torquewrenchles

Kryptonite U-lock (14mm round shackle, weight of 3.75 pounds) that doesn't easily go around the frame, back wheel, and rack:

https://www.kryptonitelock.com/Pages/...PNumber=999348


Kryptonite "mini chain" (10mm hex links, weight of 4.40 pounds) that does easily goes around the frame, back wheel, and rack:

https://www.kryptonitelock.com/Pages/...PNumber=000792


They both mysteriously have a security rating of "8", despite the chain being 10mm and the U-lock 14mm. Similar price.

The chain's made of "3t manganese steel" and has hexagonal links. Would that make it as hard to cut with bolt cutters as a 14mm round and merely "hardened" U-lock shackle?

Or do you think the chain would fall to the 2-foot bolt cutters that the petty criminals in my small city seem to favor, and the U-lock not?

Is that integrated lock on the chain bound to end up having some exploit? It says "Patent-pending end link design secures chain to hardened deadbolt eliminating critical vulnerability". Suggesting that the chain on the previous model could be pried off with a toothpick.

¯\_(ツ)_/¯

catonec 

alot of good info here.

https://www.bikeforums.net/showthread...ommuting/page3

https://gizmodo.com/5922074/the-best-bike-lock

lambo2124

The ulock looks very slim, easy for a theif to put something in the middle like a pipe and apply force. Happened to me before.
I suggest you get the Kryptonite new york noose. security rating of 10. around 50$. made of magnesium and NOTHING will break it. used to lock my 700$ bike.

fietsbob

You are going to limit what you have to lock onto with short chains and U locks..

& I dont know anything about the places you park.

how will you carry your lock?

magnesium is a soft, light alloy that will catch fire..
I think you need to go study the periodic table again..

lambo2124

ipad autocorrect.
ment manganese

torquewrenchles

Thanks for the suggestions. Anyone have experience with the Kryptonite "Evolution Series 4 1055 Mini Integrated Chain", or with how strong 10mm chain links are vs thicker U-lock shackles?

Burton

No personal experience with that chain - but can tell you that manganese steel in one of the toughest materials in the world. The reason you don't see more of it is because the stuff is so @$&? hard to machine! Normally a plasma torch is used to cut it. The lock itself would be the 'weakest link' in that chain.

That is apparently the same type of chain used on the 'New York Chain' product. But a better lock ups the protection level to '9' in that product.

torquewrenchles

I am a little leery about that built-it lock. But the New York Chain links are thicker than the Evolution chain as well (14mm vs 10mm). My main concern is to be sure I'm getting above the threshold where the chain can be cut with 2-foot bolt clippers (with ground leverage) or 3-foot bolt clippers (without ground leverage).

Unfortunately the security ratings system is pretty much useless, because all that's tested is how many seconds it takes to cut through a locking system using power tools. E.g. one U-lock is rated "10" because it takes 3 minutes to cut through it with an angle grinder and another rated "8" because it takes 1.5 minutes to cut through it with an angle grinder. You don't get any info on what kinds of attacks it can totally withstand, maybe withstand, definitely not withstand.

torquewrenchles

https://www.youtube.com/watch?v=VC3hFr8p2ck

Not sure if any of those are manganese steel, but the first one shown is an Abus 10mm hexagonal, and the last is the Kryptonite Fahgettaboutit (16mm, round, "hardened") which has a Kryptonite rating of "10".

Burton

Yeah - security is a relative thing. But I'm also thinking that if anyone can carry and use a 5ft chain cutter in public - it probably wouldn't matter how fast they cut the chain. If bystanders will ignore him for 1 minute they'll ignore him all day. Inside and controlled access is the most effective security.

I think part of the risk is also related to what you own and where its parked. I regularly parked a BMW K1 in front of the street unlocked for years with no issues. On the other hand, one of my buddies had his Harly stolen from inside his private garage were it was locked with a chain - while he was asleep in the house! Apparently they picked the garage door lock and used a torch on the chain. The bike was less than a month so my impression is that the address, make and model were sourced at the dealership.

My comment about the plasma torch was regarding machining. Anything else us too hard on tools and less cost effective.

chaadster

biting_fish

Bike chains are harder to cut because they wiggle and are hard to cut in a single place, that is why they are more secure.
Although they are heavier and harder to carry, but this isn't much of a problem if you ride with a backpack.

veloz

Own a small Kryptonite U-lock and a Kryp integrated chain. The U is lighter and easier to carry but the chain can lock 2 bikes in a pinch. I use the U most because it fits in a pocket. I try to lock up in easily watched places and not worry about it. If someone wants a bike bad enough they can even defeat the NY series locks.

jpescatore

The reality is all carriable bike locks of any reasonable weight are going to only keep the honest people honest - search the internet for "Lockpicking Lawyer" and you'll see most lock systems being easily broken through, often with smaller tools than gigantic bolt cutters.

I've always found U Locks harder to carry than cable locks, so I've mostly used cable locks. I try never to leave a bike outdoors overnight but every now and then have to do so on my car - I carry a big heavy chain and padlock for that but never carry that while riding!

nel e nel

Bolt cutter concerns don’t mean squat when thieves can have hand held angle cutters. A neighbor across the street here got his bike stolen with one of those in broad daylight, with people around!

veganbikes

Hey Fish, just fyi this thread hasn't been active since 2013 keep an eye out on dates and keep posts to active threads it helps everyone. No more zombies : )

jananji

Havent used these locks. U locks seems a little slim. Depending on the area you live, choose a combination of security locks - D locks and chain locks securing frame.

My cousin works for industry which supply raw materials for similar businesses. I just told him about this and he agreed it is indeed a strong material. He gave this info to let you about the metal - Manganese steel is non-magnetic steel with extreme anti-wear properties, high abrasion resistance, high impact strength, high tensile strength, and fair yield strength. The material will achieve up to three times its surface hardness during conditions of impact, without any increase in brittleness. The basic Brinell hardness of manganese steel is 220 but that with impact wear the surface hardness will increase to higher than 550.
Manganese steel is commonly used in the mining industry (cement mixers, rock crushers, crawler treads for tractors), rail industry (railway switches and crossings), window bars in prisons, safes, bullet-proof cabinets, anti-drill plates, metal recycling, and other high impact environments like inside a shot peening machine.

gpburdell

I suspect the OP sorted it out in the nearly nice years since posting the question...

Good info about manganese steel though.