jawfish

Strapless Biking Part 1
john posted in rides on June 9th, 2008

All you biker boys and girls who haul your bikes on trailers or pickups have a set of ratchet or cam-lock nylon webbing straps to hold them down. They work pretty well inside a closed trailer or in the back of a pickup, but on an open trailer like mine they are an irritating pain-in-the-tail. They take too long to install, loosen, flap in the breeze, jam, fray, and rub your paint. They aren’t cheap and the ratchets are designed by some drop-out from the Technical Institute of Inner Berzerkistan. The most troublesome aspect of all, is finding the right length: they just won’t work at all in short stretches, so we couldn’t tie down at the proper angle to the edge of the trailer. With a five-foot wide trailer each bike’s outside hand grip is approximately at the trailer edge, so there is no place to tie to at the proper 45 degree angle. The inner ties interfere with the other bike.

So when we saw a new (to us) kind of locking chock on a fellow’s rig, my riding partner Matt demanded that we get some. I had a set of truly fugly but battleship-rated set of chocks made from quarter-inch steel channel on the trailer. Replacing them with new Bike Shoes from Pit Posse made it lots easier to load the bikes single-handed, and gave a positive clamp on the front wheel. They cost us about $70 each plus shipping.

Part 1: The Chocks – ATK Bike Shoes (only for dirt bikes)

..The inspiration.

These chocks are intended to bolt down to your trailer bed, but as an alternative to permanent mounting, our friend had them bolted to a sheet of plywood which he just threw in the pickup when needed.

....Bolted to the trailer bed.

You can see from the pictures that they are made from tube steel and are sturdy, with good welds and paint. It’s trivial to bolt them down, just drill and bolt. Don’t forget the Locktite and big washers!

Magic thread locker goo.

The mechanism is a bit hard to understand. Look at the picture above with the blue chocks. One is in the open and one in the closed position. One hoop reaches forward under your fender to grab some tire tread, the middle hoop goes along for the ride, and the biggest hoop is pulled down to apply pressure against the tire. This holds the bike upright and locked into the chock.

The Loading Sequence:

	Rolling up onto the trailer.
	Set in open chock.
	Look Ma, even with the chock open, the bike stays up!
	Push the first hoop as far back as it will go, and tuck into the tread.
	Pull the big hoop forward until the tire is squeezed.
	That’s it!

Once we had the chocks bolted down and tested, we were still in the same old situation with the rear of the bikes. Always the rear bounces around and slides sideways, even with a pair of tie-downs. I thought at first that I’d add a piece of of steel channel to the back for each rear wheel, and just tie the wheel down to the bed. But that would have made for awkward permanent trip-me-ups right in the middle of the trailer, and it just didn’t seem like the best solution. Worse, I didn’t have any scrap of the right size, like I did for the front. See Part 2 for the solution.

Strapless Biking Part2comment
john posted in rides on June 9th, 2008

In Part 1 I showed some nice new motorcycle wheel chocks called Bike Shoes, installed on my trailer. They eliminated the problems with using tie-downs on the front of the bike. No more compressed suspension, loose ties, and jammed ratchets. And they make loading and un-loading he bikes much quicker – something that happens four times on every ride.

But I still wasn’t satisfied with the system for the rear of the bike. If we just installed some channel or blocks to hold the wheels, the bike would still jump around when the trailer hits bumps, and the attachment points on the bike are too low and too close to the trailer rings to use a proper angle with the ties. Here’s what I did instead:

Part 2: Turnbuckle Tie-Downs

One of the problems with the nylon webbing ties is that they only work in tension, not in compression. As soon as you pull on them sideways they stretch or the ratchet gives a little, and there goes your tension. I thought of making some long poles with clips on the end, but without a way to adjust them, they would have too much play. And they would flop around and be in the way when not in use. But then someone pointed out that the foot pegs were ideal tie down points. They are strong and in about the right place for the trailer. Nobody cares if they get scratched, and they have holes for connections. They are much too close to the ground for webbing ties, but a turnbuckle fits the distance, roughly 12 inches, easily.

Turnbuckles come with closed eyes or hooks, however, both of which present problems. The hooks connect easily, but not positively, so you only get tension, not compression. The eyes require some sort of clip or bolt. But the turnbuckle itself is stiff and readily adjustable. (In the picture below you can see a modified turnbuckle with larger eye.)

..parts needed.

