speyfitter

I'm curious what you look for in a towing bike? To the best of my knowledge no one makes or markets a bike specifically for towing. With the advent of bike based businesses sprouting up it may be time for a dedicated towing bike to be made/marketed? I know Surly makes a couple bikes (Troll/Ogre) that have threaded holes specifically to work with their towing fittings for their trailers but....Here are some thoughts:

1) Frame construction/material - Frame material (would steel be preferable over the long haul?), frame construction (what areas of the frame would need to be beefed up?). Also provisions for chain/seat stay mounted towing brackets, as well as a beefed up seat post & tube to accommodate seat post mounted towing set ups.

2) Gearing - obviously have gearing that is ultra low for pulling weight up hill - think mountain bike gearing or even lower. What about IGH's? Also, was thinking that the gearing might not have to be terribly complex - you could also design the gearing to limit the bikes speed to some degree by not having a very high, high gear which effectively serves as a "governor" if it's fair to say, as towing bikes shouldn't be ridden that fast for safety reasons (perhaps 18-20 MPH max speed I'd say, tops).

3) E-bike vs non-e-bike. Would be good if they made a bike such as this that came in either configuration, perhaps a mid drive motor option and a traditional crank model?

4) Any geometry or ergonomic things you can think about - things that make the riders job easier at turning the pedals to pull weight? Riding position considerations?

5) Do you foresee down the line some kind of trailer tire braking system that you can affix onto your handle bars? Even if it was cable mounted as part of the trailer and there was some quick connect system to your handle bars for towing, or what if it was a system? Maybe this is just wishful thinking.....

I'm not talking towing MASSIVE weight, but a level of overbuiltedness for those who may regularly tow with a bike to add safety, performance, and durability in the long haul.

CliffordK

I do a fair amount of personal cargo hauling. And, have been around our local co-op that also does cargo hauling (although I haven't ridden their cargo haulers).

1. Frame: Steel is good, and easy to work with if you're building something yourself, but I'm not sure I'd limit it to steel. There are some good aluminum frame bikes that would certainly be fine. I've towed my trailers a few times with the aluminum tricross. I also have a titanium winter, foul weather bike, and have no problem attaching the cargo trailer to it.
   So far I haven't towed with Carbon Fiber, but who knows, if I can get a good axle/dropout hitch, I may give it a try. Keep in mind that all the power for a bike goes through the rear hub/axle, so if one pulls off of that axle, it should put minimal extra stress on the rest of the bike.
   
   One can say that weight isn't important, and it is easy to go heavy with cargo handling equipment. But, say my bike + trailer weighs 100 lbs. Then that is 100 lbs extra that I'm pulling, not counting my cargo.
   
2. Low Gearing: Yep. It depends a bit on your expected loads and hills. Up to 100 pounds or so, just typical MTB gearing is fine. Even road gearing if the mountain isn't that big. Hit 500 lbs, and the lower the better.
   
   However, for the really heavy loads, pulling up hill, I think there are issues of traction and stability. I think I've decided that it is easier to keep pedaling than to get off and try to push/pull my cargo up hill. A trike might be nice, allowing one to drop down to just above zero, and getting weight on the drive wheels. Outriggers on one's bike?
   
   There are some super-low crank options such as the "'Mountain Tamer".
   
   An IGH would be up to you. I have a "Dual Drive" on one bike. It is currently configured with a single front ring, but it could potentially be configured with a standard 10 speed rear sprocket and triple or quad front to give one three extra gearing ranges (High, Normal, and Low). My heavy hauling cargo bike, I have a triple front on, but haven't added a front derailleur. I usually shift it into high when I'm riding empty, then drop it into the middle when loaded. Then for those hills and a heavy load, drop it down to the small front. In theory, a Dual Drive IGH could be used the same for three additional gearing ranges.
   
   I think the Co-Op has move to a Nuvinci continuous drive IGH for their tri-haulers. They have worn out hubs and motors before, but seem to be happy with their Nuvincis.
   
   More comments about speed later with brakes.
   
3. E-Bike vs not. For personal use, I'm still 100% human powered. Our co-op has been using battery assist on a few of their bikes. They often do a morning run, then hunt for a place to recharge, then an evening return. Many designs will allow a motor to be added. Lots of variables. Amount of use, range, employees vs owner, etc.
   
