Final Drive Viscosity?

[feds27]

BMW 80W140 and 10W50

I picked up my bike from it's 600 mile service last week and the service invoice states they used BMW 80W140 for the final drive. They also used BMW 10W50 for the engine. Odd that they used grades I hadn't heard discussed here before.

 

[soffiler]

I picked up my bike from it's 600 mile service last week and the service invoice states they used BMW 80W140 for the final drive. They also used BMW 10W50 for the engine. Odd that they used grades I hadn't heard discussed here before.

BMW Accessories catalog lists 10W-50 motor oil (p/n 07510412041) but I would first consult my Rider's Manual to determine what the proper viscosity is for your bike and your ambient temperatures before I condone or condemn 10W-50.

I cannot locate a BMW-branded 80W140 gear oil. Synthetic is available in 75W90 and 75W140; consensus appears to be 75W90 is correct for hexhead final drives. There is an 80W90 non-synth gear lube but the hexhead recommends synth. Does your invoice list a BMW part no. for this 80W140?

 

[feds27]

The invoice doesn't state anything specific for the part numbers other than "10W50B" and "SYN1/2 QT 80W140B". The descriptions are "BMW 10W50 Motor Oil" and "1/2 QT 80W140". This service was performed by the dealer where I purchased the bike.

I spoke with the shop foreman about the 10W50 and he said they have NEVER seen an engine failure due to engine oil grade. Oils are much better than they were 20 years ago. The 10W50 oil will allow me to use the same oil all year round without the need to switch to 10W40 in the winter. I tend to agree with him.

I had asked about using 75W140 vs. 75W90 when I dropped off the bike. They said they haven't notice a correlation between fluid grade and failures. They only use the synthetic in the final drives and transmissions which they service. They said the 75W140/final drive issue is mostly internet hype. It could be those with failures had bad seals, bad FD's, or didn't perform 600 mile service where the FD fluid gets changed.

Anyway, I just wanted to share the info on these two other grades that are being used by the dealers.

 

[soffiler]

The invoice doesn't state anything specific for the part numbers other than "10W50B" and "SYN1/2 QT 80W140B". The descriptions are "BMW 10W50 Motor Oil" and "1/2 QT 80W140". This service was performed by the dealer where I purchased the bike.

I spoke with the shop foreman about the 10W50 and he said they have NEVER seen an engine failure due to engine oil grade. Oils are much better than they were 20 years ago. The 10W50 oil will allow me to use the same oil all year round without the need to switch to 10W40 in the winter. I tend to agree with him.

I had asked about using 75W140 vs. 75W90 when I dropped off the bike. They said they haven't notice a correlation between fluid grade and failures. They only use the synthetic in the final drives and transmissions which they service. They said the 75W140/final drive issue is mostly internet hype. It could be those with failures had bad seals, bad FD's, or didn't perform 600 mile service where the FD fluid gets changed.

BMW catalog generically lists the 10W-50 as an all-season replacement for 10W-40 and 20W-50. I would always tend to follow the Rider's Manual over anecdotal/verbal advice from a dealer, if they conflict. When the dealer has a service bulletin that supercedes the Rider's Manual, obviously that's a different story.

It appears based on the description that your dealer is using a synthetic, non-BMW-branded gear lube of 80W-140 viscosity. I hope it meets the GL-5 requirement. Take your dealer's advice at your own peril. "We haven't seen any failures" is anecdotal evidence. BMW recommends synthetic 75W-90, period.

Regarding internet hype: what are you doing here right now if you've decided to place your trust in someone who dismisses the info as internet hype? Furthermore, we've heard from the likes of Paul Glaves on this subject, and if you're going to lump him into that category, well...

 

[feds27]

BMW catalog generically lists the 10W-50 as an all-season replacement for 10W-40 and 20W-50. I would always tend to follow the Rider's Manual over anecdotal/verbal advice from a dealer, if they conflict. When the dealer has a service bulletin that supercedes the Rider's Manual, obviously that's a different story.

It appears based on the description that your dealer is using a synthetic, non-BMW-branded gear lube of 80W-140 viscosity. I hope it meets the GL-5 requirement. Take your dealer's advice at your own peril. "We haven't seen any failures" is anecdotal evidence. BMW recommends synthetic 75W-90, period.

Regarding internet hype: what are you doing here right now if you've decided to place your trust in someone who dismisses the info as internet hype? Furthermore, we've heard from the likes of Paul Glaves on this subject, and if you're going to lump him into that category, well...

It's obvious you need to work on your reading comprehension. I'm not sure why you're flaming me for what the dealer said about internet hype.

 

[soffiler]

It's obvious you need to work on your reading comprehension. I'm not sure why you're flaming me for what the dealer said about internet hype.

Let's take another look at this. Your dealer said it, then you reported it here. Is there something wrong with me addressing the issue of whether it's hype or not?