Attaching to the bed:
After some thought I decided to go on using the same 3/8″ eyebolts, that I had already used on the trailer for tie-down points. I needed to connect two eyes together. They eyebolts have an eye with approximately 7/8″ inside diameter, which is way to large for a connector bolt, so I scrounged through the little baggies of gear at the store until I found a bushing that fit tightly inside the eye. I needed a little Dremel work to grind the eye larger on some, but I left the bushing alone as it had flat sides. I held the bikes up in the chocks and measured each one ( good thing – they are different) to get a trailer attachment point with a good angle to the footpeg.

Rear view showing turnbuckle angle:

..Yes, that’s a trials tire I am testing.

So now we knew where to attach to the trailer and how long the turnbuckle unit should be to be able to reach and still tighten up. The eye bolt on the trailer had to attach to the eye bolt on the turnbuckle. So I took a bolt that matches the inside diameter of the bushing, two large fender washers, and the bushing, and make a sandwich with the bushing between and inside the two eyes. This makes a fitting almost as tight as a machined fitting, yet it can still rotate in two axes. Don’t forget to add a little grease and use Locktite on the nut. This combo gives you adjustment and a simple attachment to the floor, yet retains its stiffness in both tension and compression.

..Eyebolt with bushing.

..Finished joint.

Adjusting to each bike:
Now that we have a way to attach the turnbuckle to the trailer, we can look at the length. Our two bikes are a bit different and one was too high for the one size of turnbuckle available. So I used a piece of threaded rod and a coupling nut to make an extra-long eyebolt. Of course this meant I had to use the normal right-handed end of the turnbuckle, with the left handed end using the turnbuckle’s own eye. On the other bike I was able to just substitute a longer screw eye for the one that came with the turnbuckle.

In both cases I used an eyebolt with a larger eye diameter to match the eyebolts on the trailer. You can see this in the picture of hardware above.

..Made-up long screw eye.

..Longer eyebolt:

Connecting to the footpeg:
Now I had to connect the screw eye to the footpeg with some easy device that requires no tools, because this connection will be made and broken every time you use the bike. I had a couple of crude rigger’s carabiners with threaded nuts that worked fine for one side, but I only had two, so I sat and stared at it for a while. I decided to accomplish two tasks with one device: by using a padlock as a connector I would be locking the bike to the trailer, and solve the connector problem. It turned out that a standard padlock is just the right shackle size to make a good connection, so I bought a pair of keyed-alike ones. It might make sense to just use four padlocks if you try this rig. The padlocks are really easy to use, and make a tighter connection than the carabiners.

..Carabiner.

..Padlock.

Using the system:
You could use this system without the Bike Shoe chocks, and I used to do it by myself with the ratchet tie-downs using the bike’s kickstand. However there isn’t much slack in a turnbuckle- only about 40% of total length- and it might be difficult to get the first one on without losing the bike. So you might need a helper. One turnbuckle will hold the bike ( that tension plus compression), so the second one is not a problem.

We had already installed our slick new Bike Shoes (see Part 1), so loading the bikes is now easy and quick.

1) Roll the bike up and lock it into the chock.
2) Unscrew one turnbuckle and connect it to the footpeg, leaving some slack.
3) Repeat for the other turnbuckle. At this point the bike is extremely stable, but there is some play at the footpeg.
4) Tighten both turnbuckles. (Don’t over-tighten, for instance by using a lever, because a turnbuckle can exert tons of force. You might pull the eye right out of the bed or bend your peg.)
5) You are done. Go riding.

Tightening the turnbuckle:	Ready to go.

Before, even with four tie-downs on each bike, after a run up a rough road we always had to get out and re-adjust because the bikes were flopping around. The more they moved, the looser they got. The trailer has quite a rough ride ( the next trailer I build is going to have shocks). After, with the turnbuckles, the whole trailer moves as a unit, bikes and all. The bikes’ suspension is only slightly compressed beyond the resting position, and we automatically have the security of padlocks for those long nighttime stops at the Chinese buffet.

What else you can do:
For road racers who transport bikes a lot, this would make a great system. You will have to find a way to attach to the footpeg though. You could drill a hole right through the peg, but you could also make a backingplate with two holes, one for the peg-shaft and one for the turnbuckle. Then take the peg off and re-install it with the plate between it and the frame. You might want to bend the plate to get the attachment point away from the bodywork. Some bikes will have a hollow axle where you could put a skewer through the rear. Using two eyes, threaded rod, and coupling nuts you could make a skewer that would work. You could substitute a clevis pin or even a bolt for the carabiner attachment to the footpeg, but the padlock works so well, I’d advise to keep that.

The author	Brer Matt, the chocks were his idea.
	.. Yes Matt’s wearing a genuine Sharkbait t-shirt.