Yes, but all this is the same typical sales talk. It is many times proven that things that are most expensive in their segment do not usually offer the best (or even near the best) price/performance ratio.

Where are independent test results that compare different oils? I'll start buying expensive full synth oil if I see proof that the cost is justified.

So this is all very interesting, and I'm enjoying learning a bit about motor oil formulations. Yes but however.....

Obviously, I don't need "friction modifiers" to keep my wet clutches from slipping. They don't slip. They've never slipped. I'd be willing to bet cold hard cash that they won't ever slip....until past their wear specifications, at least....and I've used all sorts of oils, at all sorts of price points, in all sorts of circumstances all over three continents. So in the absence of information more compelling than a vendor's statement that I need friction modifiers because "many cheaper oils (mainly car ones as opposed to proper bike ones) do not contain the correct addative pack and friction modifiers to stop the wet clutch slipping," I think I'll pass. And while I'm at it, I might as well pass on the rest of the advice in the same posting--either you've got credibility when making unsubstantiated assertions, or you don't.

The paste from the oil chemist is a whole different story. He sounds believable throughout (although I have to ask how fundamentally important are the marginal benefits he's describing), but this leads me to wonder: how would I recognize "a 10W/40 shear-stable semi-synthetic with some ester content" if I stumbled over it? It's the reported shear-resistance of the Rotella synth (reported by folks on another forum who routinely send their used oil out for testing after each oil change) which convinced me to use it regularly when I'm in this country. How would I know what else to use?

I can't even believe I'm participating in an oil thread! What came over me? How will I regain my former highly-prized state of aloofness?

Mark

Oilman...

You obviously know your stuff


Can you explain multigrade oil ??? 10W40 vs 15W50 etc ??

What does the W exactly stand for... Some say its the weight some swear it means "winter" etc etc.

I thought that a 10W40 will act like a nice easy flowing 10W when its cold and only get as thin as a 40W when hot ! Am I right ???

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As I understand it its the other way round.

Car oils have friction additives because the engine and clutch are house eperately, as is the gearbox. The engine needs low friction, the gearbox needs shear resistance and the clutch needs, well nothing.

In motorcycles there are no such friction additives because most bikes have engine, box and clutch all bathed in the same oil. So the friction modifiers would not stop your clutch from slipping but would, in fact, make it more likely to slip, particularly if the clutch is starting to reach service limits.... that limit may be brought forward with car oils...

Hence why car oils in a wet clutch bike are best avoided, plus the fact that a car oil is probably not designed to deal with a gearbox thrashing about

That is my understanding...

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Oilman, come back to me!

I've checked my semisynthetic motorcycle oil specs. I have on the can :

API SJ
JASO MA
SAE 10W 50

In theory, this cheap(er) oil exceeds the needs of my Honda which asks for SG. I've read your posts, and this seems to be the case.

Can the oil seller lie to me (in Europe), and sell me chip fat repackaged? There's so much consumer distrust around that oil threads get like this, as you see above.:confused1:

Yes of course no problem...............

If you see an expression such as 10W-40, the oil is a multigrade.

This simply means that the oil falls into 2 viscosity grades, in this case 10W & 40.

This is made possible by the inclusion of a polymer, a component which slows down the rate of thinning as the oil warms up and slows down the rate of thickening as the oil cools down.

It was first developed some 50 years ago to avoid the routine of using a thinner oil in winter and a thicker oil in summer.

For a 10w-40 to attain the specification target a 10W ( W = winter) the oil must have a certain maximum viscosity at low temperature. The actual viscosity and the temperature vary with the viscosity grade but in all cases the lower the number, the thinner the oil, e.g. a 5W oil is thinner than a 10W oil at temperatures encountered in UK winter conditions.

This is important because a thinner oil will circulate faster on cold start, affording better engine protection.

For a 10w-40 to attain the other specification target a 40 oil must fall within certain limits at 100 degC. In this case the temperature target does not vary with the viscosity grade, if there is no "W", the measuring temperature is always 100degC. Again the lower the number the thinner the oil, a 30 oil is thinner than a 40 oil at 100 degC., which is typical of maximum bulk oil temperatures in an operating engine.

The engine makers are, of course, very well aware of this and specify oils according to engine design features, oil pump capacities, manufacturing tolerances, ambient temperature conditions etc. It is important to follow these guidelines, they are important and are an are stipulated for good reasons.

If the engine has been modified, the operating conditions may well be outside the original design envelope. The stress on the oil caused by increased maximum revs, power output and temperature may indicate that oil of a different type and viscosity grade would be beneficial.

