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Old 09-08-11, 04:49 AM   #1
grimslade
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Jury-rigging a trailer-bike hitch to a lugged steel frame?

I have a Singular Peregrine frame, which is lovely and I love. But it has this cutely pointed lug at the top of the seat tube in the front and an integrated seat clamp.

The result is that the top of what is effectively the seat clamp is not flat.

I also have a Trek Mountain Train trailer bike, the hitch for which is designed to rest on the top of the seat clamp, with a plastic shim/bearing to allow the hitch to pivot around the seat post when turning, etc.

I could grind off the point of the lug to create a level surface for the hitch, but that seems a shame. So here's my idea, which I present for evaluation of its stupidity:

I propose to take an extra plastic Trek shim and 1.) cut a recess in it for the lug; and
2.) cut it down to the height of a seat post clamp such as this one;
3.) clamp that shim to the seat post with said clamp; and finally
4.) install the Trek hitch, including a second shim of appropriate size, above that on the seat post.
In this way, the hitch will rest on the second seat post, which will act as a collar around the lug, protecting it, and the hitch itself will pivot around on its own shim as nature and Trek intended, without the lug interfering.
So, what's the verdict? Brilliant, or idiotic?
Thanks in advance...
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Old 09-08-11, 08:37 AM   #2
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Sounds like it will work ok. It will raise the attachment point of the "traier bike" (i assume this is one of those tag-along bikes to let a child ride with you) slightly but that should be easy to adjust for. I trust you do NOT have a carbon seatpost. If you do replace it with an aluminum one first.
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Old 09-08-11, 09:26 AM   #3
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How about a seatpost clamp clamped above the frame? Might need to shim it if you can't find one small enough for your seat post diameter but shims should be readily available.
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Old 09-08-11, 09:37 AM   #4
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Is your seat, and post so low theres nothing, no length exposed, to attach to it?

wrapped around the post, a strip of rubber, with ply of fabric in it, works.
particularly fitted in a square tube on the trailer, with a bolt thru all.. ..
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Old 09-08-11, 11:07 AM   #5
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Thanks, all. I think I may have to take a picture to clearly explain the problem. There is some seat post. The problem is that the hitch is supposed to rest on the seat clamp, but the Peregrine has an integrated seat clamp in the lug, and the lug has a pointy bit at the front, so you don't have a flat, level surface to take the weight of the trailer bike when it's attached to the hitch.

The kind of lug I'm talking about is a bit like the one you can see in Unterhausen's avatar, FYI:

http://www.bikeforums.net/member.php/136384-unterhausen

You can't rest a hitch on that spike.

Last edited by grimslade; 09-08-11 at 11:17 AM. Reason: Added linkage.
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Old 09-08-11, 11:17 AM   #6
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Is the spacer thick enough to cut a small notch in to let it sit flat?
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Old 09-08-11, 11:19 AM   #7
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Some of the shims that come with the hitch are plenty thick. But the shim/spacer that actually goes under the hitch bracket has to rotate, which is why I can't just cut a notch into that.
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Old 09-08-11, 12:07 PM   #8
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Cut a notch in one then run another on top that will rotate?

Take/find a picture if you can,somebody will come up with something simple.

Last edited by Booger1; 09-08-11 at 12:11 PM.
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Old 09-08-11, 12:39 PM   #9
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Quote:
Originally Posted by grimslade View Post
You can't rest a hitch on that spike.
That's why I suggested clamping another seat post clamp to the seat tube above the frame. This would allow the plastic collar to rotate on top of the clamp.
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Old 09-08-11, 01:05 PM   #10
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Burly Travoy is their seat post mounted trailer,
maybe you can buy their whole hitch assembly..

or a plastic collar for a seat post mounted reflector ..
maybe the opening on the front where that pointy bit is?

I have one of their Flatbeds, Burly from the worker owner's era..

It fits on the left axle end under the , nut or QR ..
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