Hi All!
I am nearly finished modifying my Extrawheel trailer, and have learned a lot in the process. Since trailers are an alternative or supplement to panniers -- and this one carries panniers and is tailored for use with my Thorn Nomad -- it is time for an update:
Using the Extrawheel trailer rack with a racktop load? Then you also need the long “29er" fork for mudguard clearance
• With the standard-length fork on the trailer, everything clears fine until there is a load on the trailer rack -- the recommended 13l Ortlieb dry bag can strike the bike’s rear mudguard. These problems go away with the 12mm longer fork, and trailer handling is improved.
Rear mudflaps on the bike are a good idea when towing a trailer
• Although the trailer pivots are plain bushings made from oil-filled bronze, it is still desirable to keep them shielded from direct spray of water, dirt, and mud from the rear wheel, and a mudflap works well for this. The bushings stay cleaner and they require less lubrication because they are not subject to as much direct water spray or dust.
INCREASING VISIBILITY
Part 1: Reflectors
• The trailer really requires something to increase visibility at night. This is especially important when a load is carried on the trailer's cargo rack, because that load can hide or obscure the bicycle's own rear reflectors and taillight.
There is also a legal requirement. Here in the US, laws regulating bicycle safety equipment vary by state and are enforced unequally. In states that require a red rear reflector (or a taillight), I have been advised the attached trailer is also considered part of the bicycle and therefore is subject to the same laws and must display a reflector if the bicycle's own reflectors are hidden or otherwise obscured by the trailer.
To correct the problem, I fitted an SKS rear reflector to the trailer's mudguard. These are commonly included with SKS fenders sold in the Eurozone, but are unavailable in the US market or from SKS' American office. I sourced mine from a friend in Rotterdam.
The "Ride the World" and Nomad (Tuareg) figure on the Extrawheel fender are cut from black 3M Scotchlite. Black in the daytime, it turns a bright reflective gold color when car lights shine on it at night. I also added 3M Scotchlite spoke reflectors to the bike and trailer for added side visibility.
Part 2: Dyno taillight
Since I am running a SON28 dynohub in the trailer for charging, it may as well power a taillight. I chose a B&M Toplight Line Plus for its generaous reflector size and bright, prism-line optics to match the Nomad's, but there’s a snag: The hub produces AC current and the LED taillight requires regulated DC power. Normally, this is all sorted out by the circuitry in a headlight -- which the trailer doesn’t have, so I made my own. I designed and etched my circuit boards and soldered the needed rectifier and voltage regulator. I included several sub-circuits to smooth the power produced by the SON28 dynohub so the light does not flicker at low speeds. Though conversion and power losses are very low, I included a switch so I can cut power to the light when I wish to allow maximum charging.
I mounted the lot in my own waterproof housing on brackets made of solution heat-treated 7075 aluminum. Those brackets mount to threaded inserts I machined and fitted to the open ends of the Extrawheel rack in place of the original vinyl tube caps.
The standlight allows the taillight to remain lit even when the trailer is briefly airborne on rough roads. The supercapacitor keeps it lit for 4.5 minutes while at rest and includes an interrupter switch to turn the light off at will to avoid drawing unwanted attention when the bike is stopped or when stealth/wild camping.
Part 3: Daylight-visible 1-watt LED battery-blinky
To supplement the dyno-powered taillight, I cobbled a mount from a old reflector bracket to hold the Blackburn Mars 4.0 firmly in place.
Part 4: Flag
The Extrawheel trailer comes equipped with a high-viz yellow flag. My lighting illuminates the pennant at night, so it increases visibility at all times. On rough ground, the flag will sometimes whip enough to contact the mudguard with a loud clatter, and I’m concerned over time this could damage both ‘guard and flag. Shortening the mast by 12.7cm reduces the effective chord and stiffens it enough for silence in most use while remaining flexible enough to resist breakage. I’ll add a high-hysteresis collar to the mast to absorb shock and make contact silent in all circumstances. Shortening the mast moved the pennant down into my draft, so the flag catches less wind and flaps slowly even at speed. By happy coincidence, it also places the pennant at the same height as my black riding shorts, increasing contrast and visibility.
CHARGING AHEAD:
Part 1: Trailer as power source while riding
Where I travel alone and unsupported for extended periods in very remote areas, the bicycle's own dyno-charging system is not always sufficient to supply all my needs away from mains recharging, so I fitted the trailer with a modified BUMM e-Werk, powered by the SON28 dynohub. It uses a remote lead to allow charging away from the trailer (inside a pannier while riding, or inside the tent when in camp).
All hub wiring is in parallel for redundancy and reliability so either the lighting or charging circuit can fail and the other will remain in service. All wires are hidden to prevent damage and improve appearance. I used gold-plated miniature connectors to improve reliability while allowing individual components to be easily replaced or serviced and to quickly break-down the trailer for air transport.