4. Lots of geometry ideas. I'm still into upright bikes. Also consider the long nose front loaded cargo bike which gets the weight low, in front on a two wheel bike. I now have a trike that I've taken out a few times, still experimenting. The co-op has been building what they call "tri-hauler". Theirs is a front wheel drive.
   
   
   Human Powered Machines ? Eugene, Oregon
   
   BTW, they do have an apprenticeship program if you're interested in building. I'm not sure about their schedule, but it might be worth talking to them.
   
   Anyway, the tri-hauler has the advantage that the weight (or some of the weight) is on the bike. They also tow trailers with it. And, it can't fall over when one really has to go slow.
   
   I presume the recumbent/semi-recumbent tri-haulers are comfortable to ride. The current versions the co-op use have the rider fairly high up, and with a big mirror.
   
   From my experience with trikes, so far I can't seem to quite get the same speed/power with the trike as the upright bike. So, perhaps the trikes are good with pedal assist.
5. Trailer Brakes:
   I've thought about them some. If I was going to do them, I'd either do electronic brakes connected to one's hand brakes, or surge brakes like a boat trailer uses. Note, of course, that one's natural pedaling motion has surges, so one would have to make sure the brakes didn't engage with every pedal stroke. Also, sometimes a little push going downhill is good, it isn't always bad.
   
   However, I don't use trailer brakes now. One of the reasons is that I am limited to the same amount of power pulling cargo as I do on the empty road bike. So, if I'm pulling 50 pounds, I might hit a top speed of about 15 MPH. At 100+ lbs, maybe 10 MPH, and at 500 lbs, probably closer to 5 MPH. Plus, as a rider I know my limits, and won't go barrelling into a stop light pulling 500 lbs (conserve every ounce of energy).
   
   Anyway, I can put out 100W to 200W of continuous energy. And I think my bike brakes are sufficient to stop me from a speed attained from that same 100 to 200W of energy. Also, you asked about gear limiting earlier. For human powered, it just wouldn't make any difference. One can only go so fast with an empty trailer, and can stop it. For loaded... not so fast.
   
   I have ridden down hills. Most of the hills I hit are rural hills, and I can leave it wide-open on the descents. I did do a DRT cargo race up a hill in the city a while ago, and I was pretty careful on the descent.
   
   Pedal Assist is another issue. Say rather than 200W, one is pushing 200W + 1000W, for a total of 1200W. WHEW!!! That is where you have to think about speed governing and stopping, and trailer brakes. For the co-op powered bikes above, I think they still don't use trailer brakes, but do have some extra weight on their trike which will compensate some. Also note, with some tongue weight, it would be hard to flip a fully loaded cargo bike or cargo trailer, so one might as well mash on the front brake hard.
6. Other considerations:
   Tongue Design. My light trailers pull from one side of the bike. I do find it annoying walking the bike up a hill (I walk to the left side), and having the tongue out the left too. But, so far they seem to pull straight enough when riding. The tongue should be off-center by a few mm to compensate for the width of the typical rear wheel + frame.
   
   My "heavy hauler" is designed with a low hitch and a direct behind pull. It works very well, although I seem to have introduced some flex in the bike frame, so perhaps it will get revised sometime.
   
   Eugene CAT uses a seatpost hitch, and it seems to be sufficient for a fairly heavy load. I don't know if I'd go with that design, but it does have one advantage that they've put a handle on the hitch, and it is easy to pick the front of the trailer up and haul it around. They also typically have a fixed stand just below the front of the trailer, and apparently it also clears well enough that I haven't heard of rubbing. Anyway, that is worth considering, although I still like my low, direct tow behind hitch.
   
   
   
   Personally I don't like single sided trailer wheels, and have chosen to do double-sided on my cargo trailer (as well as most of my light kid's trailers).
   
   Ok, so much for photos of CAT bikes. Here's my bike.
   
   
   
   
   
   The heim joint works reasonably well for a hitch coupler. If only I also had put a kickstand on my bike to keep it from laying over. I would probably choose a version that maximize the range of motion (misalign).
   
