12-23-2019, 08:28 AM
Went for a ride yesterday when the ambient temperature was a cool 55 deg.F or so. After the bike warmed up the tachometer showed the redline as being the usual 9000 rpm.
However as I continued the 130 mile non-stop ride I happened to notice at some point the indicated redline had dropped to 8000 rpm. That was weird, I thought. Engine was warmed up so what was with the lower redline?
I checked ambient temperature (57 or so deg.F) and then the engine temperature (169 - 171 deg,F) and figured that maybe because the engine was running cool the redline was decreased ...? After all when you first start the bike for the day the engine is not warmed up and the redline is like 4000 rpm until the normal operating temperature is reached. I was riding between 65 and 75 mph, so it was not like I was riding slowly. I did not ride the bike to the indicated redline to see whether it would cut power at 8000 rpm.
Anyone else notice this? Just curious. I am not bothered about this on my bike.
From what I read, redline is the maximum continuous rating below which the engine and its components are designed to operate without suffering damage to itself or other parts directly connected to it. So it would depend on primary factors such as stroke / displacement, mass of components, material composition of components, mechanical arrangement, etc. Makes sense to me.
BMW Motorrad limits the redline of our engines electronically to force operation to be in a lower safe zone while the engine is being warmed up. During that time the oil is not distributed throughout the engine as designed, and the engine tolerances are not yet expanded to their design values. Makes sense to do that.
So that leaves me to wonder ... is the electronic nanny so picky that, even after warming up, it would still vary the redline depending on the cooler ambient temperature? The redline did eventually go back to 9000 rpm, but then it also dropped back to 8000 rpm at least at one point before the end of the ride.
However as I continued the 130 mile non-stop ride I happened to notice at some point the indicated redline had dropped to 8000 rpm. That was weird, I thought. Engine was warmed up so what was with the lower redline?
I checked ambient temperature (57 or so deg.F) and then the engine temperature (169 - 171 deg,F) and figured that maybe because the engine was running cool the redline was decreased ...? After all when you first start the bike for the day the engine is not warmed up and the redline is like 4000 rpm until the normal operating temperature is reached. I was riding between 65 and 75 mph, so it was not like I was riding slowly. I did not ride the bike to the indicated redline to see whether it would cut power at 8000 rpm.
Anyone else notice this? Just curious. I am not bothered about this on my bike.
From what I read, redline is the maximum continuous rating below which the engine and its components are designed to operate without suffering damage to itself or other parts directly connected to it. So it would depend on primary factors such as stroke / displacement, mass of components, material composition of components, mechanical arrangement, etc. Makes sense to me.
BMW Motorrad limits the redline of our engines electronically to force operation to be in a lower safe zone while the engine is being warmed up. During that time the oil is not distributed throughout the engine as designed, and the engine tolerances are not yet expanded to their design values. Makes sense to do that.
So that leaves me to wonder ... is the electronic nanny so picky that, even after warming up, it would still vary the redline depending on the cooler ambient temperature? The redline did eventually go back to 9000 rpm, but then it also dropped back to 8000 rpm at least at one point before the end of the ride.
Regards,
Grumpy Goat
2016 BMW R1200RS
2023 Triumph Tiger 900 Rally Pro
Grumpy Goat
2016 BMW R1200RS
2023 Triumph Tiger 900 Rally Pro