Adventures with Bike Trailers...

[bobo333]

Thanks for the advice once again Kenny

That Surly hitch looks great but I cant for the life of me figure out why the left hand axle mounted hitch is better than a hitch at the back of the bike in the middle like nearly every other vehicle trailer hitch has, the only benefit i can see is ease of attachment to any bike frame as they all have a rear axle to attach to but the surly mount had the bracket that goes all the way around the wheel anyway so wouldnt mounting the hitch in the middle be better?

The bikes handling hasnt been affected noticably with my current design, its the trailers handling that im worried about, will the longer hitch arm help prevent sway at higher speeds?

I know about loading from towing car trailers for quite a few years but thanks anyway

[Kenny]

Originally Posted by bobo333

That Surly hitch looks great but I cant for the life of me figure out why the left hand axle mounted hitch is better than a hitch at the back of the bike in the middle like nearly every other vehicle trailer hitch has, the only benefit i can see is ease of attachment to any bike frame as they all have a rear axle to attach to but the surly mount had the bracket that goes all the way around the wheel anyway so wouldnt mounting the hitch in the middle be better?

The hitch mount on the LH chain stay is typically preferred because it allows transferring the trailer to multiple bikes. The LH side because it doesn't interfere with the gearing (deraileur and IGH shifting mechs). It's also easier to install without permanent modifications to the bike.

Mountings with hitches that pivot at the center/rear place the tongue weight (and hitch pivot point) further aft of the rear tire's contact patch. This location gives the loaded trailer greater leverage to effect the bike's handling - most notably during emergency maneuvers w/heavy loads or when the trailer tire catches an obstruction such as a pot hole. Just think of the conventional automotive bumper hitch Vs. the bed mounted 5-wheel trailer, common with the longer & heavier travel trailers. Semi's too utilize hitches that place the hitch weight (and pivot) directly over the tractor's rear tire's contact patches.

Originally Posted by bobo333

The bikes handling hasnt been affected noticably with my current design, its the trailers handling that im worried about, will the longer hitch arm help prevent sway at higher speeds?

Yes. The longer the tongue, the greater the leverage because the bulk of the trailer's weight is placed further aft of the hitch pivot point, which reduces lateral dynamic loads on both the hitch and the rear of the bike. The downside to longer tongues is the minor inconvenience of greater overall length (parking) and reduced maneuverability around tight corners.

[Kenny]

There's also yet another dynamic in-play when hooking a trailer to a bike (any two-wheeled single-track vehicle).

Bikes are not 'steered' (in the conventional sense) to navigate. We steer primarily to control the bike's CoM (center of mass). We do this by steering the tire's contact patches left & right beneath the bike's CoM. When the bike starts leaning to one side, we steer in the leaned direction to stop or slow the leaning. Ultimately, the bike is continuously zig-zagging left & right as we ride, but the faster we go the less it's noticed to the rider. So how does this affect trailer towing?

The bike's left & right 'leaning' pivots at the tire's contact patches on the riding surface, and intensifies vertically. So the higher you place the hitch on the bike's frame, the greater the lateral movement of the trailer hitch (not good). Conversely, the lower you place the hitch location, the less lateral movement occurs in the trailer (preferred). Make sense?

[bobo333]

Thanks a lot Kenny, you sure do know your stuff about trailers!

All of your points make a lot of sense. I think i might see if i can get a normal rear axle instead of a quick release to allow me to build a side mount hitch after all, i think it will be easier to do a RHS on mine though as it has a disk brake on the LHS which would get in the way

Thanks again

[Kenny]

Yur certainly welcome bobo. One last suggestion....

I'm using a telescoping tongue on one of my trailers so I can vary its length with a single cross pin. All I use is compatible OD & ID round tubing, then cross drilled about 4 holes spaced about 4". It's also handy when want to experiment with different hitches 'cause you needn't butcher or remove the whole tongue.

[Grant-53]

Another reason for the left side mount was the ability to lay the bicycle down without tipping the trailer. People were concerned about the bike falling over with children in the trailer.

[euromodder]

Originally Posted by bobo333

My trailers been up and running for a couple of weeks now

If you haven't already altered the trailer tongue, in this set-up it's going to sheer off where the vertical post meets the trailer frame.
Rather sooner than later.

The high-hitched bike trailer we have at work failed in a similar spot in a short time.


