Why lighter hubs can be a heavy problem: a deep dive into bearing life
In the pursuit of performance, every gram counts. People love the idea of lighter components, and hubs are no exception. A lighter hub promises quicker acceleration, better handling, and less rotational mass. But what’s the trade-off?
At TMWORKS, we’re all about performance without compromise and that means understanding the engineering behind the parts we use. One of the most overlooked consequences of shaving weight off a hub is the effect it has on bearing size, and more importantly, bearing life.
Bearings: the workhorse of any hub
Bearings are what allow your wheels to spin smoothly under load. They take radial and axial forces whether you’re railing a corner, landing a drop, or just putting power to the pedals. In high-performance hubs, bearings are expected to do all of this with minimal friction and maximum durability.
So what happens when we try to make a hub lighter?
Smaller hub shells = smaller bearings
Reducing weight usually means making the hub shell smaller and thinner. This, in turn, reduces the space available to fit bearings. That means:
-
Smaller diameter bearings
-
Narrower races
-
Fewer or smaller balls inside the bearing
While this saves a few grams, it significantly limits the load-carrying capacity of the bearing.
The trade-off: load capacity vs. durability
A bearing’s lifespan is heavily dependent on the size and number of rolling elements (balls or rollers). Smaller bearings have:
-
Lower dynamic load ratings
-
Higher operating speeds
-
Less resistance to contamination and heat
In real-world terms, this means that smaller bearings wear out faster, especially under high torque (e.g., aggressive pedaling) or lateral forces (e.g., cornering or hard landings). Riders might notice increased drag, creaking, or even catastrophic failure sooner than expected.
Why bearing size matters more than you think
Let’s put this into perspective:
-
A standard 6902 bearing (15x28x7mm) has a dynamic load rating of around 4300N
-
A 6802 bearing (15x24x5mm), commonly used in lightweight hubs, has a dynamic load rating of around 2200N
That’s over 40% less load capacity just to save a few grams.
Why we use DT Swiss and Erase hubs
At TMWORKS, we choose DT Swiss and Erase hubs because they strike the right balance between weight, reliability, and serviceability, especially when it comes to bearing choice. The DT350 and Erase hubs both use 6902 bearings, a full-size bearing with a solid load rating and proven longevity under real-world riding conditions. Even the DT240, which is lighter and more race-oriented, opts for 1526 bearings, smaller, but still engineered with DT’s precision tolerances and reliable sealing.
These aren’t arbitrary choices. We’ve found that hubs using properly sized bearings like 6902s simply last longer, resist contamination better, and require less frequent servicing.
Final thoughts
There’s nothing wrong with chasing lighter weight, just don’t be surprised when it leads to more frequent bearing replacements, higher maintenance costs, or even unexpected failures during your rides.
When it comes to performance, longevity is performance too. At TMWORKS, we believe that smart, durable design always beats shaving a few grams at the expense of reliability.
If you’ve got questions about hub design, bearing specs, or want to see how we build our wheels differently, feel free to send us an email at info@tmworks.cc or come by our workshop and showroom in Vianen.