Rear shock preload?
 

This may sound very stupid, but i think i am having a thick morning.
I have recently bought a bike mag and at the back along with a lot of other helpfull tips on how your bike should be set up ther is a little quote in there saying " Preload dosen't actually make your suspension any diferen't it just raises or lowers the ride height "
Is this correct? as the 2 big nuts on the top of the shock are nearly all the way down as far as they will go now if i undo them say half way how is this going to effect the bike?
Cheers in advance Guys.
Hope everyone had a good one at Mallory i am definately there on the next one.

I am not an expert but, to adjust the ride hieght on a74*/916/99* there is a ride height adjuster (the alloy rod on the gear lever side that runs to the rocker that the shock attatches to at the top) this sets the ride height , set it too high and the rear end loses grip when accelerating hard, set it to low and the bike turns like a bus.

Preload sets the amount of of sag the spring has when unladen and with a rider on the bike (increasing preload will raise the back of the bike but the shock will run at the upper end of its travel and will top out, decreassing preload will lower the ride height but the shock will bottom out.

to set the ride height first set your static(unladen) and laden sag with the preload rings. I do not have the reccomended settings to hand they must have been posted on the old board try a search. only then try adjusting the ride height.

be very carefull setting the ride height maybe half a turn at a time on the adjuster rod and note the original settings if you get it wrong it can be very iffy.

the other adjustment that may benifit you is to soften the compresion and rebound damping, my 998 handles a lot better since it was set up and although the ride heightwas raised the damping was backed off. Result turns in fast and great feel at both ends.

dave

Cheers for help DAVE i have already taken the ride height adjuster to it's lowest point and to compensate the adjustment i also lowered the forks in there yokes by the same amount so it still handles exactly the same as it did before, it's just i never noticed the prelaod on the rear shock before being at it's Max? ( when all the way down ) so i should have some movement to play with yes?

Yes Preload is basically just a ride height adjuster as it is used add or remove sag, spring rate is pre-set when the spring is tempered and can not be changed by preload, although if you have progressive springs it may feel that way. This applies to both front and rear.

If you put to much preload on it will feel choppy !
As the spring is becoming coil bound with less working range !

You're confused because the author is using terminology that is more common outside the Ducati superbike world.

Ducati superbikes, unlike a lot of bikes, have a rear ride height adjuster that (more appropriately) should be called an attitude adjuster.

It's purpose is to change the bike's front-to-back height relationship thereby changing the steering head angle, the height of the center of gravity and ground clearance without also needing to change the forks position in the triple clamps.

This allows you to independently raise the front and the back of the bike equal amounts for ground clearance and to raise the C.G. for better cornering, or to raise the rear and drop the front equal amounts to change the steering head angle to quicken the steering. So its adjustment gives you more control over the chassis geometry, making it easier to affect handling objectives.

(Keep in mind that lowering the front ride height or raising the rear ride height are not equivalent adjustments. Lowering the front serves to lower the bike's center of gravity. Raising the rear raises the C.G.)

The rear ride height is set at the factory to obtain the proper chassis geometry, where chassis geometry is defined in terms of wheelbase, fork and steering head angle, ride height, weight distribution and wheel alignment.

Suspension, on the other hand, is defined in terms of spring rate, damping and wheel travel.

When you move outside the Ducati community and you talk about changing ride height, you're talking about setting how much of the suspension stroke will be available for absorbing bumps and how much travel will be reserved for extending the wheel into a drop in road contour.

Here, the ride height is being called the distance to full suspension compression. The distance to full suspension extension is called sag. Increasing spring preload reduces sag and increases ride height and vice versa.

You guys mention that the suspension "feels choppy". That's the sort of feeling I have with the front end of my 748, what can I do to aleviate this

What settings are you running as the Choppy feeling can be either to much preload or to much Compression damping !
They actually feel different but most peps describe both as feeling choppy
Also what weight are you !

Guys,

pre-load is NOT really about ride height.

Pre-load affects the way the suspension (damping) reacts when the tyre hits a bump on the tarmac. Set to hard, then the wheel will 'bounce' over the bump (and feel choppy) and potentially lose grip - not good at the front.

Too soft and it all goes 'sqirmy' (technically speaking).

To ride quickly, you do need to get this sorted - problem is of course that its probably different for track, road, two-up ....