Post by anon on Jan 31, 2007 20:56:31 GMT
From: pentagenerian Sent: 10/04/2004
I know this has been talked about before but it's bugging me. If I let go of the bars between 60 to 80 kph the bars shake pretty violently above and below that speed no shake at all. If I keep my hands on the bars I would never know there was a problem at all. I know, you should have hold of the bars anyway but the fact that the shake is there at all doesn't seem right. My Divvy has only done 3000 km so I can't see tyre wear, wheel bearings, steering head bearings as an issue. I don't know if it's been there from day one as I only just noticed it but I did have the panniers on at the time although they were virtually empty.
I have also just fitted slightly stiffer springs and changed the fork to 15 wt which has the front end feeling and handling a dream.
I would normally associate a wobble which only occurs at this speed range with a wheel balance problem. Is it a case of they all do it, keep your hands on the bars and enjoy the ride?
As I am a relative newcomer to the Divvy world I would greatly appreciate any advice you might care to share.
Thanks from beautiful Lithgow, Australia. Glenn
From: Ghotí Sent: 10/04/2004
Glen,
Panniers and or top boxes are normally to blame. Try it without any boxes on the back. I suspect (but I am no expert) that it is more to do with wind drag rather than weight in the panniers so it would not matter if they are empty or not. My 900 has the same problem with the top box on, be it empty or full, at 35-40mph (about 55-65kph I guess).
It could be tyres have worn, even after 3,000km, so they are not as perfectly balanced as when they were new.
Basically, they all seem to do that and if you do not notice anything with hands on the bars then I would not worry about it or ride above 80kph all the time.
Paul
From: pentagenerian Sent: 10/04/2004
Thanks Paul, forgot to say mine is a 900.
From: TarmacDale Sent: 12/04/2004
Glenn
What tyres are you running? Dunlop K505's caused this problem on my bike (as someone else on this site pointed out!).
Replaced the Dunlops with Bridgestones and the wobble disappeared.
HTH
Dale
From: Chicken Madras Sent: 12/04/2004
Allow me to use a Tommy Cooper joke as an analogy.
Patient: Doctor, it hurts when I do that [twists arm]
Doctor: When you do what?
Patient: Do that [twists arm]
Doctor: Well dont do it.
From: Anto-Divvy9 Sent: 12/04/2004
I know tyres / top boxes do affect this bar shake thing but mine has got progressively worse over the last year or so. It will now do it with any combination of tyre wear & luggage, it doesn't seem to matter ('97 900S - Givi Wingrack - 44k Miles).
With pressure on both bars she's fine, if you lift off one of the bars & coast it 'might' occur but seems to depend on the conditions at the time.
If you take pressure of one of the bars when the engine braking effect is quite high (i.e. weight transfer to the front of the bike) then it's horrendous at any speed above 20mph or so, into real tank slapper territory.
Bits I know are OK -
front & rear wheel bearings are in good condition
front & rear wheels appear in good condition - no obvious dents or buckles
swingarm bearings have just been replaced and are in good condition
front forks have been recently stripped, checked, and fork oil replaced (& one tube straightened slightly)
Bits I'm not sure about -
tyres are wearing down now - but I don't think this is a major contributor now
rear shock is getting a bit tired (44k miles I assume) but 'seems' OK
steering head bearings feel OK but haven't been checked yet
The next item on the list is the steering head bearings as I can't really see a soggy rear shock affecting it that much. FYI I've been trying all sorts of combinations of Front / Rear preload settings and nothing has helped so far.
Anyone else?
From: Citrüx Sent: 12/04/2004
I've read that "run out" on the back tyre can cause it. I noticed it on mine after I had a rear tyre renewed (even without a top box) but there is no noticeable run out. It seems to have diminished lately though. In the end I accepted it as a characteristic.
Paul
From: pentagenerian Sent: 13/04/2004
Thanks for the input. I am running Metzeller tyres (36/42 psi) but plan on going to Bridgestone 020's when they need replacing.
Without the panniers off the shake is greatly reduced. It strikes me as somewhat ironic that fitting panniers / top box to a bike which has great touring potential should cause any problem.
I take Chicken Madras point and agree that if you keep your hands on the bars and there is no shake then do you really have a problem. Probably not - but from my reading of others experience the shake seems to gradually reach the point that it becomes noticeable when riding with a normal grip on the bars and that to me is not particularly desirable.
Anyway I am looking forward to trying the Bridgestones as most people are full of praise for them.
Thanks again to all who have put forward their thoughts.