I have been searching the Internet looking for different methods of making the attachment to the motorcycle frame but not finding a whole lot of different option.
The most common (commercial) attach seems to be a heavy U-shaped strap around the frame tube and bolted to a metal block with an eye-bolt to attach the strut.
I was thinking of a two-piece metal block drilled through the centre for the frame tube and bolted together over the frame. Is that over-kill?
What you are speaking of is a "universal" type mount. While we offer these and for some application they work well however the best way is proper bolt on sub frames. This allows the mounts to be spread out further then you other wise could, this also allows for the lower mount to be equal distance from the ground which makes it easier to align the sidecar. Some of our sub frames use clamps like you describe where they are machined and part of the sub frame.
What bike and sidecar are you working with?
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793
I originally mounted my sidecar with the universal mounts you describe. The main issue I had is that the lower rear clamp had to be mounted horizontally. That orientation not only made my lower mounts uneven, it allowed downward forces to "rotate" the clamp around the frame tube, badly deforming it. I eventually got some purpose built mounts (From Jay, actually) and the lowers now stay put and are even distance above the ground.
I'd also avoid drilling through a frame member as the manufacturer, in order to save on weight, choose a minimal tube thickness with solo riding in mind. Adding the stresses and strains of a car AND weakening the frame tube by removing material is just asking for trouble.
jaydmc - 12/1/2014 10:45 AM
What bike and sidecar are you working with?
I have a 2002 Harley FXD. It will be a scratch-built sidecar (unless I can find an older sidecar at a bargain price).
OldSchool_IsCool - 12/1/2014 11:01 AM
I'd also avoid drilling through a frame member as the manufacturer, in order to save on weight, choose a minimal tube thickness with solo riding in mind.
Lawrdy yes! I spent my career in engineering and would NEVER weaken a structural member!!!
On your year FX we use no "universal" type clamps. The upper front is a plate that picks up two bolt holes in the gusset for the frame down tubes. The upper rear is an eye bolt that threads to the shock mounting stud. The lower front picks up the bolt holes for your forward controls on both sides of the bike and the lower rear is a sub frame that clamps to the rear frame cross tube.
We do sell the mounts, we also sell just frames and we even make a you weld frame kit where we weld all critical welds to keep the swing arm square and fit all of the other parts for you to weld.
If you do find a used sidecar make sure that it is strong and heavy enough for your bike, this means no Velorex, cozy or spirit eagle type sidecars. Safety must come first.
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793
VERY helpful information Jay - THANKS!
