Some of these may help. I've talked to some of the guys at Tires Unlimited and they are very knowledgeable. I've also contacted numerous manufacturers customer's service and have been able to talk with some of their engineers. They are always helpful, but have to be careful what they say. It's just business. Give some of them a call.
Motorcycle Tires - Brands
Ejelta.com: Tire Size Calculator
Tire size calculator
The Future of Motorcycle Tires - Motorcyclist Online
Also, North of 49, I suspect that there are no two production tires that come off the assembly line that are exactly the same. Additionally, any nominal or expected dimensions a manufacturer may assign a tire size may vary quite a bit. Then there is wear. A few mm here a few mm there.
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I guess there is another thing that needs to be said concerning tires on Trikes in general and front tires on Trikes in particular. There has been very little real research done by the manufacturers of tires or trikes on just what type tire or configuration is the best for safe operation of our Machines.
This small group we represent on this site is part of an experiment on what works best, rides most comfortably and hopefully doesn't hurt us.
As an example, when I first started riding, I didn't have a clue about the engineering of a motorcycle. My first bike was a 1947 knuckle basket with parts off of an Indian, a Cushman and many other machines just to make it run down the road. I put whatever tire I could beg, borrow or steal on the front or rear as long s it would fit. I couldn’t kick start it and had to get my buddies to push me off and then catch up. If it was squirrely, I just learned to ride it and deal with whatever was trying to kill me. Those of us, who survived, learned from our mistakes and some of us even went to school to better understand the things. Oh, by the way… That bike ended up under a 1956 Buick. Go figure me talking.
What I'm trying to say, is that anything we discuss here concerning the mechanics of our machines is little more than what we can transfer from our collective many years of riding motorcycles. At best, we're guessing.
At worst, we’re just blowing smoke with knowledge garnered from the past supplemented with a little education.
One thing is for certain. No manufacturer of a Trike or a Trike kit is going to put anything on the market that is unsafe. It wouldn’t be good business and we can bet that any information the manufacturers gain will be passed on quickly.
The tire you seem to want to use will probably work fine and you don’t seem to be someone who is going to be riding 200kph. If your Trike becomes nose heavy and doesn’t want to steer as well, install fork extenders to move the center of gravity aft and get back close to balance.
I ride a VTX1800 Panther by MotorTrike with 6* rake and 2"; fork extenders. Like many of us, I love to experiment. My next front tire is going to be a Michelin Pilot.