husband has been ignoring that light for over 3 years.
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UTC quote
This is one of those "endemic, unexplained mysteries" of the GTS, but thanks for capturing it on video. It can be difficult to explain. Perhaps it's something to do with the angle of rake in the steering is the true root cause (it is pretty steep rake). But is remedied for some with slight change to tire pressures and weight distribution on the bike.

I had it intermittently on my 2008; I didn't have this issue at all for many thousands of miles, and then it appeared suddenly when no change was made to the scoot; but it went away completely when I put new Pirelli Angels on it at about the 20K mile mark. When I went to CG2's after that for Cannonball, the issue did NOT reappear.

When I got my new to me 2006 GTS with 2500 miles, I swapped the old tires for new Michelin CG2s with recommended pressures from the sticker inside the glove box. I then went out and purposely tried to induce the wobble as shown in the video, and no wobble manifested.

Are there any GT200 riders that have had this phenomenon? The bikes are really very similar and wondering if anything changed in the front end when the GTS was released. The engine in the GTS will weigh a bit more and wondering if that is a factor in the overall balance of the bike.
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@dooglas avatar
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UTC quote
My 2008 GTS 250 had the classic deceleration wobble, and it was pretty pronounced if I did not keep firm hands on the grips as the scooter slowed down. I also had a GTS with sidecar which wobbled somthing terrible on deceleration until fitted with a hydraulic steering damper. Thanks for the video documentation.

Since those days I have owned an Aprilia SportCity 300, a BV350, and a 2015 GTS 300 with ESS front suspension. None of them showed any wobble on deceleration. My small sample would suggest that it is the geometry of the front suspension on the GTS which is the culprit. The ESS suspension seemed to either solve the problem (for me) or make it much less pronounced (some other reports), and even the recent reversion by Piaggio to something like the pre-ESS suspension seems to have some modifications to the older design that make a difference..
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UTC quote
My 2012 GTS had a minor wobble in its front end. I could only tell it was there if I was riding one handed when it would do a mild version of the wobble shown.

It's now got Bitubo front shocks and MP3 front rims with brand new CG2 tires and it is straight as a die.
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UTC quote
My 2017 GTS definitely wobbles during deceleration at around 30 to 40 mph. But only when riding one handed. With both hands on the handlebars, there's not even a slight hint of wobbling.

It's a mystery of the GTS that I love to call 'character'. I don't have any problem with it, it's just our little dirty secret .
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UTC quote
Jeez, that does look scary!

I've read about this, but always thought it is more like..well, like a slightly un-balanced tire, or something.

I can for sure confirm my Sprint did not do that, I'd have xxxt my pants the first time for sure...
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Molto Verboso
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UTC quote
Lebo wrote:
Very good video illustrating the GTS wobble. Thanks for posting. FYI my BV350 does it also. (...)
My BV 300 does not have any wobble at all. But as Steve says in his film: why would you drive without holding the handle bars.
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PeterCC wrote:
But as Steve says in his film: why would you drive without holding the handle bars.
My '08 GTS didn't require riding with no hands in order to wooble. Upon deceleration (about 40 to 20 mph) mine would wobble when you took one hand off the hadlebars, or even if you just held too loosely with both hands. And it did this during all 5 years I owned the scooter - after checking tire inflation, after new tires, after balancing, whatever.
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UTC quote
It's the crappy front wheel that is causing most of the wobble. My last GTS 250 has bad front end wobble. I then bought some newer lighter black and silver wheels from a newer model GTS 300 and it removed most of the wobble.

To minimise wobble
Heavy bar ends
Remove top box
Good quality front tyre
Properly balanced wheels
A front wheel that requires very little wheels weights to balance it
Good swing arm bearings and engine mounts
Shock absorbers that aren't old and knackered.
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UTC quote
FWIW, my deceleration wobble got progressively worse with more miles. Playing with balance or tire beads didn't make a difference. But my brand new tire equaled no wobble (sans balancing or beads—go figure). Shithouse luck.
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UTC quote
I owned an SYM HD200 some years ago that I was fond of decelerating with no hands. That scoot also wobbled on decel, but not nearly as bad as VESPAsfw3's video shows.
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UTC quote
GTdespatchcourier wrote:
To minimise wobble
Heavy bar ends
Remove top box
Good quality front tyre
Properly balanced wheels
A front wheel that requires very little wheels weights to balance it
Good swing arm bearings and engine mounts
Shock absorbers that aren't old and knackered.
+ Correct tyre pressures.
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Molto Verboso
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UTC quote
Wife got a new 900 Can-Am Ryker the other day so on the last ride I decided to take her 2013 GTV300 instead of the 1200 Sportster with sidecar. That was the first time I experienced the front end wobble on that one.

