I don't have a Thunderbird yet, but I was planning on getting one next Spring. This whole tire situation is giving me pause though. I don't ride a ton, but I'll put 5-7k miles on a year. From the sound of it, I'd need to be looking at new tires every year...and they aren't cheap. I guess I'll hold onto the Bonneville a bit longer, or look at some Thunderbird alternatives, if there aren't better tire options within the next year or so.
I totally understand, a bigger bike equals greater cost of ownership, generally...but this seems a bit ridiculous.