05 ZX6r & ZX6rr spring rates Aus

[aus636]

Just for you info I had the rear shock spring rate tested on a 636 & RR shock. The 636 was 9kg/mm and the RR was 9.6kg/mm and I notice the info from the US state 636 9.7kg/mm and RR 10.3kg/mm I suppose our US brothers are a bit heavier.

[Tinman]

cause there bigger boys over there LOL

[zenodamper]

Most springs differ ± 5%, this is the accepted norm in production - Öhlin's race dept springs give 0.9-2%; otherwise Hypercoil @ 2% - not uncommon for an OEM spring to have a slightly open end to it too, which will allow it softer until the rate ramps up when the coils close up together; so, they need be measured at about 3 different areas of compression in the tester and then averaged... (I can shoosh if that is boring )

[aus636]

No the info is interesting so the spring rate is not a matter of just mearsuring how far the spring moves when loaded. Also I was told all bike springs are linear in their action.

Also what spring rate would you estimate for a person of 76kg with no gear.

[zenodamper]

No, not all springs are linear in their action - eh, that's not a trick question is it? In that they all move one way, and then back; therefore along a line... ???

I took it to mean that they have "rates of change" that are all linear; which is not the case (naturally) - a lot of Ducati shock springs are very obviously wound differently (visually closer together at one end - Monster 750 for EG); as are some others on Jap brands - whereas the more subtly progressive types might have a mild taper, or have the ends of the coils open (which can then close together at 1/3 or mid stroke - all of those factors will allow the rate of change (spring rate) to alter slightly as it actions...

As to your spring selection for 76 keez - hmm, I would stick with the stock rate unless the valving gets altered - sounds weird right? But the fact remains that different manufacturers do run vastly different spring rates depending on how they want to try and control the wheel through the linkage - WP on yours vs. Öhlin's for a good example...

Have you tried the rear @ around 24mm rider sag yet?

[aus636]

I have been setting my rear sag at about 30mm for track. So why 24mm rear sag? The RaceTech website say that for track riding and 76kg no gear I should have a rear spring of 9.55kg/mm.