Preload adjustment

[rodsharp]

I had a replacement rear shock some time ago by BMW main dealer Whereas the original had about 20 clicks of adjustment and the handbook suggests standard setting 10 clicks from soft the replacement has 42 clicks. I am not sure of the best setting for this and have been using about 20 clicks ie half way as a compromise which isnt too bad until the pace is upped on crappy roads so just decided to set it to give me the correct level of static sag. The suspension travel is 200mm according to BMW and the sag should be about 30%. This means I need about 35 clicks from soft, ie nearly max compression . That doesnt sound correct to me and its just started raining so wont be testing it just yet. Anyone else experienced this and what are your preferred settings ?

 

[Watty100]

1. Take to a specialist to help set it up right.
OR
2. As you've had it for some time and it hasn't spat you off the bike yet, just adjust it a couple of clicks at a time, go for a ride and find the ideal setting that way.

 

[Deleted account 190920001]

Your idea of setting the sag is the right idea. Preload serves no other purpose what so ever but I would probably go for 20% . I think your old shock was duff because my 09 had about 40 odd clicks and the manual was 10 clicks solo. Trouble is that is for the BMW average person which is 175lbs. No idea your weight but the average tosser round here is well above that.

Once the sag is set if you want a sportier or softer ride use the damping adjustment and not the preload.

 

[Bendy toy]

Too much rebound damping will cause the suspension to pump up on fast rippled surfaces. Too little will kick back after hitting a bump. A shock that needs the preload gradually turning up is in dire need of servicing. Its a sign the oil has thickened and less effective at damping the spring. Wilber's say their shocks should be serviced every 15,000 miles, yet we get upset when the lesser quality OEM shocks fail unserviced at 30K.

 

[rodsharp]

Thanks for your replies and suggestions but I am still unsure of where I should set the preload as a base setting . Mark you suggest 20 percent though I googled it and 30 percent was generally reckoned to be the correct amount of sag ,the trouble is though as I said to get 30 percent I need to set it on max preload . I know the handbook says standard setting is 10 clicks but as pointed out for what weight? I am 200 pounds plus my riding gear so 10 clicks would not seem to be enough and that would give much less than 30 percent sag which is why I have been using 20 clicks as a compromise. Maybe the softness that I feel when pressing on especially on bad roads is due to not enough damping ( I have it as standard ) I don't think the shock is worn out yet though probably not at its best at 20000 miles so I will go out today and have a play.

 

[Deleted account 190920001]

If you want 30% then set it at that but sort the damping out to suit. If you can't use the manual setting for preload then your not going to be able to use them for damping. That is the advantage of the newer bikes. You can set damping up for comfort or sport as your moving. On a manual bike it's going to always be a compromise from the settings you had when you left.

 

[Bendy toy]

The preload is really just a ride height adjustment. If you set it higher but carry the same weight, the bike will simply ride higher than before. If you load the bike with a pillion the spring will sag back to the original ride height. This might need harder damping but pillions often prefer a softer ride so keeping the damping as is can be all you need to do.