10w-30 or 10w40. Is there really any difference?

[Balky001]

I have always used 10w-40 oil for my bikes but Honda recommends 10w-30.

I price difference is minimmal and I understand what the figures mean. However, as I track day and may go to Spain for a few days on track I can't helping thinking 10w-40 would be better.

Does anyone know if using 10w-40 would have any negative consequences. I've looked up on t'internet but there are many opinions based on logic rather than facts...... but I know there are some excellent oracles on the Org.

Thanks

[jambo]

For most bikes I've owned there has been an oil type recommendation per ambient temperature range in the handbook, so it'll show the temperatures at which they suggest changing to something else. I'd probably start by seeing what they say there, as the manufacturer built the motor and ship it worldwide

Jambo

[johnnyrod]

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.

[Balky001]

Thanks Jambo/JR

I ended up getting 10w-30. If its recomended and £2 cheaper then I'm in Probably change it before Spain in October anyway!

[johnnyrod]

Blimey you must be doing some miles. No reason with modern oil to change it any more often than the service interval. The oil companies spend a lot of time and money making sure it can take a good pounding, then we spend a lot of money buying it!

[Red ones]

If the Honda manual is anything like Suzuki ones there would be a chart showing what can be used. Ambient temperature does make a difference and if last year is anything to go by I'd guess Spain may be warmer than the UK.