I'd like to put a computer on my commuting/utility bicycle, but I don't want to take out it every time I leave my bicycle locked in the street. Any ideas to make it difficult for thieves to take the computer? Thanks.

There really is nothing else you can do aside from taking it with you everytime you leave the bike. Makes a good pocket watch.

Buy an inexpensive wired computer and don't worry about it. Just leave it on the bike.

Or if you use a smartphone, you may want to look into getting a cyclometer app & just use that.

+1 on the cheapie wired one. There's really no reason for anyone to snake it and if they do, you're only out a few bucks.

I leave the sending unit on the fork and take the receiver.

If any consolation at all, if the head unit is stolen, it only suffices as a clock, although that leaves a useless transmitter on your fork.

Perhaps a wristwatch based combination? often are packed with heart-rate sensor chest belt.

An older computer type , it came in a version you could fit on the right fork-blade,
so not in an obvious spot. on my touring bike, it was below the cantilever,
above the low rider rack ... i used it pretty much, just, as an odometer.

.. out of sight, out of mind, seemed to work.

Get lo-jack type software. Some computer manufacturers have a built in lo-jack chip. You need to buy the software to enable it. If someone steals the laptop you can login to lo-jack and enable the tracker. As soon as the pc gets a wireless connection it will send it's IP address, the cops can trace that easily. The one for my daughters mac will take a picture and include it also.

Or, you can by a cable lock, and lock it to your bike frame.

Probably you're talking about a $20 CatEye, Sigma, or Planet Bike computer; no one buys a Garmin for commuting alone, or refuses to take it off the bike. The good news is a used $20 bike computer isn't really a high profile target. Also, while it seems like you can just slide the computer off the mount and walk away with it, that's worthless unless the thief had the same computer but lost that part of it, or also grabs the wiring and magnet sensor. I always left my computer on the handlebars when I ran a cheap one, and never had a problem.

Another advantage to a cheap wired computer is they aren't affected by interference from traffic lights, etc. My wireless computers get crazy readings all the time when commuting, particularly if I go under a traffic light while it is changing colors. If you have an iPhone or other smart phone, there are some very good apps for tracking mileage, speed, etc. I've got Cyclemeter on my iPhone and its readings are generally very close to my cycle computer.

Cell phones also drive the milage as well as top speed, etc. up.

If pocketing your own computer each time you go somewhere is a big issue, perhaps learn to deal with cycling without a computer. Wireless or wired, most are built to quick release at the handlebar so you can do just such a thing. Start making a habit of taking it with you, ride without, or soon enough, some other cyclist might help you out with that second part...

it is impossible to theft proof a bike..with a small multi tool, everything but your frame can be easily stripped in minutes. all you can do is make your bike look/appear undesireable or not worth much.

echoing other people..if you cant be bothered to take the computer with you, you probably don't really need it. or just use a dab of super glue.

mmm...You could always put a brand new battery in the computer - then super-glue it to the bracket!
Should last a fair number of years.

Acetone MAY dissolve the glue when it's time to change the battery.

Why do people get so worked up about pocketing their lights/computers? It takes less than a second to pop it off the quick release.

Yeah, I just pop mine off. Takes about two seconds. Don't really have to though, it only cost 10 bucks from Wal-Mart anyway.
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I made a bracket that requires either unscrewing a complicated arrangement or destroying the computer to get it off. With this, I have not taken the computer off the bike for several years. The bike stands outside during the day in a busy area. Still, of course, the areas vary.

I don't think the OP is getting "worked up" over his computer. Rather, I figure he just wants to know a few details if there are any available. I'm sure he hasn't stopped eating or sleeping over it.

I'm not talking so much about the OP but there are lots of people out there who think it is a huge inconvenience to remove quick release lights and just leave them on all the time. I dunno, I guess some just value perceived convenience over security.

Without a doubt. To me, it's just a thing. I don't take myself too seriously. It would ruin my day.

Thanks all! Yes, I'm talking about a cheap computer, but I had them stolen before - purely by malice, I guess, not for profit. And I don't lose sleep over this either...

Could you please post any pics of it, or explain how you made it?

Every time I bike (instead of driving) to the gym, I worry about losing the bike computer in there. Or scratching its face. Of course, that probably means I should get a cheap computer again, and just leave it on the commuting/utility bike at all times. Plus, it's nice to have unencumbered pockets, as a general rule.