Bike Security

penguin · Post by **penguin** » Sun Sep 20, 2009 7:43 pm

Elliot wrote:
I guess tomorrow Iâ€™ll mount a tire and take it for a spin.

Might be more like a "splat"

Elorrum · Post by **Elorrum** » Sun Sep 20, 2009 8:07 pm

Elliot, impressive. You really got inspired. This is virtually invisible and that's great. You are using a fine thread bolt I think that allows for more time, probably necessary. a lower thread per inch would stop faster, but they wouldn't be able to go far enough perhaps to get some speed. How do you reset it, does spinning the wheel backwards unscrew the nut?

Elliot · Post by **Elliot** » Mon Sep 21, 2009 9:46 am

Yes, just spin the wheel backwards to reset.

Would be nice if we could keep the "bendix drive" so that it kicks in after the nut has done its "time fuse" thing. I'll pursue this later. Right now I have some "default world" stuff to tend to. How about you folks all build your own versions in the meantime?

penguin · Post by **penguin** » Mon Sep 21, 2009 12:25 pm

The brake option is all well and good for a "trap" bike, but seems like it'd be a little annoying for your daily rider...

Ride 30 feet, get off, spin the tire a dozen or so times, get back on, ride another 30 feet...

You need a way to keep the cycle still rideable... to me it'd be much more fun to RIDE the bike somewhere, hop off and then hide and watch someone try and steal it!

Hmm, how about replacing the seat post with a hot-shot

Or mechanically more challenging, but quite interesting to think about; redo the pedal mechanics so you have to pedal backwards in order to go forwards... I can think of a couple of ways of doing that, but they'd all stick out like a sore thumb if you looked

unjonharley · Post by **unjonharley** » Mon Sep 21, 2009 12:38 pm

there are some eveil minded people walking this thread..he he he..

Elliot · Post by **Elliot** » Mon Sep 21, 2009 12:52 pm

Well, I have something like 30 normal bikes here, so I think I can afford to dedicate one as a trap.

Of course it would be nice to be able to ride the bike, and set the trap only when parking it. So... I guess that is YOUR task for the day.

I have a low-end Gary Fisher with front suspension. Does that sound like a suitable bait?

gyre · Post by **gyre** » Mon Sep 21, 2009 1:06 pm

Too good.
Any bike tarted up will work.

Kinetik V · Post by **Kinetik V** » Mon Sep 21, 2009 1:06 pm

Not to rain on the creativity parade on display here...but with today's legal system being as jacked up as it is...remember the perp that tries to steal your bike may sue you if they get hurt in the process. And what's worse...they might even win their case against you in court. Examples are out there of such things happening. Having had a bike stolen in BRC I like the ideas suggested...and wish we could go a lot more hard core but it's not to be.

Elliot · Post by **Elliot** » Mon Sep 21, 2009 1:36 pm

What bike?

Do you mean the bike that the staggering drunk just fell off of? Never seen that bike before in my life.

unjonharley · Post by **unjonharley** » Mon Sep 21, 2009 1:41 pm

here let me help you up.. i'll put this broken bike off the street..

laura* · Post by laura* » Mon Sep 21, 2009 2:29 pm

Another bike booby trap idea: Make the steering freeze. In order to ride a bike, it is vital that the rider be able to make minor steering adjustments. If perhaps a ratcheting mechanism were to prevent the steering from going left of center, then the rider will soon wreck. Bonus points if the bike has a nonfunctioning coaster brake.

Bob · Post by **Bob** » Mon Sep 21, 2009 2:44 pm

You can walk a bike fifty feet in BRC and effectively disappear.

I'd bring a bike for commuting while working DPW before the event, but then stash it. Bikes are stupid during the event.

fciron · Post by **fciron** » Mon Sep 21, 2009 10:16 pm

Dammit, too slow. I've been on the look out for a three-speed, coaster-brake hub. Oh, well.

How was your ride?

[quote="Elliot"]

And here we are. Mind you, this is just a prototype. Then again... it seems to work!

Just a random coaster brake rear wheel, attached to the front fork of a random bicycle.

But...

...there is some fun inside, where the axle is now all-thread, and a nut has been welded to the cone that applies the brake. There is also a tab of flat stock welded to the nut/cone, and an other scrap of flat stock welded inside the hub barrel. When the wheel turns, the tab in the hub catches on the tab on the cone, and the cone goes around with the hub -- screwing itself along the all-thread until it applies the brake.

I get about eight turns out of this one, and that should be something like 40 feet. The brake comes on a bit slowly (because the pitch of the all-thread is so short, compared with the original â€œbendix driveâ€

gyre · Post by **gyre** » Tue Sep 22, 2009 12:16 am

My friend suggests variable threading for a quick stop.

teardropper · Post by **teardropper** » Tue Sep 22, 2009 8:53 am

Seriously, though, I just used a curly cable lock. I think most bikes just get used and the thief just goes for the easy, unlocked one. Anyway, it an old Huffy cruiser, I don't lose much. 'Cept the use of MY bike. Hate that I have to lock it, but lock it I do.

Ugly Dougly · Post by **Ugly Dougly** » Tue Sep 22, 2009 9:10 am

Elliot wrote: I guess tomorrow Iâ€™ll mount a tire and take it for a spin.

A length of paracord would do the same thing, and be invisible in the dark.

Elliot · Post by **Elliot** » Tue Sep 22, 2009 9:20 am

Yes, Teardropper, locking it makes good sense. I believe the european style lock that bolts onto the bike would be a big hit among burners since it is so quick to use.

But we are having Fun With Mechanical Stuff here! It's a Gear Head thing.

I'll look for more of these hubs, but yes, they are becoming scarce.
This one turned out to have a broken pawl, so it was a good candidate for butchering.

