Locking up through the rear triangle

The first time someone showed me this locking method, I had to stare at it for a long time. I reluctantly walked away from my bike trying to solve the 3-dimensional logic puzzle in my head.

“How can you secure a bike without locking around the frame?” I thought. Turns out, this is actually more secure than what I was doing before, which was basically locking the frame near the headset. This secures both the frame and the rear wheel.

Still not convinced? Mission Bicycle explains the whole thing.

Update: If you can, locking around the frame and wheel is always better, but if you’re limited in options this will do the job. If someone really wants your frame, they can do some damage and saw through the wheel to get at your bike, as neocoffeeboss points out:

54 Responses to “Locking up through the rear triangle”

  1. Ben says:

    This is it, friends. Tell everyone! No cable locks, no heavy chains. Simple, effective.

    • Adam says:

      … Except for your front wheel and saddle.

      • Ben says:

        Well, yeah. Most people only carry a single form of protection though, and if you’re going to pick just one, this is the best.

        • Ben S says:

          The youtube video definitely gives me pause about only locking through the wheel, but I think it’s probably still alright most of the time.

          I’m a huge fan of using locking wheel skewers to secure my wheels. I used to carry an additional cable lock just for looping through the wheels, but I’ve found it a lot more pleasant only needing to worry about one lock. Just gotta make sure you always have the key with you (keyring++) or else you may be walking home in the event of a flat. Most bike shops around here seem to carry them.


  2. Herr Doktor Professor Deth Vegetable says:

    Haw-Haw! Fixies!

    • Herr Doktor Professor Deth Vegetable says:

      Silly bicycle affectations aside, I’m looking at the inside-the-triangle locking method, and it’s a little confusing. I mean, if you unbolt the rear wheel, allowing it to shift backwards, why would that not allow the rest of the bike to be carted off, leaving just the rear wheel there all on its lonesome?

      Hmm. I’m going to have to do some experimenting at home.

      • lkj says:

        Because the lock prevents the wheel from sliding backwards out of the frame.

      • WhiskerWatch says:

        The inside seat stay is still trapped. Mentally move the frame forward with the real wheel stationary, the seatstay/forkend hits the lock.

        BUT, I still say locking the frame with it is better. What’s to prevent someone with a large pair of aircraft shears from just cutting the rim. Or jamming a jack between the rim and the bike rack and busting the lock. Sure, each ruins the rear wheel, but you get everything else undamaged.

        • Sean says:

          “What’s to prevent someone with a large pair of aircraft shears from just cutting the rim. Or jamming a jack between the rim and the bike rack and busting the lock. Sure, each ruins the rear wheel, but you get everything else undamaged.”

          A friend once imparted this related bit of wisdom: “You can’t stop a man with a wrench.”

        • Jon z says:

          I was thinking the same thing, I’m not sure bike thieves carry the sort of bolt cutter that could get through the rim, but there is conceivably a bolt cutter that could cut the rim but not the lock itself (or the frame, but god who would do that), in which case the first method would protect your frame and the second would not.

          The more I think about it, the more I think that the ease of just going through the rim is a fair tradeoff for the slightly greater chance it could be stolen.

        • Ben says:

          Paging the late great Sheldon Brown to the thread..

          “Some will object that felons might cut the rear rim and tire to remove the lock. Believe me, this just doesn’t happen in the real world. First, this would be a lot of work to steal a frame without a useable rear wheel, the most expensive part of a bike, after the frame. Second, cutting the rear rim is much harder than you might think. Since the rim is under substantial compression due to the tension on the spokes, it would pinch a hacksaw blade tight as soon as it cut partway through. Then there are the wire beads of the tire, also difficult to cut.”


          • tincture says:

            This does in fact happen in the real world. My girlfriend had her bike parked like this at 18th and Guerrero. 1 hour later, gone. Lock still attached to pole. She had built it up herself, wheels and all. Needless to say, much crying ensued.

          • kinda. says:

            there is youtube evidence of this being proven false with a simple hacksaw in about 10 seconds.

