India has the worlds largest population of two-wheelers, with 115 million registered in 2012, the latest year for which government statistics are available. Most of those units – an estimated 75 percent to 80 percent – are motorcycles, industry observers say. Scooters account for 15 percent to 20 percent, and the rest are mopeds. But scooter sales are growing faster than motorcycles or mopeds, which may partially account for the interest they are drawing from lube marketers.

Shell and Gulf Oil Lubricants India Ltd. both introduced oils last year that are formulated specifically for scooters. Shells is branded Advance AX5, while Gulfs is Gulf Pride Scooter. Their launch came four years after Castrol Indias introduction of Castrol Activ Scooter.

The lubricant needs of scooters differ from those of motorcycles. Motorcycles can have wet or dry clutches, but most in India have wet clutches, meaning the engine, clutch and gears are all contained within the same shell and are lubricated by the same fluid. This means the lubricant must have the lubricity and anti-wear properties necessary to protect pistons and other engine components but also provide the correct amount of friction needed for the clutch to function properly.

In addition, explained Debanjan Kundu, of Kline & Co. consultants, The engine of a motorcycle is placed so that natural air circulation provides adequate cooling. Hence, cooling in not the most critical property desired of oil used in motorcycles. Due to contamination risks of oil during operation, it is essential that these oils retain their viscosity for their life in use.

In contrast, most scooters sold in India today have continuously variable transmissions, which include dry clutches. The transmission still needs to be lubricated, but this is done with a separate fluid. Scooter engines are generally placed under the seat and are covered, which hinders air circulation and causes them to run hotter than motorcycle engines, increasing the potential for build-up of deposits, said Chandrabhan, chief marketing officer for Gulf Oil Lubricants India Ltd. Thus the main functions for a scooter engine oil are to reduce friction, and to prevent deposits and heat transfer, he said.

Shell said its Advance AX5 Scooter is formulated with chemical additives designed to prevent oil thickening, to reduce formation of deposits and to promote cooling. The new oil has a viscometric grade of 10W-30 and meets both the API SL specification for passenger car engine oils and the Jaso MB specification for motorcycle engine oils.

Castrol India, which claims that Castrol Activ Scooter was the first oil made specifically for scooters, says its oil is also formulated to protect from wear and build-up of deposits at high operating temperatures. In doing so, the oil helps scooters maintain their zippiness, Castrol says.

According to a Castrol spokesman, who asked not to be identified, before the availability of engine oils designed for them, scooter operators typically used motorcycle engine oils. Some operators continue that practice today because they do not understand the special lubrication requirements of scooters, the spokesman said, but use of scooter oils is growing. Scooters are particularly popular with young consumers and women, so marketers must appeal to those audiences.

Klines Kundu said engine oils for new scooters with automatic transmissions are generally SAE 10W-30 or 10W-40. Most manufacturers recommend oils that meet API SJ or SL specifications, but products meeting Jaso MB are also catching on, Kundu said, because these oils are classified as the lowest-friction oils for four-stroke engines and thus provide comparatively better fuel efficiency.