Considering all of the challenges and potential issues and disadvantages, I really don't see why someone would want to try using a car tire on a bike, with a Voyager kit or not. Is it really worth the small amount of $$ you are saving? In my humble opinion, I'd rather spend a little extra and have a tire that is designed for a motorcycle than go through all of that hassle...

But isn't the point that the back end he has isn't a motorcycle, and doesn't lean into corners like a motorcycle? It's a trike back-end, and that has two wheels on an axle, like a car or a trailer. That's why Dunlop (and presumably others) make trike rear tyres...

So, with a Voyager kit you still have your rear bike tire which is a 15" tire that stays straight up all the time and wears the tread flat . The purpose of wanting a car tire is for better wear life not to save money.

Yeah you probably get about 30,000 miles out of a car tire as opposed to a motorcycle tire and I don't know anybody that has put a car tire on a motorcycle and has experienced any problems as a matter of fact most are very happy

I'm just not sure how to go about figuring which car tire might work.

Maybe a tire salesman could help.

A 175/75/15, 185/70/15 or 195/65/15 should fit. But you are going to have to measure the overall tire width to make sure that the sidewall will clear the propeller shaft. The other thing that I did not mention is the change in overall aspect ratio (the car tire is taller) which means it will affect the gear ratio as well as can potentially strike the fender bolts when you hit a bump. Like I said before, it can be done, but there are all sorts of potential drawbacks... Or you could just keep riding the right tire and not worry about reinventing the wheel?

Yeah, I'm sure there are lots of possible issues. Who knows I may never get serious enough about it to try.

At least you know the option is out there.