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

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Originally Posted by 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.

OK... What about a bike calling for a particular xW-40 viscosity grade? Wouldn't a 5W-50 be an option here?

And because of the VIIs breaking down, wouldn't a 0w-60 or 5w-60 oil be an option.... If such an oil existed?!? (You know it's coming!)


Originally Posted by JAG
HTHS viscosity is much more important than kinematic viscosity at 100 C because..... 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%.
I saw a chart comparing oils, and the Amsoil MCF 10w-40 was shear proof! After 90 cycles, there was no shearing on this oil. This is the only xW-40 grade oil I would really want to consider on a bike calling for such a viscosity. Otherwise, it makes more sense to just give a little thicker oil that we know will shear down to a 40 weight at operating temps.

The only problem is that there are UOAs of this Amsoil MCF 10w-40 that are definitely breaking down to a 30 weight, even tho it's "shear proof" in that chart. So if that's the case, it seems like a 5w-50 with HTHS of 4.7 (higher rated than the shear stable Amsoil MCF w/ 4.5 rating!) could be a very good choice for a synthetic that offers better protection throughout the temp range for many more miles. Guess there's only one way to know for sure, though -- UOAs?
 
I feel like I've been getting kinda wordy. The too long, didn't read version ---

TL,DR: An oil that is spec'd at xxW-yy could be replaced with either a 0W-(yy+10) or a 5W-(yy+10). This presumes that the HTHS of this new oil is around 4.5 or maybe higher. But it will inevitably shear to a 0W-yy or 5W-yy, which will then be right at your spec'd oil.... with the exception that this newer oil will offer better protection against engine wear at starting (saw one statistic that startup wear causes 90% of engine wear!).
 
AtomicNumber53, Yes, its true you can start out with a big mult-grade spread oil, like 0w50 for example, and watch its high initial starting HTHS reduce down to the engine's actual target spec over time.
For example, if your motorcycle loves HTHS 4.0, you can get an HTHS 5.0 0w50 oil and it will naturally keep going down over the life of the oil to 4.0. Your engine is protected the entire time. Let it gradually get permanent shear, it happens over time & usage.
Seems like some Porsche & also Indy racers were doing that a few years ago with Mobil1 0w40, starting a race with higher HTHS, and then near the end of the race, the HTHS had dropped (due to fuel dilution & permanent VII shear), but the engine was still running well on the lower HTHS near the end of the race. They liked it because the lower the HTHS, the more horsepower the engine makes near the end of the race.
 
I have two points to make. The first is that some polymeric VIIs also come with the downside of having a tendency to increase deposit-tendency. It's not a big deal but I think is worth mentioning.

The second point is a big deal. The much higher wear rate during warmup (that matters more than just the very brief startup) than while at normal engine temperature is due to chemistry being hostile during warmup. Oil viscosity has very little to do with it, assuming we aren't talking about crazy cold temperatures. The chemistry is hostile because the antiwear additives are not as active and effective, the engine is running rich and increasing fuel dilution. Also, much more of the water produced from combustion is in the liquid phase rather than vapor phase. Cold surfaces are condensing water vapor and are slow to evaporate the water. The acids have a lot of water to host themselves in, increasing corrosive wear, and even distilled water causes rapid corrosive wear to iron and steel.

So, you aren't going to greatly decrease wear during the warmup phase by using an oil that is thinner at those temperatures. A much better solution is to pre-heat the oil and engine with some kind of electrically-created heat source prior to running the engine.
 
Originally Posted by AtomicNumber53
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).

Here's the chart I was referring to...

Pictures sure do help. It was stolen from here, where this guy claims to run 5w-50 in every car he's owned since 1995!

I'm certain that it will shear faster in a motorcycle than any car or truck, but surely there are VIIs that last longer and give Amsoil and others such high HTHS numbers. The only real downside I've read to any of these viscosities with extra wide ranges is that the VIIs don't lubricate as well as the base stock petroleum, or whatever it is that synthetics are made of these days. I'm not sure if it's true, but this is why some people ultimately think sticking to a 15w-40 oil is best.

