Breaking a U-lock
#1
Thread Starter
Senior Member
Joined: Jun 2009
Posts: 819
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Breaking a U-lock
My bike was locked to a pole.
I managed to lose the keys.
It's an On-Guard lock.
How to best break this? Maybe a locksmith could help? Saw it open? I put on a second lock which is a combination lock so that should help...
I managed to lose the keys.
It's an On-Guard lock.
How to best break this? Maybe a locksmith could help? Saw it open? I put on a second lock which is a combination lock so that should help...
#2
Senior Member


Joined: Apr 2009
Posts: 39,897
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From: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
U-locks can be broken by various means, but I don't think a public forum is the place to discuss how. If you want feel free to PM me and I'll give you a few ideas. BTW- if it isn't far from a bike shop where you have a relationship, most dealers are familiar with a variety of methods, and might break it for you at a nominal cost.
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An ounce of diagnosis is worth a pound of cure.
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FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
#3
Senior Member
Joined: Jun 2007
Posts: 12,257
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From: A Coffin Called Earth. or Toronto, ON
Bikes: Bianchi, Miyata, Dahon, Rossin
hydraulic cutter or angle grinder.
just watch, as you make a lot of noise, but no one will bother to call the police on you.
just watch, as you make a lot of noise, but no one will bother to call the police on you.
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Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
Food for thought: if you aren't dead by 2050, you and your entire family will be within a few years from starvation. Now that is a cruel gift to leave for your offspring. ;)
https://sanfrancisco.ibtimes.com/arti...ger-photos.htm
#4
#9
New Orleans

Joined: Jan 2006
Posts: 2,795
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An angle grinder can eventually get through almost anything.It took the young woman just 2 minutes to get thru about 1/2" diameter of tough steel.
The plug powered ones will work much faster-get someone with a generator and a pickup.My 4.5" one takes 570 watts-about 5amps 110 volts.
The plug powered ones will work much faster-get someone with a generator and a pickup.My 4.5" one takes 570 watts-about 5amps 110 volts.
#11
An abrasive cut-off wheel, like an angle grinder or even one in a Dremmel tool will cut it easily. I used a battery powered Dremmel to cut through the shank of 3/8" drill bit in about 30 sec. The shackle of a lock was quicker.
#13
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Joined: Mar 2005
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Here at the university, we occasionally have to cut 'em when the kiddies loose their keys. Our facilities guys always use a portable angle grinder.
I can testify that you can do it with a hacksaw and a carbide blade... About 20 minutes of steady work.
As noted, might be easier to get a key if you have the serial number...
Make sure you can prove it's your bike should someone call the police.
I can testify that you can do it with a hacksaw and a carbide blade... About 20 minutes of steady work.
As noted, might be easier to get a key if you have the serial number...
Make sure you can prove it's your bike should someone call the police.
#14
#15
Experienced
Joined: Sep 2007
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This isn't a secret. Just get a scissor jack from a car and jack it open. A small hydraulic bottle jack works nicely as well.
https://www.bikeforums.net/archive/in.../t-605009.html
https://www.bikeforums.net/archive/in.../t-605009.html
#16
This isn't a secret. Just get a scissor jack from a car and jack it open. A small hydraulic bottle jack works nicely as well.
https://www.bikeforums.net/archive/in.../t-605009.html
https://www.bikeforums.net/archive/in.../t-605009.html
Oh wait...
#22
Senior Member
Joined: Aug 2005
Posts: 33,657
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From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
You will have to use a carbide or diamond edged saw blade. A regular steel hacksaw blade won't (wait for it...) hack it.
An angle grinder or Dremel with an abrasive cut-off wheel will go through hardened steel relatively easily and there are battery powered versions of both.
An angle grinder or Dremel with an abrasive cut-off wheel will go through hardened steel relatively easily and there are battery powered versions of both.
#24
Thread Starter
Senior Member
Joined: Jun 2009
Posts: 819
Likes: 56
gah, fundamental problem is the bike key. This is an old bike lock. Ironically, my newer ulock had the key get stuck -- I also have the spares for that one readily available, but not for this older one!
Solution would be a good combination U-lock. Suggestions?
Solution would be a good combination U-lock. Suggestions?
#25
New Orleans

Joined: Jan 2006
Posts: 2,795
Likes: 3
Do you have a buddy with a pickup truck-maybe someone who owns a generator? Haul a generator there and use an angle grinder.
You can get an angle grinder from Harbor Freight for $25 or less.
A Battery powered angle grinder will work ok-take maybe 5 minutes instead of the 2 minutes the woman in the video took.
A Dremel tool will take a long time and several tiny cut off wheels.
A hacksaw will take a long time- maybe 1/2 hour-.It will be tough to get it to initially "bite into" that tough steel.It will want to slide from side to side.
You can get an angle grinder from Harbor Freight for $25 or less.
A Battery powered angle grinder will work ok-take maybe 5 minutes instead of the 2 minutes the woman in the video took.
A Dremel tool will take a long time and several tiny cut off wheels.
A hacksaw will take a long time- maybe 1/2 hour-.It will be tough to get it to initially "bite into" that tough steel.It will want to slide from side to side.





