What Is a Derby Cover?

Custom designed derby plates are quite common on Harley Davidson motorcycles, as they promote the individuality and free spirit associated with these machines. The design engraved on the plate is typically selected by the bike's owner with special symbolic expression in mind. For example, if the rider is a die -hard Harley aficionado, there is a wide selection of chrome derby plates engraved with the assorted Harley insignias. The classic Derby cover is made of simple smooth finished chrome free of any engravings.

Typically derby covers are offered in three-hole or five-hole models, depending on the specifications of the bike it is being connected to. The five-hole cover is thought to offer more durability and protection (Wilson and Rafferty, 2001). As there is a wide assortment of derby covers to choose from there is also a wide range of prices. Lower end covers go for around $7, while the higher end covers can get as high as $400, especially if they are gold plated and serve other functions, such as holding license plates.

Since derby covers are situated in an easily accessible part of the bike, they are relatively simple to change. Cycle mechanics must always remove the derby cover when checking the internal mechanisms of the transmission. For example, to check whether the throw-out bearings need to be changed, it is essential to remove the derby cover first. If by accident, the derby cover is not re-installed or is damaged, the workings of the transmission could be seriously compromised. One common mistake that bikers make, according to Woodring and Love (2006), is replacing the o-ring beneath a warped derby cover without changing the cover. The authors indicate that a warped cover can be just as bad as a damaged one, or in some cases, as not having one at all.

The origin of the derby cover is difficult to identify. The term "Derby cover" is not listed in the Oxford English Dictionary. It may have been named after the derby hat which was also an ornament of expression. This conjecture is very likely since the first Harley Davidsons were fabricated around the same time that derby hats were in fashion in the US and were worn by some eccentrically lavish individuals who attended the Kentucky Derby horse race.

Since derby covers come in so many different designs, it may be difficult to choose the one that is perfect for you. If you don't like to follow the pack, a good idea would be to design your own and get it custom engraved. There are several derby cover engravers on the Internet like who have extensive experience in dealing with this product.