“P-Clamps” Are Your Friends!

Every now and then, someone will ask us, “How do I attach a rear rack or fenders to a bike that doesn’t have brazed-on eyelets?” Some otherwise ideal commuter bikes don’t come ready with such mounting points, but there’s an easy and cheap solution to this dilemma.

“P-clamps” are your friends! Commonly available at most hardware stores, these cheap and simple devices are a savior for many a bicycle project:

p clamp

These p-clamps (properly referred to as “cushioned metal loop straps”) come in a variety of diameters to fit most, if not all, the tubing one might encounter on a bicycle frame. My local hardware store sells two-packs of these zinc-plated steel and rubber p-clamps for about $2.00. If you simply MUST have stainless steel bands and ultra-zoot silicone padding, McMaster-Carr sells them (but at a pretty steep price, compared to the zinc-plated models).

Nothing could be simpler to install — just spread the clamp open with your hands, wrap it around the seatstay or fork blade and squeeze it to close. Then, attach your rear rack or fenders with an appropriate bolt. Once the bolt is tight, these clamps will not slip.

I’ve been trying to convert my wife’s bike into a more suitable “bad weather” commuter by getting a fender on the front to help keep her dry and a rack on the back so she can carry waterproof panniers. The bike’s frame, however, didn’t have any place to mount said accessories. P-clamps to the rescue!

Here’s the top end of the seatstays where the upper rack struts mount:
upper seatstays

And the lower end where the rack legs would normally bolt into a brazed-on eyelet:
lower seatstay

Here’s a pair of larger-diameter clamps pressed into service on the fork blades…allowing me to mount a full-coverage fender (with custom rubber mudflap) to the bike:
fork blade

Try them out — they are real problem solvers, and for just a few dollars, you can make your bike more versatile.


25 Comments

  1. Rapps July 19, 2008 9:50 pm 

    I needed to attach a bar running horizontal to the front fork. I use a U bolt (has threads on each end) but I put clear aquarium tubing on it to prevent damage to the paint on the fork.

  2. Marrock July 20, 2008 8:20 am 

    You can also get the plain jane stainless P-clamps and a can of that rubber tool dip and make your own for a lot cheaper.

    You can also get the tool dip in different colors so, if you’re of a mind to, you can make the clamps match your frame.

  3. Ghost Rider July 20, 2008 5:06 pm 

    Hose clamps work well, but they can leave a lot of sharp edges to catch unsuspecting flesh…besides, they’re tacky! 😉

    Seriously, there are a lot of non-cycling-specific hardware bits — hose clamps, p-clamps, u-bolts, etc. that can help solve just about any bike problem a person might have. It pays to think outside the box! Thanks, Gregg, Marrock and Anne for posting your tips, too.

  4. MarkR July 21, 2008 5:40 am 

    exactly how I mounted my rack on my cross bike.
    The work great.

  5. Jon Karak July 21, 2008 8:24 am 

    Another product available is the Tubus Stay Mounting Clamps. I put a pair on my wife’s bike. They appear to be much stronger/higher quality than the P-clamps I had on there earlier, which began to fail at the sharp inside-bend of the clamp.

    In addition, since the adapter is attached to the frame with more than one bolt, the rack can be easily removed and remounted.

    Like the p-clamp, it can also be used on the chain stays, but you still have the problem of clearance around the seat stay on a disk-ready frame.

  6. Marrock July 21, 2008 3:39 pm 

    I am a fount of useless information.

    Primarily movie trivia and things that make law enforcement officials twitchy.

  7. Ghost Rider July 21, 2008 3:42 pm 

    Me too…except my useless information is the lyrics to any number of crappy 80s songs. These lyrics spill forth without any prompting, going from my internal dialogue to actual “out loud” speech as if they’ve got a mind of their own.

  8. Marrock July 21, 2008 4:06 pm 

    Ugh… don’t make me break out my cassettes.

    They’re around here somewhere in an old M-60 ammo can.