Furthermore, where do YOU stand? Do you trust your dealer? Do you therefore believe the 75W/140 issue is, indeed, just hype (Internet or otherwise)? Do you believe that your dealer's comments are anything more than anecdotal? Do you think it's okay to plug in an 80W/140 where a 75W/90 is the recommended viscosity? If so, why?

I had asked about using 75W140 vs. 75W90 when I dropped off the bike. They said they haven't notice a correlation between fluid grade and failures.

This is what I consider anecdotal, unless someone can show me that the dealer has made some reasonably scientific attempt to establish said correlation, with some statistical significance.

They said the 75W140/final drive issue is mostly internet hype. It could be those with failures had bad seals, bad FD's, or didn't perform 600 mile service where the FD fluid gets changed.

Yep, it could be any or some combination of the above. And yet it could also be true that 75W/140, with markedly different viscosity parameters, is the wrong lubricant for this drive. I find it offensive that this idea is dismissed as internet hype, and you're the one who reported that, so I guess you're the target of the flames. Sorry about that. We (the BMW enthusiast public) don't have much in the way of facts. We do have at least one fact: the recommended viscosity is 75W/90.

 

[cjack]

And yet it could also be true that 75W/140, with markedly different viscosity parameters, is the wrong lubricant for this drive. I find it offensive that this idea is dismissed as internet hype, and you're the one who reported that, so I guess you're the target of the flames. Sorry about that. We (the BMW enthusiast public) don't have much in the way of facts. We do have at least one fact: the recommended viscosity is 75W/90.

I find it odd that dealers deviate from the BMW specifications given for the drive, but they do.
Then, also, I don't think that using 90 or 140 would definitely hurt the drive under normal use. It must be that in a sealed drive or with cooling in mind, drives such as the 1200s have now, the 75W90 is the better choice. Have no data, but I would use it since BMW took the effort to specify it.
I also think that it is most likely failures are probably due to quality issues with bearings and bearing cages, and maybe as undetected fluid loss...say when you are riding thru the night on a 1000 mile day for example. When the drive goes, how to tell that the oil left in the dark before or after the drive failed. Just a wild unsubstantiated guess...

 

[feds27]

Let's take another look at this. Your dealer said it, then you reported it here. Is there something wrong with me addressing the issue of whether it's hype or not?

Although you took issue with the dealer's comments, you directed your comments at me. Completely unnecessary in a forum where the main goal is to share information and help each other.

Furthermore, where do YOU stand?....

I think it's obvious I was trying to share the fact that 2 other viscosities are being used by BMW dealer(s). To date I haven't seen these viscosities discussed much, if at all, on this forum. I didn't offer my opinion in the original post other than I tend to agree that a good 10W50 oil would be preferable/convenient. It could very well be the case that a good 10W50 oil was not available when the manual was printed. I have to check if the 10W50 BMW oil is SG rated.

I ride my bike year round so I prefer switching to thinner 10W40 oil in the winter to help cold cranking and lubrication during startup. The problem with 10W40 is that when Spring hits, if I don't have an opportunity to switch the oil out to 20W50 or I misjudge the weather, I could be running too thin a viscosity oil. I have had on occasion weekend trips where I'd head out in colder temperatures and then return in much warmer temps. In the cases where I still had 10W40 in my bike, I was worrying if I was causing unnecessary wear.

Regarding the 80W140, I'm not sure how to feel about it, that's why I posted the info. There are alot of variables in determining the root cause of the FD failures. Type of riding (offroad, street, aggressive, 2-up), rider+gear weight, was the owner good about maintenance, manufacture date (issues with quality control), model of bike, climate, service intervals (BMW now requires changing FD fluid at 600miles), and of course type of hypoid oil used. I don't think there is one oil for all situations.

I find it offensive that this idea is dismissed as internet hype, and you're the one who reported that, so I guess you're the target of the flames. Sorry about that.

At least you acknowledged your response was to "kill the messenger". Apology accepted.

 

[soffiler]

I find it odd that dealers deviate from the BMW specifications given for the drive, but they do.
Then, also, I don't think that using 90 or 140 would definitely hurt the drive under normal use. It must be that in a sealed drive or with cooling in mind, drives such as the 1200s have now, the 75W90 is the better choice. Have no data, but I would use it since BMW took the effort to specify it.
I also think that it is most likely failures are probably due to quality issues with bearings and bearing cages, and maybe as undetected fluid loss...say when you are riding thru the night on a 1000 mile day for example. When the drive goes, how to tell that the oil left in the dark before or after the drive failed. Just a wild unsubstantiated guess...

100% agree.

No reason to think 75W/140 will definitely hurt the drive. But it ain't the rear axle of a '57 Chevy, that would probably run if you stuffed it full of banana peels. This appears, to me, to be a really good place to be studious with the mfg recommendation.

