We just spent a week at the Bonneville Salt Flats competing at the 65th Annual Bonneville SpeedWeek. The Bonneville experience is one of those “once in a lifetime” events for many performance enthusiasts, be they bike or car oriented. It goes without saying that we’re most interested in the bikes. A few first timers joined us this year and it seems that one of the more confusing aspects of the events on the salt is the myriad of classes. There are categories for seemingly every manner of bike from bone stock to streamliners and sidecars. Having competed on the salt for several years now, I thought I’d try to take away some of the mystery of the classification scheme. This is not a rule book, just a simplistic, plain english description of the basic categories. Here then is your Bonneville Bike Classification primer.
Each bike carries a class designation that may seem like hieroglyphics, requiring some manner of Rosetta Stone to decode. Thankfully it’s not that complicated. In every case those class designations carry information about the nature of the bike’s chassis/frame and also a section that gives some simplistic information about the powerplant. We’ll cover the chassis part today and save the engine part for next time.
The first thing to do is check out the very first letter in the class designation. . There are a limited number of possibilities here.
P designates a “Production” class bike. Full production bodywork, lights, and running gear are required here. A “Production” class bike will appear, in almost every visual way, just the same as if it just rolled off the showroom floor. Inside that may not be the case but stock appearance is paramount.
M stands for Modified. Think modified street bike here. You’ve got to start with a stock frame of some manner but seats, pipes, bodywork (to some extent) are all fair game for modification. Still, in concept at least, these are (or could be) street bikes.
A means Altered, or in the parlance of Land Speed Racing, purpose built bikes. Bespoke frames, engine swaps between manufacturers, sometimes even multiple engines, and bodywork that would never be viable on a public highway are the order of the day in “Altered.” Still, these are “sit on” motorcycles – you walk up to ’em, throw a leg over, and steer with handlebars.
An S designation takes us into the world of streamliners. These are the world’s fastest two-wheelers with their fully enclosed bodies, strapped down reclining “riders”, outrigger wheels or skids for starting and stopping. They bear little visual relationship to typical motorcycles and might possibly be mistaken for a tiny missile or midget submarine should you ever encounter one in a Wal Mart parking lot.
In the Modified (M) and Altered (A) categories there are two subgroups, the so called “open” or naked bikes which carry no additional designator, and the Partially Streamlined (i.e. full bodied) bikes which carry a PS after the “M” or “A,” So, a Modified, but naked, bike will carry just an “M”
While a Modified bike with bodywork may carry an “MPS. designation”
Likewise there are simple “A” class naked bikes.
And there are “A P S” partially streamlined “Altered” bikes.
One last thing for today… let’s not forget our sidecar friends. Though it’s pretty easy to identify sidecars from the more conventional two wheelers, just remember that each sidecar will be found to have the “SC” designator in it’s class markings.
So there yoiu have it, the basics of Bonneville Land Speed Racing Frame (or chassis if you like) designations. We’ll cover the additional numbers and letters that describe the engine details in the next issue of Road Prose. And remember, there will be a test!!!