What would you spokeheads recommend for securing a bike in the bed of a pickup truck. I haven't a topper nor a "rack" for the bed. I was thinking of buying a lock of sorts that I could loop through the brackets bolted to the bed. Would that be good?

You see, I want to ride on my lunch hour, but my office is in a neighborhood of meth heads that like to steal stuff and pawn it for meth.

Or something...

Can you take it in your office?

The lock sounds like a good idea.
Another would be a bed cover. Out of sight, out of mind. Ofcourse, if they see you getting it out daily, and it's not locked, someone may take their turn at getting it out of the bed.

I keep mine upright with ratcheting straps, and I lock the back wheel to a tie-down d-ring in the bed with a cable. Not the most secure thing, but it's a deterrent, and I don't leave it out of sight anyway.

Couple of ideas, depending on what you mean by "secure" (just prevent theft, or protect it from the weather?).
I bolted two fork holders (clamps, whatever they're called: https://www.bike-racks-plus.com/saris/trapsforkmount.jpg) to a 2x6 board cut to fit across the front of the bed of my truck. The clamps hold the bikes upright (angle them slightly so the handlebars can overlap and you can carry at least four abreast). The wheels just stand next to the forks, and I run a cable from the tiedown on one side of the bed, through the wheels and frames, to the tiedown on the other side. Quick and easy, and it lifts out when I need to carry something else.
The meth aspect makes it tougher, though, because those guys are persistent. I'm lucky to have a place to keep my bike inside--you might ask at work. My boss even installed a rack for us under a rear stairwell. It's hard to get to, but it's protected and safe.
My camper shell is too low to carry the bikes upright, so when it's on the truck (most of the winter; I take it off in summer) I have to lay them down, and the truck's so small (Isuzu Hombre) that I have to stack 'em. I keep an old mover's blanket in back to throw over the lower one, then slide the other one on top and lock them with the same cable. No problems so far.

I have seen some of the fork mounts that have a lock on the quick release. My truck has bed rails, so I just use a U-lock to secure it. I know it isn't the most secure, but most of my bikes aren't worth a whole lot.

Thanks guys. There may be indoor storage, I have to ask the boss. If not, I will try to park under my window or in the lot.
Too bad the Police Department moved to a different building, eh?

I've found that with the front tire removed, my bikes fit almost perfectly inside the extended cab part of my Tacoma. So what if I end up with a little chainring tattoo on the carpet "hump" in the middle?? The bike is then inside the truck and locked up safe and barely noticeable other than the seat through the back window.

Gamecock has the right idea. YOu can make it even more secure by locking the bike to the steering wheel.

Velo- Do you use anything to secure the back end of the bike? I'm going to pick up the front fork mount, but I'm not too keen about the back end of the bike bouncing around.

Thanks,
Rick

Try one of these. It's lockable....and the rear wheel will not bounce around. It will be stable and will not move if locked down properly. I have traveled with my bikes many miles like this with no problems.

https://bikebarn.com/itemdetails.cfm?...gId=39&id=2613

So tying the rottweiler's leach to it is out?

Take the front wheel off, put it next to the rear wheel, and thread a good quality chain lock through both wheels and the rear triangle, then securing the whole thing to bracket bolted onto the truck, and it will be secure from all but very determined thieves and rain.