Tyre size dilemma: Bigger = more stability?

[mouldy]

Try driving an empty long wheelbase hi roof Hiace van over the bridge on a windy day , it moves around a lot more then my 'blabe but the blade moves more then the missus's MR2

[BMWST?]

in my experience my k100rs was only a liitle worse in cross winds than my previuos(same generation) nakeds,but was 1000 times nicer in any other wind condition for a long trip

[Ixion]

von Klunken is a KRT BMW. Barndoor fairing as big as they come. Rock solid steady in any wind, nothing moves it. Best bike I've ever had for wind.

So it's not *just* fairing = bad for wind.

[metalslug]

I can sort the sidewind-fairing-weight-tyrewidth thing easy, the WORST bike I've ever ridden in a sidewind was My ZX12, with it's large aerodynamic fairing, 210kg dry (rider around 100kg then...) and a 200 rear tyre. Almost dangerous in any sidewind with any force. I'd rather ride a KR150 in fact...

Just wondering how would that be the case? Wouldn't the extra weight ~310kg help to plant the bike in ?? going to upgrade to a zx6r soon so hopefully it won't fair too bad in the wind... I have got to cross the harbour bridge everyday

[fizzafulla]

I find narrower tyre = quicker turning and generally more fun.

[Pixie]

Belgian motorways were much the same too. Kinda weird crusing along a motorway at about 130 with your bike constantly 'listing' at about 20 degrees. Was OK as long as no sudden gusts happened.

Do they still have ditches on both sides of the roads,so their knuckles don't drag on the ground?
(old Dutch joke)

[vifferman]

Be interesting to see if others have similar experience and on which bikes

In the time I've lived in D'Auckland, I've ridden four (4) different bikes across the Harbour Bridge (5, if you count the Volty-horse loaner), in windy conditions. The bike and fairing make a big difference to the handling, and even things like the shape of the front mudguard has a bearing. The bikes were:
1985 VF500 - has a bikini fairing
1990 VFR750 - fully faired
1998 VTR1000 - bikini fairing again
2001 VFR800 - fully faired.

Of these, the VTR was probably the least susceptible to side gusts and the like. The fairing was narrow and provided less wind protection, but also had a smaller side profile. The front guard was also fairly minimalistic. The VF500 was similar, but lighter weight, and also had a more upright riding position, so the rider caught the wind more. The worst is the VFR800 - while it has a similar fairing to the VFR750, there is some weird shit happening with the front end - I think it's a combination of aerodynamics between the fairing and mudguard, and all the extra DCBS stuff on the front left fork catching the wind. Riding north over the bridge in a south-easterly gale, the bike ends up weaving each time it goes past another section of bridge railing. Disconcerting, but not dangerous. Balancing that, the fairing is easy to get down behind, which aids the aerodynamics and minimalises drag on the rider, which is a significant part of the bike moving around in the wind, particularly if the rider tenses up and fights every little movement the wind produces.

I strongly suspect nearly all tales of riders being "blown across the road" are due mainly to the rider trying to counteract the wind gusts, rather than letting the bike move around a bit. If you're counter-steering against a wind gust, when it drops off, you'll end up steering the bike, so the nett result is the bike's weaving a lot more than it should. If you relax, and look where you want to go, and don't panic if the bike leans under you, the bike may lean a bit, but will maintain a course basically where it should be going.

The fairing does have a marked effect on wind resistance, which is why Casey Stoner first had holes cut in the Ducati's fairing for tracks with strong cross winds, then more recently, they completely redesigned the fairing to improve this

[Pixie]

von Klunken is a KRT BMW. Barndoor fairing as big as they come. Rock solid steady in any wind, nothing moves it. Best bike I've ever had for wind.

So it's not *just* fairing = bad for wind.

Wheelbase,COG and steering geometry are the major factors in sidewind stability

[TygerTung]

I would probably recommend a 250 4 stroke of some description for long distance touring like that.