BMW R1200RT/R1250RT Forum

Peter Baker wrote: I think rain is pretty clear, max power is lower + ramp up is slower...

My understanding of Road vs. Dynamic is the power/torque curve to RPM is the same, however the ramp up in Dynamic is steeper meaning you effectively get more throttle at the engine for the same amount of twist on the handle bar...  Personally I am always in Dynamic practising good use of my right hand control! 

Peter

Hey Peter, finally a post relevant to my original question! I'm just trying to understand from a technical point of view what is the effect of changing the riding mode on the response of the engine ECU. I'm a design engineer, call it professional curiosity if you wish.


From your post I deduct that the rain mode changes the ECU fuel map to a lower output map, which the manual calls "restrained". I guess that this makes it also some sort of "economy" mode as restricted output is normally achieved using leaner air-to-fuel ratio.


Both road and dynamic modes use the maximum output fuel map, but the dynamic mode uses a quicker ratio between throttle grip position and throttle valves opening. For anybody that has ever used an adjustable quick action throttle on a cable system, this is the equivalent to using a larger disc at the handle bar, ie the throttle valves open more for the same amount of grip twist.

"The three Ride Modes: Rain, Road and Dynamic, deliver the same hp/lb-ft output but with markedly different throttle response. I found Road the most amenable to sport-touring, with its potent but not-hyper-sensitive throttle. When traffic disappears and the backroad pace increased, the Dynamic mapping exhibits a more engaging engine response – sporty without being harsh. Rain mode features a more deliberate throttle feel – comforting while encountering wet roads during those snow flurries. The Ride Modes also alter settings on BMW’s Automatic Stability Control (ASC) system – with early intervention on Rain, a standard baseline setting on Road and less intrusive setup for Dynamic. In fact, BMW promises minor drifting of the rear wheel is allowed on the latter setting – a claim we did not test."



"Dynamic ESA electronically adjusts suspension damping to one of three settings, Soft, Normal, Hard, depending on the Riding Mode selected. The setting can, however, be changed to your personal preference. For example, if you’re in Dynamic riding mode which automatically sets suspension to Hard, you can choose to change this to either Normal or Soft while keeping the riding mode in Dynamic."

Perhaps the Ride Modes are designed more for their impact on ASC (Traction Control),  rather than Throttle response itself, but work in conjunction with each other.

Whilst, at the same time, giving a pre-selected ESA (Damping) setting for each Mode, which can be personalised if required.

That should clear up all the questions. well found David.  No mention of fuelling changes in different modes.

It seems to me like you pay £16000 or there abouts, got all this fancy gadgetary and nobody really has a clue what it does
(standing by for flack probably BMW dealers don't either) :not speak:

Yes, you could well be right there step2534. However, doesn't the average owner just prefer a simple, one word command (ie rain, road, dynamic) as opposed to trying to understand the interaction of suspension damping with throttle demand and ASC, ABS, ESA, etc, etc...?? Provided of course that they know what rain, road & dynamic refer to in the first place...!!??

Steve F wrote:However, doesn't the average owner just prefer a simple, one word command (ie rain, road, dynamic) as opposed to trying to understand the interaction of suspension damping with throttle demand and ASC, ABS, ESA, etc, etc...?

This may well be who/what the Ride Modes are aimed at.

Read the handbook, try them all, then you know. Not difficult really.
Then again who bothers to read the book.

RTman10 wrote: Then again who bothers to read the book.

I thought us blokes only read the book when all other avenues were exhausted 

We often quote RTFM at work.

Read The F(lipping) Manual 

Read the fli**in post! the reason why I'm asking the question in the first place is that the manual is quite vague in regard. 

Well we did try. Obviously not hard enough

On a recent ride got to test out rain mode, first a five mile stretch of road leading into Death Valley had washed out and been replaced with gravel, bike felt more comfortable with the slower response in rain mode. Next test came from flagstaff Arizona to Southern California 400 miles of heavy rain, again bike felt more comfortable in rain rather than dynamic, other than the above uses, bike has always been ridden in dynamic
Great option to have
A bit off topic, the factory windshield was terrible in heavy rain
Replaced by a werks, quite ride, 100% better

In case anybody else is interested in my question from an engineering point of view, I took my bike in for her first service and my friendly and knowledgeable service manager finally gave me the technical answer I was looking for.


As expected, the difference in throttle response between the different modes is achieved by means of a change in the fuel map. The rain mode has a more progressive map and the road mode is crisper. They are both "static" fuel maps.


The Dynamic mode uses an even more responsive map, but the greatest difference is in the fact that the engine ECU and the ESA talk to each other; the fuel map is constantly adjusted in real time, based on the feedback from the active suspension sensors, to optimise the throttle response to suit the riding conditions and prevent unsettling the bike during "spirited" riding. The difference therefore  becomes only noticeable when riding hard on twisty roads, while there would be hardly any difference between Road and dynamic modes accelerating on a straight line.


I am surprised that BMW has not publicised on any of the brochures or manuals this info because I think it's a brilliant piece of engineering that would capture the interest of many.......

RTman10 wrote: Barryj . Apparently according to a recent enquirer the remapping effects all modes across the board.  If it smooths out Dynamic you got to wonder what it does to Rain.Maybe Pope can be persuaded to try it and let us know.

Ok, its raining now, so in the interest of science, i'm gonna put her in Rain Mode for my ride home from work on shitty country B roads (no i haven't tried Rain Mode since the remap).


So i'll report back later hopefully. BTW, i only ever tried Rain Mode once and it was horrible and laggy and unresponsive.