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[BusyLittleShop]

Yep, thicker oil means more film thickness between moving parts even in a transmission, and therefore less friction between them.

Mercy Zee... it's true that thicker oil means more film thickness but thicker also means MORE friction not less...

Quote VP Fuels
Is a thick motor oil better if you live in a warm climate? You might
think a thicker oil (high viscosity) would offer better protection.
Well, yes, and no. Viscosity is critical to keep metal parts separated
within the engine and the proper viscosity grade does that. That being
said, you don’t want an oil that’s too thick because it creates too
much frictional drag within the oil itself. This creates additional
heat, which causes the oil to thicken (oxidation) and can also rob
engine performance by reducing horsepower.

Quote Gmtech94 GSXR
When I raced we were sponsored by an oil company and helped with the
research of their product .The thought at the time was to run 20w50
race oil to provide for the best lubrication under racing conditions
hence no oil related failures . After many races and a lot of real
data research the conclusion was in this case to run a 10w30 oil as it
provided better lubrication and less engine wear over a long period of
time ,remember motorcycle endurance racing in 24 and 30 hour races .
Although we never had an engine failure due to oil properties we did
have a lot of feedback on engine wear as well as transmission and
clutch wear . I have to say we did abuse these bikes on occasion with
spinning the back wheel to turn the bike as well as the occasional
fall .The ignition was a weak link but I could change out the pulsers
in about 17 seconds once the bike was in the pits . In conclusion
10w30 ran cooler and did not break down as much as the thicker oils
did.

 

[ZeeOSix]

Mercy Zee... it's true that thicker oil means more film thickness but thicker also means MORE friction not less...

There are two kinds of "friction" involved - film thickness shear and rubbing surfaces friction in boundry lubrication. You have to look at what causes shear friction in the oil film vs parts rubbing friction. The velocity between the moving parts causes the shear friction in the oil film. Actual physical rubbing of two moving parts on each other causes the rubbing friction. It's the rubbing friction that needs to decrease to make a transmission shift better.

The velocity of the moving parts associated with shifting and changing gears isn't any thing even close the velocity going on inside a journal bearing. Therefore, the friction associated with shearing the oil film is basically zero, and the rubbing friction between the moving parts surfaces can therefore decrease due to the thicker oil film thickness between the parts separating them more and reducing the rubbing friction. That's why motorcycle transmissions shift easier and smoother when the oil is thicker when cold, and shifting gets a bit more notchy after the oil has gotten thinner at full operating temperature.

 

[ZeeOSix]

Quote Gmtech94 GSXR
When I raced we were sponsored by an oil company and helped with the
research of their product .The thought at the time was to run 20w50
race oil to provide for the best lubrication under racing conditions
hence no oil related failures . After many races and a lot of real
data research the conclusion was in this case to run a 10w30 oil as it
provided better lubrication and less engine wear over a long period of
time ,remember motorcycle endurance racing in 24 and 30 hour races .
Although we never had an engine failure due to oil properties we did
have a lot of feedback on engine wear as well as transmission and
clutch wear . I have to say we did abuse these bikes on occasion with
spinning the back wheel to turn the bike as well as the occasional
fall .The ignition was a weak link but I could change out the pulsers
in about 17 seconds once the bike was in the pits . In conclusion
10w30 ran cooler and did not break down as much as the thicker oils
did.

Too many factors involved with an engine used in race conditions, and basicaly unsubstanciated opions from someowne with no real test data to prove the claim. Every wear study as a function of oil viscosity shows less wear with more film thickness due to increased viscosity, all other factors held constant.

 

[Bonz]

BLS, you highlighted the point about an oil that is "too thick". What is that point in a viscosity range oil becomes too thick? When it goes thicker than what the manufacturer recommends for ambient conditions?

The VP guy said there were yes and no sides to the discussion. You highlighted the part about negative effects of oxidation increasing viscosity (change the oil regularly to avoid this) and increased heat production from the oil itself, which a properly working cooling system will deal with in a street engine. "More" friction within an oil itself leads to some additional heat, it does not NOT lead to the more damaging friction/contact between moving parts due to lack of film strength. The points you share are fixated on the last nth degree of power as an example and fall toward the bottom of what makes an oil a good choice for the focus of an owner for an everyday engine.

(Conveniently?) you failed to highlight the benefit in the article which is increased film strength and the CRITICAL (his descriptor) function of said film strength separating metal parts. Critical did not make the list of descriptors when it came to the points you chose.

 

[troop]

2022 Can Am Spyder RT Sea To Sky 1330cc Rotax triple
3760 miles (1 year)
Out:
(2) quarts Castrol Power 1 10w50
(3) quarts castrol Power 1 10w40
HiFlo filter
In:
(5) quarts Amsoil 5w40 metric motorcycle oil
HiFlo filter

BRP recommends 5w40 weight for their Spyder's. I used 10w40 for the shear factor. I figured I'd give Amsoil 5w40 a run in this interval. I will send in a sample for analysis, but it will likely be a year. Hopefully it will have for miles on it

 

[bike]

2023 Yamaha Super Tenere ES with 20,000 miles.
HiFloFiltro HF 204 oil filter
Castrol Power 1 5w40 synthetic oil
Final drive drain/fill with Valvoline synthetic lube

 

[sandcritter]

2023 Triumph Rocket 3 GT

Motul 7100 15w15 & Microgard Select MSL51358
HPL Gear 75w90

23mi (NOS bike purchase Dec ‘24)
600mi (break in service)
4600mi

 

[Bonz]

2023 Triumph Rocket 3 GT

Motul 7100 15w15 & Microgard Select MSL51358
HPL Gear 75w90

23mi (NOS bike purchase Dec ‘24)
600mi (break in service)
4600mi

View attachment 288896

Great looking bike you have there! I've ridden a first generation Rocket III a decent amount when a friend owned one for awhile. Can't even begin to describe the pull it had. With the weight reduction and displacement bump, I can only imagine the fun you have on this bike.

 

[sandcritter]

Thanks! She’s an interesting brute, the love child of a farm tractor and a Ferrari it seems, and really quite gentlemanly in manners. It corners far better than one expects; not a sport bike, but she plays at it. Tread life… looking to be a set/year at this rate. The scads of torque make it quite forgiving all around, and yes, it will “go” when you ask it to.

 

[troop]

Thanks! She’s an interesting brute, the love child of a farm tractor and a Ferrari it seems, and really quite gentlemanly in manners. It corners far better than one expects; not a sport bike, but she plays at it. Tread life… looking to be a set/year at this rate. The scads of torque make it quite forgiving all around, and yes, it will “go” when you ask it to.

Only looks semi farm tractor'sh from the left side. Triumph is lax with left side photos of the Rocket 3