Front wheel wobble

BroOKS2K9(Snip)
Can someone explain why I suddenly have a front wheel wobble? If I let go of the handlebars, anything below 40mph produces serious wobbles.  Any ideas
(Snip)


The wobble is more than likely due to the front tire cupping. A new and newly balanced tire shouldn’t wobble. That said, one of the “charms” of the Silverwing is that is does kinda wobble when the speed drops down to ~35 mph or so. It becomes more pronounced as the tire wears.

However by “balancing” the previously worn tire you’ve effectively altered the steering geometry. It wasn’t broke ‘till you “fixed” it.

You could also tighten up the steering stem nut and lock nut to put a wee bit more tension on the steering stem bearings.

Regarding the fork spring orientation, why would you 2nd guess the FSM?

C_J,

Does that mean if I do nothing but ride the scoot, everything will work itself out? Or does it behoove me to remove the weights? I can't say I notice any cupping when looking at the tire. That stated, the service tech did state there was "lots of tire left."

Yes, I'm quite aware of the wobble south of 35mph. I remember reading on this forum about someone having "no wobbles" and totally smooth to a full stop. I've always wondered how that could be.

As to "2nd guessing the FSM", I'm not. My concern was more towards the drawings and pictures not seeming to match up. If "face up" meant towards the top of the fork, then that is inconsistent with (nearly) everything I'd seen.

If it only does it when you have let go of the bars you most likely have hit on the cause and solution! Bear in mind that wobble and weave is inherit in two wheel vehicles, see https://www.cycleworld.com/why-do-motorcycles-wobble-and-weave/
Although this will be exacerbated by anything that is worn, loose etc.
Do check the front tyre, it might have lots of legal tread left but if it flattened on one shoulder it makes the handling wander about - rear tyres wear in the middle, front tyres on the shoulder.

Why do you let go of the handlebars in the first place? I can honestly say I've never ridden a moving motorcycle or maxi scooter and been daft enough or had any inclination to let go of the handlebars.

I'll take my left hand off to adjust my helmet visor, sun visor, and open and close vents, occasionally wipe rain off my visor, scratch my nose etc, and that's it.

And to think bikes used to come with steering dampers!

Meldrew wrote:

... snipped ... Why do you let go of the handlebars in the first place?

Meldrew poses an excellent question. There are many references in motorcycle rider training manuals and information books (i.e. MSF Manual, David Hough's Proficient Motorcycling etc.) that state a rider should not take both hands off of the handlebars at any time when riding. Same is true about gripping too tightly. Both actions affect the physics of how the machine responds to steering inputs.

For the record, I do not get any wobbles or vibrations at slower speeds. The only time I did was when my front tire displayed cupping which I attributed to not having the correct tire pressure in it on a consistent basis.

You might want to return your SWing to the shop that did the front end work and explain that previously, it rode smoothly and now it doesn't. Let them take it out for a spin and experience it for themselves. Obviously something changed during servicing.

Letting go of the handlebars is something I did, not something I do. It was simply a surprise to notice that much wobble. Although it may not have come across, I really wanted to know if anyone else had experienced it...in light of a recent repair.

The OP mentions my doing the front end work, not "the shop." Per everything on the list, save the wheel alignment, I find no reason for there to be a less stable ride.

As to the best part in all this...I now have knowledge I didn't have prior. I didn't even think to check the age of my tires. I now know the "birth date" of my tires and that they're 5 years old. I'm getting new tires so I'm too concerned about the other stuff now. Thanks all.

Any recommendations on what tires to get? For what's it worth, I'm in Tulsa, OK. With 40-50 degree temperature swings not uncommon, rain one minute and sunlight 15 minutes later, roads are less than stellar. Some potholes and rolling hills--all within the same mile.

Tires----Michelin Power Pure SC work well on SilverWing...and they wear round! I rode them in OK.

Wobble---first your need to look at what is added to your scooter---top box? other junk, history of bike, your weight. Scooters are not designed to be ridden hands off

I had a go at this riding with both hands off the handlebars nonsense for the first time ever today on a very enjoyable ride in rural North Yorkshire. I tried it at various speeds and ...absolutely nothing. No drama, no shakes, zilch.  As expected the throttle closes and slows the scooter down at around 50 mph, so going through this one off circus act was a complete and utter waste of time as I knew it would be.