It only happened if I almost completely removed hands from the grips while slowing down and just a very light touch on both grips would cause it to stop.

This GTV does have the taller windshield and a leather top box and has over 26,000 miles on it
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UTC quote
GTdespatchcourier wrote:
It's the crappy front wheel that is causing most of the wobble. My last GTS 250 has bad front end wobble. I then bought some newer lighter black and silver wheels from a newer model GTS 300 and it removed most of the wobble.

To minimise wobble
Heavy bar ends
Remove top box
Good quality front tyre
Properly balanced wheels
A front wheel that requires very little wheels weights to balance it
Good swing arm bearings and engine mounts
Shock absorbers that aren't old and knackered.
Geez, that's a pretty complicated fix to the wobble. There's a much simpler fix -- keep your hands on the bars! Laughing emoticon
OP
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UTC quote
Thanks everyone for your comments and sharing your experience with the "Wobble." I hadn't heard much about it in years so it was like a trip down memory lane. And just as mysterious as it was years ago it seems the same now. I've had a couple people contact me with brand new 2022 HPE models and they have the wobble.

Long live Wobble. I think Piaggio engineers must have that posted on a wall somewhere...
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UTC quote
VESPAsfw3 wrote:
Long live Wobble. I think Piaggio engineers must have that posted on a wall somewhere...
In Italian, of course. Viva il vacillare!?
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UTC quote
fledermaus wrote:
In Italian, of course. Viva il vacillare!?
"My Vespa doesn't 'wobble', it 'vacillates' at certain speeds"
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UTC quote
They all wobble, but to different degrees.

I have three GTs and have put many miles on Madison Sully's GTS.

I never take both hands off, but often ride with one hand.

They wobble with one hand on as well.

Of the four, the least wobble is the multi crashed Vanessa. She almost never shakes while being rock solid at speed.

Rocket hardly shakes either. Quite good on the road.

Razzo sometimes has a bad shake, but I have lessened it with new tires, once a 140 that eliminated it for the week or so I had it on.

The worst wobble is the GTS. It will shake almost every time I take my hand off of the grip, even at higher speeds.

I have no answer, but I have never felt it to be dangerous.

Bill
⬆️    About 1 year elapsed    ⬇️
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UTC quote
Old thread, I know.

My old 2012 GTS had the slow speed wobble. I was so happy that my 2020 GTS didn't have it, until yesterday. It was really the first time that I rode with my old GIVI case attached. Yes, the deceleration wobble was there. Son of a gun. I got home, took the case off and no more wobble.

It sure is a strange thing.
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UTC quote
bluside wrote:
My old 2012 GTS had the slow speed wobble. I was so happy that my 2020 GTS didn't have it, until yesterday. It was really the first time that I rode with my old GIVI case attached. Yes, the deceleration wobble was there. Son of a gun. I got home, took the case off and no more wobble.
My understanding is that is the reason Piaggio provides heavier bar end weights with Vespa topcases for the GTS.
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Molto Verboso
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UTC quote
bluside wrote:
Old thread, I know.

My old 2012 GTS had the slow speed wobble. I was so happy that my 2020 GTS didn't have it, until yesterday. It was really the first time that I rode with my old GIVI case attached. Yes, the deceleration wobble was there. Son of a gun. I got home, took the case off and no more wobble.

It sure is a strange thing.
Check the air pressure of the tires.
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UTC quote
Tire pressures are good and I just ordered some heavier bar ends.

The wobble only just happened when I finally had a reason to put the big GIVI top case on it, slowing down and just a very light touch on the handlebars. I usually just have a little tail bag on the back.

I just thought Vespa had fixed the issue since my 2012 GTS. Apparently not. Not a big deal and I can definitely live with it.
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UTC quote
mine did it when I put an oversize tire on the front. it corrected the speedo error but had to keep both hands on the grips almost all the time.
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Molto Verboso
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UTC quote
tonymarchman wrote:
mine did it when I put an oversize tire on the front. it corrected the speedo error but had to keep both hands on the grips almost all the time.
A different diameter of the front wheel brings exactly: nothing...

