Couldn't any bike use 0w-50 or 5w-50??

[AtomicNumber53]

I read a comment that ANY vehicle could use a 0w-50 or 5w-50 oil, and the logic seems to make sense but especially with motorcycles.

~~~~~~~~~~~~~~~~

Looking at a couple commonly available 15w-40 oils, the cSt @ 40 deg C ranges from 106 to to 117.
--- and the cSt @ 100 deg C ranges from 14.1 to 15.4.

And just looking at Mobil 1's 0w-50, for example, the cSt @ 40 deg C is 100.
--- and the cSt @ 100 deg C is 17.2.

And then looking at Mobil 1's Peak Life 5w-50, the cSt @ 40 deg C is 108.
--- and the cSt @ 100 deg C is 17.5.

~~~~~~~~~~~~~~~~

So, my thought process is that if a 15w-40 oil starts at ~110 cSt, then it's obviously capable of handling an oil that thins out to just 17.2 or even 17.5, correct??

And with motorcycle transmissions shearing oil moreso than with other applications (engines only), a 0w-50 or 5w-50 oil seems like a better choice. Or naw?

One thing I don't really understand is HTHS numbers and how to determine how much these oils will shear. Some people say that Group IV or V synthetics won't really shear that much (regardless of VIIs), while the Group 3's, like Mobil 1 and Pennzoil Platinum will shear more like a traditional oil. Anyone able to offer insight into how to comprehend HTHS or other shearing info? Or is the best way to look at UOAs after 2,000 or 3,000 miles?

 

[A_Harman]

Look at the HTHS if you want to compare oils ability to protect at high rpm and temperatures.
Spend some time searching and reading BITOG. There is a lot about the subject that has been written over the years.
There is even a currently active thread on HTHS. https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5018495/going-by-hths#Post5018495

 

[CT8]

It a 0W or 5W needed?

 

[spasm3]

When i had a little 250 suzuki, i tried 5w 40 rotella and 15w 40 rotella. The 5w40 did great until about 1000 miles then i could feel the clutch get klunky. I could change the oil and it would do the same. The 15w40 never did that. So i think the wider range oils are more susceptible to sheer.

 

[SZR48207]

Originally Posted by spasm3
When i had a little 250 suzuki, i tried 5w 40 rotella and 15w 40 rotella. The 5w40 did great until about 1000 miles then i could feel the clutch get klunky. I could change the oil and it would do the same. The 15w40 never did that. So i think the wider range oils are more susceptible to sheer.


Ditto

 

[AtomicNumber53]

Originally Posted by A_Harman
Look at the HTHS if you want to compare oils ability to protect at high rpm and temperatures.
Spend some time searching and reading BITOG. There is a lot about the subject that has been written over the years.
There is even a currently active thread on HTHS. https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5018495/going-by-hths#Post5018495

I'm still not understanding what HTHS really means, though. People talk about it like it should be replacing the later viscosity number, which would be 50 in this case of 0w-50 vs 5w-50. So a 0w-50 with a shear rate of 4.1 is more likely to turn into a 0w-40 after a thousand miles, as opposed to a 5w-50 wiith shear rate of 4.5?

Basically, how should I be comparing this 0w-50 with HTHS of 4.1 to a conventional 15w-40 with HTHS of 4.1. Are they going to shear at a rate equally from their respective standpoints, meaning that the 0w-50 will turn into a 0w-40 & the 15w-40 will turn into a 15w-30? Or is that number a better representation of the actual viscosity of the oil at operating temps, making them more or less equal from the first pour (excluding differences in their cooling & pouring properties)? I'm thinking the former, but I'm not sure.

Seems like either of these 50 weights could be similar to or slightly better than T4 Rotella, simply with better starting abilities (significant wear in itself).