Cheers

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Those specs look fine to me, if it works for your bike stick with it. I believe that the correct grade should be 10w-40 although check your handbook on this.

Cheers

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Maybe I wasn't clear that I was quoting Oilman, who stated that it is the absence of friction modifiers in car motor oil which makes it unsuited for bikes?

Three points: First, some car oils have friction modifiers. As far as I can tell, they are labeled as such ("High mileage" is one warning sign) and are more expensive. They're not appropriate for use in wet clutch bikes. Most car oils do not have these friction modifiers, and are suited, in this respect at least, for use in wet clutch bikes.

Second, empirically speaking (this means based on direct observation, not on theory or confident statements made by unknown persons on the internet), cheap car oils do not cause clutch slippage. There may or may not be other problems related to any or all of their properties, but clutch slippage is demonstrably not one of them. Of course, if someone's got actual experience contrary to mine, I'll listen; this would be someone who can say "I used this cheap motor oil with no special friction modifiers touted on its label in my bike and the clutch started slipping."

Third, it is true that wet clutches and bike transmissions impose harder and more complex working conditions on oils than would normally be found inside automotive engines. There are motorcyclists who track oil degradation by having their used oil tested by commercial testing centers after each oil change. They report on various brands and conditions of use. The consensus on a forum devoted to KLR's is that, for example, Valvoline products tend to degrade rapidly due to polymer shearing; Rotella products (especially Rotella synthetics) generally fare better, and at an excellent price point. But in any case, shearing exists, and it happens rather rapidly The consensus suggests oilchanges by (or sometimes before) every 2000 miles for this reason.

That's all I've got to go on: general understanding of the principles involved, direct personal experience, and the experience of those who take a far more rigorous and analytical approach than I (and have the test results to back their assertions).

Beyond this what's left? Lots of people with lots of opinions--some stated very compellingly but without any supporting evidence....or at least, without any supporting evidence to which I've got access. For me, statements made with passion and/or conviction don't really carry much weight unless also congruent with experience and backed with some sort of evidence.

Your mileage, on the other hand, may vary.

Mark

You're right! slip of the keyboard, 10w- 40 it is!
Of course I'll never know if it works for my bike - that needs science/engineering.

Thanks!

One interesting side note from BMW F800GS Rider's Manual (2nd ed, 2008, page 126), quote:

"Oil grades: Mineral oils of API classification SF through SH."

It is interesting to note that there is no mention of semisynth or synthetic oils.

Mark, You are of course right. The original post was ambiguously worded and I've gone back to it and amended it:

"The problems tend to start with wet clutches and many cheaper oils (mainly car ones as opposed to proper bike ones) do not contain the correct additive pack and may contain friction modifiers which may cause slippage in the wet clutch."

Guy

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I found this informative article whilst looking for something else and thought it might be of interest to you folk:

http://www.calsci.com/motorcycleinfo/Oils1.html

It was written a couple of years ago and a few of the links towards the bottom are broken, but it's well written and an interesting read. Well, interesting if you're interested in oil ;-)

Cheers
Guy

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Oilman, just to say thank you for an interesting and useful posting.
Thanks for taking the time.

+1 on the thanks to Oilman.

Another question: As a lubricants guy how do you decide your oil is worn out?

I'm from an automotive design background (not engines) and have sat through meetings where conversations have taken place certain vehicle OEMs would probably not want to talk about. They work along the lines that the engineers have done their testing and concluded part X needs a re-lube every five years and spares should come with a sachet of grease. There is then a conversation with the OE sales guys wanting it to be maintenance free and the parts/service guys wanting it done every ten minutes using grease they can buy in ten gallon tubs. Someone then points out the three year service is a little light, so that box gets a little dot in the box in the service manual.

Then there is Triumph who the day after the 6000 mile oil change Harley Sportster was launched, sent me a new service book for my Bonneville raising the oil change from 4000 to 6000 miles.

Finally there are various old boys on Enfield chat rooms and the like who change their oil every 200 yards.

I stick to the distances in the manual on the basis the OEM must have picked a distance in the right ball park and too frequent changes involve those few seconds running with the oil light on. I change sooner if there is water in there or it starts to look black.

What does the oil and lubes guy do on his own bikes?

Cheers

Andy

Well, oilmans bike is a 1912 Royal Enfield waiting restoration so not using any oil at the moment.

Oil life depends on many factors, the type of oil used (quality), The use of the vehicle and the time the oil has been in the vehicle. Most handbooks will give a guide for normal standard use and mileage and follow those and all will be fine. Once you start messing around with different oils, track time, modifications to the engine (more power) then the rules change.

Cheers

Guy

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