Extra preload needed

[CPJS]

For me the latest esa does not work as well. With the previous esa I would ride with solo preload, this was fine 95% of the time, the other 5% I could up the preload for a bit extra ground clearance, I can no longer do this so I grind metal, not so bad if it was just a footpeg that pivots, it is non moving bits of metal that touch down, not good.
The damping settings have also been changed for the worse, before i could choose one of three settings, soft, med or hard, now I have just two settings soft and hard.
For me and my weight the esa is a bit Goldilocks with Mummy Bear's porridge not there, all the middle settings are gone.

 

[ChazzyB]

Perhaps I'm not trying hard enough, but I've never grounded any part of any of my two GS's. I must weigh 110 kg suited sand booted.

 

[fred_jb]

Perhaps I'm not trying hard enough, but I've never grounded any part of any of my two GS's. I must weigh 110 kg suited sand booted.

Same here, though in my case I'm definitely not trying hard enough! This suggests that either the preload isn't working properly on the OP's bike, or else he is in the habit of riding it on road outside its design envelop - i.e. as if it were a sports bike on a track day.

 

[ChazzyB]

Or the compression damping isn't working properly.

 

[SMB]

Both level sensors ( front & rear ) are the same, ($93 each) according to maxbmw.com
My guess is that it is just a voltage divider. If you are good at electro trickity maybe you good buy are alter the "auto level" or "min level" voltage with a switch to do the changes for back and front sensors.
Then, when the alteration is switched on the auto level/ min level could give you more a bit more preload.

I guess the mothership would throw the toys out of the pram at this idea.

OK, I will get my coat.

 

[ChazzyB]

There's no level sensor for the front, is there? Shirley preload is on the rear only.


Well, well, so there is. I'd guess that sensor is also measuring speed of suspension compression to do magic with the damping.

 

[fred_jb]

Both level sensors ( front & rear ) are the same, ($93 each) according to maxbmw.com
My guess is that it is just a voltage divider. If you are good at electro trickity maybe you good buy are alter the "auto level" or "min level" voltage with a switch to do the changes for back and front sensors.
Then, when the alteration is switched on the auto level/ min level could give you more a bit more preload.

I guess the mothership would throw the toys out of the pram at this idea.

OK, I will get my coat.

Nice idea, and if it was a system with an analogue output I'm sure you could fairly easily put an offset on the output voltage.

However, I suspect these widgets do an analogue to digital conversion internally and output in digital format over a data bus, so probably a lot more difficult.

 

[fred_jb]

There's no level sensor for the front, is there? Shirley preload is on the rear only.


Well, well, so there is. I'd guess that sensor is also measuring speed of suspension compression to do magic with the damping.

These sensors may well provide info to the semi-active damping adjustment, but even if not, you still need to know the relative sag at front and rear, even though there is no preload adjuster at the front. You therefore probably need two sensors anyway as you need to know the front sag in order to work out how much to raise the rear to get a level attitude, and you can't just infer this from the rear sag. For example if you had a very heavy rider but a light pillion you would probably need to add a bit less rear preload than if you had a light rider and heavy pillion because of the difference in front to rear weight distribution in these two cases.

 

[SMB]

Nice idea, and if it was a system with an analogue output I'm sure you could fairly easily put an offset on the output voltage. I

However, I suspect these widgets do an analogue to digital conversion internally and output in digital format over a data bus, so probably a lot more difficult.

I bet the measuring system is just a rheostat, then goes to a A to D converter. Well if I wanted to get controllable preload, that is where I would start. Just a switchable resistor preset.

 

[SMB]

There's no level sensor for the front, is there? Shirley preload is on the rear only.


Well, well, so there is. I'd guess that sensor is also measuring speed of suspension compression to do magic with the damping.

Since the previous model had an automatic system for changing the damping without wheel position sensors, that worked, I guess that the damping system worked by the changing shock fluid pressure. I doubt that they would reinvent the system for the newer model. They added wheel position sensors for the automatic preload.

Just a guess.

 

[fred_jb]

I bet the measuring system is just a rheostat, then goes to a A to D converter. Well if I wanted to get controllable preload, that is where I would start. Just a switchable resistor preset.

Yes I agree it could still be possible, but it is a matter of getting at the relevant points in the circuit. You have to get inside the unit and maybe insert a padding resistor at one end of the rheostat (or potentiometer as us modern types call them) to offset the voltage either up or down as required, or alternatively put a voltage divider on the output of the potentiometer, and in either case you would need to be able to tap in at the right point in the circuit, which if it is highly integrated with the potentiometer pcb mounted and the whole thing encapsulated in a protective potting compound, may be difficult.

The other issue with this is that by dropping part of either the supply to the pot, or the output voltage from it across a resistor, you will lose part of the range of voltage output available and make it off centre with respect to the suspension's range of movement, which may upset the software which monitors it, and if the system has a self calibrating software routine it may just negate the changes anyway.

On the other hand, there may be a screw adjuster for calibration, in which case you could just mis-calibrate it a bit to get the desired effect. I haven't looked at mine, but it might also be possible to adjust the mechanical attachment to the suspension, a bit like bending the arm on a ballcock! Might still upset the software though!