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@little_jon avatar
UTC

Enthusiast
2006 GTS250ie, 2015 KTM 390 Duke, 2000 Aprilia RS50 Race Replica, Whizzer Bike
Joined: UTC
Posts: 81
Location: Payson, AZ.
 
Enthusiast
@little_jon avatar
2006 GTS250ie, 2015 KTM 390 Duke, 2000 Aprilia RS50 Race Replica, Whizzer Bike
Joined: UTC
Posts: 81
Location: Payson, AZ.
UTC quote
[/b]I have heard this term used on the forum, but have never experienced it on my 2006 GTS250ie. The facts: I purchased the scooter six months ago with 1000 original miles on it (with it's original Sava tires). Now with 2400 miles, I decided I'd pushed my luck far enough on nine year old rubber. Road eighty miles to the closest Vespa dealer and had a new set of Heidenaus mounted and balanced.

On the ride back home, the tire balance seemed fine up to 65 mph. Above that there is vibration in the hand grips. I don't recall the original tires having any of this. I called the dealer and he said they rarely have any complaints regarding their balance procedures and tbe vibration is nothing to be concerned about. I guess my question is, do you consider this a wobble, a balance problem, or merely a normal characteristic of the GTS250 ?
@big_boys_mother avatar
UTC

Molto Verboso
2010 GTV250ie - Sienna Ivory, BMW F650CS, HD 883 Sportster
Joined: UTC
Posts: 1013
Location: North Coast - Rural
 
Molto Verboso
@big_boys_mother avatar
2010 GTV250ie - Sienna Ivory, BMW F650CS, HD 883 Sportster
Joined: UTC
Posts: 1013
Location: North Coast - Rural
UTC quote
Does the scoot have a top box? If so, does it have the handle bar weights installed? If that is not the situation, check this thread at MV ... The Wobble for additional advice. For me ... the wobble was eliminated after the bar weights were installed.
OP
@little_jon avatar
UTC

Enthusiast
2006 GTS250ie, 2015 KTM 390 Duke, 2000 Aprilia RS50 Race Replica, Whizzer Bike
Joined: UTC
Posts: 81
Location: Payson, AZ.
 
Enthusiast
@little_jon avatar
2006 GTS250ie, 2015 KTM 390 Duke, 2000 Aprilia RS50 Race Replica, Whizzer Bike
Joined: UTC
Posts: 81
Location: Payson, AZ.
UTC quote
Big_Boys_Mother wrote:
Does the scoot have a top box? If so, does it have the handle bar weights installed? If that is not the situation, check this thread at MV ... The Wobble for additional advice. For me ... the wobble was eliminated after the bar weights were installed.
Thanks for heads-up on that thread BBM. It explains a lot. No top box, by the way. My issue is obviously a balance problem or perhaps the tires themselves. Believe I'll take your advice and pick up a pair of heavier bar weights. Sure couldn't hurt.
@burgerbob avatar
UTC

Molto Verboso
SYM HD200, Vespa GT200
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Posts: 1674
Location: San Jose, CA
 
Molto Verboso
@burgerbob avatar
SYM HD200, Vespa GT200
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Posts: 1674
Location: San Jose, CA
UTC quote
The vibration in the hand grips above 65 mph has nothing to do with the wobble which is evident only while decelerating at about 20 mph and causes the handlebars to shake from side to side if one releases one's
grip on the handlebars. Vibration is usually a sign of tires that are out of balance, or possibly the tread pattern could be the culprit.

Bob
OP
@little_jon avatar
UTC

Enthusiast
2006 GTS250ie, 2015 KTM 390 Duke, 2000 Aprilia RS50 Race Replica, Whizzer Bike
Joined: UTC
Posts: 81
Location: Payson, AZ.
 
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@little_jon avatar
2006 GTS250ie, 2015 KTM 390 Duke, 2000 Aprilia RS50 Race Replica, Whizzer Bike
Joined: UTC
Posts: 81
Location: Payson, AZ.
UTC quote
Burgerbob wrote:
The vibration in the hand grips above 65 mph has nothing to do with the wobble which is evident only while decelerating at about 20 mph and causes the handlebars to shake from side to side if one releases one's
grip on the handlebars. Vibration is usually a sign of tires that are out of balance, or possibly the tread pattern could be the culprit.

