You'd get confused if you were running Silkolene 5wt and went to PJ1 2.5wt thinking it would be thinner when in fact it is thicker! Please note, the given SAE figures do NOT guarantee that the 5wt in one brand is the same as the 5wt in another brand, see this chart This chart gives you the cSt40 & cSt100 values for most fork oils on the market, use it when deciding what oil weight you need. The conventional way of describing a fork oil thickness is by an SAE measurement like 5wt or 10wt, this is a carry-over from describing motor-oil weights, these descriptions were used so it's easier for the common man. The lower the number, the thinner the oil. Hydraulic oil thickness is measured by flowing the stuff through a measured size orifice at two different temperatures, this measurement is called centistokes, cSt for short, cSt40 is with oil at 40 degrees and cSt100 is with the oil at 100 degrees. I've been studying-up on fork oils lately, thought others might be interested.įirstly, fork oil is hydraulic oil, it does the same job in both circumstances but is under less stress in a pair of motorcycle forks.
