Fat Tyre Hassles

BinBike can (largely by accident) take very fat tyres - the limit is chainline rather than frame tubes and the front fork (which is easy enough to build anew). Given my current silly ideas about riding around Cape York next year, fat tyres might be just the ticket. Plus I've managed to get both a 42T and 36T chainring into the bike and the adjustment reach on the rear dropouts is just enough to let that work. But I cannot for the life of me actually find fat 406 tyres. Talk about grumpy, Trev.

The basic problem seems to be that the BMX stuff is built around 20" OD wheels, so the fat tyres used in trials riding are mostly 20"x4" but on a smaller than 406 ISO rim. I'm not really into swapping rims mid-ride to change tyres. It's bad enough just changing tyres.

There's the Schwalbe Big Apple which comes in a 60mm or 64mm size depending on whose website you look at. But that's a slick. In kinda vaguely knobbly tyres I've found the Snafu Rimjobs (my fave tyres when they were rated at 130psi, but now only 100psi) which are 50mm (2.1"). Which is not at all like 4".

I've been talking to a trials dude and actually got some 20x2.7" tyres off him, but unfortunately this is where the imperial sizing thing bites you in the bum. See, the outside of the tyre is 20", so the inside is 18" or 19" depending on who you ask (one tyre is actually a 19x2.7", but both are 369 ISO which according to our man Sheldon is actually a 17" rim Actually, they're 396 which is even worse - they're only a tiny fraction smaller than my rims. Still, Steve at MontyBikes has offered me a refund). Now, I kind of vaguely knew there was something fishy about this stuff, so I mentioned that I'd be running a 64-406 tyre on the same wheel but unfortunately the trials guy missed that, and so did I. D'oh!

So if anyone knows where to get fatter 406 tyres I'd love to hear from you.