Growing up, I remember looking wistfully at motorcycles and their chrome spoked wheels flashing in the sunlight and I also remember thinking that there couldn’t be a better sight than this ever. Foolish of me, I think because when I saw a poster of a superbike for the first time in my life, my attention was drawn to those wonderful looking wheels that really added to the oomph factor of the bike. Only later did I realize that I was staring at alloy wheels which unfortunately were not available on any vehicle in India save for a select few, namely the Enfield Fury and Explorer models but they were short lived and died an untimely death. My first bike was the erstwhile Hero Honda CBZ and that too came with spoked rims instead of alloys. However by then, I remember there were quite a few CBZ owners who switched over to aftermarket alloy rims. Much as I wanted to switch too, I did not since I had seen quite a few bikes at the service centre with cracked or shattered alloy rims. This prompted me into doing some research on alloy wheels and their benefits and this is what I would like to share with you:
Alloy wheels tend to be lighter than their spoked counterparts. This results in lesser unsprung weight on the motorcycle. Whoah!! ‘What’s unsprung weight?’ is the question that pops in mind. Well, simply speaking, it’s the weight put on the suspension that moves up and down as the motorcycle rides over uneven roads and leans in the corners. The heavier the wheel, the less effective the suspension will be in terms of coping with road surfaces. Lighter wheels like alloy wheels tend to reduce unsprung weight and help the suspension perform better.
Alloy wheels tend to put lesser load on the engine since lesser energy is required to make the wheel roll. This results in better overall engine performance. Let me try to explain that with an example- try lifting a metal ball and move it up and down around 30 times and then see how your arm feels at the end of it. Now lift a plastic ball instead and move it in a similar fashion 30 times. How does your arm feel now? Probably not as fatigued as earlier. What’s more, because of the lighter weight you must have realized that you could move your arm much faster. And there we have it. Lesser weight not only decreases the amount of energy required to move that weight but also improves acceleration in the process. That is why bikes equipped with alloy wheels can accelerate better than those with spoked wheels.
Alloy wheels tend to help with better braking, cornering and straight line high speed stability. I have already mentioned earlier how reducing unsprung weight helps the suspension perform better. Now, the suspension and the way it performs is highly important when leaning into and exiting out of corners since it needs to be performing at optimum efficiency to ensure that any surface ripples are smoothly soaked up and vibrations are not transmitted to the body frame and the rider to ensure good corner exit speeds. They also help to keep the bike stable when leaned over into a corner and prevent you from getting wrapped around the next tree or pole that you encounter around the bend. From a braking perspective, for simple scientific reasons, a lighter weight is easier to decelerate from a high speed as compared to a heavier weight at the same speed due to the mass that the object tends to gather. This implies that you can brake better and come to a stop faster on a bike with alloy wheels as opposed to one equipped with spoked ones.
Modern alloy wheels tend to be more structurally rigid as compared to spoked wheels. While spoked wheels are better at dissipating surface shocks all across the surface while off-road, on the highways at high speed they tend to have some amount of inherent flex. This flex can be very disconcerting at high speeds and can even cause fork judders or inadvertent tank slappers. Alloy wheels, due to their higher rigidity levels tend to remain more rigid and reduce flex thus improving high speed stability.
Alloy wheels also tend to be better looking than spoked wheels and are much easier to clean compared to spoked wheels that can make cleaning look like a nightmare. Also considering the current crop of design trends in motorcycle design, alloys give a much more sportier look to a motorcycle. They also happen to be zero maintenance unlike spoked wheels that might call for spoke tightening over certain intervals.