Comparative Testing

Why we test our wheels?

For us, testing is an extremely important process in the development of a wheelset. While it can objectively determine a wheel's performance, it can more importantly evaluate its safety and longevity. 

We want to make sure that each product meets or exceeds our standards for safety and longevity, as well as performance. In this article, we will explore some basic tests and comparisons between a handful of wheel models, in this case, 45mm deep wheels.

Why do comparative testing?

In order for us to understand how our wheels perform against one another, our competitors, and even different variables, such as changing from 3rd to 4th generation carbon spokes, we do multiple tests among different wheelsets. It helps us get a wholistic, objective picture of how our wheels behave.

Below are a fraction of the tests we perform on the wheels. We will also dive into some key takeaways.

Vertical Impact Test

In our mind, the most important aspect of a wheelset is not how light it is, how stiff it is, or how smooth the bearings are. The most important is how strong is it. 

While we value the UCI Vertical Impact Test, we believe that a safe wheel should ideally be much stronger than the minimum to pass for a race wheel. For this reason, we put a lot of emphasis on the vertical impact test and offer very conservative weight limits to prevent injury due to perhaps the most common case of a carbon wheel breaking, hitting a pothole or other obstacle at high speed.

The following are the impact strengths of our different wheel series consistently survive:

  1. RCX27 Hyperlight: 85 Joules (2.13x UCI)
  2. GCX Hyperlight: 100 Joules (2.5x UCI)
  3. RCX Ultralight: 100 Joules (2.5x UCI)
  4. GCX Ultralight: 100 Joules (2.5x UCI)
  5. RCX Light: 120 Joules (3x UCI)
  6. GCX Light: 120 Joules (3x UCI)
  7. RCX Team: 140 Joules (3.5x UCI)
  8. GCX Team: 140 Joules (3.5x UCI)

The key takeaway is that our heaviest wheels are the strongest and can support higher weight limits. For the RCX27 Hyperlight, we assign a max system weight limit of 90kg. For the GCX Hyperlight and the Ultralight series wheelsets, we assign weight limits of 100kg. We also assign the Light and Team series wheelsets weight limits of 120kg and 140kg weight limits respectively.

*(Detailed Vertical Impact Test Page Coming Soon)

Lateral Stiffness Test

Perhaps the greatest indicator of a wheelset's ride feel is lateral stiffness. It determines how much a wheel bends laterally when riding. Cyclists who have ridden multiple wheelsets can often tell which wheelset is considerably stiff (responsive) and which is considerably compliant. Responsive wheels transfer power better, allowing you to ride more efficiently, but they are less comfortable. Certain factors that affect lateral stiffness include the rim design, rim depth, spoke type, hub flange height, number of spokes, and much more.

The following is the deflection of each front wheel when 30kgf is applied . The less deflection, the stiffer the wheel. Wheels are ranked from the stiffest to the most compliant:

  1. GCX45 Team (4th Gen Spokes): 7.7mm
  2. GCX45 Hyperlight (4th Gen Spokes): 7.96mm
  3. GCX45 Ultralight (3th Gen Spokes): 7.97mm
  4. GCX45 Light (4th Gen Spokes): 8.63mm
  5. GCX45 Ultralight (4th Gen Spokes): 9.08mm
  6. RCX45 Ultralight (4th Gen Spokes): 10.27mm

The reason for testing only one rim height is to eliminate the rim height variable. In general, deeper section wheels are stiffer. 45mm is also our most popular rim height.

Our testing has shown us the following key takeaways:

  • GCX wheels are roughly 13% stiffer than RCX wheels.
  • 3rd generation spokes are roughly 14% stiffer than 4th generation spokes.
  • Our most compliant wheelset series is the RCX Ultralight.
  • The GCX45 Hyperlight with 4th generation spokes has essentially the same ride feel as the GCX45 Ultralight with 3rd generation spokes.

*(Detailed Lateral Stiffness Test Page Coming Soon)

Vertical Stiffness Test

It is often assumed that wheels that feel stiffer or harsher have higher vertical stiffness. The truth, however, is that this is actually related to lateral stiffness and things like tire choice. All wheels have high vertical or radial stiffness. A wheel that has very poor vertical stiffness is unsafe, as too much movement could lead to a tire deforming and dislodging.

*(Detailed Vertical Stiffness Test Page Coming Soon)

Dynamic Balance Test

One of the most overlooked tests is dynamic balance. Wheels that are not dynamically balanced will oscillate up and down while spinning. This can not only be uncomfortable, but it could also be a safety hazard, for example reducing grip while cornering.

At Particle, each of our carbon wheels has an additional piece of carbon fiber placed opposite the valve hole, as tubeless valves and inner tube valves inevitably make a wheel imbalanced. Our standard is to keep the balance of a wheel to be off by no more than three grams.

*(Detailed Dynamic Balance Test Page Coming Soon)

Max Spoke Pull-Through Test

Spoke holes are where spokes are threaded into a nipple and fixed at the rim. The area where the nipple pulls against the rim the is called the nipple bed, which needs additional reinforcement. The reason is that on poorly manufactured rims, this area is likely to crack due to high stress area, as spokes are under a significant amount of tension. The Max Spoke Pull-Through Test ensures that the nipple bed has more than enough reinforcement to prevent spokes from pulling through.

Our standard is 300kgf without spoke hole cracks or spoke pull-through. For reference, the spoke tension of our carbon spokes does not exceed 130kgf.

*(Detailed Max Spoke Hole Pull-Through Test Page Coming Soon)

Wheel Fatigue Test

The wheel fatigue test checks the overall durability of a wheel under cycling-like conditions. It shows how a wheel performs as a whole over time, revealing potential weaknesses in the rims, spokes, and hubs and their interaction with one another. The wheel is under load, and the drum it is rolling surface is uneven, simulating vibration. The test wheels run for tens of thousands of cycles. Our fatigue test results show the wheelset condition beyond 5,000 km for road and gravel wheels.

*(Detailed Wheel Fatigue Test Page Coming Soon)

Spoke Longevity Test

One overlooked aspect in term of the lifespan of a wheelset is spoke longevity. We have tested many different spokes and have measured how much spoke tension they lose over time, which can lead to wheels slowly going out of true over time, and spokes lengthening and fatiguing. This is not an issue with well-made carbon spokes. Our carbon spokes do not lengthen and fatigue over time in the same way that steel spokes do. They last many times longer.

*(Detailed Spoke Longevity Test Page Coming Soon)

Spoke Stiffness and Max Spoke Tension

One major contributor to the stiffness of a wheelset is actually the spokes. While carbon spokes are stiffer than steel spokes, the truth is not that simple. We offer both 3rd and 4th generation carbon spokes, which offer very different ride feel.

*(Detailed Spoke Stiffness and Max Spoke Tension Test Page Coming Soon)