BroOKS2K9, I just remembered, steering wobble can also occur with a loose or bad steering head bearing. That's when you really notice the wobble in "hands off" or even light touch mode ... particularly at slow speeds. Sometimes you can simply tighten the nut and life is good again. Sometimes you need to replace the bearing itself.

Meldrew wrote:

I had a go at this riding with both hands off the handlebars nonsense for the first time ever today on a very enjoyable ride in rural North Yorkshire. I tried it at various speeds and ...absolutely nothing. No drama, no shakes, zilch.  As expected the throttle closes and slows the scooter down at around 50 mph, so going through this one off circus act was a complete and utter waste of time as I knew it would be.

Different bike. Mine does this all the time new, old tire did it from new. Nature of the bike I'd say. Not a tire balance problem if it was would be more felt at higher speeds.

Mech 1 twa wrote:

Different bike.      Mine does this all the time new, old tire did it from new. Nature of the bike I'd say.  Not a tire balance problem if it was would be more felt at higher speeds.

True, but my Silver Wing and all previous maxi scooters never had any problems either.


With my Forza I realised within a few rides that the Pirelli Diablo tyres outperform OE Bridgestone Hoops or the Continental ContiMove 365 tyres I later used on the Silver Wing in every respect.

Both of the Forza's alloy wheels are balanced, hold the correct tyre pressure for far longer than the Silver Wing's ever did, and checking and inflating tyres no longer requires crawling around on the garage floor. There's puncture sealant in both wheels for good measure too.

So the pointless experience of riding with no hands on the bars is now going into Room 101.

sonuvabug wrote:

BroOKS2K9, I just remembered, steering wobble can also occur with a loose or bad steering head bearing.  That's when you really notice the wobble in "hands off" or even light touch mode ... particularly at slow speeds.  Sometimes you can simply tighten the nut and life is good again.  Sometimes you need to replace the bearing itself.

After a half day's worth of searching, I came across a 2013 post "Subject: Unpleasant Vibrations, Sat May 04, 2013 8:53 am."  I think I'm going to have a go at this; see if it changes anything.

If anyone read/remembers the discussion AND/OR has tried it, please respond.  I'd be most interested in knowing if this can simply by removing only the right 
glove box.


Admin Edit: https://www.silverwing600.com/t6177-unpleasant-vibrations

My last front tyre failed the MOT because of some cupping. To me the tyre looked fine but when it was pointed out to me, I could see this slight wear causing a cupping effect. Weird thing is, I hadn't noticed any wobble in the front end...hey..ho.

I've kept the old tyre as a 'get out of jail free' card.

Strangely, I have front wheel wobble, but only when I decelerate.

This subject crops up regularly and there has never been a definite solution, if the tyres are in good condition properly balanced and all bearings are in good condition then in my opinion it must be the nature of the scooter. My S/Wing has always done this either with new or worn tyres, balanced or not but my Sym Maxsym 400i never did, so I think it's just the design. One definite way to stop it is to keep your mitts on the handlebars then you will never notice it. I tried this after reading about it not long after joining the forum and yes it wobbled then and still does in now so don't get hung up about it just keep your hands on the bars and forget about it.

My second hand Silverwing came with a severely worn front tire. The wobble was real! No yoke. New tire w. balancing and hey presto: wobble all but disappeared!

Davetech wrote:

Strangely, I have front wheel wobble, but only when I decelerate.

That's absolutely typical of front wheel wobble. Many bikes give a bit of it decelerating and if they shake the head all the time, it's worse decelerating.

Nature of it.

An update. Got a new tyre fitted - deceleration wobbled less. Bad wobble appeared with increasing speed. Noticed the tyre fitters had not balanced the wheel. Went back rather peeved and got it balanced. Wobble at speed gone and deceleration wobble almost gone too.

Poor wheel balance will certainly do it.
I generally fit my own tires and rarely need to balance them afterwards. Just keep your eyes open and make sure the tire is bang on centered on the bead. Letting the air out of the tire after seating the bead and then pumping it up again is useful. It's better to get that right than add balance weights.

An update. Just had my forks serviced after one of the legs started leaking. No Idea when the last time was this was done as I bought the bike off of someone about a year and a half ago. Not only does the front end now feel much better, also the infamous front end deceleration wobble is all but gone. Goes to show that service intervals are there for a reason.