rydabent

Another advantage of disc brakes. With most discs they are open enough you can put a padlock thru the disc. That way at least a snatch and runner cant ride of with your bike. A padlock will fit in even most seat packs.

Troul 

Pedal padlocked to the chain works for most.

MEversbergII

Could also use a disc brake lock.

Popular on motorcycles.

skookum

At first glance it makes more sense than some of those chintzy cables we see.
Now I will wait for the video of how easy it is to defeat.

tyrion

If I tried something like that I know at some point I'd forget the lock was on the rotor, jump on the bike and try to start off, break both the rotor and the calipers, fall down and break my arm.

MikeyMK

I use an aluminium-bodied padlock through the crank and front derailleur on the Merlin. Heavy enough to break everything, light enough to be a keyring.. That's worked at least once outside a shop, where i came out to find the bike on the floor a few feet along..

I'm sure a one-piece disc would be okay, but i wonder the potential to pop the hoop off my floating disc.. They're probably more than strong enough though. I mean broken discs aren't exactly a common weak point.

MEversbergII

Well, if there's nothing locking it to an object the bike is liable to "walk away".

As for the lock itself, likely the best approach would be an impressioning tool for that style of cylender lock. If the bike is valuable enough as parts, just remove the wheel and/or brake.

Got a picture? How is it small enough to be a keyring but also big enough to be a viable disc lock?

Same. I'm surprised I haven't done this when I've locked my frame and chain ring together.

MikeyMK

It's a 30mm Master padlock with a 5mm thick hardened shackle, a disc isn't breaking that. Though there are marks in it where some have tried...

woodcraft

Sounds like a recipe for bent & greasy rotors

MikeyMK

Pic next to 9v battery. I have a 4-wheel combi version about twice the size, maybe 50mm/7mm, weight okay but not as a keyring. Combo ones aren't as strong though, size for size.

MikeyMK

And slightly bent front derailleurs in my case, but they're stronger than they look and they do bend back...

Dr.Lou

They carry it away or they/you take off without removing the lock and smash the frame and or caliper, etc.

Dr.Lou

Yep, seen that scenario play out numerous times with motorcycle riders who use locks on their rotors. Doesn’t result in broken bones, but dented calipers, hangers and egos.

MikeyMK

I've dented fenders and bent spokes, trying to ride off with a D-lock on..

Phil_gretz

Have you actually done that? Serious question.

I wouldn't attempt anything that would bend my rotors. But that's just me.

MikeyMK

How do you think they'd bend..?

You've got a shackle cross-passed through the disc. The disc is carrying the shackle up to the caliper, which has a circa 4mm gap.

The transfer of shapes is literally the same as a dog carrying a 6ft stick in it's mouth and attempting to run through a very narrow doorway... no twist, no leverage, just pure T-bone straight into a bridged lockout situation.

The only physical ways of failure i can see are:
1) disc cuts through the shackle like bolt cutters through a cable lock.
2) disc shatters like glass.
3) force of shackle being pile-driven into caliper tears the caliper off it's mount.

Also to consider; impact is very slow compared to brakes actually being used, or stones hitting disc at speed. Leverage is minimal, especially with bigger discs.

tyrion

FWIW I talked to a woman recently who wheel-locked her bike to go into the 7-11, kept the bike within her sight when she was in the store, and watched a guy on a bike swoop in and shoulder her bike and ride off with it. She said it was so fast and smooth well practiced.

(Just putting this out there to point out the limited usefulness of wheel-locking. First I'd heard of that bike-thief-on-a-bike technique. )

Gresp15C

Time honored low tech: Long shackle padlock around the seatstays and through the spokes. Caveats about wheel-locked bikes apply.

https://www.masterlock.com/personal-use/product/1517D

jadocs

I tend to shy away from anything resulting in the destruction of my bike.

fietsbob

U locks get used on motorcycles, just like that.. through the front wheel disc..

rseeker

And then get sued by the guy who also broke his arm while trying but failing to steal your bike during the time you were away.

Troul 

What if the owner filed the lawsuit first though?

TimothyH

There will be two lawsuits.


-Tim-

NomarsGirl

Wow! He must have had someone nearby with a truck. I don't imagine he could ride very far shouldering another bike.

I stopped at a convenience store yesterday and there was nowhere to lock up my bike. So I brought it inside. They screamed at me. Last time I'll ever shop there. All I wanted was a bottle of water.

Rick

I just use a U lock, a 7ft cable and a homemade electronic device that would make TESLA proud.