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Internal Hub Meets Shaft Drive

by Ted Johnson

Last week I received a shaft-drive commuter bike from Dynamic Bicycles. The model is the Crossroads 8.

Robin Carlson is Shaft

Who's the white bike geek that's a sex machine to all the chicks? Shaft!

I had short call today with Patrick Perugini and Devin Kelly of Dynamic Bicycles, and I asked them the one question that’s been on my mind about shaft-drive bikes: Since shaft-drive and internal hub technologies have been around for more than 100 years, why hasn’t it caught on for bikes?

Their answer: Commercially available internal hubs for bikes were limited to three speeds until within the last decade. So the shaft drive really hasn’t been practical until recently. It hasn’t had the time to catch on.

Don’t take their word for it. Here’s a quote poached from Sheldon Brown:

In the late 1990′s, internal gears underwent something of a renaissance, with the development of wide-range 7-speed hubs. Progress has continued since. Four different brands are currently available, with as many as 14 speeds. Three-speeds and five-speeds are still currently in production, and they offer an economical, practical alternative.

So are we bearing witness to a great catalytic moment in the evolution of bikes? Like Gregor Mendel’s research finally combined with Darwin’s theory? Like peanut butter finally meeting chocolate? Or am I just being seduced by the novelty of this stuff?

Dynamic Drive Shaft

Drive Shaft Diagram | Photo: Dynamic Bicycles

A few of us in the office took it for short test rides. Everyone was impressed. The shaft drive is very quiet and responsive. It feels different from a chain drive, and even a belt drive, but the difference is subtle. It’s kind of hard to describe. It’s very non-chainey. Was that helpful?

The photo above is Robin Carlson during his two-minute test ride. If anyone around the shop would have taken an instant disliking to the bike, I figured it would have been him.

He liked it too!

I asked my brother-in-law, Jamie Boyer, to review this bike. I don’t know anyone who can torture test a drive train better. We’ll publish Jamie’s review in about a month.

But, unless the bike explodes or something, I’m going to have to think of shaft-drive-plus-internal-hub as a valid option for bike commuters.

The biggest downside I can see at this point, is that I can’t get the theme from Shaft out of my head.

Stay tuned for the full review in the near future.

 
BOB Trailer Sale

8 Responses to “Internal Hub Meets Shaft Drive”

  1. Paul in Minneapolis says:

    I’m really looking for this review..

    One of my questions. Those who live on flat land and those who live in mountains will need very different gearing.

    > Will there be some way to raise or lower that overall gearing?

    With my Euro city bike with front and rear panniers and loads can be 100 lbs with real world hills, a 20″ or lower gear is needed ( I like ~16″). But someone who live on flat land and caries little will want the gearing much higher.

    > Will a owner be able to change the overall gearing or will it be based on when the bike was built?

    If they push this as a one size fits all (the American way) it will be doomed.

  2. The shaft drive approach for bicycles is usually panned for its higher inefficiency compared to a chain drive: a shaft and gears sufficiently small so that it doesn’t weigh too much or cost a crazy amount tends to distort under the greater forces due to a smaller moment arm than the comparable chain drive. Heavier, less efficient, and more expensive tend to work against adoption of alternates to the chain drive even when they have other advantages to recommend them.

    • Ted Johnson says:

      I think you’re right. Even road bikes made by Dynamic Bicycles have chain drives.

      However, from what little research I’ve done, it seems as though a clean shaft drive is as efficient as a dirty chain drive. For people (like me) who don’t pamper their drive train, it could be that a shaft drive plus internal hub is ideal.

      Jamie is not one to suffer inefficiency. He pampers his bikes. But he also knows you don’t evaluate a commuter bike by the same criteria you would evaluate an aggressive mountain bike. I’m as curious as anyone to see what he will conclude.

  3. Paul S. says:

    I’ve been interested in these things for years from a “boy would that simplify the black grease spots everywhere and exposed delicate gearing” perspective. But one thing I’ve never been able to understand is why they don’t integrate the shaft into the chainstay? It seams an obvious weight saver. Am I missing something here that makes this impossible or is this just an obvious trick that no one has gotten around to yet.

    • Ted Johnson says:

      Good question.

      Sonoma also makes shaft-drive bikes, but with the drive shaft in the chainstay.

      Here is what Dynamic Bicycles says about it referring to “our competitor”–presumably Sonoma:

      Our competitor’s shaft drive bike frames eliminate the critical horizontal frame stay on the drive side of their frame. This puts force and strain on the shaft drive that it was never designed to handle. Our competitor fails to understand that the shaft drive is a drivetrain, not a structural component. By eliminating this frame component, our competitor’s frames cause unnecessary loads on the gear and bearing components causing inefficiency, excessive wear, and potentially premature failure of the shaft drive and/or the frame.

  4. John Macossay says:

    I have a 7 speed Dynamic bike with a shaft drive and I like it fine. Sheldon Brown claims that the advantages of the shaft drive can be duplicated with a fully enclosed chain case, but such bikes are not available in the North American market. Those for sale in Europe are limited to single speed, and are both heavier and more expensive than equivalent shaft drive bikes.

    My shaft drive bike is particularly great in the city, where I have to stop every block or even half block. It’s nice to be able to shift gears even while the bike is stationary. Racers will not like a shaft drive because you have to ease up the pressure on the pedals when you shift, and racers don’t like to break cadence. That’s why they have so many speeds. However, this is a characteristic of the internal hub and not the shaft per se.

  5. John W. says:

    What happened to the review? Been much longer than a month. “We’ll publish Jamie’s review in about a month.”

  6. shaft , jr. says:

    I am using a Sonoma cruiser shaftdrive for around town errands, lunches, bank runs and hot dates and it is great. Not sure what Dynamic is complaining about other than lost business, but the ride is a glide, shifting is smooth, and no grease or noises to worry about. Unless you are competitive (point taken about the Dynamic roadbike with a chain) the point of biking is exercise and transportation and these bikes are great. Sonomas are half the price point or less than Dynamics, and roll just fine. Just like BMW and Suzuki cruisers!

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