ARI/Ariete fork seals quality of execution is matched only by the unique nature of the material used: the carboxylated elastomer known as XNBR. Oil seals are normally made from a nitrile rubber, known as NBR. This is used because it is cheap, and plentiful, not because NBR is the best material for the job. The graphite-rich compound creates a self-lubricating material which is both heat and abrasion resistant. We have designed ARI oil seals with a variety of lip profiles to make them longer lasting, while reducing to a minimum the friction effect against the moving shaft.

Over the years, ARI have discovered the key role of a separating lubricant between the fork tube and the rubber of the oil seal to reduce to a minimum the surface friction, without affecting the function of the oil seal. After exhaustive testing, a lubricant devised specifically as a rubber/metal lubricant for mechanical components used in the NASA space program was selected. This grease (ARISIL) extends the life of the oil seal, and helps it retain its vital characteristics of flexibility and chemical resistance. For this reason, every set of ARI FORK OIL SEALS contains a sachet of ARISIL, sufficient to lubricate the two oil seals supplied.