The rear tone wheel measures the speed for the speedometer display. To correct the displayed speed, there is the KÜBLER tone wheel:

https://www.sip-scootershop.com/en/product/tone-wheel-kubler-racing-abs-rear_KBPI0010


also available for 13 inch rims:
https://www.sip-scootershop.com/en/product/tone-wheel-kubler-racing-conversion-to-13-rear_KBPI0011
@25bikez avatar
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UTC quote
GermanGTSDriver wrote:
A different diameter of the front wheel brings exactly: nothing...

The rear tone wheel measures the speed for the speedometer display. To correct the displayed speed, there is the KÜBLER tone wheel:

https://www.sip-scootershop.com/en/product/tone-wheel-kubler-racing-abs-rear_KBPI0010


also available for 13 inch rims:
https://www.sip-scootershop.com/en/product/tone-wheel-kubler-racing-conversion-to-13-rear_KBPI0011
No ABS. No Tone Wheel. Speedometer gear in the front hub.
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Molto Verboso
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UTC quote
25BIKEZ wrote:
No ABS. No Tone Wheel. Speedometer gear in the front hub.
I had suppressed that...
@steelbytes avatar
UTC

Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5720
Location: Batmania aka Melbourne, Australia
 
Veni, Vidi, Posti
@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5720
Location: Batmania aka Melbourne, Australia
UTC quote
I balance my wheels.
I ride diablo (some tires are not as even as others).
I make sure my tire shop puts the red dot near the valve stem (not present on all tires).
I have the heavy weights that came with my topbox.
I have SIP suspension that I've dialed in nicely.
I have nylon bushings instead of the standard rubber.
I use 26/28psi (I'm not a heavy person so a higher rear might suit others).


recently got new steering bearings (top) as they died completely and it's pretty stable, I'm content.

also remember that front tires do wear in an unbalanced way. I ride on the left of the road and the right hand side of my front always wears more than the left. Not sure if this is due to the camber of the road or that it's something to do with with slope of the road during a tight left vs a tight right or tightness of radius due to which side of the road etc etc etc.


PS some will feel my pressures are too low but they rise plenty on long fast rides according to my tpms
⚠️ Last edited by SteelBytes on UTC; edited 1 time
@vintagescooterdude avatar
UTC

Hooked
2006 GT200 2009 Genuine Stella
Joined: UTC
Posts: 279
Location: Chandler, AZ
 
Hooked
@vintagescooterdude avatar
2006 GT200 2009 Genuine Stella
Joined: UTC
Posts: 279
Location: Chandler, AZ
UTC quote
I saw that video several months back. I was quite shocked when I saw it. I have had over 50 bikes total (in 46 years) 8 of them being scooters. I have ridden around one million miles. I have NEVER experienced anything like that. I certainly would not consider that normal. I would find it completely unacceptable. None of my bikes have ever done that.

I first heard about the Vespa "wobble" on another forum a few years ago. I have tried my best to duplicate it, without success. I have a GT, not a GTS. I do have a top box on it, an actual Vespa top box, and it is probably overloaded. I have what appear to be the original handlebar weights. I do balance my tires using the Marc Parnes balancer. I have tried lowering the air pressure in my tires, removing the handlebar weights, emptying the top box, lowering the preload on the shocks to the first notch (I usually keep it set at max preload) and never got even the slightest wobble. I even took it up to top speed, took my hands off the bars, and let it slow down to almost nothing. I tried it with 14 year old tires and brand new tires. Still no wobble.

The video clearly shows that it can happen, and I can think of a few things that could cause it. Worn front suspension, loose steering head bearings, worn wheel bearings, out of balance tires, tires with ply separation, and tires with seriously low inflation pressure. But none of those should present with a nearly new low mileage scooter, unless it had been crashed, and there should be signs of that.

So this this wobble thing is still a mystery to me. I have only ridden one "modern" Vespa, so I don't have a lot of experience with them. I would definitely have to test ride any Vespa before buying it, and would not buy it if it did that.
@vintage_red_matthew avatar
UTC

MV Santa
GTS250, 1975 VBC, 1980 P200E cutdown
Joined: UTC
Posts: 4798
Location: Sedgwick, Kansas
 
MV Santa
@vintage_red_matthew avatar
GTS250, 1975 VBC, 1980 P200E cutdown
Joined: UTC
Posts: 4798
Location: Sedgwick, Kansas
UTC quote
I got my GTS with 2,000 miles on it with no wobble.

The first time I changed the front tire the wobble appeared and nothing would get rid of it.

At 20,000 miles I had to drop the fork to replace the front fender. The bearing was slightly loose and notched so I replaced it.

Wobble gone.
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