Tyre size dilemma: Bigger = more stability?

[metalslug]

Hi all, quick Q about tyre sizes:

Will fatter tyre improve the overall stability of the bike? more specifically, will it make it handle better in sidewind / gravel road / open road...etc. Reason I am asking is because I have been riding a Kawa 2 stroke Kr150, with blade thin tyres (rear is 110/70)- this wasn't such an issue in the past few months since I mainly ride within the city.

But now my new job requires me to travel down from Auckland to New Plymouth on regular basis, and I don't feel confident on that 150 at all. I have taken it on the bridge before and felt like I could have been blown off any minute. (I am 70 kg btw)

Sort of looking for a hornet / VTR now since they have got the 180 rear. Any comments?

[AllanB]

Save your pennies for a larger bike - a bigger rear tyre on the 150 will add, oooh a matter of grams to the bikes weight - it's this light weight that is causing it to be blown around by the wind, plus the overall short wheelbase etc. It's a small bike thing.

Or drink loads more beer and put on a 30kg gutt:apint:

[MaxCannon]

Your job requires you to RIDE from Auckland to New Plymouth !

Two things come to mind

- How much does it pay ?

- Surely it's more cost effective to fly that distance. Anything more than 3 hours out of Auckland and the plane has to win for cost vs time.

I'd think the tyres would matter very little. The bike wasn't made for long distance touring. It's light weight and short wheelbase.
Using a non standard tyre will probably introduce as many problems as it solves.

There is nothing to stop you using the 150 for long distance riding but there are certainly better bikes for the job.

[MSTRS]

Wider tyre does not equal more stability. It doesn't even necessarily offer more grip either. The important thing is that the tyre you have is the correct one for the rim it's fitted to.

[cheshirecat]

I'm not convinced tyre size is that much of a factor in the situation you describe. More likely it's the lighter weight of the bike.
I'm not familiar to contemporary bikes, (mine is a 94) but there was a huge difference from my VF500 to my VFR750 in wind. The 500 was thrown around (but felt safe and fun once one relaxes) whilst in the same conditions of 40 to 50 knot southerly winds I hardly notice them on the heavier VFR providing it's kept moving. Likewise my earlier bikes, CBX1000 and CB750 felt relatively stable in 50 to 70 knot cross winds over bridges and motorways. Well OK the CBX was a bit twitchy but I'm still here to tell the tail. I once had to spend a day on my 500 in winds topping 90 knots - it had a 16 inch front wheel which helped big time.
Thin tyres make the bike drop into lean's faster and provide a quicker response or correcting response, it's a trade off. The larger bikes have a lot more stability. Have a chat to a couple of dealers, but I'd go for the bigger bike, those Kawka 150's look mighty light.

[jtzzr]

Some good points made .

Aucks-New Plymouth on a kr150, it would be cheaper to live down there or climb the corporate ladder and get a company bike.

Don`t fuck around with the tyres , you would just be throwing your money away, but you do get a good 6 hours on your bike.

All the best

[98tls]

Wider tyre does not equal more stability. It doesn't even necessarily offer more grip either. The important thing is that the tyre you have is the correct one for the rim it's fitted to. Says it all really,might add that even on larger rims/bikes wider doesnt mean better for sure ie 180 v190 re turn in,then theres profile blah blah blah

[metalslug]

Thanks for the info people. Btw I am working at NP 3 weeks @ a time and back in Auckland for a week. It's 2 different jobs actually, so travel expense is on me :crybaby: Atm I am spending about $130 in cage (return)...which is double compared to the bike.

Weight is probably an issue as mentioned, since the bike is only around 120-130kg. Maybe if I pull the fairings off it will be better for the wind...

guess I will just have to look into heavier options...ahhhh

[Ixion]

This illiusion has been addressed many times. It's not a car. Big fat tyres will make handling worse not better. Especially on gravel roads. Altering the tyres will simply make a bike that handles very well handle very badly

And no tyres will alter the way the bike responds to wind. I suspect you have not been riding long. All newbies experience the "eek wind I'm going to be blown off". I have only ever heard of one rider actually being blown off, and he was a feather weight chick.

However , that said , and much as I love two smokers, a KR150 is probably not a good choice for such a regular long distance commute.

[sil3nt]

Fairings would weigh bugger all and should actually cut down on drag. Try buying a 250 :bleh:

[Laxi]

Maybe if I pull the fairings off it will be better for the wind...

have you thought of adding a sail as well? will help fuel economy too

[CookMySock]

Stop overthinking it, and just jump on your KR and go for it. You will have fun for sure. Just don't fall off hours from home - its a big job putting all the little bits on a trailer.

Have a good time.
Steve

[MSTRS]

Fairings would weigh bugger all and should actually cut down on drag.

