...and thoughts on selecting the right wheels

We know that with the range of products Dymag makes, it may seem a little difficult to know what's the best, or most correct, wheel for you. We've pulled together some pertinent data that can help with decision-making. At first glance, it seems to make the question even more confusing... but don't fear. There is a logic to it all, and we'll try to make some sense of it before we're finished!

The importance of weight reduction on a motorcycle, or any performance vehicle for that matter, is so significant, that it is difficult to give it adequate emphasis. The heavier the vehicle is, the slower it accelerates, the more energy it requires to accelerate it, the slower it stops, and the more energy it requires to stop it. Further, the heavier it is, the more momentum it carries, and the more difficult it is, therefore, to change its direction. Increased mass also increases tire loads, reducing the degree to which the tires can function. And perhaps most often misunderstood is the effect of mass, especially unsprung mass (mass that is not supported by the suspension, such as tires and wheels), upon the performance of the suspension.

Many experts contend that one pound of unsprung rotational mass has the net effect on the handling of the bike of approximately 8 pounds of sprung mass. Put differently, if you can reduce unsprung rotational mass by 1 pound, its will have a comparable effect on acceleration and deceleration as eliminating 8 lbs of weight elsewhere on the bike. If you've ever tried to accomplish this, you know how hard it can be!

But even more profound, and less easily quantified, is the effect of low mass on the function of the suspension. We will leave it at this. The less weight your suspension (especially forks) have to push around, the more efficiently, effectively, and immediately they can function. This translates to smoother and more predictable operation, as well as extending the limits of what the suspension can accomplish. That is, if a fork can push the front tire down, following a bump, a few milliseconds faster, the tire can be back in contact with the pavement that much sooner, and bike settled and prepared for the next input.

The benefits of light weight to suspension function, while of enormous consequence, are difficult to measure. So for the purposes of this discussion, we will only address acceleration and deceleration-related benefits.

The first thing that comes to one's attention in looking at new wheels is the cost. Clearly, one of the most important benefits of the wheels will be weight reduction. The cost of wheels is determined in part by the materials used, and in part by the fabrication method.

To the left is a general summary of the average cost per pound of wheels made by various methods and using various materials.

There are no surprises, in particular. Carbon fiber, the most sophisticated and state of the art material available, is also the most expensive per pound of finished product. Forged aluminum, which is more common on higher-end sportbikes, and has been for many years, is the least expensive per pound.

If cost per pound were the only consideration, we would all be using forged aluminum wheels...or would we? Well, probably not if those wheels ended up weighing ten times what other wheels weigh. In point of fact, they don't. They're definitely heavier than magnesium or carbon fiber, but not by so much that it becomes a total no-brainer. To really get a handle on the question of cost-benefit, its helpful first to compare these various wheels to something we know... like a typical stock sportbike wheel.

The plot thickens a bit. We start to see that the greater the cost per pound, as shown above, in general, the lower the total weight of the wheel.

While every wheel Dymag makes is lighter than the stock ZX10 wheel, which is not, by the way, a heavy wheel, the improvement (weight reduction) of the Dymag wheel compared to the stock wheel increases directly as cost per pound increases.

On the one hand, it's one of those "you get what you pay for" kind of things. On the other hand, not everyone has the same objective or requirements. It may be that, with one wheel or another, you are getting more than you need or want, or, of course, less than you need or want.

So let's take a look at what it all translates to in terms of acceleration and deceleration gains. For these calculations, we'll take the weight reductions derived from the chart above, and multiply them by 8, the theoretical factor for converting unsprung rotational mass to static, sprung mass. We will multiply the resulting number by a factor (.122) to convert the change in mass to effective change in horsepower. (Contact us if you want more detail on this!) And here's what we get:

Now, there are some surprises here! In fact, the cost per "effective" or "perceived" horsepower gained is lowest for the carbon fiber wheels, and highest for the forged aluminum! Again, the choices seem to have flip-flopped!

But really, it can all be pulled together in a few relatively coherent conclusions:

Conclusions:

Forged Aluminum

Lighter than stock wheels. Available in a wide range of colors. Relatively inexpensive and very durable. Ideal for racers needing multiple sets of wheels, for street where the ultimate in weight reduction is not critical, or on customization projects in which the look and finish color is paramount.

Cast Magnesium

Cast magnesium wheels are lighter than forged aluminum, and a bit more expensive. Like the aluminum wheels, they are available in a wide range of finishes, providing excellent potential for show or race color integration. They are the wheel of choice for street or race where budgets may be limited, but where performance gains matter.

Carbon + Magnesium

As a result of the use of carbon rims, these wheels are lighter than the cast mags, and one step more expensive. The provide a totally unique and striking appearance, due to the black carbon contrast with the colored spokes. The spokes are available in a wide range of finishes. We tend to think of these two-piece wheels as high-end street performance and customizing wheels, as there is a small enough difference in cost and weight that most racers will opt for the forged mags or carbon wheels. These are, however, the wheels of choice where a dramatic appearance is desired, along with high levels of performance.

Forged Magnesium

The forged mags are, along with the carbon wheels, in the category of "elite" performance products. Ultra light, available in many colors and finishes, and extremely durable, forged mags are also legal in most racing venues. As such, they are the wheel of choice of most professional racers.

Carbon Fiber

Dymag Carbon Fiber wheels are the best of the best in terms of light weight, strength, durability, and overal performance gains. They are, however, not legal for racing in most venues. Further, they are not available in colors other than their natural, and beautiful, carbon fiber finish. While the impact on performance and handling with carbon wheels is nothing short of breathtaking, due to their cost, they are not for everyone. But for those seeking the best money can buy, the greatest performance gains, and the absolute maximum street cred, they are the wheels of choice.