Inside my forks

fayeslane

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These are the springs removed from my 100GS to be replaced by new progressive springs. The short springs may be valve springs? It didn't work, the front was soft as and would drop like a shot fox under brakes. It would have been better with the spacers. The rear had a WP shock sprung so heavily that my 100kgs (many pies) could barely move it. As a combo it would have been dangerous to ride at any speed. It now has a Bitubo rear shock. Once I finish the forks, using the Millichamp formula, I will spend some time setting the sag and getting operating as good as it can.

100GSforks.jpg
 
I replaced the ones in my ST a few years ago and they're still in decent nick. Problem is I can't remember what I replaced them with - and whether I should do do again, whilst it's in bits. Think I'll leave it and sort it all out once it's rolling.
 
So those small springs were in place of the plastic spacer?

Its worth fitting the standard spacers + 10mm to match the 100PD ones. Made a big difference to my 100GS basic clone.
 
So those small springs were in place of the plastic spacer?

Its worth fitting the standard spacers + 10mm to match the 100PD ones. Made a big difference to my 100GS basic clone.

Yep, by replacing the spacer with random springs of indeterminate rate it had the effect of a long soft spring. Who knows what lateral movement was involved with the springs just sitting on top of each other !! The new springs are full length and don't use the spacer, however that might change when I start setting it up.
 
Just removed a set of progressively wound springs from my Funduro. As usual the close wound springs had sagged out solid, and I had in effect a 225 mm spacer and a 325 MM spring with about half the correct number of coils - there is a reason why Ohlins, Traxion, Maxton and anyone else who knows anything about suspension does not use progressive springs.

On a GS a Ohlins with a 450 lb #80 spring at the rear 16mm preload, and damping 7m clicks out works perfectly, but it is properly damped . It gives me 45 mm rider sag, and as you want 10% more sag at the front it is set at 50 mm.
Forget the rubbish about setting the sag at 1/3 of travel , it is absolute stuff and nonsense .
Balance, front to rear is what you want, with the front 10% softer than the rear.
Spring preload should be in the range reload 14/18 mm at the rear and 12/16mm at the front - if you cant get the sag you want with that you have the wrong spring.

The springs from the HPN inserts are available from one of the German spring suppliers , and with a 90 mm spacer they give me the required 50 mm sag, and I suspect packing the stock springs as Rob has suggested will do around the same. Matches the rear perfectly for the magic carpet ride both ends.
The HPN inserts are set with minimal compression damping and almost maximum rebound damping, this can be approximated by using different fork oil in each leg 2 1/2 in the compression side and 15 in the reboind
 
This is a good read on the subject
http://racetech.com/articles/SuspensionAndSprings.htm

I reckon setting the sag is a good way of determining the condition of your current springs and, if they are OK, igetting the bike set up at its approximate optimum and it's FREE :clap

As mentioned before my GS was dangerous in the way it was set up.

You might suprised how different your bike feels after setting the sag especially if you have inherited the settings from the PO.

The bit at the end re fine tuning it to suit yourself is valid.
 


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