In part one, we talked about how every bicycle has a transmission. On a bicycle “transmission” literally means a way to transmit your power from your pedaling to the rotation of the rear wheel, propelling you forward. Even a single speed bicycle has a simple transmission.
Today we have more viable bicycle transmission options than ever before, and that can make decisions puzzling. This series of articles is an attempt at helping you make an informed choice that makes the best sense for you. We’ve sorted the essential transmission types into 3 groups, and we’re presenting pros and cons for each type.
Internal hub transmission systems-
The second-most common transmission for bicycles is the internally-geared hub. If you’ve ever owned one of the millions of English 3-speed roadster bicycles produced between ~ 1955-1985, or an American cruiser built in the 50’s or 60’s with a 2-speed “kickback” hub, you’ve probably experienced a Sturmey Archer or Bendix version that is considered primitive by today’s standards.
Outwardly, a hub transmission doesn’t show its complexity, as the bicycle chain is driven by a single front chainring and a single sprocket at the hub. Inwardly, it is a mechanical marvel, with a central sun gear driving multiple planetary gears that in turn drive a ring gear that essentially drives the hub ahead of or behind the rotation of the sprocket. Here’s an excellent brief explanation of multi-speed hubs. Today, there are more sophisticated systems such as Shimano’s Alfine 8- or 11-speed, or most remarkably, Rohloff’s renowned 14-speed hub.
Both Shimano and Rohloff have built an impressive record of reliability with these offerings. Rohloff in particular has taken pains to document the mileage and stories of hundreds of users, some having traveled over 100,000 kilometers with oil changes the only required maintenance. Rohloff’s Speedhub stands apart from other hub transmissions due to its significantly greater range or ratio from its lowest to its highest gear. At 526% total range, the Speedhub, introduced in 1996 was the first hub transmission to rival the range of a triple-chainring derailleur-based transmission.
As an example, one of our Americano Rohloff touring bikes has a low gear of 19” and a high gear of 99.6”, while its derailleur-equipped equivalent has a low gear of 20.6” and a high gear of 117.9”. Very comparable, in other words, especially considering that the lower gears are the most important for touring cyclists. Here’s an in-depth explanation of the term “gear inches”.
2. Internal Hub Transmission pros and cons
- When operating optimally, a top-quality hub transmission system is approximately 99% as efficient as a derailleur transmission. Because it requires far less maintenance, it is less likely to operate sub-optimally.
- Shifting is easy, self-explanatory and linear. You can shift to or from adjacent gears in one click, or jump from gear 14 to 3 or from any gear to any other with a simple twist of the shifter to the gear you want now. You can do this while pedaling (with a slight easing of pedal pressure), while coasting, or at a complete standstill. That’s a great convenience when you’re touring, just came to a stop at the bottom of a descent, and are suddenly faced with a steep climb.
- Although they can be set up with chain, we include the Gates Carbon Drive belts on all of our hub and gearbox transmission models (we’ll address gearboxes in Part 3). These belts outlast chain by many times, never require lubrication, and operate efficiently in all conditions.
- The inner workings of the hub transmission are neatly enclosed in a sealed system, where they’re less vulnerable to weather conditions, dirt, dust or foreign objects causing problems.
- Because the inner workings of the hub transmission are neatly enclosed in a sealed system, they require a high degree of technical skill to repair. Although regular maintenance is easy, in the rare instance when repair becomes necessary, it can mean you need to send your wheel off to the nearest warranty center. Rohloff and Shimano have warranty centers on every populated continent.
- Gates drive belts are not as commonly available as bicycle chain, so if traveling extensively in remote locations, it’s smart to carry a spare belt.
- If you’re a racer looking for the lightest and most efficient system available, you’re probably not thinking about a hub transmission. It is a little heavier, and one of the knocks against it is that its mass is located solely at the rear of the bike. This could make a difference for you if you ride a lot of technical terrain.
- Your hub-based transmission is part of your rear wheel, making it essential to secure your wheel because you’ll be crippled and financially stressed without it. Few bike shops keep a Rohloff hub in stock, ready to build up into a wheel for you. That said, Rohloff’s North American Warranty Center, Cycle Monkey, offers impressive build skill and quick delivery worldwide.