The yellow book:
So for the benefit of newbs like me- There’s a somewhat pricey title called”.
Driving a Sidecar Rig by David Hough and available via the publisher Printwerk Graphics and Design at 847-772-0320. .
BTW
DMG sidecar in WA offers it on their website for what seems a sizeable discount off MSRP
Richard Skip Green a Winona MN machinist friend loaned me his copy. If ever in Win. MINN his Apparatus MC shop is worth a visit...
https://www.dmcsidecars.com/yellow-book/Whilst the majority of the content addresses new rider orientation etc there’s a gem of a chapter at the end on setting up a hack.
For my part, eyeballing can only take me for part of the trip to finalizing the design of my rig and this book spells it all out.
Overall a rig should not weigh more than 30% of the tug. So for my K75 that’s about 150 to 200#....I’m going to end up heavy......
Car tire alignment- a skosh of toe in
Lean- tug should lean away from the rig +/- 3/4”off vertical
Rig wheel position is a longitudinal compromise between tire skid in turns and fighting the rigs tendency to high side you right and over the handle bars in heavy braking, so the author wisely proposes a compromise position 10 to20% forward of square with the rear wheel of the tug. On my &75 that’s roughly a foot forward.
My rig will have an OEM Brembo and 75S rotor and big time overkill braking capability so the author says 30% less braking authority on the sidecar wheel over all is sufficient....a proportioning valve in-line will allow me to dial this in just so when road testing with a monkey.
Leading Link- this is a big challenge area: Moving the front tire’s contact patch forward is key to overcoming the heavy steering action inherent in unmodified rigs- the cycles rake angle fights your steering inputs when un modified...The explanation in the book is worth the purchase price. Enough to say that DMG makes a custom leading link front end for my K for $2800, if you look at all the factory R bikes they use this method. Some rigs like Ural. us a steering damper. I get missed votes for this on my K...Someone suggested a type 1 VW unit works well to reduce a rigs tendency to wobble....my nemesis btw..
I could fabricate a custom Triple Tree that rotates the fork tubes forward, buy or build a leading link set up. Like is stated...This is an unre$olved challenge. Initially my rig will be a hand full until until can tackle this issue. PM me if you want specifics from the book.
Double wishbone frames are the easiest to mount to a sidecar. Again, the DMG brand K mount I own is an awesome bit of powder coated workmanship. Without it I wouldn’t be in this mess...Keith you scum!!!
Wrist clamp receivers on the lower mount points (see pics) enable a very articulate and flexible connection to the cars lower mounts. Brilliant stuff to behold when you’ve been racking your brain is search of just such an answer. Thanks to Josh a DMG for his tutelage, great guy! That, when clamped are very solid. love these “wrist fixtures!! DMG uses two designs with either a 45 degree or 70 degree “wrist twist”- my term. My bike axles sit 12 and 13 inches off the ground. These connectors can rotate to match this stance.
The diagonal braces in my rig use a combination of a HEIM connector and a clevis at the top connection. Interestingly, the threads of these adjustable length turnbuckles if you will, are the authors suggested weak point it the rigs fixtures. He also sites welds to lower mounts as frequent points of structural failure in DIY rigs.
So what’s next? I need to do a pile of TIG welding on the chassis. I am drawing a roll cage that will start with a roll bar positioned around my son’s 6 foot frame sitting in the car’s seat. Then two L tubes to an anti submarine bar forward of the rider.
Currently I am staging to machine a swing arm mount to match the K75S swing arm, so some bends on a press break, some welding some tapping and finally painting.
Cheers!
Snow on April 11 is just so sick and wrong.