Bob
Thanks Bob. I'm very familiar with a high speed wobble on a m/c. Just wasn't sure what folks were referring to on the scooter. Now I understand it's primarily on accel or decel at lower speeds. Guess I can count myself fortunate that my GTS hasn't shown those tendencies. I agree with your analysis on the balance or tread possibilities.
@dooglas avatar
UTC

Veni, Vidi, Posti
GTS 300ABS, Buddy 125, Buddy Kick 125
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Posts: 13319
Location: Oregon City, OR
 
Veni, Vidi, Posti
@dooglas avatar
GTS 300ABS, Buddy 125, Buddy Kick 125
Joined: UTC
Posts: 13319
Location: Oregon City, OR
UTC quote
Burgerbob wrote:
The vibration in the hand grips above 65 mph has nothing to do with the wobble which is evident only while decelerating at about 20 mph and causes the handlebars to shake from side to side if one releases one's grip on the handlebars.
Exactly right from my experience . The "wobble" on the GTS expresses itself on deceleration from about 30-20 mph. Let go of the handlebars or hold them very lightly during deceleration to see if it occurs.
⚠️ Last edited by Dooglas on UTC; edited 1 time
@breaknwind avatar
UTC

Ossessionato
Red Devil SH150i (10,000)
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Posts: 3228
Location: Orange Park Florida
 
Ossessionato
@breaknwind avatar
Red Devil SH150i (10,000)
Joined: UTC
Posts: 3228
Location: Orange Park Florida
UTC quote
Burgerbob wrote:
or possibly the tread pattern could be the culprit.

Bob
My SH had stock Dunlops. Before I replaced the front, there was a light wobble at WOT. Michelin didn't offer City Grips in the size for the front wheel in the U.S. at that time. So I put a Metzler Feel Free on and balanced it. At WOT it had a wobble 3x as bad as my worn out Dunlop. I rebalanced it and no change. I tried different shock adjustment and different air pressures but no luck. I had to lean back as far as I could to lessen the wobble(the opposite of tank slapper).
About 6 months ago City Grips were released for sale in the U.S. Even though I had half life left on the Feel Free, I replaced it. The new City Grip is smooth as glass at WOT. I'm no expert, but this leads me to believe that type of tire has a lot to do with the handling of the bike. Both the Dunlop and the Feel Free had a groove at the center of the tire, the City Grip doesn't.
The Dunlop had a strait groove in it. Notice the curved groove in the Feel Free.
The Dunlop had a strait groove in it. Notice the curved groove in the Feel Free.
⚠️ Last edited by breaknwind on UTC; edited 2 times
@gtdespatchcourier avatar
UTC

Molto Verboso
Xevo 250 ie
Joined: UTC
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Location: Sunshine Coast, Australia
 
Molto Verboso
@gtdespatchcourier avatar
Xevo 250 ie
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Location: Sunshine Coast, Australia
UTC quote
Check the front tyre pressure. They often over inflate the front tyre when fitting. Should be 26 psi on the front. You can also check the position of the wheel weight, has it been moved? If not then they didn't balance your tyres at all. It also helps to have a front tyre with a centre line tread.
@wleuthold avatar
UTC

Veni, Vidi, Posti
2006 Vespa GT (Rocket): 2005 Vespa GT (Razzo): 2007 Vespa GT (Vanessa): 2009 Yamaha Zuma 125: 2018 Yamaha Xmax (Big Ugly), 2023 Vespa GTS300 (Ghost)
Joined: UTC
Posts: 5182
Location: Jacksonville, Florida
 