I plan to run a few UOA's for my bike. A 15W-40 vs a few xW-50 weight oils with obviously more VIIs. Should be fun, even if it takes me a couple years to actually hit the mileage necessary to convince anyone of anything.

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Jag has explained it really well, and gone over a few points a couple of times.

Alas, you seem to be fixated on an outcome that confirms your already held views.

Wear is not lack of oil on starting, it's during warmup...and minor differences in KV40 aren't going to change that.

High viscosity index is a good thing...until it becomes a bad thing, when it's chased simply to chase Viscosity Index. High viscosity Index base oils are great. Oils with Viscosity Index Improvers are still great...oils that have 10% VII to target Viscosity Indeces of 190-200+ are great too...in a Prius, or ewhen chasing warmup fuel economy, and don't have a shared gearbox to slice and dice the now abundant polymer molecules.

What's the lowest temperature that you are going to start your bike ?

Pick a "W" grade that best suits that ambient (0W is for -40C/F)...then the grade that fits the top end with respect to robust HTHS.

That's how you end up with 15W40 being one of the most recommended.
 
Here's a blend guide from Mobil...

Note that as the spreads within a grade become wider, the base oil becomes thinner, and the amount of VM (Viscosity Modifier) increases quite dramatically.

mobil blend.jpg
 
Originally Posted by Kamele0N
How do we know when monograde is real monograde and not lets say "relabeled" 15w30?
What if a 15W-30 is a straight 30 with more pour point depressants? We are just the consumers in this whole deal.
 
Originally Posted by Kamele0N
How do we know when monograde is real monograde and not lets say "relabeled" 15w30?


Per J300, if it has viscosity modifiers added, it MUST be labelled as the appropriate W grade.
If it's truly a monograde, but because of the quality of the basestock meets 15W, they can label it either way (or both like Amsoil ACD)
 
Originally Posted by Shannow
Jag has explained it really well, and gone over a few points a couple of times.

Alas, you seem to be fixated on an outcome that confirms your already held views.

Wear is not lack of oil on starting, it's during warmup...and minor differences in KV40 aren't going to change that.

High viscosity index is a good thing...until it becomes a bad thing, when it's chased simply to chase Viscosity Index. High viscosity Index base oils are great. Oils with Viscosity Index Improvers are still great...oils that have 10% VII to target Viscosity Indeces of 190-200+ are great too...in a Prius, or ewhen chasing warmup fuel economy, and don't have a shared gearbox to slice and dice the now abundant polymer molecules.

Many people have said many good things that I now understand. I'm just trying to find out at what point people around here WILL recommend a 0w-50 or 5w-50 over a 15w-40.

Will the HTHS need to be 7.5, or even higher? Seems like the shearing from our shared gearboxes attacks these oils almost equally -- 10w-40 Amsoil w/ HTHS of 4.5 should be shear proof, but maybe just in a car! 5w-50 is sheared to a 5w-40 and a 15w-40 is sheared to a 15w-30.

If there's no spec that can possibly identify an oil as shear-proof in a shared gearbox... then why not use the polymers to our advantage by adding more to our oil changes, in anticipation of them shearing?? If there is a spec that can point to which 15w-40 will remain a 40 weight longer than a 0w-50 can, I'd like to learn more about it. HTHS seems somewhat irrelevant for this purpose.

EDIT: Does the percentage of PAO basestock need to be considered? Seems that's why more people recommend 0w-20 over 5w-20 (in cars, obviously), even though the former has more VMs, VIIs, whatever... There is certain things that should be taken into consideration, and I'm trying to understand what those things are...

P.S. - Shannow, I think you missed my other post for you... https://www.bobistheoilguy.com/foru...nfluenced-your-oil-selection#Post5024279
 
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Originally Posted by AtomicNumber53
I'm just trying to find out at what point people around here WILL recommend a 0w-50 or 5w-50 over a 15w-40.
Climate. Cold start-up protection requires a "0w" or "5w" oil for wear protection. Thick oil doesn't get into tight clearances & reach bearing surfaces quickly enough. Generally, if you always start an engine above 32F, a "10w" oil is adequate. If you start something down to as low as 20F, then a "5w" is good enough. Below 20F, there is real benefit to a 0w oil. ... Some others above underestimated wear problems at cold temperatures, which doesn't match reality. Viscosity & flow do matter.

