The dreaded oil question. 2002 bmw r1150rt. Your opinion is appreciated.

[pglaves]

It should be stated that oils like those with weights 20w50 can and are still being produced to meet the API SG/SH grades because there is virtually zero chance that this heavy weight of an oil will make it to a vehicle that has a catalytic converter. Lighter oils, those destined for use in cars, with weights of 5w15, 0w30, etc., will never have these anti wear additives which are needed for the older engines.

Motorcycle specific oils in weights 20w50 and 10w40, with API SG ratings can be bought at either Auto Zone or many O"reilly stores, and at some Walmart stores. 10W40 is in spec for a number of cars with cat cons, and let us not forget that many recent BMW motorcycles:

a. have catalytic converters

and

b. are specified to use 10w40 or 20w50 viscosities with SG ratings.

 

[20774]

My point was, and I certainly could be wrong, is that the number of vehicles that specify the heavy weighted oils AND have a catalytic converter is very small compared to the larger automobile market which began to use lighter oils. Because that large pool of vehicles were having their cats plugged due to the anti-wear additives, oils were changed to accommodate this pool. Plus on-going design changes to engine designs, and the need to squeeze every bit of gas mileage out of the engines, further drove the oil industry to come up with 0w oils and the "energy conserving" oils. Since the proportion of oils that still needed the 20w50 was small, it appears the oil manufacturers got a "pass" and could still produce that oil.

 

[pglaves]

My point was, and I certainly could be wrong, is that the number of vehicles that specify the heavy weighted oils AND have a catalytic converter is very small compared to the larger automobile market which began to use lighter oils. Because that large pool of vehicles were having their cats plugged due to the anti-wear additives, oils were changed to accommodate this pool. Plus on-going design changes to engine designs, and the need to squeeze every bit of gas mileage out of the engines, further drove the oil industry to come up with 0w oils and the "energy conserving" oils. Since the proportion of oils that still needed the 20w50 was small, it appears the oil manufacturers got a "pass" and could still produce that oil.

Oh, I don't disagree with this at all. In fact, when the initial SJ standard was published 20w50 oils could exceed the ZDDP limit and still be SJ rated. So until about 2 years ago, Castrol GTX 20w50 was still labeled SG/SM. It is now just rated SN.

For the curious, the main area of concern for BMW is the flat cam followers scuffing along on the cam lobes, unlike most cars that now use roller cam followers. There are other wear areas of concern (eg: piston skirts) but camshaft lobes and followers is the big one.

Also, interestingly, BMW has never been concerned with cat con failures from SG oils in their motorcycles. Exactly how these differ from typical car can cons exceeds my meager 1 year of college chemistry.

 

[tangoalpha]

Lots of great comments, suggestions and thoughts on this thread, so thank you to everyone who has responded. I realize that for some people, this topic is one that sends them in to fits of rage or sends to the brink of insanity, fortunately, that doesn't seem to be the case here. Everyone seems to have survived the dreaded oil thread and has come out unscathed and with all their mental facilities intact. Well....for the most part. I'm still getting to know you folks, but I think a few of you may have a screw loose. Ha! Ha! Anyway, my theory has always been, if you don't like a topic don't click on the thread. Just show some self control and move on with your life. Most people don't enjoy reading snarky replies and becoming embroiled in flame wars. I really must say, I appreciate the decorum the members of this forum exhibit and the courteous tone in which members discuss ideas, answer questions and offer feedback. So thanks again for all your input, it is sincerely appreciated.

With all that said, I set out to garner some feedback on what oil to use in my RT and I've feel that I now have the information I was searching for. It's obvious some of you have a very technical background and can speak with some authority on this subject, so I especially enjoyed reading your comments. I found a rather informative oil essay written by a person who goes in to great detail on explaining the different additives, why certain oils are better for bikes than others. It's a rather longggggg read, so I suggest reading over this one with a cup of coffee when you have some spare time. For those interested, here's the link: http://bmwmotorcycletech.info/oilessay.htm

 

[Rinty]

Hate to break up the oil fest but here's the thing.

