Locks again: Bike chains get the chop...

[Greenbank]

So ... if a 'friend' had a bike hanging in their garage for years, with a D-lock through the back wheel, and err... mislaid the key; what's the best/affordable way to "dis-engage" the lock from the bicycle?

[Hopefully any answers will also shed light on the original topic!]

When the key stopped working in my D-lock I carried the bike down to my LBS and asked them to chop it off (which they did with an angle-grinder). It was a relatively old Squire D-Lock and they were surprised at how much effort it took with the angle grinder.

I think they charged £5 for doing it.

They know me so I assume they trust me, plus it was my £300 hybrid hack and, if they had been worried and checked with the police, would have found it registered to me anyway on immoblise.com.

[Greenbank]

Reminded of this thread by a photo I just found.

Here's part of what protects my bikes in my Trimetals bunker:-

http://www.greenbank.org/misc/chain50p.jpg

Yes, that's a 50p to give you an idea of the scale.

That was a slow commute home carrying that thing (I also had two Squire MC4 chains and three heavy duty padlocks). Over 20kg of chains/padlocks.

[Charlotte]

I have the evolution mini D, like vorsprung linked. 

After seeing it in the Condor sale, I've just got hold of one of these as well. 

I'm guessing that it would actually be more effective than a full size lock of a similar grade because once you've got a frame tube, wheel and Sheffield stand inside it, there's no room for a bottle jack.  Besides, even if you could get something in there, less length of the shackle means it'll deform less under load, so it's less likely to be sprung open.

The main reason I like it is that combined with a second lock of a different kind, it provides an acceptable level of security for a more or less sensible weight.

Oh - and it fits in the back pocket of my skinny jeans, innit.

[Sergeant Pluck]

I have the evolution mini D, like vorsprung linked. 

After seeing it in the Condor sale, I've just got hold of one of these as well... with a second lock of a different kind, it provides an acceptable level of security for a more or less sensible weight

I got one too Charlotte (currently at a rather decent discount at Parkers). I've had the NY Fah Mini for a while now, so a comparison is possible. I think you made a good choice. The NYFM is a much heavier and more convincing device, but it is just too heavy for general carrying around. Great for static use but it just gets left behind on rides. The Evo Mini D feels readily portable, sturdy enough, and I can see it getting regular use along with a cable.

[Biggsy]

I have an Evo Mini as well for my utility bike.  The shortness makes it fiddly to use sometimes, but I've never not been able to lock the bike because of it.

[Karla]

So ... if a 'friend' had a bike hanging in their garage for years, with a D-lock through the back wheel, and err... mislaid the key; what's the best/affordable way to "dis-engage" the lock from the bicycle?

[Hopefully any answers will also shed light on the original topic!]

When the key stopped working in my D-lock I carried the bike down to my LBS and asked them to chop it off (which they did with an angle-grinder). It was a relatively old Squire D-Lock and they were surprised at how much effort it took with the angle grinder.

I think they charged £5 for doing it.

They know me so I assume they trust me, plus it was my £300 hybrid hack and, if they had been worried and checked with the police, would have found it registered to me anyway on immoblise.com.

According to someone who knows, the Squire Ds are good because their end pieces are built of harder steel than most, so present more of a challenge for an angle grinder.  On a lot of locks, the end piece is made of much softer steel than the shackle, so they're much easier to cut through even though they look a lot fatter.

[mrcharly-YHT]

I dunno about that. I'm not a professional bike thief, but I've spent an awful lot of time using an angle grinder.  They'll cut anything hard. People only have trouble when they try to force a grinder through, or use the wrong type of disc.

If a lock maker wanted to make a lock grinder-resistant, they would just need to make it partly hollow and fill the hollow bit with fibre, like that found in chainsaw-protective clothing. 'harder' steel will do very little to slow a grinder.