Panniers and high speed weave

[BruKen]

Last year I took YAPI on a 3k mile trip all kitted out which included everything AND the kitchen sink. Yes she was a tad heavy. The panniers for those of you that recall stuck out quite wide.

Anyway she suffered a bit of a wobble on flat straights at 75mph +

I say a bit, but it was terrifying :roll:

My question is, which is the main culprit ... altered geometry or wind turbulence?

If its geometry I can lower the forks in the triple tree, up the preload and stiffen rebound and damping.

If it's turbulence I have to rebuild the whole pannier system from scratch (ouch! its a lot of work)

Just planning ahead for this summers european trip to Spain and Southern France.

oh BTW any intrepid travellers who are laid back and want to join for a 2 week sojourne in Sept. let me know.

[Mustang]

yes on both counts

A steamer with luggage will be very light on the front wheel creating the weave at 80 mph and yes the luggage will cause the weave also because of the air flow ......double edge sword at play here .

you haven't lived until you get the 100 mph high speed wobble on the interstate in amongst the 18 wheel trucks .

Being in the truck turbulence will make a steamer with luggage really squiggly.

[JetdocX]

How old is the rearshock?  Did you rebuild it?  I can't remember.  Definitely more preload to weight the front more.  Did it go away when you were braking?

Edit:  Toss the panniers and strap a duffel to the rear rack, and a tank bag.  That will eliminate the turbulence problem.

Oh, and where might a guy be able to rent a bike for a few weeks during that time?????? :D

[BruKen]

Thanks for giving me some hope then Mustang  

How old is the rearshock?  Did you rebuild it?  I can't remember.  Definitely more preload to weight the front more.  Did it go away when you were braking?

Edit:  Toss the panniers and strap a duffel to the rear rack, and a tank bag.  That will eliminate the turbulence problem.

Oh, and where might a guy be able to rent a bike for a few weeks during that time?????? :D

Yes I rebuilt the shock, it is now in good condition and is perfect for 1 up conventional riding. It's a Showa and typically has a strong spring soft damping characteristics which isnt brilliant with load.

As for renting a bike, plenty of places will rent out a bike at remarkably cheap prices when all is concidered. You are looking at 250 -350 GBP per week.

[D-Fuzz]

Good topic.  I have been wishing I had panniers for my bike, but maybe I will be best served with the softbags I currently have.  Have you ever ridden with a passenger to see if just the extra weight alone causes the wobble?

[BruKen]

The only people I know who will ride pillion with me are daughter or missus and I wont deliberately chance them, so no.

In so saying, I do believe the culprit isnt weight, but exacerbated by weight. I am leaning towards turbulence starting (for want of a beter word) a sympathetic resonance. And the reason I say this is unlike a tank slapper speed wobble which feels as if it starts in the front, this seems to feel as if it starts at the rear. (big oscillations to begin with tightenning up until its a handlebar shake).

I'm hoping I'm wrong though.

[Mustang]

Good topic.  I have been wishing I had panniers for my bike, but maybe I will be best served with the softbags I currently have.  Have you ever ridden with a passenger to see if just the extra weight alone causes the wobble?

It's the bags.......... at speed they don't like it .......when you find the dead air spot behind a semi truck she is rock solid

[BruKen]

Well there goes hope. Building those panniers was such a heartache that without a promise of success I am loathe to make another set. Who'd have thought welding a box would be so much work.

[Mustang]

New tires with a nice round profile will compound the problem ..........as the rear tire wears down flat the weave is not so bad . At least thats how it works for me , and BTW the Givi's are probably the best the metal boxes tend to weave more in my experience

[BruKen]

The tyres were new. But always will be for a long trip. I'll give soft luggage a go over a few long weekend aways and see. I dislike motorways and avoid them if not breaking the back of a journey. As the euro motorways are 80 mph i would like to be able to do that comfortably. Ie push any weave to 90 plus if I can't get rid of it.