Tuesday, June 10, 2014

High and Low Profile Tyres for Two Wheelers

Tyres and Wheel Rims have always been a point of discussion when we look at any motorcycle. We often hear about low and high profile tyres many times when we speak to both car and bike enthusiasts. But we can get confused when we’re at the tire Shoppe looking for a good low profile tire that would suit our machine. I know even I used to get confused. Hence we would require a little attention to understand the word “LOW PROFILE”.
So, A tyre has got some dimensions for example height, width, thickness etc. In order to fit Low profiles tires on a bike, we must first understand the fact that tyres depend on wheel rims. I mean to say both the tire and the rims must be compatible with each other. Confusing?…Well yes it can be, but a tyre dealer would take advantage of your confusion and sell tires which he would claim to be low profile but in reality would be high profile ones.
In simple language, A low profile tyre means tyres which are short in height. We could find such tyres at most tyre shops but we could to forget to check whether our motorcycle has got suitable rims for low profile tyres or not. For example FZ, P200 has got rims which are suitable for low profile tyres. I have seen people running low profile tyres on an R15 rear wheel, It was amazing how they managed to fix it on the rear rim which was designed for use with high profile tyres. That very fact can be explained by understanding that a Tyre is made up of a flexible material which is mainly RUBBER. That means it can stretch or can be pressed. Lets check the figure or the drawing. The drawing which I am showing is just for understanding and reference purposes.
Fig no.1 Shows us rims from the R15 and FZ
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Fig no. 2 Explains the width and height of the tyre from the R15 and FZ.
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The R15 rim has got a smaller width than an FZ rim. Now consider fitting an FZ tyre on R15 rim. Think…
Check fig no.3 now consider fitting of a FZ tyre on R15 rim. What will happen? It will fit but lets see the height and width of a FZ tyre on R15 rim….Remember The FZ has got a low profile tyre.(I know R15 tyre will not fit on FZ rim…anyways) So as you can see the change. The Tyre can be fitted on R15 Rim but the design of the rim would make such a tire look like high profile ones. What you had on the FZ would change into High Profile. The tyre becomes high in height and low on width. So the meaning of a LOW PROFILE TYRE has been lost.
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This change in profile happened due to the RIM. When the rim is broader, you can go for low profile tyres which are suitable for the rim. But if the rim is small in width then the tyre should be in that ratio only. So a ratio between rim width and tyre height is one of the important criteria.
A change in tyre other than manufacturer’s recommendation would also bring with it various other changes such as ride height and performance. We also need to remember that as the ride height increases, the tendency for the pillion to be hurled forward increases when the front disc brakes are applied. Therefore we can’t ignore gravity, inertia and the load of the bike. The handling of the bike would also change according to the tire which in severe cases would result in accidents.
Aesthetics are not the only principles of a motorcycle, there are lots of other crucial factors to be aware of. Do not mess with the geometry of the bike without having done prior research on its outcomes. Small changes can often make huge differences. Always Ride Safely…And Enjoy Life.