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P-clamps issue

Old 09-10-21, 01:24 PM
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P-clamps issue

I want to attach a rack to a bicycle but the bike frame does not have eyelets. I plan to use p-clamps but the the frame at the clamping point is not completely round. It flattens out about where the wheel begins. Can a p-clamp tighten on a more rectangular surface?
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Old 09-10-21, 01:38 PM
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Probably, yes, but it might move around a bit and require tightening after a few rides and it has found its natural resting place. However, P clamps are not great for holding a load - they will probably eventually break if you are using them as structural supports at dropouts. This is not a problem with using p clamps on the seat stays for the upper supports because these don't hold any weight. But at the dropouts they're best for only light loads.
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Old 09-10-21, 09:10 PM
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What kind of bike are you clamping on? Carbon is a no go and if the frame isn't designed for a rack probably that is the manufacturer saying maybe not a rack. Remember if you do end up using p-clamps you will likely void the warranty, and won't be able to hold as much weight.
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Old 09-10-21, 11:04 PM
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For road bikes, look at something like this:

It attaches via the rear QR skewer and the seatstay bridge eyelet.
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Old 09-11-21, 09:26 AM
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Originally Posted by PDKL45 View Post
For road bikes, look at something like this:

It attaches via the rear QR skewer and the seatstay bridge eyelet.
That is what I have on my bike. It has held up to about 1,500 miles. But the bike does have that eyelet whereas some bikes might not have that attachment point.

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Old 09-13-21, 11:30 AM
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one might use some padding around the frame part so that the p-clamp will be snug

this is a home made clamp, on the right

I use p-clamps to hold the rack on my road bike, but it's not ideal. they are strong enough but there are more elegant ways to do it
this is one of mine. it is not quite tight enough but there is minimal movement due to it's location, but the frame does show some wear

Last edited by rumrunn6; 09-14-21 at 01:09 PM.
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Old 09-13-21, 04:32 PM
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Use them at work.
Yes they’re strong enough.
But all the work applications clamp around much thicker wall thickness than a bike frame. FWIW.
Also, if clamping around something not actually round, might have to experiment with the next size down than you might think and re-bending and re-tightening after awhile.
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