The Ultimate Foldmodular eCargo Thingamabike Experiment

I love clever designs of objects that fold up small — not just bikes. Before my first folding bike, I had a folding dinner table, a collapsible ladder chair, a folding book shelf, and other folding stuff.

Closely related to my folding fetish is my modular fetish. The idea that one thing can be many things if you have the right accessories.

A couple of months ago, I was on the verge of experimenting with a fantasy bike. Remember this? It was the Montague Boston 8 folding commuter bike with a modified*  Extrawheel Voyager Bike Trailer  and a    Clean Republic Hill Topper Electric Bike Kit. This setup promised to be The Ultimate Foldmodular eCargo Thingamabike.

Montague Boston 8 with Extrawheel Voyager and Clean Republic Hill Topper
More research needed: With Extrawheel Voyager and Clean Republic Hill Topper

I was on the verge of the experiment, but stuff happened. I wrapped up my sojourn in Tucson. I got a new job. I boxed up the Montague and sent it home. Maybe it’s better to not to live out your fantasies.

But I brought the Extrawheel trailer and the Hill Topper to Flagstaff, and decided to try out one part of the concept: Using the Extrawheel as a removable push trailer. The Hill Topper is intended to be a front-wheel e-bike kit. (See Pete Prebus’ review of the Hill Topper.)

Aside from satisfying my folding-things and modular-things fetishes, another reason to do this experiment is to see if this system would work for someone whose main bike (or whose only bike) is not suited for utility cycling — a fancy road bike or mountain bike.

The modularity would mean that Mr. or Ms. Fancybike could carry groceries and do more practical things. The Extrawheel trailer doesn’t have a hitch, per se. Instead it uses rounded nubs on the end of  special axle nuts (for a solid axle), or a special quick release skewer. Weight weenies could live with it. The throttle and cables attach with Velcroâ„¢ so all of that can also easily come off on weekends. Their Fancybike friends would never know the dirty little utilitarian secret.

One part of the experiment that required a little imagination was the “removable” part. In my fantasy, I would have some custom cables and couplers that would make the trailer easy to pop on and off — like a Ridekick Powered Bike Trailer. And, like the Ridekick, the battery would ride on the trailer.

Custom Cables for Extrawheel and Hill Topper
I want a coupler where the pink cable meets the yellow cable. And I also want a pony.

Lacking these magical cables, I used the standard Hill Topper cables. This meant that I needed to install a rear rack on my mountain bike; there was no other way to make the cable lengths reach the motor, the battery, and the throttle.

I reconfigured the Thule Tour Rack that had been on the Montague bike to fit my more traditional diamond-framed Diamond back mountain bike.

I lose stuff. But somehow I had managed to keep track of the extra frame struts that allow me to adjust the rack to to the angle of the seat stay. And I also still have release key which allows the rack to be removed without use of a box-cutter knife. (See my review of the Tour Rack.)

Thule Tour Rack Frame Struts
Instead of winning the lottery, I found my Thule rack frame struts

With the Thule rack on my mountain bike, and with the Extrawheel trailer tethered to this bike by non-coupled cables, what I had was The Ultimate Foldmodular eCargo Thingamabike. Except not folding, and not modular.

But at least I was home in Flagstaff.

Extrawheel & Hill Topper & Panniers
Ready for grocery shopping.

The first thing I did was take the system grocery shopping. I attached my Ortlieb Back Roller Classic Panniers to the Extrawheel trailer, and my Thule Commuter Pannier. I rolled downhill to the my favorite grocery store, just more than a mile away. I barely touched the throttle.

The first thing that I discovered was that this extended rig is hard to lock up. I only had one long-ish cable lock with me, but it still wasn’t long enough to thread through all three wheels and through both the bike and trailer frames. Since the Extrawheel trailer and the Hill Topper kit are worth more than my whole bike, I locked up everything except my front wheel.

Inside the store, I loaded up my cart and went through the self checkout.

Uh oh. I was wondering if three panniers would be enough carrying capacity.

Self Checkout
Yes, plastic bags. I use them to pick up after my dogs, if you must know.

Barely. I got all of those groceries into the panniers. The hard part was wrestling with the bike and trailer, which reticulated with will of its own, and without a kickstand to keep the whole system stable.

