Six Characteristics of Quality Carbon Rims

The purchase and arrival of a new wheelset is an exciting moment for any rider. We have compiled a shortlist of carbon rim characteristics to look for when unpacking your latest Light Bicycle purchase.

Quality Rim Trait #1: Smooth Wall Edging

The smoothness of the rim wall requires precision molding and stringent quality control, but some cheap mass production rim makers lack this attention to detail. Why does edge smoothness matter? Not only is it a mark of quality, but it also prevents people from getting cut or scratched when mounting tires or building the wheels.


Quality Rim Trait #2:Deburred holes

Cured carbon fiber is a hard material, consisting of thousands of fibers per tow. Given this physical quality, hole drilling can leave burrs that prevent precise wheel building. Removing burrs is critical to wheel performance and lifespan.

How do we achieve smooth hole drilling? One is the diamond drill bit, perfect for hard material drilling. Two is the computer numerical control (CNC) milling machine, guaranteeing precise movements. In the detailing process, deburring is carefully done to ensure full smoothness of the hole edge.


Quality Rim Trait #3: No fiber patching

Rotate the rim to see if there is a patch in the rim bed. Some carbon wheel manufacturers leave a hole in the rim bed during the layup process to remove the core. After core removal, the hole is filled in with a patch.

We have an alternative approach to core removal that does not disrupt carbon fiber continuity at the valve hole. Given that the core is soft and elastic, removing it through a small valve hole requires delicate work, but the time and effort are worth it. Continuous carbon rims are stronger and stiffer than those with patches.


Quality Rim Trait #4:Proper rim bed depth

Rim bed depth is easy to overlook, so why does it matter? Bed depth is directly related to the sealing effect, tire mounting, and rider safety.

If the rim bed is too shallow it’s difficult to insert the tire beads into the spacing, not to mention inflating the tire. Meanwhile, if the rim bed is too deep, tiring mounting will require high air pressure, possibly risking tire blowups.


Quality Rim Trait #5:Painted or paintless

Most rims are wet-sanded and then finished with a matte or glossy spray. Some refer to this as a “painted” rim. Rim coatings can cover carbon fiber imperfections like dust contaminants picked up during the manufacturing process.

With a sense of environmental responsibility, a handful of rim makers including us have developed a new process - we are able to make rims without post-production, including water sanding and painting. This bold move is backed by technical innovations that avoid compromising riding performance. These “paintless” rims have more of a glossy look and you can visibly see the carbon more clearly as the outer resin layer is preserved.


Quality Rim Trait #6:Rim roundness

It sounds obvious, but it’s not always the case - all rims should be round! Some rim manufacturers produce rims in pieces that are then spliced together. This process yields a rim that is not perfectly round and often requires irregular spoke tension to create a round wheel.

Why are our rims more round than competitors? For one, our layup is continuous and not done in multiple segments. The other reason is that once a rim layup starts, it is quickly moved through the next manufacturing steps. This short interval between steps is critical because there is less influence of gravity when the resin is in a softened state. The end result is a rim that will build up nice and round and with even spoke tension.


Our final wishes…

We have strict quality control standards and take pride in our work. We’re excited for you to ride our product and want to provide the best possible experience. Please take some time to get to know your LB rims and we would love to hear your feedback.

If you’d like to take a closer look at how every LB rim is made, don’t miss these tech talks:

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