Elliot · Post by **Elliot** » Tue Sep 22, 2009 11:10 am

Fciron, I do have an other three-speed coaster-brake hub; a Sturmey Archer TCW III from 1967. But it is still on the bike, and I hesitate to part this bike out because it is a fairly complete Hercules (a Raleigh brand by then, as was Sturmey Archer all along) with the "sports car" shifter on the top frame tube. These old Nottingham bikes are nice novelties to hang on the barn wall, and ride once a year.

Shimano made similar hubs. Much better to cut up one of those.

fciron · Post by **fciron** » Tue Sep 22, 2009 11:29 am

Eliot, if that three speed had a broken pawl then I'll quit moping.

Might have to break down and buy one, I have been having a hard time finding them around here. The grocery bike could benefit from some extra mechanical advantage and a vintage hub would have been a good fit.

Of course, as soon as I wrote that I thought of someone. Duh.

Back on topic. I imagine that less mechanically inclined folks could just tie a bit of cord to the hub and let it wind up like a yo-yo. Tie the other end to something solid and when it's all wound up -BANG! Also it would be easy to undo if you needed to use the bike.

Elliot · Post by **Elliot** » Tue Sep 22, 2009 12:58 pm

...cord...yo-yo....
Steel wire rope ("aircraft cable") -- one end fastened to a spoke or two, and the other end to the fork. Should work like gangbusters. But so obvious. The coaster brake arrangement looks more like an innocent emergency repair. "It was the only spare wheel I had, and I figured it would work as a temporary front wheel."

unjonharley · Post by **unjonharley** » Tue Sep 22, 2009 1:37 pm

Elliot wrote:
...cord...yo-yo....
Steel wire rope ("aircraft cable") -- one end fastened to a spoke or two, and the other end to the fork. Should work like gangbusters. But so obvious. The coaster brake arrangement looks more like an innocent emergency repair. "It was the only spare wheel I had, and I figured it would work as a temporary front wheel."

I figured useing the bate bike at night.. Flip a spot light on and yell.. That would make em move faster. For a better jerk at the end..

Just acord hanging from the handel bar to the spoke near the axel.. It would also yank the bar side ways

Ugly Dougly · Post by **Ugly Dougly** » Tue Sep 22, 2009 1:41 pm

Don't forget the "Youtube" camera.

unjonharley · Post by **unjonharley** » Tue Sep 22, 2009 1:43 pm

Ugly Dougly wrote:Don't forget the "Youtube" camera.

I have nite vision on the camcorder..

Elliot · Post by **Elliot** » Tue Sep 22, 2009 1:58 pm

I need to do some of that "work for a living" stuff now, but if each of us builds such a bike, we should be able to have a good "life in Metropolis" stunt next year!

Elorrum · Post by **Elorrum** » Tue Sep 22, 2009 6:25 pm

This could be fun. I think I'm leaning more toward a screaming shock and awe shame sort of bait bike. Megaphone and spotlight. This could be like fishing though... you don't want to scare the others away when you've caught the first. WWAFD? What would Alan Funt do?

unjonharley · Post by **unjonharley** » Tue Sep 22, 2009 6:44 pm

Elorrum wrote:This could be fun. I think I'm leaning more toward a screaming shock and awe shame sort of bait bike. Megaphone and spotlight. This could be like fishing though... you don't want to scare the others away when you've caught the first. WWAFD? What would Alan Funt do?

I watched a guy with a big glow stick and a fishing pole.. There was no end to the bites and laughs

Elliot · Post by **Elliot** » Tue Sep 22, 2009 7:22 pm

...screaming shock and awe...

Coil spring in the seat tube? Bike rolls 30 feet and then the pin gets yanked out and the saddle lobs the rider halfway into orbit?

OOOoooooo..... I know, I know! Seat tube! Saddle! Yesss! Put a set of bevel gears (from a lawn tractor differential) on the crank, inside the bottom bracket, so that a shaft inside the seat tube rotates when the pedals go around. This shaft is a long screw, like from a jack. As the rider pedals, the saddle rises until he can no longer reach the pedals!

There is probably no limit to what we can come up with. The problem is finding the time to engineer and fabricate the stuff. I've been working for a living at this typewriter the last couple of hours -- hate when that happens!

Elorrum · Post by **Elorrum** » Tue Sep 22, 2009 7:36 pm

here's another one: pedals glued so they do not spin freely. reverse attach the cranks so the pedals unscrew as you pedal forward. x numbers of rotations, very high seat to compound the issue....

Elliot · Post by **Elliot** » Tue Sep 22, 2009 8:06 pm

Good one. Mechanically perfectly doable. Either cut and weld, or simply put the chain on the left side. (Left side freewheels are readily available.)

How about lock up the freewheel, and watch him get whacked in the back of the shins with a pair of Sharkbite pedals?

Here is an other thought: Build a rear wheel with two identical sprockets -- one on each side. The regular, right side, freewheels normally, but the left one is fixed to the wheel. On the crank put a 44 tooth ring on the left and a 45 tooth on the right. Give the left chain a bunch of slack, kept under control with a tensioner (like a derailer). As the bike rolls, the fake chain will become one link "shorter" for each crank revolution. When there is no more "extra" chain, the system locks up.

Edit: Elorrum: Since left side freewheels are available, it follows that left side cranks are available. (This is BMX hardware.) Just install a left crank the normal way.

Post by **mdmf007** » Tue Sep 22, 2009 9:41 pm

How about a bait bike, that is way underdriven so the perp cant go fast.

When he steals the bike half a dozen or so people come running out of the wookwork on cue with signs saying "BIKE THIEF" with arrows pointing to them!!! Since the bike is underdriven and easy to keep up with they are obviously caught in the act, look stupid and are shamed.???

*(all on video of course)