As suggested, put the hitch as low as possible on the bike.
I have yet to see a motorcycle trailer with a high hitch position

Bigger wheels would help, too.

[bobo333]

I did a few mods to the rear carrier yesterday as it was coming loose a bit and swayed side to side, some triangulation when looking from the top fixed that as well as bigger bolts holding it on...

but in the process i removed the trailer hitch mount at the back so now i need to redo that

Side mount is looking like the best option so that will be done when i get some spare time to nut it out

[Sven7]

Brought the good trailer home... used it to haul a project bike to the shop lol.


Varsity Towing par Tyler Linner, on ipernity

[Sven7]

Turns out I haven't updated this in forever. The wood trailer didn't really work out. It was too heavy to carry up and down stairs and didn't offer the smoothest ride in the world.

After that I tried to make a trailer out of a 66" (1.67m) long plastic toboggan that was on sale. I figured that it was long enough to fit big items, but perfectly fit my plastic bins side to side. Mounting some angle iron underneath it, I put the allthread axle through and bolted my white 20" wheels on. I had a friend weld up a hitch arm and bolted in the hitch from the blue trailer. It didn't work very well. The whole thing twisted really badly and it was too long to carry up the stairs to my apartment.

I salvaged the good parts off of it and took a look at my friend's trailer. He used a Kmart In-Step kid-hauling trailer as a basis for a big flatbed. Removing the fabric canopy, he added an X-frame over it with a piece of plywood on top. It was tall enough to clear the top of the tires, acting as both fenders and a way to carry really wide items without hitting the tires. Buying a ready-made trailer took over the work of building a sturdy frame- all he had to do was adapt it to his liking.

Picking up his new bike at the UPS center


I decided I liked the basic premise, but wanted to undersling the cargo bay and make use of the trailer's design. I bought an almost identical In-Step trailer for about $125 (I thought it was going to be on sale), obnoxiously hauled it home by bike and promptly stripped it down. After a bit of work and some eye rolling from the girlfriend, I ended up with this.



Supported by 2x4's scavenged from a discarded pallet, and topped with a sheet of luan plywood. I positioned it to balance fairly well over the axle and screwed it on through the metal frame.




It got a coat of primer, then Rustoleum to protect against bad weather, since I am quite hardcore about this and will not bat an eye at cargo biking in the rain or snow. I noticed, though, that my cargo kept sliding over and rubbing the wheels. This was especially problematic when hauling bikes. I was just barely able to carry a Schwinn Varsity to a flea market.

I was also having a hard time finding places to strap things down, and, worshiping the Bungee Gods, needed to add some hook points.



Some side plates just barely fit on the inside of the frame rails, so I drilled some 1" holes and bolted them on. They're not yet fully painted.

The local bike junk shop (I say that lovingly) had a random axle block sitting around, so I picked that up and mounted it on the front. I can now haul most bikes upright on the trailer with no issues at all. The whole thing is about the length of a bicycle wheelbase, so they barely fit. I picked up my fatbike in December by towing the trailer to the bike shop, attaching it to the new fatbike, and towing home my "old" commuter. It worked alright.

I made some small aluminum L-brackets and attached coroplast fenders with splash guards to keep my cargo dry. Then I added a few reflectors for visibility and continued to beat the crap out of it. I actually used this trailer and my fatbike to move a good deal of stuff from my old apartment to my new house. It performed quite well. Six paper boxes full of random junk did not stress the trailer, but they were a bit heavy for my taste.



It even takes longer things, if I'm very careful.



That's about where I'm at with this whole trailer thing today, but I'm not done. A few things that need fixing are:

-Hitch is too high, so I'm planning on transplanting the 20" wheels onto this to level it out.

-Trailer is too short on the front, and I can't balance really long items on it without hitting the bike tire. I am planning on building a longer hitch arm and extending the cargo area.

-2x4 structure is heavier duty than the luan, so I want to build a new top using 2x2's topped by 1/2" OSB.

-The side plates are great, but a little weak at the frame attachment point, and I wish there were more of them. I'll figure something out...

And so continues the DIY bike trailer saga; I am forever building the perfect trailer. It should be said that all the above was done with hand tools and a DeWalt corded drill in a second floor apartment. Nothing fancy (you can do it)! If anyone has questions about trailer construction or whatnot, feel free to PM me. I've got ten years and five trailers of experience!