Customised suspension

[BigKev67]

I have a 2021 GSA Rally TE
I find it odd that BMW have such a clever suspension system that dosnt allow the rider to set it up as he wants.
For instance I have two suspension modes that I use, ROAD and DYNAMIC.
In ROAD I find the ride is plush and bouncy, a bit too bouncy
In DYNAMIC it dosnt bob up and down like ROAD and handling is better, but it transmits more jarring.
What I would like is a setting between ROAD and DYNAMIC.
Has anyone found a way to alter settings, maybe through the dealer ?

 

[hawkeye]

There are a couple more settings @BigKev67 apart from Road and Dynamic which you can adjust - you can set the preload to Max, Min and Auto - so for instance you might find setting MIN and Dynamic meets your needs possibly. At present I imagine you have the Preload in Auto.

 

[bosnjo]

That is why I ordered my bike customized the way I wanted it. One of the things was non-ESA suspension. When the bike came out of the dealer, the suspension was too soft for road riding. Went to the friend of mine that is good with suspension adjusting and adjusted it to my weight. Then counted the clicks on the remote knob from the zero. That way if I ride with the pillion I can count the clicks to put it back to where it was. And, one thing less to brake on the bike.

 

[BigKev67]

There are a couple more settings @BigKev67 apart from Road and Dynamic which you can adjust - you can set the preload to Max, Min and Auto - so for instance you might find setting MIN and Dynamic meets your needs possibly. At present I imagine you have the Preload in Auto.

My understanding is that pre load will only alter the ride height, it wont affect spring rate or damping. It allows the bike to sit at the correct geometry whatever the load applied. The spring rate will remain the same so the suspension response to road conditions will remain the same.
BMW did have a way of changing spring rate on my earlier bikes by the use of an elastomer that worked in conjunction with the spring, but I am not aware that the current bikes have variable spring rate
I think the difference between ROAD and DYNAMIC is the rebound damping.

 

[3bikesnospace]

Yes road is a little bouncy till you get used to it but the dynamic suspension setting absorbs rough roads better than any suspension on previous bikes including my 08 GS with ESA.

 

[Nin]

These active systems, like passive systems, use a generic spring rate for an average rider, then adjust damping for comfort/behaviour and preload for ride height.

So if you’re a larger person than the average rider, you’ll experience perfect ride height with auto preload adjust, but possibly:

- a bit harsh if over damped and under sprung, typically the more sporty settings.
- a bit bouncy if under damped and under sprung, typically the more comfort settings.

I never got round to changing springs on my Adv, but that would give you the ideal setting, if the front and rear springs were selected for rider weight.

On every bike I buy, I change the springs to suit my weight - 100kg in my gear, vs usually 75kg standard. I find it makes a huge difference, your experience may differ.

 

[Neil W]

Yes road is a little bouncy till you get used to it but the dynamic suspension setting absorbs rough roads better than any suspension on previous bikes including my 08 GS with ESA.

Still not as good as standard non esa never mind one fitted with good quality aftermarket made to measure shocks

 

[Nin]

I’m not so sure, I think a properly sprung active shock would be excellent, especially on a GS or RT.

 

[3bikesnospace]

Still not as good as standard non esa never mind one fitted with good quality aftermarket made to measure shocks

Well it's the best suspension I have experienced in 44yrs riding so I doubt that , sure for a race track you could fine tune after market to perform better but for all round road use no .

 

[Flipfly]

My understanding is that pre load will only alter the ride height, it wont affect spring rate or damping. It allows the bike to sit at the correct geometry whatever the load applied. The spring rate will remain the same so the suspension response to road conditions will remain the same.
BMW did have a way of changing spring rate on my earlier bikes by the use of an elastomer that worked in conjunction with the spring, but I am not aware that the current bikes have variable spring rate
I think the difference between ROAD and DYNAMIC is the rebound damping.

