Thanks for the info about this ride being referred to in Bicycles up
Kilimanjaro. I will have to give it a read.
This first Cleland / Snowdon ride is also described on page 177 & 78 of Charlie Kelly's and Nick Crane's Richards Mountain Bike Book of 1988.
This concentrates more on the ride, the bad weather and what was learned from the experience. There is less here about the details of the Geoff Apps Range-Rider bicycle being ridden.
Nick Crane does comment that the low pressure, tungsten carbide studded snow tyres "gave it enough traction to power it up slimy rock steps and shale that skittered like ice". I wholeheartedly recommend low pressure studded ice tyres for use on most slippy surfaces. I have also found to my embarrassment that this does not include the marble flooring at Waterloo train station.
Crane also says that... "this was probably the first mountain in Britain to be 'mountain biked'.