          • Ben S says:

            Consider me convinced. I always try to lock through the rim and the frame whenever possible, but I’ll think twice about this technique in the situations where I can’t.

      • Sweet T says:

        Because of the way the wheel attaches, it’s locked inside the rear triangle. You won’t be able to separate the two.

      • Herr Doktor Professor Deth Vegetable says:

        Interesting! I really will have to try this out.

        • Bob says:

          I’m still not entirely convinced, and probably need to see it in action.

          Why can’t you slide the frame forward to get the wheel free, then finagle the lock-wheel-rack to be thin enough to fit through the space between dropouts?

          • beau d says:

            the lock can’t pass through because it’s locked to the pole. (at least this is my best guess at solving this puzzle.)

  3. kinda. says:

    1. yes it locks the rear wheel and frame

    2. yes they can simply cut your wheel to remove the lock, but the rear wheel is an expensive (read: sellable) part, and would not be able to ride away. this would not stop them from throwing it in the back of a truck and driving off with a still mostly sellable bike.

    3. if they want your bike, no amount of locking will prevent it from being taken.

    • kinda. says:

      oh and another thing, if you do not lock either/any wheel, expect to come back and find your wheelset gone. learned this the hard way (thankfully with low end weinmanns).

  4. thanks says:

    i know it works, but i’m wary of this method because i fear some dim-witted bike thief with a poor grasp of physics will smash the shit out of my rear wheel trying to take the frame.

    • Ray Greenwell says:

      Exactly. Perception matters. If it looks less secure, then someone might start trying.

    • Herr Doktor Professor Deth Vegetable says:

      Excellent point.

      • Sweet T says:

        That’s my worry too. If most of us have to look at it for a while to understand the physics, some jackass, amateur bike thief is definitely gonna’ think he’s scored.

  5. whit says:

    if it were a smaller ulock i’d be convinced.

  6. scum says:

    Why do people put stupid shit between their spokes?

  7. neocoffeeboss says:

    No method is perfect

  8. get real says:

    Did anyone notice that only the rear wheel is locked in the photo? – just a 15mm wrench away from a new orange fixie. With only one wheel left you will still make it all the way to four barrel.

  9. MrEricSir says:

    This reminds me of those metal toys where you have to get two hopelessly entangled metal things apart. What fun!

  10. I have a brilliant development concept for a Kevlar (TM) “bike envelope” with titanium grommets (pat. pend.) which may interest those of you with (future) trust-fund money to invest.

  11. Michael says:

    anecdotal, but: I started using this method (locking just the rear rim through the triangle) three years ago and have not lost a bike yet. Parking in the castro, mission, mid-market, noe valley, oakland. Of course my bike got nabbed while unlocked in my garage in a very quiet area. Of course I replaced all quick releases with hub locks (wheels) or allen bolts (seat). Of course I manage to get around on a plain-jane bike rather than a fashion accessory, so yeah, I don’t have a Brook’s saddle or $1,000 wheelset.

  12. dave says:

    To me the biggest issue with this method is that the prongs of the u-lock have a bunch empty space between them. If you were to stick a standard car jack in there you could bust the lock without damaging the frame or the wheel (much). I’d use this method if I had one of those tiny messenger style u-locks and wasn’t going to be gone long; otherwise I lock my rear wheel and and seat tube (sticking my helmet on there to take up even more space), then I cable my front wheel. I’ve even gone to the extra (crazy) effort of using a seat leash AND gluing ball bearings into the heads of the hex bolts on the seat post clamp and seat clamp.

  13. LilSpicyMeatball says:

    For those that still don’t see how you can’t just slide the rear wheel out to take away the frame: Basically, you are locking something that is inside the rear triangle (between the seatstays / chainstays – my bike terminology is deplorable) to something that is outside of it and bolted to the ground. I would guess if a bike thief thought they could just remove the back wheel and slide it out, they would do so, and then realize its going to be a lot more work than they thought, and bail on the realization that to continue would probably get them caught, or just move on to an easier target. Plus, a bike thief inexperienced enough to think it was a viable option is probably not a bike thief carrying the appropriate tools to cut through that wheel. Not 100%, but in my opinion, the best option we got.

