Issue with 2017 self leveling suspension.

[fred_jb]

I found an interesting issue with the self leveling suspension this weekend. If my wife is going on the bike I normally move off the drive onto the road before she gets on, so I don't normally have the side stand down. This time I didn't so still had the stand down while she got on, and was surprised to find that with the extra sag of the suspension due to her weight (not excessive, but neither is she a lightweight) I could not retract the side stand due to lack of ground clearance. Maybe this is not helped by the fact that I have the low chassis version, though I thought this came with side and centre stands suitably modified.

As the engine was running I had expected the suspension, which was on the auto setting, to adjust immediately but it didn't, though when I changed the preload setting to max or min it did adjust right away with us both sitting on the stationary bike. I thought maybe there was a fault, but looking into this later I eventually found a mention in the handbook that in auto mode it adjusts once you start riding. This seems wrong - I think it should do an immediate adjustment, as it is evidently capable of doing so, so that you start moving with a correct setting even if it fine tunes it once underway. This would also avoid the possibility of an unretractable side stand.

Any thoughts, and has anyone else noticed the same behaviour?

Fred

 

[Andrew997]

Just a thought, if the bike's ride height was to adjust immediately, perhaps it would have the potential to make you lose your footing? And should you not be holding the bike level off the side stand for your wife to get on?

 

[POL382]

On the Dynamic ESA bikes there is a quote in the handbook which states 'If the temperature is very low, take the weight off the motorcycle before increasing spring preload; if applicable, have your passenger dismount.'

I don't know if your model has the same line in the handbook.

 

[ChazzyB]

The system could not calculate the load properly if you were sitting on it with your feet on the ground. As soon as the bike moves, it can be sure all the load is on the suspension.

 

[fred_jb]

Just a thought, if the bike's ride height was to adjust immediately, perhaps it would have the potential to make you lose your footing? And should you not be holding the bike level off the side stand for your wife to get on?

I do always hold the bike level for my wife to get on as I would never trust the side stand to take the weight, plus if I did it would then be quite difficult to lift the bike to a level position with a passenger on board, but the fact that I had forgotten to retract the side stand on this occasion, and then was unable to, highlighted this unexpected behaviour of the suspension.

I don't see how immediate adjustment of the suspension should be a problem as all it should be doing is restoring the lost ride height caused by the passenger getting on, and no more. Assuming you have your feet comfortably planted before the passenger gets on, the suspension then sags further making the bike lower, at which point all the suspension needs to do is restore the initial position.

There is no reason why the suspension should adjust up to the max height position if set on auto, though if it did I would agree that it could reduce your contact with the ground as it goes surprisingly high even with a passenger on board.

 

[fred_jb]

On the Dynamic ESA bikes there is a quote in the handbook which states 'If the temperature is very low, take the weight off the motorcycle before increasing spring preload; if applicable, have your passenger dismount.'

I don't know if your model has the same line in the handbook.

Yes my handbook has the same line, and having previously had problems with another make of bike where the electronic suspension adjustment failed with an error in cold weather, and the adjustment could only be made after a few miles of riding, when presumably the oil in the shock adjuster had warmed up, I can understand why they put that warning in.

However, this warning makes no sense when set on the auto setting as you have no control over when it makes the adjustment, and in fact if the passenger is not on the bike, it won't make the adjustment needed for them, though maybe this is a clue as to why the auto adjustment only takes place while riding. Perhaps the system wants to give the shock a chance to warn up before making the adjustment - though I don't see the need for this if the ambient temperature is high enough, and the bike has a sensor for ambient temperature so should know whether auto adjustment can be done immediately or needs to be delayed.

 

[fred_jb]

The system could not calculate the load properly if you were sitting on it with your feet on the ground. As soon as the bike moves, it can be sure all the load is on the suspension.

Yes, but it can immediately detect the extra sag caused by the passenger boarding, and I see no reason why it can't correct for this to put the bike in a more stable attitude before you set off, and in fact I think this would be highly desirable behaviour. In the case where the rider had been taking a significant amount of their weight off the bike then it would sag a little further once the rider's feet were off the ground, but the system could then fine tune the preload to correct this once underway.

 

[matchbox]

I think perhaps it does not adjust immediately since it averages the reading from the ride height sensor(rather like auto headlight does not immediately react to changes in light from trees, bridges etc). Otherwise suspension would be up and down all the time affecting geometry and giving a very uncertain ride.
One question, when your wife got on could you not lean the bike to the right to free the stand? Also I guess the same problem would occur on non esa machine!

 

[ChazzyB]

Yes, but it can immediately detect the extra sag caused by the passenger boarding,

Only if the ignition is switched on. If I were developing the algorithm to adjust the height, I'd want to have one set of conditions on which to trigger the measurement and adjustment, and that would be when the bike moved under its own power, in gear, with the clutch out and the side-stand retracted.

 

[Traffic893]

When I have the wife on the back and I have checked the suspension setting to make sure it is right I have noticed the suspension lift or lower slightly before moving anywhere. I would have thought automatic would mean exactly that.

