Alphasyn or Optigear: Choosing a Castrol Industrial Gear Oil

Enclosed gear drives are unforgiving. The oil sits between hardened steel surfaces under high contact pressure, often at temperature, sometimes for years between changes. Castrol splits this work across several ranges, and the differences are worth understanding before you order.

Alpha: the mineral baseline

The Alpha range covers mineral industrial gear oils. For a gearbox running within its design temperature, at moderate load, with a sensible drain interval, a mineral oil does the job and costs less. Most general industrial plant sits here.

Alphasyn: synthetic, for harder conditions

Alphasyn is the synthetic range. Synthetics earn their price in three situations: sustained high operating temperature, very cold starts, or extended drain intervals where you are trying to reduce downtime. A synthetic will hold its viscosity across a wider temperature band and resist oxidation longer than a mineral equivalent.

If you are changing oil more often than you would like because it darkens or thickens in service, that is usually a temperature problem, and a synthetic is the usual answer.

Optigear: load carrying

Optigear is built around load carrying capacity for heavily loaded gear sets. Where you have shock loading, low speed and high torque, or a history of micropitting, this is the range to look at.

Worm drives are different

Worm gears involve a high proportion of sliding rather than rolling contact, and they often call for a different chemistry entirely. Do not assume a standard EP gear oil is safe in a worm drive without checking, because some EP additives are aggressive to the bronze wheel.

Greases are a separate decision

Where the application is a bearing rather than an enclosed gearbox, you are looking at Spheerol greases instead, and the selection logic is different again.

Tell us the gearbox make, the operating temperature and the specification in the manual, and we will confirm the grade. Request a quote for pallet quantities.