 

[AtomicNumber53]

Originally Posted by spasm3
When i had a little 250 suzuki, i tried 5w 40 rotella and 15w 40 rotella. The 5w40 did great until about 1000 miles then i could feel the clutch get klunky. I could change the oil and it would do the same. The 15w40 never did that. So i think the wider range oils are more susceptible to sheer.

I think I read that both the T5 5w-40 and the T6 5w-40 had a low HTHS rating, definitely below 4. Perhaps this is why?

It seems like there is some type of rating(s) that better describe what our bikes really need. And seems like if taking the inevitable hard shearing into account, one of these 50 weights would just provide for more reasonable, extended oil changes.

 

[stoan]

FS 0w-50 was my favorite Mobil 1 oil in my VFR800, and I tried lots of them. When NAPA has it on sale it's about half the price of the Mobil 1 motorcycle oil.

 

[rubberchicken]

Originally Posted by stoan
FS 0w-50 was my favorite Mobil 1 oil in my VFR800, and I tried lots of them. When NAPA has it on sale it's about half the price of the Mobil 1 motorcycle oil.


M1 had a 0w-50 ? I recall a 15w50 but not a 0w50.

 

[ZeeOSix]

Originally Posted by AtomicNumber53
I'm still not understanding what HTHS really means, though. People talk about it like it should be replacing the later viscosity number, which would be 50 in this case of 0w-50 vs 5w-50. So a 0w-50 with a shear rate of 4.1 is more likely to turn into a 0w-40 after a thousand miles, as opposed to a 5w-50 wiith shear rate of 4.5?

Basically, how should I be comparing this 0w-50 with HTHS of 4.1 to a conventional 15w-40 with HTHS of 4.1. Are they going to shear at a rate equally from their respective standpoints, meaning that the 0w-50 will turn into a 0w-40 & the 15w-40 will turn into a 15w-30? Or is that number a better representation of the actual viscosity of the oil at operating temps, making them more or less equal from the first pour (excluding differences in their cooling & pouring properties)? I'm thinking the former, but I'm not sure.


HTHS (High Temperature High Sear) is the viscosity of the oil under extreme shear rate while it's at 150 dec C, like it would be inside a rod or crankshaft bearing, or in some other hot area like piston rings, etc. The "40" or "50" weight rating is a range of defined viscosity for the oil when at 100 deg C. A higher HTSH value means the oil is more robust and more likely to protect engine parts from contacting each other. Typically, the higher the viscosity at 100 C the higher the HTHS, but that is not always true.

Different oils shear down differently ... so you can't always assume that the one with the highest spread is going to shear the worst.

I don't know what vehicle or motorcycle you are planning to use this oil in, but pretty much any good 10W-40, 15W-50 or 20W-50 motorcycle MA rated oil is going to be fine. A xW-50 will give a bit more protection especially in air cooled engines, but IMO not really needed in water cooled engines as the 10W40 is more suited for water cooled bikes. Personally, I wouldn't run a non-MA approved oil in a bike because of the wet clutch.

 

[A_Harman]

Originally Posted by AtomicNumber53
Originally Posted by A_Harman
Look at the HTHS if you want to compare oils ability to protect at high rpm and temperatures.
Spend some time searching and reading BITOG. There is a lot about the subject that has been written over the years.
There is even a currently active thread on HTHS. https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5018495/going-by-hths#Post5018495

I'm still not understanding what HTHS really means, though. People talk about it like it should be replacing the later viscosity number, which would be 50 in this case of 0w-50 vs 5w-50. So a 0w-50 with a shear rate of 4.1 is more likely to turn into a 0w-40 after a thousand miles, as opposed to a 5w-50 wiith shear rate of 4.5?

Basically, how should I be comparing this 0w-50 with HTHS of 4.1 to a conventional 15w-40 with HTHS of 4.1. Are they going to shear at a rate equally from their respective standpoints, meaning that the 0w-50 will turn into a 0w-40 & the 15w-40 will turn into a 15w-30? Or is that number a better representation of the actual viscosity of the oil at operating temps, making them more or less equal from the first pour (excluding differences in their cooling & pouring properties)? I'm thinking the former, but I'm not sure.

