Homologation is a technical term, to signify the granting of approval by an official authority. This may be a court of law, a government department, or an academic or professional body, any of which would normally work from a set of strict rules or standards to determine whether such approval should be given. In our case it is the committee of the BLMRA and the idea behind it is to make sure that any lawnmower that is used as the basis of a racer is built to a set of rules that are intended to make racing fair for all concerned.
When you think about it it does make sense especially where Group 4 machines are involved. With such a large variety of donor mowers out there, ensuring that there is parity between them all would be extremely difficult if certain rules weren’t laid down. It also means that rather than having a ‘one rule suits all’ situation, each mower is viewed in its own right so that the widths (track) and length (wheelbase) of Group 4 racers can be different as these dimensions are based upon the original donor mower. Therefore, choosing your donor machine is made more interesting as you search out that elusive mower that is light, low and wide!
When you have a mower homologated you will be given an homologation sheet that not only lists the wheelbase and track, but other things such as the position of the engine, the height of the deck (chassis), tyre sizes but crucially you will also be advised about areas where you can cut out parts of the bodywork (usually to accommodate the seat base) and those parts that you cannot cut. Other build advice is also given and it is as well to listen to this as it is being given to help you!
