What to look for?

[mabi_r1100rs]

Hi,

After reading along for some time it is time for me to post a question.

In nothern Europe the 'standard' recommendation for BMW oil-head boxers is a mineral or synthetic 20W-50 oil.

As the availability of full-synthetic 20W-50 oils is not that good in Europe I have the preference to switch to a full-synthetic 10W-50 oil. Also because I like the flowing properties when it is cold.

According to the operators manual a 10W-50 is suitable for use in the ambient temeprature range from -20 degrees C to over +30 degrees C, as long as it is a 'special-oil'. I don't have a clue what makes an oil a special-oil.
On top of that BMW has issued a notice that a 10W-50 should only be used at 'low' ambient temperatures. This because of the fact that it may get too thin at higher ambient temperatures. This statement has been made without any difference between low-spec mineral or high-spec full-synthetic oils.

My assumption is that BMW has made the above recommendation because of the risk of 'wide-spread' multigrades thinning out due to the shearing of the viscosity-index-improvers that might be present in the oil.
As I have understood this risk of thinning out applies especially (or only?) to mineral oils as these contain relatively large amounts of viscosity-index-improvers. This should not or less be the case when it concerns a full-synthetic oil.
Would you agree with my assumption?

If I want to safely use a full-synthetic 10W-50 oil in my BMW oil-head, what specification should I be looking for? Is it the HT/HS value?
According to the operators manual the minimum spec to be used is API SF. For the HT/HS value the API standard refers to the SAE J300 standard. For a 50-weight oil the SAE J300 standard requires a minimum HT/HS value of 3,7. Will this do to prevent thinning out of the oil and therefore wear? If not, what would be the minimum HT/HS value I should be looking for? I currently have a can of Castrol Power RS Racing 4T 10W-50 with a HT/HS value of 4,5.

Any help on this interesting but complicated subject is much appreciated.

Regards,

Martijn

 

[berlyn]

Hi mabi_r1100rs,
Welcome!
after a lot of searching here in BITOG (and as you will check by comparing data for your bike from other guys in BITOG with BMW boxers)
I would recommend considering that you are in Holland everything from the following:
mobil 1 v-twin (black bottle)(be careful here in Europe a 15W-50 mobil motorcycle oil is marketed in a silver bottle,made in Luxembourg or Belgium,not this one)
amsoil MCV 20w-50
maxima extra 20W50
redline 20w-50

all of them have super low temp and HTHS specs.
Nice bike!

 

[duaneb9729]

Welcome to the forum!! I agree with berlyn on the oil as well as the bike!

 

[EagleFTE]

Here in the states we have millions of air cooled bikes and huge variations in temperature environments. Red Line, M1 Vtwin, and Amsoil MCV are what I think are top shelf options and have proven track records. Maxima and Motul are probably in that group as well but I have no experience with those.

The true synthetics (Group IV/V) have properties that do not require a lot (any?) VI improvers. But here in the states Group III base oils are also called synthetics and I'm not sure what the amount of VI improvers would be used in those. The shared engine/transmission/clutch application will shear the VIIs down so a valid concern on your part. But I think the oils listed by Berlyn would be pretty immune to that. Note that some of the Red Line products do have a lot of Moly and could have some clutch slip implications according to some. Not an issue with the typical American Vtwins as they don't share engine and clutch oils.

 

[mabi_r1100rs]

Thanks for the replies so far. Any more answers, suggestions or remarks are much appreciated.

The products mentioned are, as far as I know, not available in the Netherlands and are therefore not an option for me.

On top of that I would like to switch to a 10W-50 because of its excellent flowing properties, and therefore lubrication, at low temperatures. Because of the wide viscosity spread IMHO this should be a full synthetic, apart from the other benefits you have with a full synthetic.

Apart from knowing what oil to choose I also want to understand which mechanism's are at work here .

The shearing of the oil in the transmission or possible clutch slippage is not an issue with a BMW oil-heed because it has a dry clutch and a seperate transmission.

Martijn

 

[Ausfahrt]

Hey Martijn,
I have a 2007 boxer and there is a guy on one of the other forums that I visit that has over 400,000 miles on his 1995 R1100GS!! He uses Mobil 1 20w-50 ( I think its now a 15w-50) and 5000-6000 mile OCI's. Check out this thread:

http://www.advrider.com/forums/showthread.php?t=278021

 

[mabi_r1100rs]

In the mean time I have requested for HT/HS values of some oils just to compare them. The results were not what I expected them to be.

I have requested the HT/HS value of Castrol Power RS Racing 4T 10W-50 which is a so-called 'full synthetic oil'. The HT/HS value of this oil is said to be 4,5 cP. I have no idea whether this is high and whether it provides enough protection in my bike. I know that the minimum HT/HS value for a xxW-50 oil is 3,7 according to SAE J300.

For comparison reasons I have also requested the HT/HS value of Castrol Act>evo GP 4T 20W-50. This is a mineral oil. As BMW recommends the use of Castrol lubricants (at least in europe)and they recommend the use of a mineral 20W-50 oil this is probably the oil they recommend to be used (it is advertised to be by some suppliers). To my supprise the HT/HS value of this oil is said to be 4,9 cP.

With the limited knowledge I have, I have a tendency to draw the following conclusions:
* as far as wear protection is concerned the Castrol mineral 20W-50 oil provides better high temperature / high shear wear protection than the full synthetic 10W-50 does
* if you want the wear protection of your oil to be on the level that BMW recommends you would be looking for an oil with a HT/HS value of at least 4,9 cP (well this is not necessarely true because I don't know if the HT/HS value was the determining factor for BMW to recommend this mineral 20W-50)

Do you agree with my conclusions or is there another way to look at this?

 

[tmcafe]

Originally Posted By: mabi_r1100rs
According to the operators manual a 10W-50 is suitable for use in the ambient temeprature range from -20 degrees C to over +30 degrees C, as long as it is a 'special-oil'. I don't have a clue what makes an oil a special-oil.
On top of that BMW has issued a notice that a 10W-50 should only be used at 'low' ambient temperatures. This because of the fact that it may get too thin at higher ambient temperatures. This statement has been made without any difference between low-spec mineral or high-spec full-synthetic oils.

My assumption is that BMW has made the above recommendation because of the risk of 'wide-spread' multigrades thinning out due to the shearing of the viscosity-index-improvers that might be present in the oil.
As I have understood this risk of thinning out applies especially (or only?) to mineral oils as these contain relatively large amounts of viscosity-index-improvers. This should not or less be the case when it concerns a full-synthetic oil.
Would you agree with my assumption?
I'm not an expert, but from what I've read so far it seems that you're nailing it right here in your comment. So yes, at least in general, the dino oils tend to shear out of grade faster if the gap between the "winter" and "summer" (low and high) viscosities is bigger. Hence a 10=50 will likely get to a 40 or less faster than a 20-50. It's because the viscosity enhancing additives play a bigger part in the oils with a wider gap between the low and high viscosity. Even the synthetics are not exempt from this. Somebody found out that for instance Rotella 5-40 "fully synthetic" sheared out of grade faster than the dino Rotella 15-40. So synthetic is generally better, but not immune. Some of the top shelf oils, such as Motorex, have 10-60 grades, which I assume should cover a wider range of temperatures. Of course, that comes at a price, and I don't know how fast they lose their higher grad--down to 50 or even less? Probably any good 20-50 or 10/15-50 oil should do well. Not sure what's available in Europe, although some of the more specialized motorcycle oils come from there: Elf, Agip, Motorex, so there should be a lot to pick from.