    I wonder if anyone out there has ever come out to their bike to find the rear wheel dismantled but it and the bike still present in its entirety otherwise? (indicating someone attempting to steal it and failing)

  14. Ryan says:

    Been doing this for years. Get one of the fat small U Locks and you can get the rear wheel and the frame in there, no problem. Far and away the best way to lock your bike.

  15. kinda. says:

    seriously yall, this isnt the magic bullet.



  16. The_Audacity says:

    I don’t understand why people don’t get this. This is not new info.

    This method + a lasso cable around front wheel and in u-lock = best possible theft DETERRENT. I say deterrent because there is no theft PREVENTION in this goddamn city.

  17. Dizerker says:

    I like to use two U-locks, and a cable through both, all connected to my girlfriend’s bike. Hexnuts on the seatpost work well too, and I never leave them out overnight.

  18. Jack Walker says:

    I’m saddened to see poorly locked bikes. I’m doubly saddened to see bike professionals recommend a seriously flawed method. As the video points out, get over trying to wrap you mind around not locking the frame and only the wheel as a magical idea and instead focus on the no-account meth head and the attack vectors at his disposal. Low-life fuck-face could easily have at his disposal any one of the following tools, hack saw, bottle jack, lever, felony pliers, allen wrench, crescent wrench, vise grips. He’ll attack the bike susceptible to the tool he has.

    I’ve seen some folks lock only the frame. Guess what, if you have expensive components, I would snap the thin double butted frame in half like a pop can and take it away. Similarly I’ve seen folks lock the spokes and frame. Same thing, cut the spokes and frame and take it away.

    I suggest you read Bruce Schneier’s security blog. I don’t think he’s ever written about bikes but the principles of attack and defend and the mindset needed to understand security are richly described.

    • waldito says:

      hmmm. I read Bruce Schneier frequently, and yet I don’t see how this method of locking is an outright fail.

      One thing I take away from Mr Schneier is that there’s no such thing as total security. You make strategies based on the value of the thing you’re securing, and the difficulty and cost of the security methods.

      I wouldn’t lock a road frame with full dura-ace at 16th & mission with the rear wheel thru frame only. But I would lock a fixie in front of Arizmendi that way.

      I maintain some DBs that need very strong security, and some others where ‘security thru obscurity’ is enough. When the latter got hacked it was not fatal or surprising, but dealing with that cost me less time than a full SQL lockdown would have.

      There’s a right job for every tool. The dumb handlebars and front brake on that bike make it just right for the security tool deployed.

    • Soledad Dolores says:

      I feel your double sadness and weep some tears with you.

  19. dave says:

    The truth is you only have have to lock you shit better than the sucker next to you on the bike rack. By the way, I have come back to my ride to see that some genius has taken of my wheel without noticing it was cabled to the frame. If you’re not traveling around with a 5mm wrench then could be walking. This method seems like it might invite such fuckery.

  20. Soledad Dolores says:

    locks only keep the honest people from stealing your bicycles. I tear when I see the kids and women today on the new styles of bicycles knowing they will feel the sadness of loss one wet night near the willow trees.

  21. Justino says:

    Nobody’s mentioned locking the back rim simultaneously with the seatstays? this securely locks frame and rear wheel and doesn’t give the illusion that they can be separated. then i take off the front wheel and lock it in there, too. and usually my helmet. by the time this is all done there’s virtually no room for a jack or anything else to be fit in there (obviously i can’t get all of this with the short U-lock).
    of course, some of the meters sleeved with the thicker pipe make it harder to angle the U-lock enough, or to get the helmet in there at the end, but by and large i’m able to do this nearly every time. it takes a little extra time, but it sure LOOKS secure, and, as was pointed out above, perception is huge.

  22. Terry B says:

    A few years late on this one. Always carry two U-locks.