  9. Kevin July 21, 2008 7:59 pm 

    Hi, I’ve been looking for some of these clamps for a few days, and can’t find any; are they specific to plumbing, electricity?

    thanks for the info!
    Kevin

  10. Ghost Rider July 21, 2008 8:03 pm 

    They’re not specific to a particular application, though I suspect they’re most used in stringing electric wires.

    In any hardware store/big-box DIY store (Lowe’s, Home Depot, etc.) that carries them, just look for the aisle that has all the nuts/bolts/screws bins and they are usually located in the “specialty fasteners” bins.

  11. Marrock July 22, 2008 7:36 am 

    Just don’t get the nylon ones, they’re less than useless.

  12. Gregg B July 22, 2008 10:43 am 

    Oh yeah, I clipped the extra length off the hose clamp with a wire cutters so that the clipped end sits under the screw. I then got a small file to round off the sharp edges and used a screwdriver to press the clipped part as flat as possible.

    The whole thing is ugly and tacky – excellent!

  13. electric September 30, 2009 7:38 pm 

    You can also buy zip-ties, the type with an eyelet( http://www.drillspot.com/pimages/409/40938_300.jpg ) on them, though these are only suitable for mounting a fender, and I would only recommend them on suspension forks where p-clamps with a clamp diameter larger than 1″ are harder to obtain or disc tabs interfere.

  14. dave May 10, 2011 11:49 am 

    thanks for this, I am a complete cycling noob, found you via a google search as I am trying to adapt my recently aquired but old bike (Dawes Shadow) to take panniers. I have a pair of beautiful army surplus rucksacks to put on it, waterproof and very strong.

  15. mikros August 9, 2011 6:47 pm 

    Thanks for the tip! Now my old Peugeot is sporting a rack and some sweet old H. W. Carradice saddlebags. Also I can get the baby seat on – so the little dude is psyched.

  16. noan May 11, 2012 2:26 am 

    very nice info…

  17. David May 30, 2012 4:29 pm 

    I had the same thought when i was trying to solve this problem. I’m wondering how much these little guys will hold. Ive got to commute with up to 40 lbs sometimes, you think it will hold?

  18. Grizzly907la February 10, 2013 4:21 pm 

    How do they hold when you put weight on them?

  19. Ghost Rider February 10, 2013 5:39 pm 

    They hold up fine under a load, provided they clamp tightly to the frame. If you install them and the screw passing through them bottoms out or presses both “legs” together, it’s not going to be tight enough for more than a few pounds of load. What you want, then, is a bit of a gap once the bolts are snugged down.

  20. Chris December 18, 2014 8:15 am 

    One word of caution: if you mount anything around the middle a tapering fork blade, there is the danger that it could work loose, slide down the fork and rotate into the front wheel, where it would become an instant, absolute brake.

    I knew someone that was killed by a mudguard stay coming loose and jamming in his front wheel. He faceplanted in front of a lorry. A sad end to a lovely, lovely man.

    Be careful out there! :-)

  21. Raiyn December 19, 2014 11:02 pm 

    @ Chris
    First, I’m sorry for your loss, and I’m certainly not trying to discount your story, but I don’t think you’ve accurately stated the facts of your friend’s demise.
    .
    Having a long and varied history with bike mechanics and mechanics in general, there are only two ways I can envision what you’ve described in a sudden incident is if the user supplied bolt used to fasten the P-clamp had failed. This would potentially allow the stay to rotate into the wheel the way you’ve described.
    The other way would be a failure of the stay.
    I don’t see the clamp itself failing due to the minimal stress imposed by a mudguard / fender. It wouldn’t flex anywhere near enough for metal fatigue.
    .
    Coming a bit loose and / or sliding down the taper (even less likely with the rubberized clamps typically found and recommended.) wouldn’t do this as the stay would still be attached to the clamp AND the fender and could not enter the wheel in the manner you’ve described. One would think that someone who had performed this setup on their bike would notice a severely loose p-clamp long before the loss of the nut as it would certainly rattle and cause a wobbly misalignment of the fender.
    .
    At any rate, this story is one more reason to use properly sized bolts with nylock nuts when using these clamps. I’d even go so far as suggest washers sandwiched on either side to ensure the clamp’s bolt hole is as flat as possible.

    But that’s my 2p worth.

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