Cassette Hubs

What is a cassette hub and why is it so popular?

The cassette hub is the standard in BMX. Its main feature is the **Driver** (an integrated cog with a freewheel mechanism). It offers direct engagement: as soon as you pedal, the power is transferred immediately. When coasting, the pawls create that distinctive "clicking" sound. Cassettes are lighter and require less maintenance than freecoasters but force you to pedal backward when riding fakie.

How is a cassette hub constructed?

Hub Shell

The aluminum housing that holds the spokes and bearings.

Driver

A one-piece gear (usually 9 teeth) containing the pawls and springs. It sits directly on the axle.

Pawls

Small "teeth" inside the driver that engage with the hub's ratchet ring when pedaling. The more pawls/teeth, the more direct the engagement and the louder the sound.

Axle

The connection to the frame (14mm is standard).

What special types are there?

Besides the standard (fixed LHD or RHD), there are smart systems:

SDS (Switch Drive System)

These hubs can be converted from RHD (Right Hand Drive) to LHD (Left Hand Drive) by flipping the pawls. Perfect if you are not yet sure which side you want to grind on.

Hybrid Hubs

Some modern hubs (e.g., from eclat or Wethepeople) can be converted from cassette mode to freecoaster mode. Ideal for riders who want to try both.

Which materials are used?

Hub Shell: Aluminum (6061-T6, 7075)

The standard is 6061-T6. It is robust and affordable. High-end hubs (e.g., Profile Elite) or hybrid hubs often use 7075 Aluminum for even greater hardness and lower weight.

Axle: 4130 CrMo (Chromoly)

The standard for durability. Withstands even hard street use.

Upgrade: Titanium (Axles & Drivers)

For Park and Race riders who want to save every gram. A Titanium driver or axle (e.g., from Profile Racing) saves massive weight but is more expensive.

Which cassette hub suits my riding style?

• Street: Choose a hub with a 14mm Male axle or robust Female bolts. Large bearings and compatible Hubguards are important. If you grind, LHD is often useful (to protect the sprocket from the grind side).
• Park & Trails: Weight and response time matter here. Hubs with many "Engagement Points" give you instant thrust when pedaling. Female axles and Titanium upgrades are very popular here.

How do I install a cassette hub?

1. Place the chain on the driver and set the wheel into the dropouts.
2. Pull the wheel back to tension the chain. Ensure the wheel runs centrally.
3. Tighten the nuts firmly (approx. 30-35 Nm for 14mm axles).
4. Check that the chain is tight but does not "bind" (too tight), as this can damage the bearings.

Common problems and maintenance

• Skipping: Usually the pawls are stuck (old grease) or the springs are broken. -> Clean and replace springs.
• Ghost Pedaling: If the crank turns while pushing the bike, the driver bearing is often defective or tightened too much.
• Maintenance: The driver should be removed occasionally, cleaned, and lightly oiled (do not clog with thick grease!).

What do the specifications mean for cassette hubs?