What is a friction modifier, **?

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What the heck is a friction modifier and is there really such a thing in synthetic oils. I moderate several motorcycle groups and it seems the frase "friction modifiers" but does it have a meaning and why would one want such a thing in a synthetic oil. The car popular low viscosity oils have lower viscous friction because of the lower viscosity but I can hardly call that a friction modifier. I don't use those thin oils in bike motors. I do use Mobil 1 15w-50 and never had a problem and doubt I ever will.

Perry
 
From what I understand, a friction modifier is just that - an additive to reduce the friction in the oil. You don't want this in a motorcycle because the wet clutch will not lockup correctly and you will get increased wear and/or overheat the clutch. That is why you should never put auto oil in a motorcycle (although Harley Davidson says it is okay to use oil made for Diesel engines in a pinch).

From what I understand, it doesn't have anything to do with viscosity as I have a 90W oil in my limited slip differential and I added a friction modifier to keep the wheels from chirping around corners (the LSD needs to be able to slip a little bit).

Hopefully I gave you good information, but I am sure to be corrected if I didn't. You came to the right forum to ask. There are a lot of pretty smart people on this forum.
 
quote:

Originally posted by perryg114:
I do use Mobil 1 15w-50 and never had a problem and doubt I ever will.

Perry


Tech support at Mobil claims that Mobil 1 15W50 now includes friction modifiers.
 
Well, I currently have M1 15w/50 'gold cap' in my '97 Honda 750 and it shifts great. Bike has 60K on it. Tech support at Mobil is spotty- they want you buy the special M/C oil...
rolleyes.gif
 
Mobil's motorcycle oil ALSO CONTAINS a friction modifier in just about the same quanity as the 15w/50 gold cap - so if the gold cap shouldn't be used for that reason, then Mobil's motorcycle oil also needs to be excluded.

It's sickening when truth is withheld for the sole purpose of increasing profits. The only way to escape this is knowledge.

RevRider
 
quote:

Originally posted by RevRider:
Mobil's motorcycle oil ALSO CONTAINS a friction modifier in just about the same quanity as the 15w/50 gold cap - so if the gold cap shouldn't be used for that reason, then Mobil's motorcycle oil also needs to be excluded.

It's sickening when truth is withheld for the sole purpose of increasing profits. The only way to escape this is knowledge.

RevRider


According to the mobil 1 website, the motorcycle oil does not contain friction modifiers:

http://www.mobiloil.com/USA-English/MotorOil/Oils/Motorcycle_Oil_FAQs.aspx

(excerpt from the above page)
"so unlike Mobil 1 for cars, Mobil 1 MX4T has no friction modifiers, which could lead to clutch slippage. "
 
Laminar,

It doesn't make any difference what they say, it is what is in the oil, check out the VOA's on this oil, it contains MOLY, which is a friction modifier...

Then check out the gold cap, the Moly content is about the same...

Both oils contain friction modifiers - so if the motorcycle oil is ok, so is the gold cap.

Would you agree?

RevRider
 
RevRider,

I checked the VOA and see what you are talking about. MX4T, according to the Cat tests (I assume that is what you were talking about) shows a Moly content of 91

http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=11;t=000310

However, Sportrider says MX4T has an "undetectable amount" (they used Analysts Inc for their VOA).

see chart:

http://www.sportrider.com/tech/146_0310_oil/

What is equally interesting is that earlier in the article it states that Moly won't cause your clutch to slip.

So someone's numbers are wrong. Or perhaps Mobil 1 changed the formulation after 2003 (when the sportrider article was written).

If indeed they are the same moly content, I would agree with your point that the gold cap Mobil1 would work be fine also. Sportrider seems to think that Moly won't have an effect on your clutch. I would probably say that if your clutch is marginal, moly might put it over the edge. So I think there is truth i n both points of view. There are so many factors (like how hard you ride, spring strength, engine mods, etc.) that can play into whether your clutch slips or not, I beleive that moly is a contributor but probably not a major one.

Either way, it sounds like you could use the gold cap oil if you wanted to. It's not something I would do as I prefer motorcycle oil in my motorcycles. But, as I said before, even Harley says you can use Diesel engine oil in the shop manual (both in the 1996 Road King and 2002 Fat Boy shop manuals).

Then again, Harley Davidson was adamant that synthetic wasn't good for their engines. My mechanic, who I really trust, was equally passionate about this topic and said synthetic would cause flat spots on needle bearings. As much as I trust the guy to wrench on my bikes, I'll take the word of the lubrication engineer that has a PHD after his name over my mechanic. Hence, my Harleys have had synthetic in them since the first OCI.
 
quote:

Originally posted by Laminar Lou:
My mechanic, who I really trust, was equally passionate about this topic and said synthetic would cause flat spots on needle bearings.

This is from the same school of thought that taught us that synthetic oil was bad for roller cams in autos
rolleyes.gif
.
 
Many riders with wetclutch assemblies are using Redline oils w/~600ppm Mo, with no reported problems.

I have tried, but I can't find the study that Rotax engine did on using moly in the wetclutch sump. I think it stated that they found that their engines would tolerate moly until the count was >1000ppm and the fluid had sheard way down. I suspect clutch problems with sheared down oil, Mo or no Mo.

I'm certain that the oil companies, who peddle overpriced, moto specific, MA certified fluids absolutely LOVE the misconceptions about engine oils. How else can the high price point of these fluids be justified?
The phrase; "Whatever the market will bear" would certainly show itself if we all knew the truth about what works and what doesn't. Because the market surely wouldn't bear the high cost of these boutique oils, and they would be forced to price them as their comparable counterparts on the Walmart shelf are.

Anyone who uses these oils should NEVER gripe about inflated big oil company profits.
 
Ok just doing some reading it looks like there is some confusion between antiwear additives (AW) and friction modifiers (FM). AW additives like Moly are ok as long as the quantity is not such that is cakes up on clutch surfaces. AW additives are only effective when the oil film is not there and you would have metal to metal. Friction modifiers coat all surfaces, metal or organic, and can cause clutch problems. Since clutches work by the friction of two surfaces, one metal and one organic you have a problem. Friction modifiers or antiwear additives don't do anything unless the surfaces touch. In a perfect world you would never have two surfaces touch because they are separated with a thin layer of oil. Certainly this is the case with journal bearings like on a crank. With cams and gears it is not such a perfect world and things do touch. So you need one or the other to protect the metal surfaces from wear. Now from what I read the friction modifiers and antiwear additives perform the same function for the most part but the friction modifiers have a smaller coefficient of friction than the antiwear additives do when two surfaces touch. Now since the new car oils are very thin, metal to metal contact is more likely which is going to offset the benefit of thinner oil because now you have metal rubbing against metal. Well this is not a good thing and of course causes friction. To combat this problem they put in friction modifiers and to protect the metal and reduce the rubbing friction. All this is to save the car manufacturers butts from the evil CAFE standards for fuel mileage. It is really splitting hairs but I guess it gives them another mile or two a gallon. Does this sound correct to you folks?

By the way I have a pretty good supply of the oil red cap Mobil 1 15W-50 so I don't guess I will have to worry too much about friction modifiers till I run out of it.

Perry
 
it seems you have a semi good understanding.
if you look on the back of the bottles for the donut, some (lower vis) have "Energy Conserving" and those with higer vis do not. which matches up with your thin fluid comments.
all of the manuals that i have seen for motorcycles say that you should NOT use "Energy Conserving" or "Energy Conserving II" oils. which none of the thicker oils are.
 
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