Help! Mounting Burley Rack on Thick Alu Seatstays

I was wondering if anyone as any experience mounting racks that will
bear a lot of weight onto MTB frames without top-of-seatstay braze-ons,
and with thick alu seatstays. (A 3/4 inch p-clamp wraps around my
stay). The seatstays connect at the seat-tube, so this is not a
wishbone stay. My frame has threaded eyelets near the drop-out, so no
problem there.

The load-bearing nature of the Burley Moose rack is a little different
than most pannier racks because it is used with the Burley Piccolo, a
trail-a-bike. This puts more backward force on the rack, especially
when climbing. Here is a link to the Moose Rack/ Piccolo set up for
those interested yet not familiar:
http://www.burley.com/products/child...?p=Piccolo&i=3

I have run into difficulty finding a safe way to mount the top lateral
rack braces to my frame. I broke off two p-clamps today during a ride
with my son, and feel lucky that we did not have an accident.

Two questions:

1) Does any one know a good source of heavy-duty p-clamps. The ones I
used were from Home Depot and made for wiring. They are thin and
pliable.
2) Any other mounting ideas? I don't have welding or machining tools.
Hacksaw and drill is about as industrial as I get. Note that these
braces are load bearing.

For further info, here is the email I just wrote to Burley, basically
asking the same question. Thanks in advance for any help or ideas. My
oldest son and I really enjoy our rides together!

- Harrison

Sent to Burley:

Hi, I love the Piccolo. I have a question on the best (read: safest)
way to attach the Mooserack to my MTB. My MTB does not have rack
braze-ons near the top of seat stays. Nor does it have the traditional
smaller-diameter road seat stays that accept the mounting hardware 1/2
in p-clamps that are usually used to connect the lateral rack braces to
the seat stays of a road bike. The diameter of the alu seat stays
accepts - pretty perfectly - a 3/4 inch p-clamp. I actually installed
it this way, and split both 3/4 in. p-clamps on a ride with my son
today. I imagine the clamps split from metal fatigue. They are the
normal metal p-clamps marketed for wiring purposes, and are pretty
thin. Had I not installed a home-made safety brace 1/2 way down the
rack between the midpoint of the seatstay (below the brake) and the
mid point of the vertical rack rail, the rack would have fallen behind
the bike.

Further details - we ride on some steep hills in Seattle and Portland,
about as steep as you will find. My son weighs 50 pounds.

What do you suggest in this instance?

Thanks,

wrote:

Two questions:

1) Does any one know a good source of heavy-duty p-clamps. The ones I
used were from Home Depot and made for wiring. They are thin and
pliable.

Page 1374 at "http://www.mcmaster.com/" or search for "P Clamp." Get the
3/64" stainless steel, part number "3225T66". Unfortunately, they come
in a pack of 50 for $23.30 (this is for 3/4" outer diameter tubing).

Also look at "http://www.cabelas.com/products/0013622011843a.jsp" at the
"Rail Clamp Base" This uses a 3/8" bolt, so you would probably have to
modify the pieces that go from the rack to the stays (or buy some
aluminum flat bar at Home Depot to make your own pieces, and drill holes
as needed). This would certainly be strong enough. Use some pieces of
rubber to protect the frame from scratches, and don't tighten to the
point where it crushes the tube.

You could modify the pieces that go from the rack to the stays, to use
small U bolts--again, you might have to fabricate new pieces from
aluminum flat bar, and drill holes as needed. Use stainless steel U
bolts, and cover them with a piece of small plastic hose to protect the
paint. McMaster has U bolts as well.

2) Any other mounting ideas? I don't have welding or machining tools.
Hacksaw and drill is about as industrial as I get. Note that these
braces are load bearing.

I modified two regular rear racks to accept the Piccolo mounting device,
using steel and aluminum pieces. If you can mount a heavy-duty rack,
such as a Specialized Expedition rack, on the bike, I could send you
information on how to build an adapter for these racks.

I have made rack mountings for many hybrids, using a long piece of
aluminum flat bar, bent at gentle angles, and mounting to the frame hole
where either an old type of brakeset, or fentder is supposed to be
mounted. But the Piccolo rack doesn't have a way to use a single center
support, rather than two side supports.

Reminds me to put my Piccolo up on craigslist! It was great, but I don't
use it anymore. These fetch high prices on the used market.