Re: Silverbear's sidecar
160 pounds is a lotta dog! I'm sure your dog would love going for trailer or sidecar rides, but I'd want to be sure that the trailer or sidecar was up to the weight. The instep trailers I have are rated at 100 pounds, but no doubt that is to avoid law suits and there may be a good bit of extra maximum weight capacity. Also, I would think that with a sidecar the bike is taking on some of the weight that a trailer by itself would have. I think it depends on how well the trailer is made. The Instep model (Ride N Stride) I used for this sidecar is less sturdy than the lightning model which is square aluminum tubing and has well made wheels. The 100 pound rating may also have to do with the floor and seat of the trailer being just fabric. Beefing that up would make a real difference I would think. Something like strapping going back and forth under the fabric would do the trick and weigh very little. If you pull this thing off you have to promise to post some pictures!
I've had a few big dogs through the years and one in particular comes to mind. Krosivi was a Borzoi (Russian wolf hound) who didn't weigh in like your mastiff, but stood tall and could run like a big greyhound. He was a good buddy who never barked, had a lot of dignity... never begged. Those log legs made for a lousy canoe dog and he wasn't much better in a fishing boat. I took him camping one time only even though he had a great time. In the middle of the night he was running in his sleep (you know how dogs dream a lot) and he stretched those long legs out... I woke up to the sound of the tent ripping as his legs went through the tent wall.
Aaniimoosh The Wonder Dog makes for a more manageable size. I do know that very often big dogs are the most gentle and most want to be lap dogs... just overgrown puppies. It is the little chiwawas (can't spell that one) that are ankle biters. Tell your dog that Aaniimoosh says hi and that I'm wagging my tail.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...