Originally Posted by AtomicNumber53
Will the HTHS need to be 7.5, or even higher?
Depends on the engine. If the owner's manual says to use a 50 weight oil, you only need HTHS 5.0 tops, and HTHS 4.0 minimum. If a 40 weight oil is the recommendation, you're fine with HTHS 3.5 to HTHS 5.0.

Originally Posted by AtomicNumber53
If there's no spec that can possibly identify an oil as shear-proof in a shared gearbox... then why not use the polymers to our advantage by adding more to our oil changes, in anticipation of them shearing?? If there is a spec that can point to which 15w-40 will remain a 40 weight longer than a 0w-50 can, I'd like to learn more about it. HTHS seems somewhat irrelevant for this purpose.
HTHS changes during the oil usage interval. A 0w50 probably starts out with HTHS 5.0 and gradually lowers down to HTHS 3.5 at oil change time. A full syn 15w40 will probably go from HTHS 4.0 to HTHS 3.5 at the end, ramping down, but not reducing as much as the high-VII 0w50 does. .... Those VII chemicals probably do add to deposits, especially if the formulator hasn't put in clever detergents & carbon cleaners in the oil. .... All that shearing and deposits we worry about is addressed in the specs the oil meets, so not to worry too much about it.

Originally Posted by AtomicNumber53
Does the percentage of PAO basestock need to be considered? Seems that's why more people recommend 0w-20 over 5w-20 (in cars, obviously), even though the former has more VMs, VIIs, whatever...
PAO is an expensive raw material, so when it is in the oil, you can bet it's there to increase performance. Otherwise the maker would just put in cheaper all Group3 and it can still say "Full Synthetic" on the label for marketing purposes to lure customers. .. POA is indeed a sign the oil is a long lasting, high temperature, low temperature, performer, although the latest Group3+ (GTL) comes very close to being as good. ..... For example, notice Mobil1 Extended Performance car oils have more PAO in them than other oils, and that oil is made to hold up better over time. Also, a lot of racing oils are all-PAO, or PAO+POE (no Group3). All that said about base oil selection, there is a also a big role to play for how smart the company is in putting together a great additive package, the VII, anti-oxidants, dispersants, etc. which complete the picture. Notice how Exxon-Mobil and SOPUS have a lot of patents on additives, along with their co-owned additive company Infineum, so you can usually trust they produce optimized products. Lubrizol does well too, and sells additive technology to any oil blender who buys it, making other oil brands very good as well.
 
Originally Posted by oil_film_movies
Originally Posted by AtomicNumber53
I'm just trying to find out at what point people around here WILL recommend a 0w-50 or 5w-50 over a 15w-40.
Climate. Cold start-up protection requires a "0w" or "5w" oil for wear protection. Thick oil doesn't get into tight clearances & reach bearing surfaces quickly enough. Generally, if you always start an engine above 32F, a "10w" oil is adequate. If you start something down to as low as 20F, then a "5w" is good enough. Below 20F, there is real benefit to a 0w oil. ... Some others above underestimated wear problems at cold temperatures, which doesn't match reality. Viscosity & flow do matter.

Which is precisely the foundation of me starting this thread...

And perhaps the reasoning behind oil manufacturers recommending [and possibly requiring?] 0w-xx oils across their vehicles, irrelevant of their climate.

It makes sense. If you can formulate an oil that has a KV40 of 50 and a KV100 of 17.5, it would theoretically be a great option for these shared sumps (and possibly any vehicle, as it would seem a pretty decent "universal oil"). The only issue is how do we determine how long those VII polymers will keep the KV100 above 14? I'm assuming that periodic UOAs are the only option here, as there is no spec that rates "gearbox shearing resistance". . . .

I'm clearly talking theory here. Some say the products available today aren't good enough for their bikes. But what would you need to convince you that thia "new" 0W-50 is the better replacement? A good basestock? A certain brand of polymers? A certain quantity or ratio of detergents? HTHS? UOAs only?

