Hi, this is my first post in this forum. I'm a C&Ver/roadie but my cycling has expanded lately to utility, and I'm about to build a 2 wheel trailer. It would be used to carry dog food bags, plastic chlorine cans, 2-week groceries, etc. Max load shouldn't be over 40 kg, speed no more than 20kph, max distance 10 km, always on flat paved roads.
Now I have a pair of 26" low end MTB wheels in good shape (and I'm a bit of a cheapskate ). Some say 26"s are too big, CG too high, stress in corners greater, better 20"s or even 16"s. But on the other hand, I think big wheels roll easier, and speed would be fairly low. What do you think about it? Could it work?
Thanks in advance.

Build it so you can change the wheels to smaller ones later if needed. You already know the answer to your question.

I built this trailer back in the '80's using salvaged materials and old 20" wheels from a kids bike. Since this trailer is wood the center of gravity can be adjust just fine to fit 26" wheels.
https://www.motherearthnews.com/Do-It...e-Trailer.aspx

I don't know the answer because i haven't tried it yet, I was just asking if someone had actual experience with 26" wheels.

The link didn't work for me, thanks anyways.
I'm considering building the bed lower than the axles to lower the CG.

I've seen DIY trailers with 26" wheels. If anything, they'll roll over obstacles easier, like you said. I don't believe there would a problem with larger wheels when cornering. They're meant to carry people after all at much higher speeds.

One thing to keep in mind: watch your center of gravity; the lower, the better. So keep that in mind. With small wheels achieving low center of gravity is easier, depending on your design, of course.

Earlier this year I build myself a trailer with 26" MTB front wheels that I had lying around. Frame welded from Ikea sleeper sofa frame recovered from the street. Hooked up to the bike at the rear axle level (Burley style). Bed lowered for better gravity. I fit 2 x 15-20 gallon buckets with garden trash on it. Sometimes pretty heavy depending on what gets taken out of garden (grass <--> soil). Ride to the dump is about 2km each way. Part of it includes a reasonable downhill (Switzerland). Must have hit around 40kph on that. Trailer is very stable, both at low and high speeds, on straight and in turns. The only moment you really feel it is over speedbumps when loaded. This generates the same push-pull sequence as on a tandem bicycle. Apart from that, no problems, even when riding no hands on the bar.

I built the same trailer that Nightshade did and used 27" wheels. It did just fine. Smaller wheels will allow you to lower the center of gravity and they will take side loading better. But I always believe in "run what ya brung". Do what you can with what you have and keep on rolling. In my area 20" wheels aren't hard to come by at all. You just pick them out of the trash, along with the rest of the broken BMX bike.

Nightshade's link works fine for me. Run a google search for Mother Earth News Bike Trailer.

Aaron

fixed link.........

https://www.motherearthnews.com/Do-It...e-Trailer.aspx

Thanks all! I'll try the 26" wheels on a trailer built along Nightshade's plans, but with a 10 cm lowered bed. Will post when finished to let you know how it went.

Look into designs that place the floor of the cargo area below the wheel axle, several ways to skin that cat:

https://www.biketrailershop.com/blog/...-bike-trailer/

https://www.instructables.com/id/Bicycle-cargo-trailer--200-lb-capacity,-$30-for-pa/

keep the trailer C of G low, by building single sided wheel axle mounts
relatively high on the sides of the trailer. https://cycletote.com/

Vehicles that bank, and those that don't put different loads on the wheels.

On a two wheeled bicycle, due to the fact that the bike banks for turns, the wheels take minimal side loading, basically only when "throwing" the bike when off the saddle.

A two wheeled trailer puts side load on the wheels when it corners. Giving the wheels slight negative camber (leaning in at the top) not only gives the trailer a wider and more stable stance, but decreases the side load on the more heavily weighted outside wheel.

Burley dished the wheels a bit on the kid hauler I tow. This gives it a wider track, and helps keep the side panels out of the tires (still a problem) but it is exactly the wrong thing to do from a strength standpoint. (they are stronger if installed "backwards")

Wheel strength is only likely to be an issue if you use a highly dished rear bike wheel on a trailer. In this case, install it with the cog (flatter) side toward the center for best strength.

I'm using a front wheel and a rear one, but I removed the freewheel-side axle spacer/nut and redished the wheel to center the rim. OLD is only 110mm vs. 98 for the front one. Probably will space both dropouts at 110mm and put some spacers on the front axle.