SV650.org - SV650 & Gladius 650 Forum - View Single Post - 10w-30 or 10w40. Is there really any difference?

johnnyrod · 18-06-13, 01:43 PM

The 30 or 40 is an indication of the oil film strength, the 10 is the viscosity rating (in simple terms). A single-grade oil has a strength that goes up with its viscosity, evne in a multigrade like 10/30 there is still a tie between the two but less so, if you're with me (best of both worlds but part of both). So 10W/40 will be fien but they have made the engine to be okay with thinner (less trong) oil like 10/30 and take advantage of it being easier to pump beacuse it's runnier. I take it you're talking about an inline four, the thump from each cylinder is smaller than a twin and closer together so the crank bearings have a more even load.

18-06-13, 01:43 PM	#3
johnnyrod Member Mega Poster Join Date: Jul 2003 Location: Doncaster, oop norf Posts: 2,128	Re: 10w-30 or 10w40. Is there really any difference? The 30 or 40 is an indication of the oil film strength, the 10 is the viscosity rating (in simple terms). A single-grade oil has a strength that goes up with its viscosity, evne in a multigrade like 10/30 there is still a tie between the two but less so, if you're with me (best of both worlds but part of both). So 10W/40 will be fien but they have made the engine to be okay with thinner (less trong) oil like 10/30 and take advantage of it being easier to pump beacuse it's runnier. I take it you're talking about an inline four, the thump from each cylinder is smaller than a twin and closer together so the crank bearings have a more even load.