• Posted Aug 5, 2015

After discovering the existence of "chainless bikes" three years ago, I have been casually researching them and asking every bike shop I visited if they carried any. No luck. In fact, beyond one news posting here on Bike Iowa from 2008, I could find virtually no references to chainless bikes anywhere in Iowa. When an opportunity came up to review one, I jumped at the chance.


Dynamic Bicycles out of Rhode Island has been producing a small line of chainless bikes for the past ten years. They have a few models of street bikes, a hybrid, and even a folding bike. Instead of a chain and standard dereailleur, the bikes feature a shaft drive (by Sussex) and internalgear hub (by Shimano, the same type used in some trikes). Beyond the custom frame and shaft drive, everything else about the bikes is pretty standard.


The Runabout 8 is a hybrid bike (available in 16", 18" and 21" inch models). Although it has a list price of $999, I have never seen it sell for that. Recently, itwas on sale at 40% off for $589 (or 30% off the "Premium" version). It seems the normal discount is 25%-35% from list price.


The Runabout 8 weighs 31 pounds, which makes it about the same as a 2004 Trek 7300 hybrid (30.8 pounds) and a bit heavier than my 21" 1998 Trek 6800 mountain bike (27.4 pounds). The bike uses a Shimano twist grip shifter but can be custom ordered with a speed shifter instead. A few accessories can be ordered from the factory, but all are standard off-the-shelf items you can find at local bike shops usually at a lower cost due to not having to pay for shipping.

Chain versus No Chain

Going chainless has many advantages, but the main one is simplty not having a chain to maintain or deal with. Changing the back tire becomes a very simple thing involving removing a dust cover, losening two bolts, and undoing a cable before sliding the tire out. Compare that to the mess an inexperienced biker (like myself) might have doing the same with a derailleur. In 17 years with my Trek, I have only changed the rear tire once so I have never gotten "good" at it. I already feel I could confidently change the rear tire of the Runabout 8 without getting grease all over me.

Speaking of grease, it is also a much cleaner bike. Since all gearing is internal, you can wear long pants without having to tie them up, and there's no grease when you load or unload the bike from a rack.

Maintenance is also greatly reduced since you can go hundreds of miles (they claim up to 5000) without having to do anything beyond adding some more grease or oil. I had seen videos that showed using a grease gun, but that was for earlier generations of the bikes. The current model does not need anything special to add more oil or grease when needed.

If the gears of a derailleur are slipping, the process of adjusting them takes a bit of time (if you don't do it all the time). On the chainless, it's a matter of removing the rear hub dust cover, shifting to 4th gear, and then twisting the shifter barrel adjustment until two indicator marks are lined up. Simple and quick.

Lastly, you can shift at any time, including when standing still. Gone is the frustration of trying to downshift from a high gear when you bike to the top of a hill. Just twist and you can go instantly from 8th to 1st gear without even needing to roll.

Dynamic Bicycles claims that, due to most bikes not being properly tuned at all times, the overall efficinecy in the shaft drive system is better than what most bikers will ever experience with a chain drive.

8-Speed versus 21-Speed

Dynamic Bicycles has a gear ratio chartthat shows how the 8-speed Shimano hub covers about 90% of the range of a 21-speed bike, just with larger gaps between the gears. It also avoids the redundant gears (where a high speed of one gear is the same as the low speed of the next gear). For casual bikers that might primarily stay in the middle range (speeds 8-14), this 8-speed gearing actually gives a greater range of gears to use. Still, gear addicts might miss the two higher gears and one lower gear than a 21-speed offers.

The best part isyou don't have to be a pro biker to know how to use these gears efficiently. On a 21-speed, shifting down from gear 8 to gear 7 would require dropping the front gear (which puts you in 1st speed) then increasing the rear gearSIX times (to get up to 7th speed). I like to think if it as like automatic transmissions on cars -- you can be more efficient with a stick shift, but most folks prefer things to just be easier. To me, it's just much more fun to shift now.


With the 700x35c wheels, with seat post and front suspension, it rides and feels very much like the Trek 7300 hybrid does. The same caveats about street bikes versus mountain bikes apply, and it's a rougher ride than what I am used to on my Trek 6000.

The ability to shift from lowest to highest seems to give much more abiliity to use "all" the gears, which seems to have me riding this (slightly) heavier bike (than my 6000) at faster speeds.

The most interesting part of riding this bike (other than all the attention it gets from people who notice its lack of a chain) is the noise it makes: none. The bike is SILENT other than the sound of the tires on the road. When coasting, there is not tick-tick-tick-tick sound of the chain. When you shift, there is no clunk and the chain jumps to the next gear. So far, the worst sound I hear is a muffled "grinding" noise that can happen during the first 100 or so miles as the gearbox gets worn in. It's very much like how a Prius feels the first time you drive up on someone in a parking lot and they don't move because they don't hear the gas engine running.

Warranty / Satisfaction Gaurantee

The shaft drive is covered by a limited lifetime warranty against manufacturer defects. Outside of that, a replacement is $129. (I have no idea how much it costs to replace a derailleur for comparison.)

Dynamic Bicycles also offers a 30 day satisfaction gaurantee (with a restocking fee) to take some of the risk out of buying a bike mail order.


After a half dozen rides of about 100 miles or so, I wish I had gotten one of these years ago. (Though, earlier generations were not as good so maybe not.) I love not accidentally getting grease on me every time I load the bike in to my car, and now I find myself riding in a higher more regularly than I ever did with my 17-year old Trek.

For dozens of photos, see:

For a detailed multi-part review, see:







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