jskita

I am building a 2 person (adult) trailer. It's a project that has gone a bit out of control with the weight and budget! Started with scrap metal then over built it for safety. I have been trying to find inexpensive wheels for it. I designed it around 26" wheels and initially thought of getting an old CL cruiser and use the tire and wheels but then thought about the sprocket that I don't really need.


Is there a type of wheel that I am not privy to. My gut tells me that it might be a steel 20" but I have been trying to avoid more weight because it's so heavy already.


My guess the trailer is around 50 lbs+ with no wheels.


Anyone know about these wheels? They are flat free but will they go 10mph?

https://lappwagons.com/product/flat-...BoC44gQAvD_BwE


This one looks better:

https://www.northerntool.com/shop/to...0579_200660579


But I am wondering if anyone has experience with this and has any better suggestions.


Thanks!

JoeTBM 

Not sure if "inexpensive" for a set of wheels for a 50# trailer + 2 Adults works

Not sure what the bearings would be in the ones you listed, watch your axle diameters too, you have 3 different sizes there.

I would think that a rear wheel set for an adult trike would work, available in 20", 24' & 26"

If you want to build the wheels, here is just the hub

https://www.walmart.com/ip/Sun-Bicyc...3f9d112b9b3334

20" wheels (pair)
https://www.ebay.com/itm/20-tricycle...IAAOSw7R9cL-br

24" wheel
https://www.ebay.com/itm/Rear-Wheel-...wAAOSw5wJcIDnZ

26" Wheel
https://www.ebay.com/itm/ADULT-BIKE-...gAAOSwNDJac6MS

AnkleWork

It's usually a very bad idea for a trailer to out-weigh its tractor, especially so when the tractor was not designed for towing.

dsbrantjr

Have you given any thought to the kind of brakes you will need to stop the bike, the trailer and 3 adults? I am pretty sure that the bike's brakes will not do an effective job, and jackknifing the trailer will be unpleasant to say the least. You will need a pretty stout trailer hitch as well.

jskita

The thoughts on braking did cross my mind. I will not be going fast though. I also have gears so the tractor should be able to pull some weight. I might break my cranks though.

I was hoping to find some advice from forward thinkers (or maybe just plain crazy) like CliffordK https://www.bikeforums.net/20928718-post25.html

I'll send some links of the hitch ideas once I'm on a real computer. It all should work if I go slow.

hokiefyd 

I have a trailer that I fashioned out of a Thule Chariot 2 purchased for $25 with faded/molded/rotted canvas. The first picture shows the hitch type and some of the trailer when I was still building it, and the second picture shows the complete deal. I estimate the trailer to weigh about 20 pounds, and I pulled my 11 year old daughter around the block when I was testing how it handled weight. I guess it probably grossed at 100 pounds.

I would not want to tow more than that, and I actually wouldn't even pull anywhere close to that on a regular basis. The bike handles okay, and the braking is okay, but there's significant strain on the drivetrain, especially when cranking up a hill (even in low/low). Fortunately, there's not a lot of direct stress on the bike's frame, as the motive force is right at the axle (where the hitch also mounts). If you have your hitch connected somewhere else on the bike, then you would be directing that force through the bike frame.





Another comment I have is regarding weight distribution. With as large as it sounds like your trailer will be, weight distribution will be difficult to manage, or even get right to begin with. Please excuse my comments if you already have a lot of experience with towing, either behind a bike or behind a motor vehicle, but you'll need to make sure to get weight distribution correct. You generally want the axle to carry most of the load, with the tongue (hitch) carrying some of the load. A good rule of thumb is about 90% / 10%. I don't know if your two adults would be sitting longitudinally, bobsled style, or two-abreast. If the former, it'll be very difficult to design the system to be correct -- you'll have to know the weight of the riders and position the seats so that you get most of the weight carried by the axle. In that case, you'd have to always have two riders, or carry ballast if one is not there. If the latter, it'll be easier to accommodate a missing rider, but the reduced length of trailer means it'll be more difficult to balance. Under no circumstances do you want more weight behind the axle than in front of it. In that case, your hitch area will become light, potentially lifting the rear of your bike off the ground if the momentum of the force is strong enough.

