Engine Oil Weight

Go ahead use it ! It covers the range your bike requires . It will work in slightly lower temperature's than the 10 W 40 weight*!

 

+1

 

Taken from another bike forum but think it gives a good explanation to your query
Rant alert.. Went to a well established Yamaha/Honda dealers today for some 5w40 oil just to top up. So they didn't have any I went to purchase some 10w40..The sales assistant then explains to me I couldn't use that as it has different Weight and the 10w will sit on top of the 5w even gets the mechanic to back him up.. So I say 5w doesn't stand for weight it stands for winter..He gets really aggressive and says why don't they do 10s40 for summer then?? and says I've only been doing this for 20yrs what do you know.. Well I actually know alot as I used to work as a chemical engineer for BP and I used to blend the Castrol power1 oil... And the base oil is the same usually 9001-006 for most fully synthetic then adjustment to make the specific grade 5w/10w/40 etc so they definitely do mix and also it's fork oil that means weight 5wt/7.5wt etc..What annoys me is these shops are supposed to be there to help not be an arse and give bullshit information..They also told me you cannot mix fork oil to give a different weight bullshit..

 

That's interesting I was aware that the w was for winter, but thought the numbers were referred to as weights as some way of describing viscosity.

 

The 'w' should be read as a German 'v' as on viscosity ! The lower there numbers the cooler/colder the climate it is recommended for !! So 5-30 W would suit somewhere between Iceland , Canada , Norway and 30-50 W would be England Europe through the Tropics and Africa , Australia

 

Hi ftel, seems like you're not up to speed with what the numbers mean 10w-40, 5w-40 etc etc.

It's all about the viscosity or thickness at certain temperatures. The first number 5w (W standing for winter) refers to the thickness of the oil at 0° c (32°f) the second refers to the thickness at 100°c. The idea is that for different ambient temperature ranges you can use different thickness oils.

So for instance you're in Texas I believe, so if your ambient temps in winter were 10°c at the lowest and 40°c at the highest, then a 10w-40 would be fine.

If however your lowest temps right now are 0°c or lower then a 5w-40 would be more suitable.

Honestly either would suit your application, just wanted to give you a bit more insight.

 

I don't think Ftel was suggesting the w stood for weight. I think weight is another way of describing viscosity.

 

The viscosity question is one asked a lot on lots of forums...you can pretty much disregard the first number unless A you live in the Arctic or B you live in the Sahara whether its 0w or 20w it will be fine in our climate.

The second number is the one that actually going to have more affect on how the motor responds too low than its recommended grade and it will tend to run hotter with lower hot oil pressure and too high and it will increase oil pressure but put more strain on the oil pump and pressure relief valve.

Although newer engines/materials are designed to run on semi or fully synthetic oils most engine will run happily on mineral or semi synthetic oils and vice versa
the only real differences are the frictions modifiers added to modern synthetics allow for higher temperature tolerances without dropping viscosity too much unlike mineral oils.