The best thing would be a two-legged kickstand, like the  ESGE Double Kickstand. (See BluesCat’s review of the ESGE Kickstand.) But, unfortunately, that kickstand thing is probably a deal killer for Mr. and Ms. Fancybike. The more I wrestled with the bike to load it, the more this seemed like a failed experiment.

Once loaded, I thought the hard part was behind me. Knowing I had electric assist gave me confidence that I could get all these groceries up the hill that makes the last homestretch to my house. I was not shy about using it.

The Hill Topper is not the gutsiest e-bike system I’ve ever used. The throttle is on/off — either full power or no power. Near the base of the hill, something went wrong. The wheel was rubbing on something. I stopped and saw that the axle had liberated itself from the dropouts of the Extrawheel trailer.

In spite of some torque-blocking gadgets on the axle, the axle still powered itself free. The Extrawheel is made for a passive wheel, not a powered wheel. Furthermore, this particular wheel had these nifty solid-axle quick release levers, which meant that the axle wasn’t as tight as it would have been with a regular axle nut tightened with a wrench.

Liberated Axle
Liberated Axle

There by the side of the road, I had to reattach the wheel to the trailer. The axle doesn’t just slide in. The aforementioned torque-blocker things need to be lined up with angle of the dropout slots. Which sounds easy, but the bike really wanted a wrestling rematch. (I was also right in front of someone’s house, and I really needed to pee, which made the whole situation even more stressful.)

I tightened those quick release levers by lying the bike and trailer on the road and stomping down with my foot. The axles didn’t torque out again, and I made it home with some electric assistance up the hill. Whoop de do.

Xtracycle and Hill Topper
Fully loaded with groceries, and back home.

The next day I commuted with this setup, but no panniers. In my fantasy modular version, I would have removed the trailer and battery. Instead, I deadheaded this rig to work. (How about that use of trucker jargon?)

The Extrawheel bounced wildly — even on paved surfaces that were only slightly bumpy. I can see that this trailer is not designed to be towed empty. The system is so lightweight without any cargo that I hardly could get any push benefit from the motor.

So what did I do? I took it on some single track — the scenic route.

Boing! Boing! Boing!   Scrrrrch!  

I was dragging the trailer on the ground by the motor cable. I had boinged the trailer right off of the trailer fork.

Deadhead Extrawheel Boinged off the Fork
What do you think I am? A BOB trailer?

If it’s not clear that I was abusing an already experimental setup:  the Extrawheel fork is a cleverly designed thing that holds to both the trailer bit and the skewer end with reciprocating tension — no pins or other mechanical method of locking the fork to the bike and trailer. It’s kind of ingenious, but it’s made for touring when the trailer is loaded. The mass of the cargo keeps the everything stable. And if it’s adjusted properly, it’s very unlikely to pop off.

Extrawheel Bike Trailer Fastening Fork | Photo: Bike Trailer Shop
Extrawheel Bike Trailer Fastening Fork | Photo: Bike Trailer Shop

Fortunately, the ingenious design means reattaching the trailer to the fork was easy.

When I got to work, I encountered that weird how-to-lock-this-long-ass-rig problem again. And again I left my front wheel most vulnerable.

The next day, I dismantled the entire thing. I’d had enough.

Those special magic coupling cables would be the key to making this system successful; making it much more like a Ridekick trailer — easy on, easy off.

The advantage of this system would be greater carrying capacity on the trailer, in your favorite panniers. Another advantage would be that the Extrawheel trailer is a great touring trailer — without the hub motor — if you are into that sort of thing.

Ridekick Electric Powered Bike Cargo Trailer
Ridekick Electric Powered Bike Cargo Trailer

Once again: More research is needed. But I think I got this experiment out of my system. I won’t be returning to this project.

The Hill Topper e-Bike kit is available from  Clean Republic with kits ranging from  from $399.00 to $1,195.00.

The Extrawheel Voyager Trailer  sells for $268.99, and is currently on sale for  $239.99.

*The trailer’s frame was widened near the dropouts to accommodate the width of the hub motor. This was done by a professional bike mechanic who had done this sort of thing before.


Ted Johnson lives in Flagstaff, Arizona. Follow his hardly-ever-about-bikes blogging at  Half-Hearted Fanatic, and tweeting at  @TedJohnsonIII.

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