Have you ever wanted to keep your bike on your car carrier unsupervised but worried that someone might try to steal it? After all, it is pretty much just sitting on your car asking to be stolen. Anyway, I found myself thinking about this situation and wanted to find a solution. Upon a quick Google search, there did not seem to be much in the way of bike-to-car locks (at least not easily installed or cheap). Left with no good consumer options, I decided it was DIY time (queue the Batman theme). The following is my solution:
Step 1: Materials and Tools.
-chain- 10' for $9.98 from Lowes
-18 gauge steel galvanized wire (wire from a coat hanger might work as well) - had this from previous projects, but $4.88 from Lowes
-PVC tee- $1.87 from Lowes
-tube insulation (for pipes?)- OPTIONAL $4.98 from Lowes
-padlock- had it from a school locker, but from Lowes I see one at $2.98
-black electrical and duct tapes or tape of your choice- had them in the tool chest (I assume you might as well...handyman's secret weapon and all)
-pliers with wire cutting capability
-Dremel tool with cutting disc or bolt cutters- OPTIONAL
Grand total: $24.69
Obviously, you could get all of this from someplace other than Lowes and probably for cheaper (especially if you recycle). You just never know what you might find on the curb or the free listings on Craigslist. Seriously, you'd think people's pianos and treadmills were possessed or something....but I digress.
Step 2: Making the trunk loop.
For this step, simply take as many strands of wire as you feel makes your bike(s) safe and twist them into a single big multi-stranded wire using your pliers. I used four strands so the trunk would not have any trouble closing. You should be fine using more, I was just being conservative. Anyway, take the big wire and thread each end through the opposing ends of the PVC tee and feed them through the middle opening. From here, liberally (and I mean LIBERALLY) twist the ends together. The safety of your bike depends on this. After you have the tee and the wire loop all put together, you can wrap the wire with electrical tape (or the tape of your choosing) to help protect the trunk from scratches and the wire from the elements. The entire thing can now be taped to the inside of your trunk. I used duct tape. The main goal here is to tape the tee and the wire down so that the wire loop can adequately stick out from inside the trunk. Someone could probably figure out a prettier way of doing this, but it works. You want to be able to thread your chain through the loop, so keep that in mind with your placement. Basically, the idea here is that the PVC tee is being utilized as something of a stopper inside the trunk to keep the wire anchored and secure.
Step 3: The chain and padlock
For the bike chain, I just grabbed 10 feet of precut chain that looked adequate for the job. After threading it through everything to test it for size, cut off any excess you don't want. I ended up using about 8.5 feet or so and cut off the excess with my Dremel. Cutting off the excess is totally unnecessary unless you are planning on driving with the chain on. It may drag otherwise. One perk to cutting the excess is that the 1.5-2 feet of extra chain is perfect for making a more portable bike lock if you have another padlock. Once you have your chain, you can insert it into the tube insulation. This particular insulation comes with sticky tape on opposing surfaces of the seam to seal itself. Simply remove the plastic and seal the surfaces together. The chain is now enclosed and padded. This should help protect your bike, your car, and your carrier. The insulation is totally optional, it just depends on how worried you are about scratches. From here, just thread the padded chain through the trunk loop, the bike carrier, and your bike and padlock the ends of the chain together.
Voila! You now have a bike-to-car lock. Good luck and happy biking!
Note: Try this all at your own risk. You can't hold me responsible if something bad happens. As with anything, if a thief REALLY wants to steal your bike or your carrier, this lock isn't going to stop them. With the right tools, they can still get through. Consider this fair warning. Regardless, this lock should stop your average grab and go hooligan.