If youre suffering under the misapprehension that your bike isnt fit to tackle the untamed gravel of the Home Counties without the latest 1x13 electronic groupset, complete with dinnerplate-esque 10t/46t cassette, this Viking expedition bike is the antidote. Turns out, all you need for the very worst terrain is iron-clad resolve, legs of steel and one fixed gear.This impressive expedition bike was built for Bernard Heath, an equally remarkable adventurer, who, together with Rough-Stuff Fellowship (RSF) members Dick Phillips, Raymond Bottomley, and Ron Bartle, made the first unsupported two-wheeled crossing of Iceland's interior in 1958. They cycled identical Viking steel fixies uniquely adapted for the task; the most obvious modification being the girder-like rack brace thats brazed directly to the seat tube.You could jump on that rack, its so strong, says current owner Richard Hoddinott of vintage specialists The Velo Pages. The whole bike is incredibly beefy. The front dropouts are clearly quite agricultural but built for punishment. (Image credit: Future / Richard Butcher)Similarly, the bottom bracket features a modified tandem shell for increased strength. The bikes had to be tough; they carried everything, including a rubber dinghy for river crossings.The adaptations were a wise precaution. The four RSF riders, all in their twenties, were taking on the Sprengisandur (roughly translated: ride a horse to death), an ancient 260-mile pass that lies between three central Icelandic ice caps. (Image credit: Future / Richard Butcher)If the lava fields were daunting a seemingly endless rotation of boulders, scree slopes and knee-deep, soft grit the numerous, broad, icy river crossings were downright hazardous.Reading their expedition notes, its remarkable how rudimentary much of their kit was. The defining adjective is stout stout rope, stout cycling shoes and, of course, stout bikes. Bernard Heath went on to found the Mountain Bothies Association a legacy for which every walker, climber, and bikepacker remains in his debt.(Image credit: Future / Richard Butcher)