the shocking truth about shock absorbers... (noob questions as asked by myself)

[Paul the 6th]

just had a response from hyperpro. I copied luckypants' input about the dangers of limited travel since I wouldn't be able to explain it better:

"Hello Paul,
This sounds like someone who doesn't understand progressive suspension too
well.

With linear springs, the coils along the spring are at equal distances all
the way down. This means that you have to wind the preload up to make it
firmer based on the combined weight of you and your motorcycle. More preload
will result in 'shorter' springs (less travel). You only need a constant
amount of pressure before this spring becomes 'coil-bound'.

With progressive springs, the coils gradually get closer together as you go
down the spring. Now what happens here is: when you apply the weight, the
top coils touch and are affectively 'removed' from the spring - This makes
the spring shorter and more resistant. The more pressure you apply, more
coils will touch and the spring will rebound more. It is significantly
harder for a progressive spring to become 'coil-bound' in comparison to a
linear spring, and this is why we recommend progressive suspension over
linear. It improves general handling, braking, accelerating and is perfect
for the bumpy roads of the UK.

It is very hard to explain in writing, but if you are local and can swing
by, I have two handheld springs (one Linear, one constant) which demonstrate perfectly what I am trying to explain.

Kind regards"

nice of him to explain, and although he tried to diss luckypants' thoughts/comments, I still get what LP is trying to say. Still a bit pricey at 105 quid! plus 10 quid postage

time for a bit of bargaining

Sorry not read the pages and pages of replies if you already have a resolve, but to my mind ....


03-08 SV650 330mm 430# <<<==== stock 2nd gen...05 should be the same

05 GSX-R 1000 332.5mm 450#

03-04 GSXR1000 332.5mm 480#

Looks to me the 03-04 would have been ideal/better buy.

But as you have the 05 I'd stick with it ... the ZX shock on a pointy will be stupid hard ....

[yorkie_chris]

This means that you have to wind the preload up to make it
firmer based on the combined weight of you and your motorcycle. More preload
will result in 'shorter' springs (less travel). You only need a constant
amount of pressure before this spring becomes 'coil-bound'.

No it doesn't! That sounds like someone who doesn't understand a bloody spring...

F = ks (hookes law)

Constant force will settle at an equilibrium position "s", with a progressive spring the "k" constant changes depending on how far it's been compressed.

Also forks will hit the hydraulic lock piece way before the spring becomes coil bound. Neither does preload affect travel, in fact preload set correctly will give you more travel as you're not putting the sprung part on it's stops just taking up static forces.

He's trying to sell you something.

I agree with getting progressives, but this guy's physics arent making much sense. Gah. In fact, I'd buy some from elsewhere just based on that email

[yorkie_chris]

Originally Posted by Miles

Apologies for being basic, I can't visualise it. In my mind the spring was being compressed more and shortened, and the rod was moving in as well, shortening it. But for fear of looking even more stupid, I'll take your word for it!

I think 325mm is right then, but will check when I get home over the weekend.

Well the spring is trying to extend the shock to it's full where it's "topped out" so the more you compress the spring, the more you "stretch" the shock out to it's full length.


As I've said, fit the K5 thou shock, it'll be an improvement. Fit some cheap springs, and proper oil, it'll be a massive improvement. If it needs more fettling, then there's lots of adjusters on the shock to put in the wrong position and frustrate you

[Paul the 6th]

iv had enough now. cheap springs chris? gonna ring maxton and the others 2morra and find out who's got a good price. Failing that, there's some at aldi on offer next week

[yorkie_chris]

Hagon progressives are cheap and work. They come with a suitable oil. I'm almost certain that we'll be able to set those up to work a lot better than stock. In fact just firing them in with hagons "one size fits none" settings will work a lot better than stock.

Originally Posted by yorkie_chris

Also forks will hit the hydraulic lock piece way before the spring becomes coil bound. Neither does preload affect travel, in fact preload set correctly will give you more travel as you're not putting the sprung part on it's stops just taking up static forces.

preload does affect travel.reason you want correct rate spring and correct amount of preload on it.

[yorkie_chris]

Trying to say not having enough preload will mean suspension is nearly bottoming out with just rider, meaning there'd be no travel left to use up when wheel hits a bump.

I find it hard to imagine what he says about springs becoming 'coil bound'. Surly the springs and forks are setup in souch a way that the springs are no where near this point even at Maximum travel!?

right.or other way around where to much preload will take away travel at full extension and wheel will bounce of on that same bump.
so preload does affect travel