Part 2: Trailer as power source in camp
Next, I’ll modify the trailer to charge my devices in camp while I sleep. My prototypes work perfectly, and I just need to finalize the design to work on the trailer. The solution is so deceptively simple I initially missed it.
OTHER ISSUES
Uh-oh; where’d the paint go? Solving pannier abrasion
The glass-filled lower nylon backing plates of my Ortlieb BikePacker Plus' panniers rubbed on the sides of the trailer frame, scuffed the paint finish, and would soon have worn through to the steel frame tubing. To prevent the problem, I constructed some nylon bands from bicycle reflectors. These bands serve as standoffs between the lower pannier mounting plates and the trailer frame. They also capture the light and charging wires without added zip-ties.
Q/R-hitch still needs improvement, and Extrawheel are working on it
The quick-release/hitch still needs improvement. The problems with the present model are twofold:
1) The q/r lever lacks a hard "bed-stop" so the lever can rotate completely around and self-loosen if the lever is tightened with relatively low torque, as required with Rohloff hubs to prevent end-loading and binding the hub bearings. The tolerances are also too loose, which contributes to the problem.
2) The inner faces need to be textured or knurled to provide a firm hold on ramped dropouts. Currently, the quick-release/hitch works alright on vertical dropouts, but is not secure on bicycles with ramped dropouts.
The replacement q/r-hitches Extrawheel sent me promptly under warranty work better than the ones I ordered with the trailer, but still need improvement.
Extrawheel have an evolutionary q/r-hitch design in development as I write this; they are committed to continuing improvement.
To prevent theft and allow recovery, the trailers need to be serially numbered for registration as one would register a bicycle. I’m adding a stamped serial number to mine so I can register it.
RIDE IMPRESSIONS:
The trailer is largely unnoticeable to the bike when towing unloaded. The biggest things I can notice are the occasional clatter of the flag mast against the mudguard on rally big bumps and the scrub/wheel hop of the trailer when testing with deliberately tight, high-speed turns where I don’t lean much. That’s about the only handling quirk I’ve noticed, and it took so effort to produce it.
With a load, you can feel a difference proportional to the load. Even though the bike isn't carrying all the load, it is towing it, and this affects acceleration, braking, and handling. Extrawheel place the load well forward on the trailer to weight the fork (tongue). While this makes for better handling, it also means a greater load on the bicycle's rear axle, and that can be felt when towing a heavy load. the bike's handling does change much as it does when riding with panniers, but not as much. You do have to allow for it, and it does take a period of adjustment; you can tell it is no longer an unladen bike.
There are some surfaces that affect trailer tracking. It does best off-road and on dirt and gravel, unlike most trailers. When on-road, there are certain surfaces that induce a bit of sway into the trailer, though it doesn't seem to affect the bike. I am still testing, but it seems to be independent of load and is triggered by a smooth surface with severe off-camber crowning or a smooth surface interrupted by undulations, as when tree roots heave the pavement. I am still investigating and plan to rig a camera to the rear bicycle rack looking backward so I can see what's going on.
The trailer does go airborne on a number of occasions, as the only suspension is in the tire. To that end, a user has to re-think tire pressures according to load and reduce accordingly. I’m finding for most reasonable loads, somewhere around 1.4bar/20psi is *plenty*, perhaps too much. I am still experimenting for the ideal pressure at a variety of loads. Running at appropriate (low) pressures reduces hop while making little of any difference to rolling resistance. Even fully loaded, the trailer tires carry only the load of a single bike wheel/tire.
Compared to other one-wheeled, sled-type platform trailers I’ve tried the Extrawheel has some advantages:
• It is lighter.
• It is shorter overall, making for easier parking.
• It is no wider than the bike, so there are no “corners" to catch and it is comparatively easy to tow in tight quarters without snagging, even with panniers mounted. 40l panniers and a 13l dry bag on the rack give 53l capacity, enough for most use.
• The Extrawheel can carry only panniers and a small rack-top load if equipped with the optional rack. This requires a more disciplined approach to packing, and is not as versatile for hauling large or odd-shaped gear.
• Ground clearance is comparable to a low-rider front rack. This, coupled with the short wheelbase makes for little chance of high-centering. Lean angles are outstanding (very high)
• It can be quickly reduced to a very small package. When reduced down,it packs smaller than any other trailer.
• The larger, bike-sized wheel prevents it from falling into potholes and such and makes the ride on rough ground almost unnoticeable wrt drag. Small wheels tend to catch and snag, and this can be felt in the bike when towing. On the other hand, larger wheels are much heavier and this can be felt in slower acceleration. The larger diameter more than makes up for this off-road and on rough surfaces.
