Introduction: Anti-Theft Moto & Bike Helmet Tether Lock
Oh, the beauties of motorcycling and biking. While riding on two wheels is among life's best pleasures, arriving to your destination with several pounds of gear to store most certainly is not.
This guide is going to illustrate the best way to securely tether your helmet, jacket or other gear to your bike or motorcycle. To boot, it's quick and cheap to make, and can be custom made for any gear, lock, bike, or situation. You can even use the same technique to make a security tether for a Go Pro action camera, to crimp high amperage battery lug cable terminals, to make stainless steel rope balcony barriers, or heavy duty load bearing slings. It really is an awesome and versatile thing to be able to make and skill to have, so I'm sure that you'll find plenty of future uses for it.
Tool Level: Basic-Intermediate
Time: 1 Hour
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Step 1: What Is This?
Most motorcycles these days come with a metal hook of sorts under the seat to be able to hook your helmets D-rings. While this does work, I've never been fond of it. Sometimes the D ring strap just isn't long enough to reach the hook with the seat attached, and besides that, the strap is way too easy to cut to even be called theft resistant. You might say "sure, but if you cut the strap the helmet is worthless", and you're completely right. The problem is that most thieves find this out after cutting the strap. Doh!
Looking for a better solution, I didn't find anything reasonably priced, or versatile enough to be worth it. Sure, there are retractable cable locks out there, but the cable is way too short, and so thin it can be cut with a pocket multi-tool and some patience. I wasn't really willing to trust my 400$ helmet to that. Eventually I just resigned myself to make my own, and I'm totally glad I did.
The cool thing about this is that you can make it as short as possible for compactness, or long enough to hold two helmets or to loop through the sleeve of a jacket. You can also make it with thin wire, or with a beefed up wire for extra toughness. It's your call.
Security-wise, I feel pretty confident with this. No, it's not theft proof. Nothing is. But for the weight and size of the cable you can't beat it. Personally, having used bolt and cable cutters since I was a kid, I find it much easier and quicker to cut budget bar locks than safety cable like this. Any cheap bolt cutter will cut a budget lock rod instantly, but to cut a thick cable quickly with hand tools you need either an expensive cable cutter, or time. You'll get through both in the end anyways. All in all, this is what you'll need to ward off opportunistic theft when parking the bike for short to medium stops. Even safer if you put the helmet in a helmet bag. Like they say, the game is not about being theft-proof, but about being more theft resistant than the guy parked next to you.
I personally use mine all the time. And hopefully you will, too.
Step 2: What You'll Need
- Vinyl Coated Stainless Steel Wire Rope: This is the main component, and it comes in different thicknesses, wire material, wire configurations and coatings, etc. For a short helmet tether, I prefer the thicker sizes. For a longer tether to be used with a jacket, I'd go with a thinner one (for portability, mainly). The one linked is 1/8" stainless steel wire coated with clear PVC Vinyl to 7/32". Inventory does vary, so the thickest wire that coated is around 5mm would be best.
Aluminum Crimping Loop Sleeve: This is what we'll be crimping to secure the wire. We need it to fit at least the diameter of the coated wire. They can be purchased in different materials (and sizes), but for this purpose aluminum is the easiest to crimp, cut and grind. Plus they're cheap. If you're okay with a longer shipping time in exchange for a cheaper price, click here.
- Hydraulic Crimping Tool: This is what we'll be crimping the sleeves on with. If you don't have this type of tool in your garage already, you're gonna like it. It applies 10 tons of crimping force, and can be used for crimping battery terminals, hydraulic or pneumatic lines (within reason), and of course, steel rope crimping sleeves. I used to use a manual swaging tool (which ironically cost me more than the hydraulic one) but it leaves horribly deformed sleeves (perfectly secure, but not as streamlined). The hydraulic tool is a lot more versatile and useful.
- Saw: I used a deep cut saw to cut the rope and the sleeve, but a manual saw and some patience would also work fine.
- Bench Grinder: Used to grind down the sleeve after crimping to make it smoother. You can also use it to cut the wire rope in a pinch.
- Adhesive Heat Shrink Tubing: Depending on what sleeve you use, and how you crimp and grind it, one size or another will be needed. I like the adhesive type of heatshrink better since it's thicker, seals the wire, and doesn't move. Don't skip this step since this heatshrink is what will be keeping the sleeve from scratching your fairings, helmet and frame.
- Heat Gun: Used to shrink the Heat Shrink Tubing.
*Note: For more info on wire rope, such as strength, wire configurations, etc...click here.
Step 3: Make Some Decisions
The first step is to take a look at your bike, helmet, and tools to decide how you are going to do this.
I've made this type of tether for a plethora of bikes, but today we'll be working on a 2017 Kawasaki Ninja 650 ABS (though it would probably also apply entirely to the Z650). It's an odd specimen, since it has the cut in the fairings for a helmet strap, but it isn't advertised as having helmet hooks in the owner's manual. Anyway, that hook there is perfectly suitable as a helmet hook so that's what we'll be measuring off.