Unless you:
- take apart the engine
- mic the crank, bearings, cam lobes etc. etc.,
- put it back together
- pour in your new oil
- run it for a specified amount of time under controlled conditions (like an F1 race for example)
- pull the motor out and mic EVERYTHING again
- calculate exactly how much wear has occurred
Now...
- Do ALL of that again for the oil you are comparing to

Now you have some actual data and some answers. Maybe.

And here's the downer. Everything else you think, feel, perceive, guess, read somewhere, whatever.... is meaningless.

And that's what Consumer Reports did in 1996, with a fleet of New York taxis. The results are interesting;

http://www.xs11.com/xs11-info/xs11-info/articles/51-consumer-reportstruth-motor-oils-july-1996.html

 

[tangoalpha]

And that's what Consumer Reports did in 1996, with a fleet of New York taxis. The results are interesting;

http://www.xs11.com/xs11-info/xs11-info/articles/51-consumer-reportstruth-motor-oils-july-1996.html

Great article! Thanks. Hard to find a better test lab than a fleet of 60 NYC taxi cabs running around the clock. Talk about extreme duty.

 

[markaz]

Great article! Thanks. Hard to find a better test lab than a fleet of 60 NYC taxi cabs running around the clock. Talk about extreme duty.

Perhaps, but running around the clock is not the way most people drive their cars/motorcycles. Cold starts, heat up/cool down cycles, sitting idle for days at a time, short trips, etc put a lot different stresses on the engines & oil. I'm not sure their test is really all that applicable to the general driving public.

 

[classicvw]

Perhaps, but running around the clock is not the way most people drive their cars/motorcycles. Cold starts, heat up/cool down cycles, sitting idle for days at a time, short trips, etc put a lot different stresses on the engines & oil. I'm not sure their test is really all that applicable to the general driving public.

To my mind, with the majority of bikes not yet being water cooled, an oil's resistance to thermal breakdown IS of interest to us riders, and taxis running 'round the clock in city driving is a good test for that.

 

[20774]

Oil is designed to have the viscosity capability to keep the metal parts from touching each other...to act as the layer between these moving parts. To keep their viscosity levels up, mineral based oils have viscosity improvers (VIs) added...these are polymer chains which hold together and maintain the viscosity of the oil. But over time, these chains get broken down by the mechanical action in the engine and likely get acted on by the combustion products. If you're going to use a mineral oil, it's best to have one that rates high in the range of viscosity limits for that oil, say a 50w. If it's high in the range, it can give up some of the viscosity over the usage period and still be rated as a 50w. If it's low, then giving up a bit of the range drops it into the 40w category, and potential harm to the engine.

Synthetics on the other hand can be blended so they don't need the VIs, thus they tend to hold their viscosity levels over a longer period of use. Semi-synthetics, though, which have some mineral oil in it, maybe a bit more subject to viscosity break down due to the inclusion of these VIs which will shear apart over time.

It's possible to use the test labs to evaluate oil during the usage period to see what is happening. I'd be interested in where the viscosity index is as time goes by. I'd also be interested in the ratio of the TAN (total acid number) and TBN (total base number). An oil starts out with a TBN on the high side, then degrades as the base parts of the product are overcome by the acids from combustion. I've read where fleet operators continuously sample the oil in their vehicles until the point where the TBN value goes below the TAN. That signals a time for a change in oil.

As has been said, using a reasonable quality oil with recommended oil change intervals can't be all that bad. Likely the engine will not have an oil failure problem in the life of the owner.

 

[tangoalpha]

Just another thread I thought I'd update you guys on. After much debate and analysis, I did decide to go with the Mobil-1 20w/50 V-Twin formula. The oil ranked very high, at or near the very top in the oil analysis, and since I've trusted the Mobil-1 products in just about everything else I own that has an engine, I thought I'd try it in Der Bimmer. I rationalized that if I saw any leakage that I'd switch to the factory oil, but I must say so far I have turned just over 1,000 miles since the oil change and I haven't seen a single drop of oil anywhere on my garage floor. While servicing the bike, I also switched a K&N oil filter and also K&N air filter. The bike is running great and I must say, that I enjoy riding it more and more each time I ride it.

Thanks for everyone's insights, recommendations and opinions.