• The trailer follows the bike very closely and is impossible to jackknife when going forward. It’s “head tube” angle is such that it also leans into corners, which aids maneuverability. On the other hand, the same maneuverability going forward makes it extremely difficult to push the bike and trailer backwards when parking and maneuvering off the bike.
• Compared to even my own cargo-box two-wheeled trailers, the one-wheel trailer has it all for off-road maneuverability and can lean with the bike. Two-wheel cargo trailers place the load above the axle centers for a much higher center of gravity, and the double track means at least one wheel always hits an obstacle the bicycle can miss. The smaller 16in wheels also fare much less well off-road than the Extrawheel's 26-incher.
• My goal is to also use the trailer to provide touring cargo capacity, power, and lighting for a rental or cheaply purchased bike on arrival at a destination and so avoid added expense or damage compared to flying with my own bike. The reduced trailer and bags will fit in an astonishing small container and it can be as cheap to buy a bicycle on arrival (and perhaps sell it on departure) as it is to ship one’s own. The trailer would also be a nice way for a companion to tour with me using their own bicycle -- even a sporting bike otherwise unequipped for touring and lacking its own racks and lighting/charging systems. With two panniers at 40l capacity and a 13l dry bag and cargo limit of ~31kg, it is possible.
It is important to note -- as with any trailer -- the need to appropriately match load to bike. Generally, very light bikes with small-diameter tubing in the rear triangle will be less-suited to towing heavier loads, so weight should be adjusted accordingly if a lightweight road bike is used. An MTB, my touring tandem, or the Nomad have much more robust construction and will be less affected by the trailer’s mass. I will likely use mine most on rough roads and to carry extra food and water. My two 10 MSR Dromedary water bags weigh a bit more than 20l/44lb when full, and I can feel the difference in the trailer’s handling and in the bike's. Even though a trailer carries weight (mostly) on its own wheels, the bike still has to cope with the same mass when accelerating and stopping, so gearing and brakes are affected accordingly and steering to a lesser degree.
If you place some or the bulk of your touring load on a trailer, it can be parked at your destination and the unladen bike ridden with greater ease. Except on really flat, smooth surfaces, the unattached Extrawheel trailer is not very stable standing alone and is happier laid on its side.
• The trailer attaches by setting the fork 3cm narrower than the q/r-hitch ends, then spreading the arms apart; spring action holds the bronze pivot bushings on the spherical stainless steel hitch ends. It is really, really difficult to attach or detach the trailer if you're alone and the bike and trailer are both loaded and there is nothing to lean either against. There are several tricks to make the process easier:
• Lean the bike against something. Lacking that, a kickstand or Click-Stand are invaluable if you're alone.
• Attach the trailer to the bike when both are unladen, then load the bags on each.
• Attach one side of the trailer fork, then you only have to deal with the other arm.
• Better yet: Attach the fork alone to the bicycle's dropout q/r-hitches, *then* attach the trailer to its fork at the kingpin.
All of this is a bit harder if you have a Rohloff hub with external shift-box, as the trailer fork wants to snag the click-box under tension. The solution is to engage the left (shifter) side first, then attach the right side.
• On the downside, this trailer -- any trailer -- is not the same as riding only a bike with panniers. It requires some effort to remember the extra length when maneuvering in tight places, and it can make access to and parking in public restrooms impossible.
• While it is always nice to have the option in an emergency, I really can’t see much call for the trailer as an emergency replacement front wheel. Front wheels are evenly dished and therefore sturdy and fail infrequently. For real emergency use, it might be better if there was an option for a wider trailer frame that could take a rear wheel for a derailleur bike, complete with cassette. As it stands, the trailer does provide a source for a second tire, tube, and rim if needed to repair the bike’s rear wheel.
• The trailer does impose a speed limit on the bike. With a 25kg load in the trailer, I found going downhill at speeds faster than 60kph/37mph, the whole train begins to sway in a sort of lateral sine wave, as if someone were pushing the bike gently but firmly from side to side in the middle -- completely unlike a shimmy. Extrawheel and other trailer makers warn of this, and -- yes! -- it is a good idea to limit speeds when towing, just you would when pulling a caravan with a car.
Finally, Extrawheel have been outstanding about warranty and shipping issues, responding immediately and never quibbling over a legitimate claim. When I experienced a problem with the q/r hitches and explained and illustrated th eproblem, they immediately sent me hand-checked replacements and moved up their campaign to improve and refine them with a new design. When I sent for the longer fork, I also ordered a spare flag, which was broken in-transit. I simply sent photographs of the damage and a copy of my Postal damage report and they sent a replacement immediately. The trailer has a five-year warranty much like SON and Ortlieb products, and Extrawheel's swift responsiveness is reassuring.
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To this point, the Extrawheel Trailer Electification Project has been a great success. It powers its own taillight and produces electricity reliably even at low speeds. I plan to take it farther, and will report back with updates.
Best,
Dan.