Veni, Vidi, Posti
@wleuthold avatar
2006 Vespa GT (Rocket): 2005 Vespa GT (Razzo): 2007 Vespa GT (Vanessa): 2009 Yamaha Zuma 125: 2018 Yamaha Xmax (Big Ugly), 2023 Vespa GTS300 (Ghost)
Joined: UTC
Posts: 5182
Location: Jacksonville, Florida
UTC quote
After three other GT's, that have has very minor wobbles, my new 2005 has a big wobble at all speeds from 20 to 40. It has a top box and bar end weights. It did it with the old tire (Pirelli GTS) and a 5000 mile City Grip off Rocket. I will try it with a new tire this weekend. I have varied pressures with no change. I have had the top box full and empty with no real change. It is the only thing about this scooter that I don't like. Not sure what to do next.

I know. Buy a new 300 GTS?
@rkcoker avatar
UTC

Addicted
Piaggio BV350
Joined: UTC
Posts: 950
Location: Mesquite, TX
 
Addicted
@rkcoker avatar
Piaggio BV350
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Posts: 950
Location: Mesquite, TX
UTC quote
little jon wrote:
Big_Boys_Mother wrote:
Does the scoot have a top box? If so, does it have the handle bar weights installed? If that is not the situation, check this thread at MV ... The Wobble for additional advice. For me ... the wobble was eliminated after the bar weights were installed.
Thanks for heads-up on that thread BBM. It explains a lot. No top box, by the way. My issue is obviously a balance problem or perhaps the tires themselves. Believe I'll take your advice and pick up a pair of heavier bar weights. Sure couldn't hurt.
Another possible cause is the new tire tread pattern reacts differently to the road surface. At least it happens at a highway speed and not all the time.
@jimc avatar
UTC

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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Posts: 43356
Location: Pleasant Hill, CA
 
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@jimc avatar
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: UTC
Posts: 43356
Location: Pleasant Hill, CA
UTC quote
My GTS gradually developed a *horrible* wobble. The front Power Pures had done over 17,000 miles and had worn into a definite 'V' shape. Slower tight twisties were becoming bloody dangerous, the bars would shudder rapidly from side to side.

Installed a new City Grip on the front yesterday - and the wobble has almost completely disappeared. I can just induce if I try by releasing the throttle and the bars at about 20mph, but it's hardly discernible.

So tyre profile (especially with badly worn tyres) can definitely affect the lower speed wobble that we normally talk about on MV.

However, any vibration above 60 mph is almost always down to non-optimal balancing - the rear is as important as the front. I've never had an issue with the balancing done by my dealers, but if I was in any doubt I'd be buying a Marc Parnes balancer or equivalent, and checking it myself.

Weaving a bit side-to-side at speed, especially on fast gentle curves, can often be the swing-arm bearings. They come with minimal grease from the factory and will inevitably disintegrate in time. A set of new needle roller bearings and filling the whole swing-arm tubes with grease eliminates it for the life of the bike. Another possible cause is if the steering bearing develop a notch, but that's unusual on the Vespas - though a regular maintenance item on the larger heavier scoots with tapered steering bearings. This is normally noticed as a fault far earlier in those locales where lane-splitting or filtering is the norm, as a notchy steering bearing makes slow straight travel tricky.
@salima_draghetta avatar
UTC

Molto Verboso
GTS 250
Joined: UTC
Posts: 1518
Location: Utah, USA
 
Molto Verboso
@salima_draghetta avatar
GTS 250
Joined: UTC
Posts: 1518
Location: Utah, USA
UTC quote
GTS 250ie 2007 here.

When I bought it, it had the two new stock Savas, and I never had any wobble problem. Fast forward until the stock Savas needed to be replaced due to expected wear and tear, and sure enough the wobble started. Over the years, I have tired more tire combinations than I care to remember ... most made the wobble worse, others made it somewhat more tolerable.

About 2 years ago, I finally landed on the combo that works for me: Pirelli GTS23 on the front wheel, and Michelin City Grip on the rear wheel. I inflate the Michelin to manufacture's specs. The front Pirelli gets 2 psi more than specs.

So, that's how I found my peace ... not experiencing the wobble anymore. But boy, do I miss those Savas ...

Salima
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