Seems like either of these 50 weights could be similar to or slightly better than T4 Rotella, simply with better starting abilities (significant wear in itself).


In general, the higher the spread between the W-number and the high-temperature number, the more permanent shear viscosity loss an oil is likely to have. The 0w50 with the 4.1 HTHS may lose 10% of the HTHS if it is in an engine that shears oils. The 15w40 with the 4.1 HTHS may lose 5% of the HTHS in the same engine. And if you had a 40 monograde oil with 4.1 HTHS, it wouldn't lose any HTHS.

In a motorcycle, I don't think you need a 0W- or 5W- oil at all. How much do people really ride motorcycles in sub-freezing temperatures? You just don't need the low temperature flow characteristics. 15w40 would be fine.

 

[Kamele0N]

Originally Posted by A_Harman


In a motorcycle, I don't think you need a 0W- or 5W- oil at all. How much do people really ride motorcycles in sub-freezing temperatures? You just don't need the low temperature flow characteristics. 15w40 would be fine.

This!

 

[AtomicNumber53]

Originally Posted by A_Harman
In general, the higher the spread between the W-number and the high-temperature number, the more permanent shear viscosity loss an oil is likely to have. The 0w50 with the 4.1 HTHS may lose 10% of the HTHS if it is in an engine that shears oils. The 15w40 with the 4.1 HTHS may lose 5% of the HTHS in the same engine. And if you had a 40 monograde oil with 4.1 HTHS, it wouldn't lose any HTHS.
Thanks for some estimations!!

Using the 0w-50 as an example, then --- after 1,000 OR 2,000 miles, perhaps, it could lose 10% of its HTHS and probably also its cSt @ 100 deg C.

So the 0w-50 at that time would then have an HTHS of 3.7 and a cSt @ 100 deg of 15.5 (essentially turning this 0w-50 oil into a stout 0w-40). Basically, this 0w-50 is going to offer slightly better protection and for a much longer time period (which seems very important with a shared sump).

Originally Posted by A_Harman
In a motorcycle, I don't think you need a 0W- or 5W- oil at all. How much do people really ride motorcycles in sub-freezing temperatures? You just don't need the low temperature flow characteristics. 15w40 would be fine.
A lot of the comments saying that you don't need a 0w- or 5w- rated oil seem to be based on available 0w-40 and 5w-40 oils. If a 15w-40 is recommended and has a cST @ 40 deg of 108 to 117, then a 0w-50's cST @ 40 deg of 100 is virtually the same when cranking the engine. The 0w-50 will be slightly better at start, it will resist shearing better, and last longer. Just seems to me that a 0w-50 or 5w-50 would make so much more sense looking at the numbers alone.

Even looking at the 5w-50, the cST @ 40 deg is 108.... which is right on par with the 15w-40s. But the cST @ 100 deg is 17.5. Which takes us back to my underlined question in the first post: "So, my thought process is that if a bike running 15w-40 oil starts at ~110 cSt, then the bike is obviously capable of handling an oil that thins out to just 17.2 or even 17.5, correct??" Basically, any air-cooled bike happy with 15w-40 should be happier with 0w-50 or 5w-50.

And now that I've read so much about HTHS and GDI fuel dilution, I think I might even need to try a 0w-40 in my Kia Rio.

It seems that more people are becoming aware of 0w- oils offering better (i.e. - quicker) cold start protection... but motorcyclists have correctly feared it due to the shearing found in our shared sumps. But when looking at a 0w-50 or 5w-50, the lower winter viscosities begin to make more sense. Like so much sense that these are the oils that shared sump bikes should have been using since their invention but just never existed until recently.

