Oil Temp Chart

[Bill1948]

Purchased a 99 R1100R last month with 12,000 miles. Changed the fluids using Mobil 1 15/50 syn and Mobil syn 75/90 gear oil for trans and final drive. My question is, why does Clymer book chart on oil show the 15/50 oil only good to 85 degrees and the BMW manual shows it good to over 100 degrees? Clymer does show 20/50 good for over 100 degrees. Looks like I may have to change to 20/50 when it get's warm, live near Palm Springs.

[Boffin]

Clymer got the spec wrong. Go with the BMW reccomendations for their engineering.

 

Andy

[dirtrider]

Morning Bill

 

Remember Clymer is mostly based on a translation of BMW service & owners manuals. The U.S. owners manual is based on a translation of the original German manual so lots of places for mistakes to be made in translation.

 

I have seen the BMW owners manuals for some of the oilheads missing > (above) or < below signs on some of the oil recommendations.

 

ALL the oils you are quoting in your post are 50 weight oils & have (by rating anyhow) the EXACT same 50 weight rating at 100°c (212°f). So common sense would tell us that they are all good for the same warm engine ambient conditions.

 

Where those oil's differ is in the low number & that is at 0°c (32°f). So the cold starting usage range is a bit different.

 

The other thing you have to keep in mind is the "number combinations" as they can in some cases (in the US) point to different oil types (not always but usually). In most (but not all) cases a 15w50 rated oil is a synthetic or synthetic blend. With 20w50 going either way. When the owner's manual for your 1100 was written not many synthetic oil's available for motorcycles so most of the oil data was written for conventional oil's.

 

Bottom line here is: a premium 15w50 synthetic is as good or better for high temperature engine operation than most all the 20w50 conventional oils ever were.