 

[fred_jb]

I think perhaps it does not adjust immediately since it averages the reading from the ride height sensor(rather like auto headlight does not immediately react to changes in light from trees, bridges etc). Otherwise suspension would be up and down all the time affecting geometry and giving a very uncertain ride.
One question, when your wife got on could you not lean the bike to the right to free the stand? Also I guess the same problem would occur on non esa machine!

Well as we sat on the bike with the engine running for a few minutes expecting and waiting for it to do its thing with the auto adjustment, I think it had ample opportunity to detect that the condition was stable and make the needed adjustments.

To answer your question - I did try to lean the bike to the right to free the stand but it was not possible to do so with a modest amount of lean that would not risk dropping the bike to the right. I didn't want to risk leaning it any further.

 

[fred_jb]

When I have the wife on the back and I have checked the suspension setting to make sure it is right I have noticed the suspension lift or lower slightly before moving anywhere. I would have thought automatic would mean exactly that.

That is what I would have expected, but my bike made no discernible adjustment, as shown by the fact that the side stand remained trapped, and it was only the fact that I had accidentally left the side stand out that alerted me to this behaviour. Unless I noticed the excessive sag, I would normally have just set off and been unaware that the adjustment would happen while moving.

I still don't understand the thinking behind this, especially as I believe the previous generation ESA required the rider to select the most suitable of the three preprogrammed preload settings before setting off, which seems the right thing to do to make the bike as stable as possible for the load it is carrying.

I'm not very happy that it seems that in AUTO mode I have to ride away with excessive rear sag and a less than optimally stable machine before the bike does anything about adjusting the preload. To make it worse, the only other options you can set before riding off are MIN (too low) and MAX (too high) and you then cannot change this setting while moving.

 

[matchbox]

Presumably, when your wife got on, the side stand came into play and therefore prevented the bike detecting the sag?

Also, as I mentioned before, it averages height reading.

 

[fred_jb]

Presumably, when your wife got on, the side stand came into play and therefore prevented the bike detecting the sag?

Also, as I mentioned before, it averages height reading.

Not quite sure what you are getting at. The bike did sag when my wife got on, that is why the side stand became trapped in the forward position. As the bike sagged the little arm from the swing arm to the position sensor would have moved, so the bike would have the ability to know that the suspension had become compressed into a non-optimal position.

Obviously when on the move you don't want every little jiggle to result in a preload adjustment, so there will a longish time constant in the system to average this out, but that does not mean that the bike could not sense and respond to a static and stable compression of the suspension while the bike is stationary. It seems that for some reason BMW have seen fit to not do this, and hence force owners with the latest auto levelling suspension to start their journey with an unsuitable and potentially unsafe amount of suspension sag.

 

[andylel]

Have you checked that the side stand being down did not prevent adjustment. I can't check at the moment but IIRC stand up is one of the conditions for suspension adjustment on the older bikes and it may well be the case on the self levelling ones also?


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[ChazzyB]

Have you checked that the side stand being down did not prevent adjustment. I can't check at the moment but IIRC stand up is one of the conditions for suspension adjustment on the older bikes and it may well be the case on the self levelling ones also?

Not sure that's the case. I could see the seat on my last GS rising when I adjusted from Rider to Rider+luggage, with the bike leaning on the side stand.

 

[fred_jb]

Have you checked that the side stand being down did not prevent adjustment. I can't check at the moment but IIRC stand up is one of the conditions for suspension adjustment on the older bikes and it may well be the case on the self levelling ones also?


Sent from my iPad using Tapatalk

Good suggestion - I will try that next time I have the bike out, though I think it unlikely as I haven't seen anything to suggest that in the manual, and it was able to go onto the MIN and MAX positions OK. Having said that, I think the manual is largely based on the previous one and seems a bit light on comprehensive descriptions of the new features.

 

[Tyzer]

I hate to admit it but I prefer the GS with the non ESA suspension.I ride with a pillion most of the time and once I had manually adjusted the suspension it coped with everything i needed it to,another twiddle with the knobs when loaded with luggage and it was fine.
ESA Is ok and I'm adjusting to it but don't really see the benefit, for me anyway,I have an exclusive so it came with it.Im also not sure what the point of "min" and what conditions you would use it as it bounces like a kangaroo when solo obviously not tried that setting with the wife ,and I'm not that heavy!

 

[Hairyweasel]

Have you checked that the side stand being down did not prevent adjustment. I can't check at the moment but IIRC stand up is one of the conditions for suspension adjustment on the older bikes and it may well be the case on the self levelling ones also?


Sent from my iPad using Tapatalk

This could well be the case, at the weekend I was on mine on some pretty sketchy ground on a car park and I had left it set to 2 up and my toes were only just on the floor.
I reset it to solo and it dropped enough that I could get good footing without moving the bike but the stand was up.
Once I was on better ground I had a play at all 3 pre load settings and it was going up and down on command.

 

[ChazzyB]

I refer people to page 117 of the Rider's Manual for BMW's words on the ESA "Next-Generation" Riding Position Equaliser's engineering details.

I guess if anyone thinks it should operate differently, you had best take it up with BMW's development engineering team and their lawyers.