Seems like a 0w-+10 rating could work with almost any vehicle... just that air-cooled motorcycles need it far more than the others. If you've been using 10w-30 or 5w-30, then 0w-40 could be a better choice. Same if you've been using 15w-40, 10w-40, or 5w-40 -- a 0w-50 could be a better choice. I'm sure many of you have seen the chart of conventional oils' vs. synthetics' viscosities at different temperatures. The viscosities of these oils at different temperatures should be more like a flat line (synthetics) than a sharp angle downward (conventionals).

 

[oil_film_movies]

Originally Posted by AtomicNumber53
One thing I don't really understand is HTHS numbers and how to determine how much these oils will shear.
HTHS is just hot viscosity, that's all, saying how much oil protection you have in the hot parts of the engine. ................. You probably need about HTHS = 4.0 to 7.0, somewhere in that range, for most motorcyles. ...... The concept of "shear" is another subject entirely, and it involves some weird physics, but interesting. "Shear" is basically when an oil gets thinner due to a permanent break-up of it's VII molecules, or it can also refer to some temporary thinning at high-RPM conditions, either of which is an issue but usually its not bad enough to cause engine problems. Its true that the less VII chemicals an oil has, the less permanent or temporary shear happens, and full syn oils with small multi-grade spreads do use less VII, so you're right.

https://www.oronite.com/products-technology/viscosity-modifiers/default.aspx
"temporary and permanent viscosity loss
During routine engine operation and through continued use, engine oils are exposed to more extreme shearing mechanisms that break down the polymer molecules, reducing the oils molecular weight. This can lead to viscosity loss and a subsequent decrease in oil film thickness. If too severe, this can cause undesired friction and engine wear with oils that are not formulated with the proper viscosity characteristics.
Under no shear/no flow conditions, the polymer coil is roughly spherical in shape. As the oil begins to flow, the flexible polymer coil reacts to the velocity gradient within the oil. The coil deforms (becomes elongated) and becomes aligned to the direction of flow. The distorted coil impedes the oil's flow less than the original spherical coil did, and the oil's observed viscosity falls. This is known as "shear-thinning" behavior. When the shear stress is removed, the distorted coil resumes its original spherical shape and the oil's viscosity returns to its original value. This shear thinning is therefore termed "temporary viscosity loss." "

Originally Posted by AtomicNumber53
And just looking at Mobil 1's 0w-50, for example, the cSt @ 40 deg C is 100.--- and the cSt @ 100 deg C is 17.2.
That's a Racing oil. Lots of friction modifiers in that one (moly). If the transmission is sharing the oil, you don't want much friiction modifiers (FM). The issue using small amounts of FMs or not is a little complicated.
See https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=3039662 for some discussion.

 

[AtomicNumber53]

Originally Posted by oil_film_movies
HTHS is just hot viscosity, that's all, saying how much oil protection you have in the hot parts of the engine. ................. You probably need about HTHS = 4.0 to 7.0, somewhere in that range, for most motorcyles. ...... The concept of "shear" is another subject entirely, and it involves some weird physics, but interesting. "Shear" is basically when an oil gets thinner due to a permanent break-up of it's VII molecules, or it can also refer to some temporary thinning at high-RPM conditions, either of which is an issue but usually its not bad enough to cause engine problems. Its true that the less VII chemicals an oil has, the less permanent or temporary shear happens, and full syn oils with small multi-grade spreads do use less VII, so you're right.

Thank you! That makes plenty of sense, that shear and HTHS are different. A 0w-50 will shear more than a 5w-50, but it's due to the VIIs and not the HTHS rating.

Originally Posted by oil_film_movies
That's a Racing oil. Lots of friction modifiers in that one (moly). If the transmission is sharing the oil, you don't want much friiction modifiers (FM). The issue using small amounts of FMs or not is a little complicated.
See https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=3039662 for some discussion.

True. I haven't really looked that deep into this yet. Just trying to figure out if the these xW-50 weight viscosities are actually better for an air cooled bike than a 15w-40. They're certainly better at starting temps...