I've got to imagine that such an oil isn't too far away from reality, because the 5W-50 specs look very appealing to me, even in a subtropical climate (same KV40 as 15w-40s, or maybe just a tad thinner). The only downside to such a "perfect" motorcycle oil on a viscosity-temperature scale would have to be cost, which isn't that big a deal to me.

I wouldn't mind thicker 50 weight protection over the recommended 15w-40, but the 15w-50's I've seen are definitely thicker at startup, hence, the reason for this thread. Viscosity and flow DO matter. Thinner at startup would be best. Slightly thicker at operating temps might be best and would definitely be best if that KV100 drops 20% in 2,000 miles.
 
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Originally Posted by AtomicNumber53

It makes sense. If you can formulate an oil that has a KV40 of 50 and a KV100 of 17.5, it would theoretically be a great option for these shared sumps (and possibly any vehicle, as it would seem a pretty decent "universal oil").


HTHS and MRV are arguably better proxies to find your most optimal oil (we want to direct you to understand that first), but yes, along while considering:

Originally Posted by AtomicNumber53
I'm assuming that periodic UOAs are the only option here, as there is no spec that rates "gearbox shearing resistance". . . .


Allison TES-439 is a specification covering shear in a gearbox. It can be argued that motorcycle transmissions will put less load on the oil than an Allison transmission, so you could expect similar overall shear. A few heavy duty engine oil blends are formulated to satisfy this cert.
I wish I could give more relatable certs. UOAs are the other confirmation of shear resistance in gearboxes.

Originally Posted by AtomicNumber53


I'm clearly talking theory here. Some say the products available today aren't good enough for their bikes. But what would you need to convince you that thia "new" 0W-50 is the better replacement? A good basestock? A certain brand of polymers? A certain quantity or ratio of detergents? HTHS? UOAs only?

I've got to imagine that such an oil isn't too far away from reality, because the 5W-50 specs look very appealing to me, even in a subtropical climate (same KV40 as 15w-40s, or maybe just a tad thinner). The only downside to such a "perfect" motorcycle oil on a viscosity-temperature scale would have to be cost, which isn't that big a deal to me.

I wouldn't mind thicker 50 weight protection over the recommended 15w-40, but the 15w-50's I've seen are definitely thicker at startup, hence, the reason for this thread. Viscosity and flow DO matter. Thinner at startup would be best. Slightly thicker at operating temps might be best and would definitely be best if that KV100 drops 20% in 2,000 miles.


It needs to be able to startup and the engine able to flow the oil to the bearings.
Thinner at startup would be best to save wear on your battery.
 
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This "flow" thing is silly.

If the oil is in it's pumpable range, the galleries will be filled at the same rate.

at 0C (32F), It doesn't matter WHAT the "W" grade is, what the KV40 is, the galleries will fill at the same rate.

And the bearings aren't running "dry" until they get oil, there's plenty of oil left over from last time.it was run...anyone who has pulled engines apart knows that.

The "startup" wear is actually "warmup wear"...the oil is there, it's flowing, and the engine is wearing. SequenceIVA, the industry standard wear test, the engine is running, but purposely held at a lower temperature to simulate warmup.

So above freezing, 15W40 is not going to disadvantage warmup wear over a 0W50.
 
Originally Posted by AtomicNumber53
Many people have said many good things that I now understand. I'm just trying to find out at what point people around here WILL recommend a 0w-50 or 5w-50 over a 15w-40.


You won't find me recommending highly polymer thickened oils in a shared sump/gearbox.

Unless maybe you are a drag racer, and going from start to burnout to run on a cold engine.



Originally Posted by AtomicNumber53
Will the HTHS need to be 7.5, or even higher? Seems like the shearing from our shared gearboxes attacks these oils almost equally -- 10w-40 Amsoil w/ HTHS of 4.5 should be shear proof, but maybe just in a car! 5w-50 is sheared to a 5w-40 and a 15w-40 is sheared to a 15w-30.


Firstly, it doesn't work like that...the HTHS of a straight 50, no polymers is in the low 6s...you cannot build a multigrade that exceeds that, as the polymers are subject to temporary shear...and in gearboxes and the like that indicates a preference for permanent shear.

