On sidecars, I have come to the conclusion that there is no magical formula. Read, keep notes, design and be prepared to adjust the outside wheel location and camber. Everyone will have to find their own sweet spot so that they get the best and safest ride for them.
Well put dog catcher & to that point I plan a mount/frame that has initial adjustability for testing and tweaking & testing with and without weight in the car. The documented work of others will no doubt get me in the ball park range. The bike won't be the subject of change at all I want the solo bike to retain it's current ride feel when ridden solo. I feature the car primarily as a conveyance for a Lab puppy that is definitely in my future, but built large enough for a moderate size individual to use as well. The interior will be Spartan because I want it to be dog friendly and not concerned about claw and tooth damage. Cushion seats will be removable for human comfort, the dog is in it for the joy of the ride ...a real purist at heart! This will be a town & country rig not to be used on highways,and this allows me a bit of leeway, design wise, not in order to avoid sound setup, but in actual use holding to moderate speed does allow a greater range of safety.
I've only had one real ride & drive experience with a well setup motorcycle rig and it was interesting and informative to feel the strange sensations of the forces at work with the outrigged third wheel, fixed rig hack and this on a mid size cruiser, 6 to 7 hundred pounds without the car. My Simplex, solo, is a mere 180 lbs. at this point & I'm hoping to keep the car well under 100 lbs. with a quite low center of gravity. My weight has remained pretty constant for the last thirty years or so at just under 180, so I believe my bikes loaded center of balance an easy calculation. I've a 24 hour certified vehicle scales located just 3 city blocks from my house so weights are exact & not estimates. I've also a couple of hundred pounds of loose weights available to be used for testing the car loaded.
The hack will run an 18" D.O.T. certified wheel and & 2.5" wide moped tire. It's setup for a standard bicycle disc rotor.
The kayak donor shell is lightweight & will be chopped to an approximate 6 foot length. & total height for the side car will be about equal to the mounted tires height which is just about 23". Car ground clearance is in the 4" range. I'll include a sturdy hand rail fore and aft to assist in mounting & dismounting the car. No problem for the dog but I feature human riders to be quite young and flexible...mostly female. Now you see the old dog planning ahead! The kayak plastic is quite study but the handrail design will protect from any eventual cracks developing. I do have plans for a bracket to mount a spare wheel and tire to the rear of the car as well.
I'm quite certain the upgraded CG 125 engine has enough power to pull the extra weight. My only real concern is that by going to the small rear sprocket used to clear the current rear disc brake setup I've not enough gear reduction to propel the additional rig weight. If this proves to be a problem I'll machine a more aggressive primary gear reduction cluster to lower the final drive ratio.
So there's my updated plan to this point and as usual I expect changes to occur along the way. I'd really like to have this ready for my puppy this Spring. The car really is mostly about the dog at this point. I'm over (mostly) my mourning the loss of my last black Lab 7 years ago, so the puppy is in my future as I really miss my canine companion.
Rick C.