Keep in mind that many off-the-shelf hitch systems have an engineered point of failure. In the Thule system that I have, the hitch cup mounted to the frame is metal (appears to be cast aluminum), and the tow arm (tongue) mounted to the trailer is metal (box-formed aluminum), but the hitch coupler itself (the ball) is plastic. Most hitch systems are similar, so that something is designed to break away in the event of something unexpected (like too much weight, or too sharp of a turn, etc). In my case, the plastic ball is going to fail before something metal bends or cracks or snaps. Whatever hitch system you're using, be sure that any designed-in weak point will be strong enough to support and tow the load you have planned.

AnkleWork

With about 500 lbs. all up, cheap bike wheels on cantilevered axles will look funny when they buckle.

Try something like:


Load rated and very cheap.

hokiefyd 

Ya know -- that hand truck wheel gave me an idea that may be helpful to the OP. Rather than building a typical single-axle trailer, you could build more of a "wagon" for transporting multiple adults. Think of a gardening wagon with four of those pneumatic tires suggested above, with the front axle being steerable. That would completely eliminate the problem of proper weight distribution, and would remove all weight carried by the bike itself. You'd still have the issue of drivetrain strain, braking capacity, and bike frame torque if your hitch is not right at the rear axle, but you would add a margin of safety with a "wagon" instead of a "trailer".

AnkleWork

Or a big tricycle with only one steerable wheel in front, you know, to save weight and money. LOL!

jskita

I was thinking of a seatpost mounted hitch - along these lines.


@hokiefyd - I think I lucked out regarding the weight distribution part because it's just forward of the axle
@AnkleWork - I did design it for a larger wheel but the 500lb capacity sounds great!

My passengers are seniors who started shrinking already. Doubt they are over 100lbs. I just want them to get some fresh air.

AnkleWork

Maybe lose the bike and its problems altogether. Build an adult sized one of these:

jskita

After looking at that seat post mounted hitch it looks like I need the other end to take care of the up and down rotation, like on a hill or gutter. This ball might take care of that but now I am thinking of that axle mounted design.


@ hokiefyd - thinking of the front wheel idea, but would that create a strange connection between the bike and trailer? I guess maybe pivot points a both sides of the connection. I imagine the bike going down a curb and the trailer then pivoting on the front wheel and the rear wheels coming off the ground?

AnkleWork

Just WOW! You should probably consider dynamic loads.

hokiefyd 

Looking at your drawing (nice, by the way!), I think your static weight distribution will be okay (favoring in front of the axle), but with a trailer that short, and with your weight essentially directly over the axle (which is where you want it), the dynamic load will vary quite a bit. Going up a hill, or your passengers lean back or forward, or even if you go off a driveway dip or similar. The shorter your tow bar, the more your trailer will pitch back and forth, which will definitely change your dynamic weight distribution.

Regarding going off a curb or an uneven surface with a self-supporting wagon/trike/etc., I think you'd have to have a movable tow bar. Literally like a wagon, where the tow bar could move up-and-down and side-to-side in relation to the bike.

jskita

Ok I took a trail run today...wife actually volunteered to be the passenger! She's survived but the hitch did a weird thing so I am trying to rethink that hitch. It swiveled around my seat post then lowered itself because of the balls attachment to the post. Gouged up my rear rack a bit too. Thought the safety chain came into play but the hitch stayed on the ball.

I think the ball is great because it can swivel on multiple axis so the seat mounted clamp needs a way to stay fixed.

Sorry I don't have pics of it mounted. Also I never got my tires and wheels yet, I just took front tires off my other bikes for now.

hokiefyd 

Wow...that's quite a trailer! I imagine that's a pretty heavy pull. I'd probably be wanting something electrified before too long! :-)

It looks like very nice craftsmanship...great job so far.

Leebo

Over thinking it. Ever seen a pedicab? Trike, driver pedals, double seat out back. They are in most big cities in the US. Just buy one.

Retro Grouch 

Look at the front wheel design on tadpole recumbent trikes.

Bicycle wheels are designed to be supported on both sides. There are lateral forces while cornering to be considered too.

CliffordK

For Kid's trailers, I much prefer a wrap-around frame design like the old Burley Trailers.



