1) I leave my bags unlocked ... after all, I'm not carrying anything of real value in them. It's all easily replaceable ... sleeping bags, matress pad, some clothing, a few toiletries, and some tools. I carry anything of value (i.e. my paperwork) in my carry on.
2) Personally, I wouldn't even try to bring tools of any sort
in my carry on. No locks, no tools, no pedals ... nothing that could even remotely be considered dangerous. Oh, you know about the ziplock baggie full of your liquid stuff, right?
The reason I give the warning about tools is this ... I have been "caught" twice with things I forgot I had left in my carry on. The first time, I had a miniature eyeglass screwdriver. It was about 2" long, and about 2/3 plastic, with a tiny metal tip that was the screwdriver part. They spotted it! They gave me the option of either throwing it out or mailing it home to myself. I told them to just toss it ... it was something I'd picked up at a $$ store for about 0.50. But they made a big fuss about it. The second time it was a pair of those little folding scissors you can get for a couple dollars. They fold into themselves and are very handy on a tour. When they are expanded out into useable form, they are about 2.5" long. Again, huge fuss and they confiscated them.
Now I don't bring anything metal with me on the plane, except my camera, loose change, and the zippers on my bags. I don't even wear jewelry.
Also, I was going to bring a cinch strap with me on my trip to Europe. I had meant to put it around my pannier bag, but forgot. Then I thought I'd bring it with me in my carry on. At the very last minute, I changed my mind. They could look at it and see it as a weapon. I didn't even bother to temp fate.
Air Canada has a 50 lb per bag limit too ... and my luggage, including my bicycle, was well under that. If you're just touring ... go light. It's so much easier on so many levels.
Oh, are you going Air Thai at any point? If so, have a good look at their luggage limits. I believe the limit for all your baggage, including carry on, comes to about 30 kg (~66 lbs).
And, are you travelling through Heathrow at any point? If so, you know about the "One and only one piece of carry on" luggage limit, right? A lot
of people were caught on that when I went through a few weeks ago.
Be sure to check the rules of the airports as well as the airline rules, sometimes they are different, and the airport rules overrule the airline rules.