[Terry Wellsworth]

Hi guys,

I have bought a new bike Karizma ZMR 250 cc two weeks ago. It is of red color, so what are the additional gears and additional body parts I have to attach so as to give it a extravagant look.

Any impressive ideas please!!!

Thanks in advance.
– Terry

[madjak30]

We don’t get that one here…that’s the Hero – Honda bike right? It looks like it has the same engine and trans as the CRF223 that we get here, except you get fuel injection…223cc and 5spd trans…or did it get the upgrade to the CBR250R engine…249cc and 6spd?

Is this similar to your bike?

Later.

[TrialsRider]

fender eliminators, aftermarket exhaust and aftermarket shocks are the popular upgrades, it looks hot now and the only way to make it look like a ‘bigger’ bike is to fit it with bigger rims and tires which is expensive. Just keep it clean and keep the suspension all working perfect, ride lots.

…I hope this was not just a spam post, why does it have a link to nexx helmets?:i which btw are terriffic helmets lol

[eon]

Hmm, I agree it looks suspicious so I have removed the link for the time being but have left the post. If Terry is a real person then I guess we will find out soon enough.

That CRF223 is a nice looking bike.

[bigguybbr]

Those sure are some skinny tires…

[Jeff in Kentucky]

Skinny tires equals less weight and more speed, if the engine power and weight are low enough to not break the tire traction in corners.

Here is a good article about 125cc 2-stroke MotoGP bikes, soon to be 450cc 4-strokes instead like a dirt bike race engine:

http://www.fasterandfaster.net/2007/06/ktm-vs-suzuki-125cc-gp-racer-vs-1000cc.html

[bigguybbr]

…But also less of a contact patch when at speed in inclement conditions, and while cornering. It would be my guess that this is designed to be something like an urban commuter bike, but with full plastics?

[eon]

Contrary to what seems obvious, the contact patch of your tires has no impact on the amount of grip you have. All that matters is the coefficient of friction between the two surfaces and the amount of weight (or pressure) pressing them together. If you halve the surface area you double the pressure and the amount of grip remains the same. However halving the surface area increases the amount of load the rubber has to endure and heat to dissipate, so I suspect that’s why powerful bikes have fat rear tires (leaving aside aesthetics in some cases).

http://en.allexperts.com/q/Physics-1358/2009/1/surface-area-effect-friction.htm

[bigguybbr]

This is a super hot forum debate topic for a lot of car and bike forums…

From what I subscribe to, the coefficient of friction doesn’t really apply to tires in any useful way as it is too simple, only modeling sliding friction and not rolling friction or the effect of deformation(such as while turning). Grip is a function of the mechanical (not just tread pattern, think tire pressure) and thermal properties of the tire along with the riding surface, the weight of the motorcycle, rider, and gear. While the size of the contact patch does not form a direct linear correlation with grip, a bigger contact patch influences the magnitude of the coefficient of friction due to temperature and abrasive effects.

So theoretically it is possible for the narrow tire to have equal grip, but practically, not so much.

Now the real question is, why do we call them tires while the rest of the world calls them tyres??? Where’s the theory on that one!?!?

[Author]

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