That they do...but naked bikes generally handle side-wind better, due to the lack of sail effect

[Patch]

.but naked bikes generally handle side-wind better, due to the lack of sail effect
wot a load of old bollocks.


Eat more pies and harden-up. Learn to ride in the conditions. A bike is just a bike, it's what's between your ears that matters the most and your ability to use it.

[MSTRS]

I stand by what I said. A crosswind has more effect on a faired bike, and the fuller the fairing the greater the effect. Cut a load of holes in a yacht's sail and see how well it 'goes'...

[gammaguy]

I have only ever heard of one rider actually being blown off, and he was a feather weight chick.




fuck,that must of been a hell of a wind gust-gave him a sex change at the same time:shutup:

[pritch]

Wider tyre does not equal more stability. It doesn't even necessarily offer more grip either. The important thing is that the tyre you have is the correct one for the rim it's fitted to.

Wot he said!

[pritch]

wot a load of old bollocks.


Eat more pies and harden-up. Learn to ride in the conditions. A bike is just a bike, it's what's between your ears that matters the most and your ability to use it.

Have you actually ridden in the wind much? Your post suggests otherwise.

Over the years I've been caught out in some gale force winds and I'd far rather be on an unfaired bike in those conditions than my old BMW K100RS or the VFR.

Given my choice of weapon for wind, I'd choose a Harley.
Unfortunately there isn't one in the garage.

[xwhatsit]

I stand by what I said. A crosswind has more effect on a faired bike, and the fuller the fairing the greater the effect. Cut a load of holes in a yacht's sail and see how well it 'goes'...
Damn straight. I ride a similar size and weight bike to a KR150 and don't weigh much myself, but I'm quite happy in the wind probably due to it being nekkid.

There's nothing wrong with doing Auckland-New Plymouth regularly on a KR150. You'll get a sore arse from the piddly seat and sore wrists due to it having a windscreen, but there's no reason why it can't do it -- bar the small-capacity two stroke that's supposedly not going to want constant throttle/RPM. A heavier bike might be more `stable' but big whoop.

[cheshirecat]

I stand by what I said. A crosswind has more effect on a faired bike, and the fuller the fairing the greater the effect. Cut a load of holes in a yacht's sail and see how well it 'goes'....

For interest when I added full fairings to my previous bikes (albiet 80's models) they became more affected by crosswinds but strangely my VFR seems impervious to them (unless the dog house is on the back). It might be the vents under the screen or moon crossing uranus. 'Pritch' above as had a different experience on his VFR so there is goes!

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

[Cheshire Cat]

I dont know the exact size of my tires but they're probably the same size as yours. I've been to taupo and back twice no probs!!

I say it's not the bike its the rider. You should be fine!:niceone:

[sil3nt]

Two cheshire cats? Which one is the evil one?

[Cheshire Cat]

Two cheshire cats? Which one is the evil one?

Oh you got me!:devil2:

[martybabe]

Wider tyre does not equal more stability. It doesn't even necessarily offer more grip either. The important thing is that the tyre you have is the correct one for the rim it's fitted to.

Yes!


That they do...but naked bikes generally handle side-wind better, due to the lack of sail effect

OH Yes!




I'd choose a Harley.
.

Who are you and what have you done with my mate Pritch. :laugh:

[MDR2]

I feel im pretty well qualified to comment for once!

I had a Rg150 with similar sized tires to the KR

I am now on a hornet with a fatter front then the rear of the either the KR or the RG's rear! fatter tires, as already established, won't provide any extra stabilty. In fact I felt more at home on teh thinner wheels and had more confidence when it came to tipping the bike over.

Fairing... makes a huge differince when your talking 100kph speeds 6+ hours without a fairing would be quite tiring i imagine. I miss having a fairing to tuck in behind. Need to splash out on a givi screen or something to take some pressure of the chest.

[metalslug]

heres an update:

2 weeks ago I traded in the Kr150 and got the Hornet 250 instead. Have to say I am very very satidfied. Rode across the harbour bridge in a windy day and don't really feel it at all. For some reason I feel more confident cornering as well, probably cuz the kr was a bit too flimsy and you have the feeling that it can drop anytime. . .

[DEATH_INC.]

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...

[scracha]

wot a load of old bollocks.


Someone is tlaking bollocks but it aint him. We had to abandon a bellypan in holland once and pick it up on the way home. Serious bloody north sea winds hit that flat reclaimed land. Bike needed two whole lanes to itself with the bellypan on.

[slydesigns]

Someone is tlaking bollocks but it aint him. We had to abandon a bellypan in holland once and pick it up on the way home. Serious bloody north sea winds hit that flat reclaimed land. Bike needed two whole lanes to itself with the bellypan on.

Do much sailing or windsurfing? lol!!

[scracha]

Do much sailing or windsurfing? lol!!
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.

[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 :wacko:

[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.