Your front is a 110/80 on an 18 inch rim. The rear is 150/80 on a 16 inch rim. All the manufacturers make tyres in these sizes, but not necessarily in the speed ratings that you may prefer.
For example, like Rincewind, I really like the Avon Azaro ST45/46 combo cos I like to go scratching, and if they're good enough for the Sprint and the other zoomy Sport Tourers, they're well good enough for me. They come in the Z speed rating which means they are good for 150+ which is way over a TB's top end. But a V rating (<149) or even an H rating (<130) would suffice.
So, you can go for 110/80*18 and 150/80*16 where the asterisk represents ZR, VR or HR or even just Z, V or H. Click here for more info at Webbikeworld.
So, if you browse the online motorcycle tyre suppliers and look for the tyre specs I've quoted above, you should hit paydirt. You just got decide what brand/spec of tyre you prefer. Now I did read on this forum that Avon wouldn't be producing the ST45/46 in our size rear tyre in the future but then someone added a postscript that they would - so I'm not sure on that.
(Edit - Denny's post confirms that the Avon Storm complements the Avon Azaro range - so in fact Avon will continue to produce the rear for our TB's in the Azaro range, but the front will now be in the Storm range. You can see that on Coopers website for Avons)
By the way, do you use the Advanced Search here? It's way better because you can limit the search to just this forum and search for all or any keywords. Using it to search on the obvious keywords like tires and/or tyres and/or brandnames returned loads of posts on people's preferences and experiences.
[ This message was edited by: parrycm on 2007-01-18 22:31 ]