Regarding undetected fluid loss, I can speak as one of the lucky ones who experienced an outer seal failure on a short trip. I am certain it wasn't leaking at the start (because I'd just cleaned the bike upon return from a 3200-mile trip, and observed pretty much every surface of the bike upclose and personal) and 70 miles later the right sidewall of my rear tire was substantially streaked with oil. I conclude based on my sample size of 1 that this seal can fail rapidly and if it happened on a long trip, it may not be noticed for hundreds of miles, which could potentially leak a fatal amount of lube.

 

[soffiler]

...I don't think there is one oil for all situations...

I know you're talking about final drives there, but you DO seem to think there's one ENGINE oil for all situations (10W50). Why not FD's?

 

[feds27]

I know you're talking about final drives there, but you DO seem to think there's one ENGINE oil for all situations (10W50). Why not FD's?

Not really. I tend to think 10W50 fits my situation. If I lived in a hotter climate year round, I would use 20W50 no doubt. And if I raced my bike I might actually use a single grade oil like some people do. There are +/-'s for each so it's about compromise. I'm sure 10W50 has some comprise (typically shortened life due to viscosity modifiers wearing out). I change my oil regularly so it shouldn't be a problem but I would like to see a test that compares the BMW 10W50 to the BMW 20W50.

Any ideas as to who would provides BMW with 10W50 and 80W140? Valvoline, Castrol or Spectro?

 

[feds27]

I've sent my 10W40 and 20W50 to Blackstone for testing in the past for my R1100S. I guess I can send the 10W50 for testing but it wouldn't be an exact comparison given different bikes.

 

[soffiler]

Any ideas as to who would provides BMW with 10W50 and 80W140? Valvoline, Castrol or Spectro?

I've yet to see evidence that the 80W/140 is BMW branded.

 

[gulfcoastbeemer]

I find it odd that dealers deviate from the BMW specifications given for the drive, but they do.
Then, also, I don't think that using 90 or 140 would definitely hurt the drive under normal use. It must be that in a sealed drive or with cooling in mind, drives such as the 1200s have now, the 75W90 is the better choice. Have no data, but I would use it since BMW took the effort to specify it.

Actually, the original gear oil specified by BMW was Castrol SAF-XO. SAE90

When I inquired of BMW NA regarding final drive oil they stated "either BMW Super Synthetic 75W90 or BMW Super Synthetic 75W140 is RECOMMENDED" -- (their exact words).

At this point I'm convinced the gear oil issue is a total red herring.

It's not so much the oil, as it is the oil change interval, the design of the FD, and its component materials.

 

[ANDYVH]

All I know is what works on my 94 R1100RS, now at over 128,000 miles. I have always used Castrol Synthetic GL5 75W90 gear oil in my final drive. In all those miles I have probably changed the FD fluid maybe five times. No problems, no leaks, no bearing issues, no noise/whine. I have done a lot of rain riding in those years/miles. I know what works for me.

 

[gulfcoastbeemer]

No problems, no leaks, no bearing issues, no noise/whine.

...and, different final drive. [oilhead/hexhead]

 

[cjack]

I've yet to see evidence that the 80W/140 is BMW branded.

Red Line makes some.

 

[TomR1200]

The 10W50 oil will allow me to use the same oil all year round without the need to switch to 10W40 in the winter.

Just some food for thought; my R12R manual says 20W-50 is good down to 32F. Do you ride in colder weather than that? I go out at 35F and warmer myself, but the first start of the day is from a heated garage, so I'm not terribly worried about 20W-50 for my particular style of winter riding. Yes, I'm sure 10W-40 would be better. Maybe my boxer engine will only last 199,000 miles instead of 200,000.

Bear in mind that 20 weight base stock in a 20W-50 only needs an additive package that gets it to perform like a hot 50 weight oil (2.5 times more viscous, corrected for temperature) whereas a 10W-50 needs to get 5 times "thicker" to behave like a hot 50 weight oil. IMO, if you're going to use something with such a robust additive package, you might want to consider more frequent change intervals.

 

[soffiler]

Actually, the original gear oil specified by BMW was Castrol SAF-XO. SAE90

Yes, the specified product is a European Castrol SAF-XO. NO, it is not SAE90. It is synthetic 75W/90 GL-5, as we've been discussing for, oh, 150 posts or so.

 

[soffiler]

Red Line makes some.

Yes, Jack, but, is it sold in BMW-branded packaging? That's the issue I was addressing. feds27 asked "Any ideas as to who would provides BMW with 10W50 and 80W140? Valvoline, Castrol or Spectro?" and my response wondered whether ANYBODY is providing BMW with 80W/140. In other words, I think that dealer is using something else, maybe Red Line (not that there's anything inherently wrong with Red Line). I don't see any 80W/140 anywhere in the BMW system (but my info is limited to the BMW catalogs and fiche on the Max BMW site).