It preloads the spring (which in turn raises the ride height slightly because a preloaded spring will reduce the static sag). That is how it raises/lowers the ride height, it is not a separate mechanism. Adding preload will make the ride firmer, removing it will make is softer.

I find that preload low and dynamic is quite a nice setting for gentle bimbling around the back lanes. The steering goes a bit lazy, but it soaks up the bumps so much nicer than in Auto mode.

It’s just a shame it can’t be adjusted on the move, it’s a pain in the arse stopping to change the preload.

 

[BigKev67]

It preloads the spring (which in turn raises the ride height slightly because a preloaded spring will reduce the static sag). That is how it raises/lowers the ride height, it is not a separate mechanism. Adding preload will make the ride firmer, removing it will make is softer.

I find that preload low and dynamic is quite a nice setting for gentle bimbling around the back lanes. The steering goes a bit lazy, but it soaks up the bumps so much nicer than in Auto mode.

It’s just a shame it can’t be adjusted on the move, it’s a pain in the arse stopping to change the preload.

I dont believe that altering pre load in isolation affects the firmness of the suspension. If you increase pre load the bike can support more weight before the spring starts to compress and therefore the ride height increases, or put another way the sag reduces. Once moving the spring rate is the same so the suspension feels the same although you are sat higher.
Now in the case of the GSA altering pre load does in fact alter the damping because the ESA sends a signal to the rebound damping motors when you change pre load. So a heavier rider automatically gets a stiffer rebound setting when the pre load is set to auto. Setting pre load low will drop the ride height and set the damping softer for ROAD and DYNAMIC.
I have not tried anything other than AUTO so I will try setting LOW and see if i can get damping a bit less jarring than DYNAMIC on AUTO.

 

[Spareparts]

These active systems, like passive systems, use a generic spring rate for an average rider, then adjust damping for comfort/behaviour and preload for ride height.

So if you’re a larger person than the average rider, you’ll experience perfect ride height with auto preload adjust, but possibly:

- a bit harsh if over damped and under sprung, typically the more sporty settings.
- a bit bouncy if under damped and under sprung, typically the more comfort settings.

I never got round to changing springs on my Adv, but that would give you the ideal setting, if the front and rear springs were selected for rider weight.

On every bike I buy, I change the springs to suit my weight - 100kg in my gear, vs usually 75kg standard. I find it makes a huge difference, your experience may differ.

^ this.

The rider makes up too large a percentage of the overall sprung weight for there to be a perfect one size fits all suspension solution - especially as riders may vary by 100% of their weight between 60-120kg. The average healthy adult may be somewhere between 75-80kg and it would make sense for the factory suspension to be tuned for this bell curve average. Maybe there should be a no-cost option when speccing a bike from new as ‘Fatboy’ with a spring rate for riders over 100kg

 

[Mr Bean]

Maybe there should be a no-cost option when speccing a bike from new as ‘Fatboy’ with a spring rate for riders over 100kg

With or without riding gear?

Without I'm fcuked, with I'm in no need for the 'Fatboy'

 

[Flipfly]

I dont believe that altering pre load in isolation affects the firmness of the suspension. If you increase pre load the bike can support more weight before the spring starts to compress and therefore the ride height increases, or put another way the sag reduces. Once moving the spring rate is the same so the suspension feels the same although you are sat higher.
Now in the case of the GSA altering pre load does in fact alter the damping because the ESA sends a signal to the rebound damping motors when you change pre load. So a heavier rider automatically gets a stiffer rebound setting when the pre load is set to auto. Setting pre load low will drop the ride height and set the damping softer for ROAD and DYNAMIC.
I have not tried anything other than AUTO so I will try setting LOW and see if i can get damping a bit less jarring than DYNAMIC on AUTO.

But preloading the spring will surely make the next inch of spring harder to compress?

I can only go off how it feels to me, it is definitely softer on low and road than in auto and road…..and I’m a fat bloke.