I'll go ahead and mention it now while I'm here. I was considering taking pictures of a test hanging a hundred pounds or so of sand bags from the tether, just to prove it's strength, but I deemed the effort pointless. A chain is only as strong as the weakest link, and in this case that link is that small little helmet hook. The 1/8" wire rope used has a breaking strength of 1760 pounds, so you could hang the whole bike from it, or rip the helmet apart. In either case the cable's strength isn't the issue. Anybody stealing the helmet would cut it (versus tugging on it) anyway.
As far as the helmet goes, I'll be using my awesome HJC RPHA Max Evo Dorgon, which I imported from Europe just because I'm a micrometric quick release strap fanboy (Though if you want to add a quick release to your helmet, I made an Instructable for that). Let me say by the way that that's as expensive a helmet you'd want to attach to your bike this way. Any more expensive and you really should be taking that helmet with you.
Step 4: Cut the Sleeve
Properly crimped, the sleeve should withstand as much strength as the rope itself. In this case that would mean 1760 pounds, which we really don't need at all. What we do need is a compact joint, which is why I cut the sleeve in half. This makes the tether a lot more conveniently shaped for ease of use, and I recommend doing it.
Also worth mentioning now is that when you crimp the sleeve, it expands outwards. In other words, if now the crimp is long, it will be a bit longer crimped.
Step 5: Place the Sleeve on the Wire Rope
Decide how big a loop you want. Personally, I find it best to make a loop as small as possible, only big enough to fit on the bike's helmet hook. We will have to pass this loop through the loop on the other side of the tether, so smaller is better.
To push sleeve closer to the loop and make it smaller, pinch it with some pliers to make the wires parallel. Then you can move the sleeve up.
Don't worry about the excess wire, we'll be cutting that later.
Step 6: Make the First Crimp
Now it's finally time to start crimping!
Working the crimping tool is a lot like using a car jack. Rotate the knob clockwise until it's fully closed, and start pumping the handle until you can just barely fit the sleeve in. Then place it inside, make sure the jaws are parallel and the sleeve properly positioned, and start crimping slowly. Once the jaws are touching, stop.
You'll want to totally crimp on one side first, and then the other. Don't try doing it all in one go. Also, remember that the tool applies up to 10 tons of force, so keep your fingers to yourself.
I should also add that, if strength was a concern, you really shouldn't be crimping over the coating. The coating should always be removed under the sleeve. However here the priority is not scratching the bike or the fairings. No one will be pulling on the tether with more than a hundred or two pounds of force (in a worst-case scenario), nowhere near the almost two tons of pull the wire can take. The helmet hook will fail much, much sooner anyway. In other words, here we can crimp over the coating with no fears at all.
Step 7: Finish the Crimp
Now we have to finish the crimp. Crimp the uncrimped portion of the sleeve, and then release the mighty force of hydraulic pressure.
You can then keep crimping on any uneven portions of the sleeve until you're satisfied.
Step 8: Test Fit
Test it on the helmet hook just to make sure no screw ups were made.
All good? Good.
Step 9: Beautify the Crimp
Crimped sleeves don't have to be pretty. And they seldom are. However here we don't want jagged edges scratching the fairings or helmet, and we also need it to accept the heatshrink well.
First cut off any excess rope, and grind it to remove all the sharp edges. Extra points if you form it until it looks streamlined like above. It goes without saying that you shouldn't remove too much, though.
Step 10: Add Heatshrink
To keep the aluminum sleeve from scratching the helmet, frame or fairings, Double Walled Heatshrink is a must. "Double Walled" refers to the fact that the heatshrink has a thermal adhesive on the inside which melts when the tubing is shrunk. It's also known as adhesive or marine heatshrink. This type of heatshrink is also a lot thicker than the normal heatshrink, which is desirable here.
And while I'm sure that more heatshrink gets shrunk with Bic Lighters than with any other tool known to mankind, the right tool to use is a heat gun, preferably adjustable. I used a rework station heat gun set to 250 degrees centigrade to shrink the tubing for the best result.
Finally, test it again to make sure all is well.
Step 11: Slip on the Heatshrink
This is the part that always gets forgotten. Before crimping the other side, we have to slip on the heatshrink that will cover it. Once both sides are crimped you can't slip on the heatshrink. Guess how I know...
Step 12: Crimp the Other Side
Now we have to repeat steps 5 through 10 on the other side.
Same as before, just that this time we need to make the loop much larger. That's because the other loop has to be passed through this loop.
Step 13: Test the Final Product
Test it to make sure it works. The typical errors are a too short (or too long) tether, or a loop that doesn't fit through the other. Occasionally there will be issues with the wire rope interfering with the seat closing and problems of that nature, so make sure to check.
The main thing to keep in mind is that the helmet should not touch any metallic parts (read rear pegs, rearsets or fenders) that might scratch or damage it. Also make sure that any intercom units are not in a bad position.
Finally, never, ever drive around with the helmet attached like this. On most bikes it will move around and eventually touch the tire when the suspension compresses leaving you nice black scuff marks on your helmet.
Step 14: All Done!
Well, that's it!
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