Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Lightweight wheels

[spinoli1]

Thank you Guys,

Well, I'm glad we got that cleared up.

To give some idea of the path of my confusion -

The wheel has less mass and inertia on the compression stroke - so I would have thought more compression damping is needed to regulate the faster stroke.

Likewise, on the rebound stroke, less inertia would need more damping to regulate the stroke.

However, the as the wheels are lighter, it would seem natural that the suspension is not being "worked" so hard and would not need to be so "stiff".

I tried taking the concept to extremes - wheels with zero weight need infinite damping. No that makes no sense.

Wheels with infinite weight need no damping. This actually makes a little sense, as they would never move. Accelaration would suffer a bit, though.

I agree with the comments regard preload - but then again, I'm probably wrong.

It will surely be a case of see how it goes, and adjust by feel. At the moment, and on the road, the suspension feels like it has a little too much
compression damping.

I've been caught out before by terminal chatter under braking from high speeds on the track, and the result was not pretty.

My first track day this year is at Nogaro (not been there before) in 3 and a bit weeks. Have you seen the length of the main straight, and the hairpin that follows it? My buddies stock 03 R1 touches 170mph before braking.

So I'm a bit paranoid about about chatter, hence the questions.

Thanks to everyone for their input.

Spinoli

[Mike Davis]

Sorry Skids I`m in the Felix/Rattler camp, the springs do not need to be altered to suit lighter wheels.

The spring and preload rate are affected by bike and rider weight.

This season lighter wheels will be mostly affectin rebound and compression.

[Felix]

Originally posted by spinoli1
The wheel has less mass and inertia on the compression stroke - so I would have thought more compression damping is needed to regulate the faster stroke.

Likewise, on the rebound stroke, less inertia would need more damping to regulate the stroke.

You've got that the wrong way round, and Skidlids is right there. Less inertia produces less deflection over bumps, therefore you need less damping on both compression and damping, i.e. softer suspension as expressed in terms of damping.

Keep in mind, that this is pretty much a theoretical point because suspension setting are influenced by many factor. That's why most suspension related adivce is preceeded with the word "generally".

Just go ride the thing and adjust one thing at a time based on your feedback. Start with the current setting. The worst thing to do, most likely, would be to change a bunch of settings based on theoretical physics.

[spinoli1]

Thanks Felix,

You are, of course, completely correct. I'm pretty sure you are anyway.

Fully adjustable suspension should not be made accessible to muppets like myself. Still, at least I've stopped myself from random twiddling. I'll just ride the thing and try to deal with any wayward symptoms as they arise.

Hmm, there's nice hardtail XS 650 in the rag this week. If only it had shaft-drive and an automatic transmission.....