 

[Nin]

But preloading the spring will surely make the next inch of spring harder to compress?

I can only go off how it feels to me, it is definitely softer on low and road than in auto and road…..and I’m a fat bloke.

It took me a while to get my head around this - and I’m still not fully there, but as I understand it preload doesn’t change the force required to compress the spring, it just pre-compresses the first part of it. The rest of it still works as it did before, but it has less length to compress so you get less travel - that might be what you’re feeling as “softer”.

TBH I was a huge sceptic until Premier Bikes encouraged me to talk to Mark Hammond to get my 1290R suspension set up. He fitted an updated rear spring which transformed it.

 

[knutk]

I think there is some misconception here regarding spring preload.
Even if the word preload is used, technically, what the preload adjustment do is not preloading the spring as such, it merely moves the lower part of the spring along the schockabsorber, in the same way that we did with the old bikes using an external tool that would move the spring up/down on the schockabsorber.
Of course, we may claim that the spring is more compressed, but this is due to added weight forced upon it by a fat rider/pillon/heavy luggage etc which makes the adjustment required.

 

[CPJS]

Take a spring that moves 1" per lb of weight applied. Put on two pounds of weight on it and it moves 2". Apply 1"/1lb of preload then put your 2lb weight back on it, the spring will only move 1" as the other 1" of movement has already been 'stored' in the spring. Add any more weight and the spring will continue to move at 1" per lb, that is it's 'spring rate'. Adding preload does not stiffen the spring it changes the weight needed to start moving it.
Your bike is designed to operate at a predetermined ride height with a rider on board, this is dynamic sag and is very important as it keeps the right ratio of total loaded bike weight on the front tyre and the correct steering head angle.
Too little preload is potentially more dangerous than too much as you risk bottoming out the shock at the same time as taking weight/grip off the front tyre, not good.
Motorcycle manufacturers spend a huge amount of R&D on getting this right and in BMW's case they have thoughtfully put an auto setting to save us from ourselves.

 

[BigKev67]

Edit: Sorry CPJS - I was writing my post as you posted, therefore mine is a bit of a repeat of yours.

Pre load really does cause some confusion.
It did for me until I sat down and thought about it.
You cant change how a spring reacts to a change in its length by applying preload. A springs rate is constant and each millimetre change in length requires the same amount of additional load regardless of preload.
So what exactly is preload.
If you had a rear shock in your hand, the spring has preload, thats why the spring isnt rattling around. There is a strong force keeping the shock fully extended.
Now fit the shock to the bike and sit on the bike. The combined weight of the bike and you exceeds the spring pre load and the shock compresses until the spring force equals the downward load. That movement is called sag and its the datum for the shock to start doing its job.
Now if that shock had more preload it would move less before the balance point was reached as it would take more load to begin the compression and therefore less load would be available to compress the spring - and you sit higher.
Now its the next bit that causes confusion. YOU HAVE NOT MADE THE SPRING STIFFER. As you ride the spring rate remains

so every millimetre change in spring length requires the same change in load regardless of pre load - but you are sitting at a different ride height.
If we all weighed the same, didnt carry luggage or a pillion then there would be no need for pre load adjustment. The designer would set the spring rate and the SAG would be spot on. So adjustable pre load is the designers way of keeping the bikes geometry correct when load changes - but at a cost - as the shocks operating range has been compromised, but thats another story.
There is one other thing to add, all of whats been said assumes that the spring has a linear spring rate, which most do. Some springs have coils tightly wound at one end, this allows the spring rate to increase as the shock compresses - in which preload can change the spring characteristic.
I must admit, in the old days I wrongly believed we were stiffening the suspension as we used our C spanner to compress the spring. I suspect that belief was because bikes weighed less and the dual shocks was fully extended when the rider got off, ie no static sag. So with a lot of pre load the bike sat down less when the rider got on (dynamic sag), he thinks ahhh less movement, it must be stiffer, not so.