There are three good tires for the TR1: Bridgestone BT45, Bridgestone BT45, and Bridgestone BT45.

Gruss,
Georg

It's always a god idea to have one in reserve...

100/90-19 and 120/90-18 are the right dimensions. You don't nee the speed index V, that's right, but i think they do not cost very much more than the H-rated tyres...

Bye,
Georg

Thank you Georg and Alex.  
I find that I can have the pair of V-rated BT45s delivered to me for <$200.00 so it seems like the right thing to do.

I'm a bit late, I suspect, into this party.  I've posted a similar question this afternoon. I'd agree that BT45s are good, having had them on a Suzuki GS650GT and a Yam XS650.  But!  I've heard some good things about the new Avon AM26 Roadriders.  With tyre (sorry, tire - we must make allowances for our colonial cousins... ) technology moving constantly forward, and the Avons being a considerably newer design, logic suggests that they might be the equal, or even the superior, of the Bridgestone.  Oh for the olden days, when the only tyre (sorry, tire... what the heck; we invented the darned language!  Tyre!) to have if you ever took a corner - apart from nothing Japanese, of course, was the Pirelli Phantom!  Now that was a great looking tyre, and very sticky as well.  I wonder how they'd compare nowadays...?

Funny how perceptions change.  It's a bit like bikes themselves.  Way back in the dim and distant past, the Triumph Bonneville was the dog's wotsits, with magazine tests banging on about 'arm-stretching acceleration'.  Then in the seventies we had the Honda CB750, which 're-wrote the book' on performance.  then came the Suzuki GS1000 and the Kwak GPZ900R, which are both now called 'slow', when compared to the latest tackle.  I'm rather glad I decided early on to opt out of the horsepower race, preferring to take the Rolls-Royce view - 'sufficient' is, er, sufficient.  TR1s rule!  Back on topic: anyone have any experience of the Dunlop Arrowmax GT501?