Look up the Amsoil motorcycle oil tests, and you will see that M1 V-Twin, which is a zero VII product, displaying no temporary shear in it's HTHS to Kinematic ratios doesn't shear...all the rest do (bar 1 or 2, same diff)

Compare the starting HTHS for the oils that sheared, then work out that the finishing HTHS is reduced by half the percentage ratio....
Castrol V-Twin loses 20% of it's KV100, so roughly 10% of it's HTHS...Starts at 4.8, ends up at 4.3.


Originally Posted by AtomicNumber53
If there's no spec that can possibly identify an oil as shear-proof in a shared gearbox... then why not use the polymers to our advantage by adding more to our oil changes, in anticipation of them shearing?? If there is a spec that can point to which 15w-40 will remain a 40 weight longer than a 0w-50 can, I'd like to learn more about it. HTHS seems somewhat irrelevant for this purpose.


I fail to understand the logic in intentionally using a highly polymer treated oil and relying on it to shear, versus using the Amsoil 10W40 that starts there...and stays there...

HTHS IS the determining fctor in the oil film thickness in plain bearings and high shear rate components like pistons and the like.

I think that you would like to discount it as you WANT 0W50 to be the best, and are trying to push the thread around to us validating it in a shared sump application...won't happen....and if you look at M1 Rcing 0W50, it only STARTS at 3.8HTHS

Originally Posted by AtomicNumber53
P.S. - Shannow, I think you missed my other post for you... https://www.bobistheoilguy.com/foru...nfluenced-your-oil-selection#Post5024279


Go back, I'd responded about the 15W some posts before...only 15Ws are dinos, if I want so much as a syn blend, it has to be 10W or better.

Inherent VI is the viscosity index inherent in the basestocks.

Mineral are typically 95-105
Group 2 and 3 around the 120 mark, and synthetics (and I include GTL) up to the mid 130s, occasionally 140.

Amsoil ACD is straight basestock, no polymer, and around the 140 mark...HTHS is 3.6, and that's where it stays. It's an SAE30, but also meets 10W because of what it's made of. Shell had a peoduct "XMO" in Oz 30 years ago, that was nade with their XHVI slack wax process, that was a 15W30 without VII addition.

So if you see a synthetic with a VI of 150 (or 200, or 220), then it has been polymer thickened, and by necessity has a thinner basestock for the final KV100 number.
 
Shannow has this well explained.

I wouldn't use a 5w-XX just because the viscosity is thinner at low temps--it doesn't earn the user much.
If you start your bike in frigid temps, then go for it, but that's about all. I don't, so I take the robustness where I can.
 
I don't know if this helps, but I have a vtwin engine that shares the engine oil with the transmission gears and is known to be an oil shearer. I run it year round, and it sees temps from a tad below zero F° to about 100 F°. Its water cooled. The suggested oil is 10w40, but it's authorized to run anything from 0w40 to 20w50 if conditions warrant. I ran Amsoil Motorcycle 10w-40 (now called Metric or whatever [censored] name Amsoil decides to call it this month) for quite awhile. I ran several UOA's on it with 500 to 900 miles, and it stayed in the 40 weight range every time....but just barely.
After a bunch of miles, it started to burn some Metric. So I switched to Maxima Extra4 15w50. It burned less of that, and seemed to run a tad cooler as my fan didn't come on as often. But I was concerned about running 15w50 in the winter, so I called Maxima. The nice technician there that I talked to said that their Extra4 15w50 is good down to 14 degrees F°. My owner's manual says 10w40 should only be used down to 15 degrees. So, I gather that Maxima group 5 ester 15w50 is pretty dang good stuff, and it will work 99% of the time I ride. On those 10 or 12 days that it gets colder than 14 degrees, I will just push it in the garage to start it up. And on those days where I'm baking under 100 degree heat, I like the 50 weight confidence.
 
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Thank you for your responses, guys! I think I'll have to re-read a few of these posts more than once to really comprehend it all, but I'm 100% sure I'll be doing several UOA's on my vehicles for different reasons (shared gearbox, fuel dilution, extended changes, etc.). Some of this stuff seems irrelevant if I just change the oil every few thousand miles (or once a year for some of my lesser driven vehicles), but where's the fun in that?
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