Spring Change-How much oil in forks?

[kdscoates]

I am going to be putting in my new sonic springs on friday.
I have done all my research and I have decided on this.

15 wt oil at 135mm from the top
1.2 sonic springs with a 5/8" spacer
I am a 255lb guy and more like 275 with gear.
my bike is a 94 st1100 abs with the progressive rear with 10 wt oil and it is great!!
I am pretty sold on this combo!

My question is how much fork oil goes in the fork total.
I have bought a 1 liter bottle of 15wt and I am wondering if I should get a second?

Thanks in advance
Steve

 

[John OoSTerhuis]

Hi Steve,

1,000ml should be enough, even with the higher levels you've selected. Why not initially use the spec'd levels (R-177mm/~372ml, L-174mm/~418ml)? Filling the fork tubes with enough additional suspension fluid to raise the level another ~40mm works out to about 1 ? inches higher than spec...

John

 

[Brant]

Hi Steve,

1,000ml should be enough, even with the higher levels you've selected. Why not initially use the spec'd levels (R-177mm/~372ml, L-174mm/~418ml)? Filling the fork tubes with enough additional suspension fluid to raise the level another ~40mm works out to about 1 ? inches higher than spec...

John

possibly stop travel before utilizing its full extent?.........hydraulic lock?

 

[John OoSTerhuis]

Doing some simple math here to support my assumption above, the additional suspension fluid works out to approximately 86 ml (43x2) more than the spec quantity.

This assumes a nominal fork tube ID of 37mm. Note that 1 ml = 1 cm[sup]3[/sup].

An estimated 27.3 ml (.923 fl oz) of suspension fluid increases the level in 91-02 standard and 92-95 ABS models' fork tubes (41mm OD) one inch (25.4 mm). Every fluid ounce (29.6 ml) raises the level 1.08 inch (27.5 mm). Sooo... roughly one fluid ounce per inch.

Fun with math FWIW

John