But yes, finding one without friction modifiers is another thing. I just recently read that any "Universal" Diesel/Engine oil will lack friction modifiers, or in other words, almost any xW-40 and xW-50 weight will lack friction modifiers. And even oils that are MA rated might still have moly, like the T6 5w-40. But knowing what I know now, I would never run that T6 in my bike because of its lower HTHS.

Speaking of the T6 5w-40, though, the spread between the winter and operating viscosities is only 35. A 0w-50 would have a spread of 50! But its slightly higher HTHS means that it is thicker and will probably remain thicker for longer. The problems associated with a 0w-40 or 5w-40 shouldn't necessarily be associated with a 0w-50.

 

[stoan]

Originally Posted by rubberchicken
Originally Posted by stoan
FS 0w-50 was my favorite Mobil 1 oil in my VFR800, and I tried lots of them. When NAPA has it on sale it's about half the price of the Mobil 1 motorcycle oil.


M1 had a 0w-50 ? I recall a 15w50 but not a 0w50.



Found one of my old bottles, it was 5w-50, not sure why I was thinking 0w.

 

[ZeeOSix]

Originally Posted by oil_film_movies
Originally Posted by AtomicNumber53
One thing I don't really understand is HTHS numbers and how to determine how much these oils will shear.
HTHS is just hot viscosity, that's all, saying how much oil protection you have in the hot parts of the engine.


It's also at a defined shear rate of 10^6/sec .... that's the "High Shear" part of HTHS. It's the "apparent" viscosity under varying degrees of shear and temperature.

https://wiki.anton-paar.com/en/basic-of-viscometry/#apparent-viscosity

PDF is downloadable in upper RH corner of this page.
https://www.researchgate.net/publication/305787812_Study_of_HTHS_Viscosity_of_Modern_Motor_Oils

 

[oil_film_movies]

ZeeOSix, HTHS is just hot viscosity in the hot parts of the engine. Yes, those hot parts of the engine are undergoing at lot of shear, no doubt. HTHS tries to roughly duplicate actual hot viscosity in there, yes, under high shear. The consumer just needs to know it is a hot viscosity that an engine maker specifies a range for.

 

[ZeeOSix]

Originally Posted by oil_film_movies
ZeeOSix, HTHS is just hot viscosity in the hot parts of the engine. Yes, those hot parts of the engine are undergoing at lot of shear, no doubt. HTHS tries to roughly duplicate actual hot viscosity in there, yes, under high shear. The consumer just needs to know it is a hot viscosity that an engine maker specifies a range for.


That's what I already said, please go back and read it again.

WRT your last sentance, that's not HTHS but the yy in the xxW-yy rating, which I also mentioned earlier.

 

[JAG]

Because of the large concentration of viscosity index improvers in 0W-50 oils, I would not use them in a motorcycle calling for a particular xW-50 viscosity grade. I wouldn't use 5W-50 either. I would choose either 15W-50 or better yet, 20W-50. HTHS viscosity is much more important than kinematic viscosity at 100 C because the HTHS viscosity test accounts for temporary viscosity loss caused by viscosity index improvers aligning with the direction of shear. Both tests are done on virgin oils. During use, viscosity index improvers break apart, causing permanent viscosity loss. In used oils, the percent decrease in HTHS viscosity has been found to be around 1/2 of the percent drop in kinematic viscosity at 100 C. In a motorcycle, the kinematic viscosity at 100 C of a 0W-50 may be expected to drop from 17 to 13 cSt (or even lower) which is around 25% drop, so HTHS should drop by around 12.5%. A good 20W-50 will have a higher virgin HTHS viscosity, and it should lose much less percentage of that HTHS viscosity than a comparable 0W-50.

The type of viscosity index improvers in motorcycle oils tend to be of a more shear-stable type than those used in automotive oils. Mobil 1 0W-50 is made for automotive engines. Mobil 1 20W-50 V Twin is a very different oil.