Sinking rear suspension under hard acceleration

Have a good long hard think about it before you accuse others of being daft. ......

Go on then, explain it to me. Daft is mild compared to what I was going to say. It’ll rise if you accelerate with the front wheel against a wall.
 
Let me contribute to the possible 20 pager and help it get there at the same time.

Loose some weight for a start. Only bodybuilders, fat fucks and aliens weigh that much. Not that I now what composition you are, you might be 6'4'' and quite attractive to either or most sexes in this woke section of UKGSer.* You don't have to explain how much you bench or press, what planet you are from or that you have been on weight watchers since January. By the way I roll (as in spar) with a former wrestler that is about 110 to 120 kgs of muscle and about my height and I'm only 93kg.
I have mentioned before that the dynamic suspension on the new bikes are flawed as to the inconsistent feel and feedback you get from the continually adjusting that goes on underneath you. I don't like it so I don't have it and I'm much better for it thanks. If BMW continues down this road it will have been my last modern GS/GSA I bought. Comments below I you believe I'm talking shit. Not even Lotus (some of the finest handling sports cars) consider putting electronic adjustable suspension on their cars because to them it doesn't offer the best of both worlds and it is flawed at either end of the adjustment. It is not even favoured by racers on their team bikes. Make of that what you will.
Electronic preload is not the be all and end all. Get some springs that actually sets the static sag up for you. It will be much better.
You can also have the valving adjusted at the same time to suit the riding style.
I mean, you probably spent to what amounts to close to 20k bike value in a PCP payment deal you might as well spend a few hundred more to get the bike to suit or just starve a little bit with the added bonus of saving some pie money for your euro jaunt on that awesome steed.

No matter what bike you ride, you are outside of manufacturer spec for the suspension settings. Adjust to suit ie springs and valving or another lower cost option is available. The latter being far healthier for body, mind and wallet.

*Disclaimer. I know you not but if you are a fat obese fuck and if offended by such comments you have only yourself to blame unless you are on medication or have a health condition that makes you balloon in which case I say, 'all the best with your health'.
 
Go on then, explain it to me. Daft is mild compared to what I was going to say. It’ll rise if you accelerate with the front wheel against a wall.

Nope, i''ll let you work out why BMW designed the paralever in an attempt to stop what is called, "shaft jacking" on the rear of their shaft driven bikes.

Remember, the clue is in the word "shaft".

One might want to research a phenomenon known as 'the shaft effect' :thumb

Yep, pretty straighforward. Raises under acceleration, compresses when you shut off the throttle. :D

As you'd have experienced big time if you ever rode a pre paralever BMW hard, especially if you shut off the throttle coming up to a corner and the bike squats down, and then the bike raised up as you accelerated away :eek:
 
As the OP is nearly 19 stones or 120Kg so a fairly well built chap we can assume (presumably in just his undercrackers) it may indeed be that a stiffer rear spring would be of some help, especially if you include the likely future additional weight of riding kit, luggage, pillion etc?

Perhaps a chat with Denz0 of this parish could shed light on the OE spring rating and if an 'upgrade' might help?

ESA settings will change preload and damping, but can't cure an undersprung bike.

IINM, isn’t the standard BMW suspension setup for an average 75-80kg rider? (Or somewhere in that vicinity). If OP is +50% then that will surely affect handling (as intended) and ride more like a 2-up bike…
 
Nope, i''ll let you work out why BMW designed the paralever in an attempt to stop what is called, "shaft jacking" on the rear of their shaft driven bikes.

Remember, the clue is in the word "shaft".



Yep, pretty straighforward. Raises under acceleration, compresses when you shut off the throttle. :D

As you'd have experienced big time if you ever rode a pre paralever BMW hard, especially if you shut off the throttle coming up to a corner and the bike squats down, and then the bike raised up as you accelerated away :eek:

Thanks for the explanation. I am currently adding salt to a plate of humble pie.
 
Just to add, I’m 17 stone and changed to an up rated spring and it made a massive difference.
 
So we had 'shaft jacking' on the old bikes - BMW design the 'paralever' to mitigate this - which leads to the paralever bikes either staying level, or maybe 'squatting' or 'rising' just a tad during hard acceleration.

Sooooooo what is making the OP's bike 'sink' a lot during acceleration? Is it because he's a larger than average chap??? or is his suspension knackered?
 
Just to add, I’m 17 stone and changed to an up rated spring and it made a massive difference.

What spring did you opt for buddy?
(Would you happen to have any details/specifications/make/model/link please?)

Thank you in advance :)
 
He is Denz with a zero at the end, not an 'O'.

Drop him a PM he is based in Croydon and does mail-order.
 
Sooooooo what is making the OP's bike 'sink' a lot during acceleration? Is it because he's a larger than average chap??? or is his suspension knackered?

It is probably a bit of both, again easily fixed by a suspension expert who can revalve, fit new seals, alter stroke length and replace springs for more suitable rates.
 
Do Nippy Normans do a chain conversion?.....you know where you are with a chain.
 


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