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Custom trailer build questions

Old 10-23-22, 09:46 PM
  #1  
tegnamo
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Custom trailer build questions

I’m looking to make a cargo trailer akin to the Surly Bill https://surlybikes.com/parts/bill_trailer or the Bikes at Work trailers (their site is down at the moment).

That Surly one is 24” wide but I’d like to get closer to 4ft wide. I realize wider gets dicey traveling in bike lanes and such, but I don’t plan to use it in the city.

I’m looking for a sort of DIY kit to get me started. But maybe someone has a handy bill of materials for what to buy to create the rolling chassis? I’m sure it’s easy to buy the proper wheels and all that but if there’s a “go to” list of items for the axle, wheels, hitch thingy, etc that would be swell.

I’m hoping it can handle at least 300lb like the Surly can.

Maybe I can just buy the Surly and cut it down the middle, and widen it with some new square tubing

Last edited by tegnamo; 10-23-22 at 11:27 PM.
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Old 10-24-22, 10:20 AM
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Unless you plan to use it on a different planet than the Earth, a 4' wide trailer is just a non-starter. Even rural roads that are almost off-grid constrain the size of what you would pull behind a bicycle. Have you looked at motorcycle trailers? I can't see anything wider than 36" being practical. I'm sure there is stuff at Instructables.com to get you started, but you really should think about why the existing trailers on the market are ALL built the way they are.
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Old 10-25-22, 06:32 PM
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I'm going to use it on my farm/property.

I did look at some ATV and small conventional trailers. There is one from Harbor Freight that is kinda weighty. It could work, but it's wasting a lot of the towing capacity of my bike setup.

I'll look at motorcycle trailers!
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Old 10-25-22, 11:09 PM
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Originally Posted by tegnamo View Post
I'll look at motorcycle trailers!
Motorcycle trailers are going to be even heavier. You really can't do better than the Bikes at Work stuff. I saw one that must have been 8' long. If you want uber wide you really are going to have to build it yourself. Atomic Zombie has some interesting stuff if he is still active.
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Old 10-26-22, 07:59 PM
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Looks like Bikes at Work sell their wheels and axles and a few other bits. Possibly I could work up something custom based on that.

I had a really weird idea of buying some aluminum motor ramps and welding them side by side, and making that the platform for the trailer. They are rated for pretty high weights!
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Old 11-15-22, 09:54 PM
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My trailer search has come to an end it seems.

I considered:
  1. Buying a welder and welding my own. Not in the cards for a few reasons right now.
  2. Buying tubing and lots of screws and bolts. I just felt like it would be a little fiddly and I'd be chasing loose joints. At least for the size I wanted to build it didn't seem practical.
  3. Buying a Bikes at Work trailer. But their lead times are 6 months unless you tack on $240 for rush and then it's still not for another month or so.
  4. Following the lead of this cyclist from Boston. He bought an aluminum cargo basket that goes into a car hitch and then bought some BaW parts and made a trailer. The basket is only $150 or so! That's pretty crazy. I didn't want a "basket" style so much, however. I want a sturdy flat deck. Maybe coulda made it work, but didn't go this way regardless.
  5. Making one from t-slot (80/20) extrusion. I spent quite a few hours playing with the 80/20 catalog in Solidworks and seeing what I could come up with. I think my design is sturdy enough, and if you have the cash it's actually a pretty easy assembly process with no fab required I think. I also like that you can make adjustments to the components. So if you wanted to slide the axle forward or back, you just loosen the t-nuts and do it. You could even set it up where the whole trailer body could be widened or narrowed on the fly. Bikes at Work sells the axle, wheels, and hitch, and then you just need to create the main frame. Unfortunately after all was said and done, I had a trailer that cost between $1300 and $1400 at a minimum. A bit rich for me. But it was a fun exercise! Here's what I came up with before I realized it was a bit too expensive.

I used the lightest 1.5" extrusion and tried to not go overboard. If I had my own little machine shop I could have made some of the more costly aluminum parts I'd buy from 8020's catalog. They charge a fortune for little bits of aluminum. The extrusions aren't actually that expensive for what they are. $270 for all of the extrusion cut to length at the factory. But BaW's parts contribute a significant cost as well.

Okay, so what did I actually do? I eventually decided to buy the very last Surly Bill trailer from QBP! I definitely appreciate the steel construction and it seems quite nice although I haven't received it yet. I may have gone with a BaW trailer if their lead times were not so long. Alas, I couldn't convince myself to wait. It's more narrow than I'd like but I can build around it I think. I just have to be careful that I don't create something too tall and tippy because the trailer is only 2 feet wide! I bet...given some more time investment, I could widen the axle and get an extra 6 inches on each side. The axles are a cool quill-stem design which means you can just pop them out. Would actually be a nice axle to DIY a trailer with.