   

CliffordK

Oh,
I should have mentioned, Eugene CAT (Center for Appropriate Transport)/Human Powered Machines does make a few of their tri-haulers a year, and could potentially build one, or rebuild one, or a couple of them for you. I assume they could be shipped, although perhaps awkward to ship.

Center for Appropriate Transport ? 455 W 1st Ave. Eugene, OR 97401
Human Powered Machines ? Eugene, Oregon

Let me know if you try to contact them and have troubles getting through.

The photo above looks topless, but they've also been experimenting with roofs. The latest version I've seen looks like a monster sized surfboard from front to back, made out of clear greenhouse twinwall polycarbonate siding. I doubt it keeps the rider dry from windblown rain, but it will help some.

Apparently UPS has also been experimenting with delivery bikes, I assume pedal assist.

dabac

1) tow bikes are likely to remain specialty items. Small production runs. For that, steel is easiest, most rational. Don’t think they’d need that much reinforcing as long as you’re relying on human power alone, we’re just not that strong. Biggest enemy would be flexing leading to fatigue, not power as such.
2) IGHs often have a torque limit - ”do not use a smaller chainring than xx together with a sprocket larger than yy”.
Unless you’re looking at trikes, there’s not that much to be gained from going custom. A standard triple crank with one of those extra wide cassettes ought to drop the gearing ratio to where maintaining balance becomes difficult. Assuming the derailer capacity is sufficient...
3) laws aren’t the same all over. But Europe is introducing laws to allow more high powered ebikes particularly for cargo applications. Mid- or hub drive isn’t that important if it’s already a purpose-built bike. Mid-drive allows the use of regular wheels, but I believe hub motors can be made stronger.
4) ergonomics doesn’t change much. The lower speeds will lower aero requirements, that’s about it. A good unloaded climbing position ought to be similar to a good flat towing position.
5) easier to use a hitch brake, like on car trailers. Basically a brake that activates automatically when the trailer starts pushing on the bike. Might need a lock-out on this if people are in the habit of pushing bike + trailer backwards.

elocs

I have been car-free for the 4 years of my retirement and so I use a cargo trailer to haul everything I need to haul. I never looked for anything in a towing bike but simply used the one that I have owned for 16 years now, a long wheel based recumbent--a Sun Easyracer EZ Sport and it will be the only one I ever use for towing since my back-up bike is another EZ Sport that I bought this past summer. It is a heavy and very comfortable bike that has worked just fine for me towing my cargo trailer in the city where I live which is built on a prairie and so it's flat.
My towing is all done strictly in the city where I live so gearing is not a big deal and there is never a need for speed.

I tow a Cycle Force Trail-Monster cargo trailer:
which I have modified by getting rid of the 20" quick release wheels and replacing them with the 16" Skyway Tuffwheels used by Bikes at Work which has made the trailer much less likely to flip over plus the 3" wide tires it came with made the trailer bounce. I got rid of the surrounding frame and so I saved 10 pounds and it rides smoothly and quietly. This trailer does have a 300 pound tow limit and I have hauled 250 pounds of patio blocks with it. But most of the time I'm not hauling heavy loads so in order to haul things and keep them out of the wheels I've used an under-the-bed plastic storage unit that takes up nearly the entire floor space and is a half inch higher than the tires. I spray painted it black so it matches the trailer and my bike is black as well so it looks very nice together. This is what works for me and my needs where I live, both bike and trailer.

hermanchauw

1) Frame. Steel. Possibly a heavy touring bike would be good for towing, but i am using a standard disc ready mountain bike and it's fine. No flex. A rim brake only bike could have more flex. I can't feel any flex towing an axle mounted trailer with 40+kg. I feel significant flex lugging weight on rear pannier and platform rack.

2) Sub 20 gear inch low gear. Standard mountain bike gearing. Mine goes to 18.75 inch and it is really neccessary on the hills. Not sure if lower is practical.

3) No comments. I have never tried ebike so i can't comment.

4) Full rigid. Fairly upright to have good agility. Wide handlebars for control. Mountain geometry to keep weight as rear as possible for braking.

5) No comments. I don't do long descents so i can't comment.

Overall, i think a standard mountain bike is good enough for this job without modifications.

fietsbob

Mid drive motor conversions have the various rear gear ratio combinations to apply that power..

hub motors lack that torque , but move you more quickly over flatter ground.