IS 10W40 OK for Winter

I am changing the oil & filter in my 2000 R1100RT and have both 15w50 and 10w40 synthetic Mobil One. In the midwest is 15w50 going to have winter (40 degree or above riding) cranking problems or should I go with 10W40?

You won't have any problems with 15/50 above 40F. I've run 20/50 synthetic into the teens. Fun pic

Unless you plan to ride your bike in weather below 30 degrees there is no reason to change the oil to a lighter weight. None at all because you really don't gain anything by doing it. Using synthetic oil, of the normal rating, does help because most synthetics maintain better flow characteristics at cold-start conditions. Beyond that it doesn't matter.

To hell with the oil. I'd save my money for an airplane ticket and MOVE.

I ran my airhead through Colorado winters with synthetic 15/50 without any trouble. I generally rode if it was at least double digits F and dry. Maybe a little slow cranking for the ride home on really cold days, but it would always start. That was garage kept at night, but out in the cold all day while I was at work.

You will not have trouble with 15W50 in any weather a "normal" BMW rider would ride in. (above 20F)

However I use 5W40 synthetic Rotella in winter simply because the engine "feels" better to me during warm-up. It will crank a little faster, and when I ride off after a short warmup of about 45 seconds (back down driveway and watch the door close) it is more willing to rev thru the gears( I always restrict RPM to under 4K and use small throttle openings until at least 3 bars). It will idle smoothly at normal speed at my first stop at 1.3 miles. It is within BMW recommendations for the temperature, lots of people use it for winter oil. I also get about 1 whole mile more per gallon using it in the winter.

I also think the lighter oil will go thru the oil filter with less chance of opening the bypass. I have to ride out on a 55 MPH highway with other people trying to get to work on time, so I need to be at 60 in the first 1/4 mile or less.

This is my preference, and the engine will outlast the bike if you only use the 15W50 oil or if you use ligher oil in the winter. Some people use the 5W40 year round without problems, so I do not worry on the occasional warmer spring day.

Basically, though the engine really only needs at least 3 quarts or reasonably good oil close to the recommended viscosity changed at reasonable intervals. It really is not fussy. I use the other oil only for subjective reason of how it feels.

Rod

RJM2096 said:

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Nice pic...looks like my old Honda XL except it wasn't parked and we'd have a foot of snow or more on the road during those big snowstorms.

Reminds me of the days I drove to and from work all winter long. Best rider training one could ever get.

BTW, the 20W-50 is fine as denoted by the scale in your BMW Owner's Manual.