I think it allows a strong, lightweight trailer that uses standard quick-release (or bolt-on) wheels.

It also somewhat isolates the wheels from bumping into stuff.

If you do decide to use the one-sided trailer or trike wheels as above, I'd encourage using a full width solid axle.

My "Heavy Hauler" has wheels with coaster-brakes from kid's bikes. I had originally intended to design surge brakes for the hitch (like many boat trailers use), but never got around to hooking that up. I have seen someone who has done it.

My belief is that if one is riding mostly flat land, and only human powered, that one can generally stop if one's careful. You'll need much better brakes if you are doing electric powered.

CliffordK

Oh, and here is the Heavy Hauler.



Wheels are 16x3 from a Schwinn Stingray OCC kid's bike. Tires are a moped tire.

As mentioned, it has the original coaster brakes on it, but not hooked to anything. I had thought I could probably attach the brake to either the sprocket or to the reaction arm.

Litespud

braking considerations aren't for slowing down under controlled conditions - they're when you have to slam on the brakes due to some unforeseen circumstance - it's at that point the weight of the trailer - which up to that point had been manageable - becomes a serious issue, as that heavy unbraked object either tries to run you over or pull you to the side.
Clink & Clack the car guys tell the story of a couple of "mooks" who were transporting some large sheets of plywood on the roof of the car - one driving with one hand and holding the sheets with the other, and the passenger holding the sheets on the other side. They accelerated slowly, cornered gently - everything was going great, until someone pulled out in front of them, and Driver Mook had to slam on the brakes. The previously-manageable plywood shot forward off the roof, taking the hood ornament (and some of the hood) with it.
Everything is under control until it's not.
You want the trailer to be doing at least some of the braking. Since you're clearly able to design and fabricate, I would look into some form of rider-operated cable brake (cable would allow you to incorporate a cable splitter for detaching the trailer). If the bike is going to be dedicated to this purpose, you could operate the trailer brake off the bikes rear brake lever

CliffordK

For 100% Human Powered, I find is that speed is related to weight.

So, if I'm pulling 400 lbs, I'm lucky to get 5 MPH on the level, sometimes even slower. It is frustrating when pedestrians start passing me.

Although, liability when you're pulling "Precious Cargo" is also more important.

Hills, of course, completely change the brake equation. A major hassle for climbing the hills, but descents can be tricky if a rapid stop is required.

Electric Assist changes the equation, so if you're pulling a load that you should be pulling at 4 MPH, but rather are pulling it at 20 MPH... you need to be prepared to STOP.

jskita

It's heavy, but I don't intend to go over 5mph. It's got some pretty ugly welding. But thanks for the compliment.

@Leebo
It's built with a lot of scraps and remnants. I've not seen any affordable pedicabs so which is why I made it. Only intended to get my in-laws some fresh air.

Vintage Schwinn

From your photo it appears that the engineering and design are indeed , top-notch, however the weight will likely make it a perfect candidate for an EZ-GO or CLUBCAR and not for a bicycle powered by just one human.

It is a very cool design. I'd imagine that if you could design it to have a some "train like coupling" where you could connect a "train" of two or three of these (exact clones of your proto-type design etc.) behind a four wheeled, battery powered (electric) EZ-GO or CLUBCAR golf car. That would be an excellent pracical use for your well-built prototype. I think that you will find that though your design is just too heavy in its current configuration to be practical for use with any bicycle.
You might wish to see and essentially copy or acquire one of the old ancient Rickshaw type cab bicycles that were everywhere in Vietnam and are still seen in India and sometimes among some of the destinations that contestants on the active television game show, "THE AMAZING RACE" visit during their travels during the competition.

3alarmer 

...if you do this again,, buy a surplus wheelchair at goodwill or the salvation army. A significant number of homeless guys here use wheelchairs as gear transportation vehicles. It's not difficult to pull the wheels, hubs, and axles from a wheelchair, and they're designed to bear a heavy load. Please do not take one from someone who needs it. Look for one not with solid tyres, but inflatable tyres to save on weight.

The problem with attaching your trailer hitch to your seat post is that all the forces from the trailer are directed pretty high up, relative to COG. So most serious trailers are designed to attach at the rear hub/dropout/axle area.