15w50 in a 1200/1250 LC - Long term tests anyone ? (Not an oil thread 🫣)

[MotoRevive]

I'm looking for case studies of people who have run a heavier 50 weight oil in their liquid cooled BMW. Specifically the 1200. Which are meant to run 5w40

And if they have found any problems or benefits over 10,000 miles of use.

Thicker oil arguably provides more long term protection. But also more friction. So lower mpg. Harder cold starts and more strain on small batteries.

Manufacturer oil recommendations are based as much on economy and efficiency (Euro standards) as much as they are with engine health. We can see this in the car industry as oil weights get lower and lower.. Even zero weight oils to improve efficiency. At the cost of catastrophic engine failures.

This can also be seen with the retrospective swap to 80 oil for BMW bevel drives from 75w90.

However, swapping engine oil isn't that simple. Engines could have tolerances that a thicker oil doesn't penetrate. Or
oil jets that can not spray far enough etc.

Any case studies here ?

Cheers.

 

[shifty]

often wondered about this too,, my bike does the majority of miles on trips to places like spain, southern france italy etc, and i dont run it through winter so have thought of trying a 10w 50 in it, like my ktm 1290 uses,
watching with interest

 

[Buckingham]

I doubt whether one increment increase in viscosity is going to do any harm.
I read that some of the cars running very thin 0W20 have heavier options for arduous conditions.

 

[HxH]

According to Ai and gathered information, (taken as a reply, not a given fact)

Running 15W-50 instead of the recommended 5W-40 can reduce cold-start protection and may slightly increase engine wear in cooler conditions, since 15W-50 is thicker when cold.

Impact of Using 15W-50 Instead of 5W-40 Oil​

Cold-Start Protection​

Using 15W-50 oil instead of the recommended 5W-40 can lead to reduced cold-start protection. The thicker viscosity of 15W-50 when cold means it does not flow as easily as 5W-40, which can result in:

• Increased Engine Wear: The engine may experience more friction during cold starts, potentially leading to premature wear over time.
• Difficult Starts: The thicker oil can make starting the engine more challenging in cooler temperatures.

Long-Term Effects​

While using 15W-50 oil may not cause immediate damage, the long-term effects can include:

• Increased Wear: Continuous use of a thicker oil in conditions where a thinner oil is recommended can lead to higher wear rates on engine components.
• Reduced Efficiency: The engine may operate less efficiently, affecting fuel economy and overall performance.

Recommendations​

To avoid potential long-term damage, it is advisable to:

• Follow Manufacturer Guidelines: Always use the oil viscosity recommended in the motorcycle's user manual.
• Consider Operating Conditions: If riding in colder climates, stick with the recommended 5W-40 for optimal protection and performance.

In summary, while using 15W-50 oil may not cause immediate issues, it can lead to increased wear and reduced efficiency over time, especially in cooler conditions.

Explore More​

What are the long-term effects of using 15W-50 oil in a bike engine?
Using 15W-50 oil in a bike engine can provide better temperature stability and protection under heavy loads, making it suitable for high-performance or older engines. However, if the engine is designed for a different viscosity, it may lead to increased wear or overheating over time.

Imho, I have always only ever ran the recommended oil stated in the Bike manual, sticking to what manufacturers say is best as they did spend £millions on development studies, while the aged biker only wants what's best for his/her engine, with perhaps less cost to them, choice is with the owner. Hope this helps.

 

[Buckingham]

I'd like to see the evidence for increased wear.
We already know that the manufacturers aim for reduced friction and therefore reduced emissions and fuel consumption & road tax above everything else and that includes longer term reliability. In the car market especially, fuel consumption and emissions drive sales above everything else.