One thing that will be interesting is how I hitch it to my Tern. I wound up buying the Big Dummy hitch because the other one wasn't in stock. I think I can ditch the long bar and just connect the joint to my Burley hitch which is bolted to the side of the Tern. We'll see...

Last edited by tegnamo; 11-15-22 at 10:15 PM.
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Old 11-15-22, 10:00 PM
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I made a torsion box trailer out of 1/2"plywood and 1/4" plywood skin I used the wheels and mounts off my burly trailer and the hitch too. it was about 35 pounds for a 4 foot long trailer. made a 6 footer too. I did use my Cnc router but it was nothing special. really ribs that were hollow.
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Old 11-15-22, 10:10 PM
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Do you have any photos? And can you explain "torsion box"?

Sounds neat! I totally could have made one from wood. I'm sure it would have been great. Maybe when I have more space...
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Old 11-27-22, 10:50 AM
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Looks like you made a good choice. A liitle more info: Not only is that slotted aluminum very pricey, it also does not assemble in a very rigid manner, lots of the connectors are single screw and can rotate. Great for prototyping when you need flexibility, not the way I would go for final product - price or rigidity
Originally Posted by tegnamo View Post
My trailer search has come to an end it seems.

I considered:
  1. Buying a welder and welding my own. Not in the cards for a few reasons right now.
  2. Buying tubing and lots of screws and bolts. I just felt like it would be a little fiddly and I'd be chasing loose joints. At least for the size I wanted to build it didn't seem practical.
  3. Buying a Bikes at Work trailer. But their lead times are 6 months unless you tack on $240 for rush and then it's still not for another month or so.
  4. Following the lead of this cyclist from Boston. He bought an aluminum cargo basket that goes into a car hitch and then bought some BaW parts and made a trailer. The basket is only $150 or so! That's pretty crazy. I didn't want a "basket" style so much, however. I want a sturdy flat deck. Maybe coulda made it work, but didn't go this way regardless.
  5. Making one from t-slot (80/20) extrusion. I spent quite a few hours playing with the 80/20 catalog in Solidworks and seeing what I could come up with. I think my design is sturdy enough, and if you have the cash it's actually a pretty easy assembly process with no fab required I think. I also like that you can make adjustments to the components. So if you wanted to slide the axle forward or back, you just loosen the t-nuts and do it. You could even set it up where the whole trailer body could be widened or narrowed on the fly. Bikes at Work sells the axle, wheels, and hitch, and then you just need to create the main frame. Unfortunately after all was said and done, I had a trailer that cost between $1300 and $1400 at a minimum. A bit rich for me. But it was a fun exercise! Here's what I came up with before I realized it was a bit too expensive.

I used the lightest 1.5" extrusion and tried to not go overboard. If I had my own little machine shop I could have made some of the more costly aluminum parts I'd buy from 8020's catalog. They charge a fortune for little bits of aluminum. The extrusions aren't actually that expensive for what they are. $270 for all of the extrusion cut to length at the factory. But BaW's parts contribute a significant cost as well.

Okay, so what did I actually do? I eventually decided to buy the very last Surly Bill trailer from QBP! I definitely appreciate the steel construction and it seems quite nice although I haven't received it yet. I may have gone with a BaW trailer if their lead times were not so long. Alas, I couldn't convince myself to wait. It's more narrow than I'd like but I can build around it I think. I just have to be careful that I don't create something too tall and tippy because the trailer is only 2 feet wide! I bet...given some more time investment, I could widen the axle and get an extra 6 inches on each side. The axles are a cool quill-stem design which means you can just pop them out. Would actually be a nice axle to DIY a trailer with.

One thing that will be interesting is how I hitch it to my Tern. I wound up buying the Big Dummy hitch because the other one wasn't in stock. I think I can ditch the long bar and just connect the joint to my Burley hitch which is bolted to the side of the Tern. We'll see...
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Old 11-30-22, 12:37 PM
  #10  
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Originally Posted by SoCaled View Post
Looks like you made a good choice. A liitle more info: Not only is that slotted aluminum very pricey, it also does not assemble in a very rigid manner, lots of the connectors are single screw and can rotate. Great for prototyping when you need flexibility, not the way I would go for final product - price or rigidity
Yeah I had to spend quite a bit of time figuring out how to prevent rotating of the struts. There are a few connectors they sell which prevent it for sure. But not as robust as welding!
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Old 12-01-22, 11:03 AM
  #11  
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Originally Posted by tegnamo View Post
Yeah I had to spend quite a bit of time figuring out how to prevent rotating of the struts. There are a few connectors they sell which prevent it for sure. But not as robust as welding!
As you noted stopping rotation is a constant issue and the hardware is comically expensive. The connectors are all expensive, but the ones that have multiple connection points that stop rotation are comically expensive. Great for prototyping, but as you said, a few pieces of steel or aluminum tacked together will be stronger and cheaper.
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