Open Full fairings are allowed. If it's human powered and conforms to the safety rules, it's in. All entries the subclasses below also qualify for Open.
Part-faired A front fairing OR rear fairing is allowed, but is not required. From the side the view of the rider's torso, head and upper leg must be uninterrupted by aerodynamic additions, though the tail fairing may protrude forward to the mid point of the rider's torso
Unfaired No fairings are allowed (wheel discs are permitted). Unfaired machines also qualify for the "Part-faired" class
Multitrack A machine with three or more wheels in 2 or more tracks. The wheels must be structural, a bicycle with lifting or flexible 'stabilisers' is not considered Multitrack. Full fairings are not allowed. Entries in this class also qualify for Faired Multitrack, are eligible for the Part-faired class and, if they have no fairings, for the Unfaired class.
Faired Multitrack As Multitrack, but full fairings are allowed.
Armpowered Powered by arms alone.

Two further classes serve to provide an entry-level competition for riders who do not (yet) posess an out-and-out racing machine, and to promote the development of road-going machines with fairings. These classes do not have strict technical specifications. Eligibility will be determined principally by the competitors or, if arbitration is required by the Competition Secretary

Sports This class is for unfaired bicycles that are suitable for use on the open road. Tail boxes are permitted, if they are practical luggage-carriers. Typical examples include: Kingcycle (without nose cone), Challenge Hurricane, Challenge Mistral, Burrows Ratcatcher.
Street Also for bicycles suitable for use on the open road, but front and tail fairings are allowed (side fairings and "bags" are not considered suitable for road use and are disallowed). Examples: Kingcycle with nosecone, Challenge Mistral with Zzipper fairing, Geoff Bird T7. Sports-class bikes are also eligible for Street.

General Rules

BHPC aims to foster the development of Human-Powered Vehicles, free from the constraints of arbitrary technical specifications. Therefore we have very few rules governing the construction of race machines. There are a few rules, however, regarding safety. The race committee has the last word on all of these; if in doubt, please ask.

Helmets 
All riders must wear (on your head) a helmet approved by a recognised national standards authority (e.g. Snell, ANSI, TUV, etc.) The sole exception to this rule in in the case of a faired machine where the rider's head is enclosed, in which case any helmet designed to protect the head (such as a leather "hairnet" type helmet) may be used.

Brakes
You must have an effective means of slowing down, appropriate to the event. For a velodrome no brakes are required IF and only if a fixed-wheel is used. For closed, road circuits at least one effective brake is required. For any events on public roads, legal requirements apply, i.e. two independent braking systems must be fitted. The race committee has the last word on this sort of thing, so if in doubt, ask.

Starting, Stopping And Signalling
For events run on the public highway, such as time-trials, riders must be able to enter, start, stop, and exit their machines without assistance. They must also be able to give clear signals. This isn't our rule, it's Her Majesty's Government's. (No 2010 season races are on public roads.)

Guards
In accordance with the need to remove all forward pointing "sharp" bits, the chainring must be covered by either a fixed shield or by a strong rotating chainguard (including those with a single chainring). A lightweight chainguard for protecting the rider's trousers from the chain will probably not be sufficient. Any homemade guarding must be free from sharp edges. Competitors who fail to do this will be warned; a second warning will mean you will not be permitted to compete. If you are unsure - ASK! Looking for ideas? Check out the chainguard photo gallery. If your machine has any other projections that may be dangerous to other riders or yourself (open-ended tubes - think apple-corer - are one of the more commonly seen dangerous design "features") you may be asked to remedy it before being allowed to race. Again, if unsure, ask.

It is strongly recommended that those riding bikes without the benefit of a hard-shell fairing use elbow guards, and that everyone has a rear-view mirror.

Number boards
You must display legible race numbers on the left and front of your machine, at least A5 sized. Failure to show numbers may result in failure for your result to be registered.