We tend to think of important international-level race courses in the pre-war era as being similar to the tracks we see today, only with stone walls, and no run-off areas or hay bales. In fact, smooth and well-paved race tracks were the exception, and only purpose-built tracks such as Brooklands, Montlhery, Avus, and Monza had really good pavement. The rest of the 'road' courses tended to have a mix of tarmac, gravel, cobblestones, and occasionally dirt, unless we're talking about races in the US, Australia, New Zealand, South Africa, or South America, where the racing courses were entirely dirt, or even sand. Thus, our favorite racing motorcycles were treated to the great indignity of breathing hard through a dirty haze, unless they were out in front of the pack, and only one motorcycle per race got such satisfaction.
My great contributor Dave Martin, miffed at the suggestion that racing motorcycles were meant for smooth pavement, sent along a few choice examples of famous race courses in the day. The top pic is of course Daytona beach in Florida, where the cream of American and European racers were treated to an invigorating salt scrub. With the poor cambox sealing on those ohc Norton 30M racers, I can't imagine what the rocker box looked like at the end of the race. Yet, sand racing was very popular from the 'teens through the 50's, and legendary battles were fought at venues such as Pendine and Southport Sands, and Invarcargill in New Zealand.The second photo shows the Ulster GP around 1933; Dave says, 'wot, no yellow flag for cow pats?'. Obviously a wet day, with unprotected spectators lining the outside of a very messy corner, and water-filled potholes in evidence. And for many years the 'Ulster' was the fastest road race in the world!
The third pic shows Wal Handley at the most famous course of all, the Isle of Man TT, in 1929, which is clearly a packed gravel road at this juncture. The Mountain course underwent a gradual series of improvements over the decades since that first race (on an oiled gravel and dirt road) in 1907. By the mid-20's, much of the course was paved, but certainly not all. Even in the 30's, there was quite a lot of gravel to be found on this very fast road race, making 90mph laps all the more impressive.
In the US, all of our race courses, since the disappearance of the fearsome Board Tracks, were dirt, or sand, combined perhaps with a short bit of pavement. Most of the races were held on 1-or 2-mile oval dirt tracks, on which machines could be held flat out for long stretches, before sliding around the (sometimes banked) corners at either end. These two photos, from my own archive, show the Cedar Rapids, Iowa, track in 1942 (yes, Yanks were still racing, but not for much longer!). The photo above shows racer Jack Kulan on his '39 Rudge Ulster 500cc four-valve, preparing for a race against a mixed field of Harley and Indian 750cc sidevalves, and a few 500cc Triumph Tiger 100's and Ariel Red Hunters thrown into the mix (click on the photo - you can see Jack is revving his engine, as the primary chain is blurred). Cedar Rapids was a massive track with a very large grandstand, although only a few hundred attended the race on this day. The track itself looks as if an earth grader scraped a smooth oval out of the adjacent corn fields, and that's exactly how it was made. The photo below shows Jack at speed, rounding the corner at full bore, probably 90mph. A water truck usually circulated between heats to damp down the dust, hence the darkened surface, and lack of a large rooster tail of dirt.
Thus, the best riders certainly were well-versed in the vagaries of loose surface control, and the motorcycles were regularly dismantled and cleaned out!