Suspension Settings

[johno1642]

Hi

Can anybody out their advise me what the sag should be on the rear shock, on my F800GS? The owners manual simply gives a basic dial setting for an 85Kg rider.

Cheers

 

[Greggers]

The best way to go is middle settings on both damping and preload, then change one at a time to see how best you like it.

Personally, I'm on middle damping, max pre-load and weigh a trouser busting 100kilos in my socks

 

[Micky]

Sag should be 25% to 30% of the total suspension movement up and down.

If the total suspension movement (front or back) is say 4" then when you sit on the bike in your normal gear, it should sag by about 25% to 30% ie about an inch!

If it sags 2" (half it's movement) it's too soft (50%) then you want to wind up the preload.

If it sags 1/2" ( an eighth of its movement) it's too hard (12.5%) so you want it with less preload

THEN you need to set the rebound damping... as little as you can get away with. Back it right off... right off. You'll probably pogo stick down the road so wind up the rebound a couple of clicks.

If the bike rides back end down then you have too much rebound ... the spring doesn't 'recover' before it hits the next bump, so remains partially compressed. If it boing boings down the road then another click or two on the rebound should sort

BUT the normal BMW suspension fitted as standard aint good enough in reality and a click here and a click there won't make much noticeable difference. Fit good aftermarket suspension such as Ohlins or Wilbers and you can then fine tune and tell the difference.

Good suspension is worth 20 bhp

 

[Dave Ett]

Good suspension is worth 20 bhp

And costs one arm and one leg!

 

[Micky]

And costs one arm and one leg!

errr mmm aaaagh ... no!

My Wilbers, front springs and oil, rear suspension unit, were supplied FOC by Wilbers

 

[mcbikerider]

Sag should be 25% to 30% of the total suspension movement up and down.

If the total suspension movement (front or back) is say 4" then when you sit on the bike in your normal gear, it should sag by about 25% to 30% ie about an inch!

If it sags 2" (half it's movement) it's too soft (50%) then you want to wind up the preload.

If it sags 1/2" ( an eighth of its movement) it's too hard (12.5%) so you want it with less preload

THEN you need to set the rebound damping... as little as you can get away with. Back it right off... right off. You'll probably pogo stick down the road so wind up the rebound a couple of clicks.

If the bike rides back end down then you have too much rebound ... the spring doesn't 'recover' before it hits the next bump, so remains partially compressed. If it boing boings down the road then another click or two on the rebound should sort

BUT the normal BMW suspension fitted as standard aint good enough in reality and a click here and a click there won't make much noticeable difference. Fit good aftermarket suspension such as Ohlins or Wilbers and you can then fine tune and tell the difference.

Good suspension is worth 20 bhp

I surely appreciate the in-depth explanation. However, being a norwegian I just need to make sure I understand this 100%:

Sag: this is adjusted using the "big" dial using the tool under the seat.

Rebound: this is adjusted using the smaller (lower) knob using a screw driver?

Did I get this right?

Thanks!

 

[v8legend]

I surely appreciate the in-depth explanation. However, being a norwegian I just need to make sure I understand this 100%:

Sag: this is adjusted using the "big" dial using the tool under the seat.

Rebound: this is adjusted using the smaller (lower) knob using a screw driver?

Did I get this right?

Thanks!

My neighbour is Norwegian, and he's also easily confused. fit wife though! Oh and yes, you've got this right.

 

[mcbikerider]

My neighbour is Norwegian, and he's also easily confused. fit wife though! Oh and yes, you've got this right.

Yeah - the wives are good And thanks.

 

[Micky]

I surely appreciate the in-depth explanation. However, being a norwegian I just need to make sure I understand this 100%:

Sag: this is adjusted using the "big" dial using the tool under the seat.

Rebound: this is adjusted using the smaller (lower) knob using a screw driver?

Did I get this right?

Thanks!

Yup ... just about right mcbikerider

The sag come preload wants setting before you start with the rebound compression. We don't have adjustable compression damping on our bikes... or most bikes for that matter. So that's the spring your adjusting.

In simplistic terms, lets say for the front, with the bike stood upright, on its wheels, (you'll need a little helper) measure from the beak to the ground. Then sit on the bike with your normal gear and measure again.... take the 'sat on' measurement away from the first and this will be your sag, which should be about 25% to 30% of the total suspension movement.

Any rebound compression settings won't affect these measurements, and you adjust the spring to give you the correct 'sag'.

Then you can start on the rebound damping as above. As little as possible to start with and then dial a half turn in at a time... just enough to stop the bike pogo-ing down the road.

There are more precise ways of setting your suspension up, but but this is a reliable, accurate and easy way of doing it

 

[mcbikerider]

Great. It's been done and I'll try it tomorrow. I had my wife sit on the bike telling her that I assumed her weight without riding gear was equal to mine with riding gear Not very popular so I had to fetch a neighbour to help me out. But should be OK now.