KHE Mac 1.5 / 2 BMX tyres
 

I know sod all about tyre compounds - are these a viable option for general useage or given that they're designed for BMX riding will they wear through really quickly, or have too high a rolling resistance?

Having searched the forums there's only 2 references to these tyres, I guess hardly anyone is familiar with them.

There's a similarly light-weight BMX tyre by Maxxis, the Grifter. 20 x 1.85 and around 375 grams.

With folding bead tyres is it the case that they have to be run at a high PSI because the flexible bead means they're more prone to deforming in that region, causing pinch-flats or . . . what, coming off the rim?

A folding tire generally just means lighter weight since each section of the bead can be made with a lighter material, generally Kevlar. But this construction will usually cost you more as well. A Kevlar bead folding version of a tire runs about 30%-50% more than a normal version of the tire with the same make and name. A folding tire can also stored easily in any luggage.

FWIW, in my experience, a folding tire is more prone to blowing off the rim at high pressures. I've noticed that the Kevlar beads isn't as thick as the wire beads. But these are personally experiences with one brand of 700c tires on one set of rims. YMMV.