Steering wobbles at 40-50km/h

8 posts / 0 new
Last post
AndY1
AndY1's picture
Offline
Last seen: 9 years 2 months ago
Joined: Tuesday, June 17, 2008 - 04:29
Points: 1071
Steering wobbles at 40-50km/h

At speeds of 40-50km/h, my steering wobbles quite a bit, if I don't hold it with both hands. It didn't used to. Does that mean, that the front wheel is in need of balancing?

Above 50km/h and below 40km/h, there's no wobble in the steering.

tom5007
Offline
Last seen: 8 years 2 months ago
Joined: Tuesday, July 29, 2008 - 08:56
Points: 147
Re: Steering wobbles at 40-50km/h

I have the same with my bike. I read in other forums that this seems to be the case with other motor bikes and scooters too. All seem to relate to the weight distribution. Doesnt solve the problem but at least provides some comfort knowing that there is no problem lurging around the corner.
Norman

Elektro
Elektro's picture
Offline
Last seen: 11 years 8 months ago
Joined: Monday, May 11, 2009 - 02:02
Points: 45
Re: Steering wobbles at 40-50km/h

I have exactly the same problem with my new Vectrix I purchased only a month ago. From my point of view it's not acceptable for a new vehicle. The dealer will setup the bike at the end of this mount. I’ll keep you informed about the result.
From other Italian Vectrix forum it was reported that the Steering wobbles has been resolved simply changing the tire with a Michelin.

AndY1
AndY1's picture
Offline
Last seen: 9 years 2 months ago
Joined: Tuesday, June 17, 2008 - 04:29
Points: 1071
Re: Steering wobbles at 40-50km/h

Do you know the specification, which Michelin tire was that?

Thanx!

Edit: I didn't have the problem at the beginning. It appeared about a month ago.
Edit2: This one? Pilot Sport SC Front 120/70 R14 TL 55H M/C
http://ssl.delti.com/cgi-bin/rshop.pl?details=Ordern&cart_id=69566981.144.4434&typ=R-118106&ranzahl=1&Breite=120&Herst=Michelin&...

siai47
Offline
Last seen: 12 years 10 months ago
Joined: Monday, July 21, 2008 - 19:27
Points: 91
Re: Steering wobbles at 40-50km/h

A lot of steering wobble has to do with how ridgid the front forks on the scooter are. For the weight and weight distribution of the Vectrix, I believe the diameter of the forks and the way they are mounted lead to flexing between the fork clamp and axle starting the wobble. Over time, this wobble starts to "cup" the front tire leading to an increase in wobble. Many motorcycles use large diameter forks and fork braces to reduce this problem. For example, the Yamaha Tmax scooter has a 43mm diameter fork and is a similar weight vehicle. The only easy solution is to run with a high tire pressure on a new front tire (inflation about 10% over the max). Once the cupping begins, there is no stopping it. Many motorcycles have this problem and increasing tire pressure is recommended on many forums. Unfortunately, the Vectrix tire is already overloaded so overinflate at your own risk. This problem has been brought up before on another thread and I was reminded that Ducati was involved in the design of the Vectrix and therefore there could be no issue with the fork design! I have run my Vectrix overinflated since new as I noticed the wobble on day one. It has not gotten any worse after many miles of operation.

Wotnopetrol
Offline
Last seen: 9 years 2 weeks ago
Joined: Friday, August 22, 2008 - 01:40
Points: 207
Re: Steering wobbles at 40-50km/h

It's probably worth checking the head bearings for any slack too.

Simon

Elektro
Elektro's picture
Offline
Last seen: 11 years 8 months ago
Joined: Monday, May 11, 2009 - 02:02
Points: 45
Re: Steering wobbles at 40-50km/h

the specification of the tire Michelin that solved the wobbles problem is Michelin 120/70-14 m/c 55s gold standard.

Magendanz
Magendanz's picture
Offline
Last seen: 1 month 1 week ago
Joined: Sunday, July 13, 2008 - 00:21
Points: 155
Re: Steering wobbles at 40-50km/h

I see this shimmy at the same speed, and I'm pretty confident now that it's a wheel balance issue. We seem to reach resonance at about 50kph, and you'll notice that the overall amplitude of the vibration waxes and wanes due to the slightly different wheel diameters.

Log in or register to post comments


Who's online

There are currently 0 users online.

Who's new

  • JoeBauers
  • lumpykeyword
  • Mrelectric
  • wanroy
  • copaji4473

Support V is for Voltage