Banshee Rune V3 (and a Husky!)

dazz

Queen Karen of Ballarat
Well then, since nobody asked! Here's my description of how the HC97 functions, enjoy.

Essentially all dampers work by controlling the flow of oil through an orifice or orifices. Designers have come up with all kinds of different designs that control how much oil flows through the holes depending on either how fast the fork is moving, or how far into the stroke the fork is, or both.

With that out of the way, let's get onto the HC97 circuits:

Starting with Low Speed Compression damping
380221

When the fork moves in compression, the piston (which has the rebound valve in it that also functions as a one way valve) pushes oil up the middle and past the orifice that I've circled in orange. The blue needle valve can be adjusted in or out to alter the size of the orifice and voila, you have achieved low speed damping. The oil then just flows out of the assembly through ports in the side (see photos below) where it makes it's way to the other side of the piston. Boom, simples right?

The magical High Speed Compression damping
380225

So the thing with the LSC damping described above is that the size of the orifice is fixed by the position of the blue needle valve and does not change once set which is all good while you're cruising along the trail running over small bumps and what not, but wait, whats that ahead? A big root sticking out from that tree right across the middle of the track! You're too late to bunny hop over it and plow straight into it at full speed! Fully puckered, white knuckle death grip and eye's shut, dead sailor here we come right? With your life flashing before your eyes thinking 'is this it?' HSC damping flies into action to save the day!!!!
When the piston moves so fast that the LSC valve cannot flow enough oil to keep up, the pressure builds up and pushes the high speed compression valve (dark grey disc) open against the spring. This allows additional oil to flow through the damper during high speed impacts resulting in the fork absorbing the impact of that tree root, phew. The white knuckle terror is over and you open your eyes again wondering what miracle of magical divine intervention just saved you from certain death. The extra oil flow through the HSC valve joins up with the flow from the LSC valve and heads off to report for rebound duties. The operation of the HSC valve is changed by adjusting the pre-load on the spring. This is achieved by turning the large (outer) adjuster knob which rotates the whole LSC valve assembly inside the fork, winding the pre-load nut down onto the spring.


Here you can see the port in the side of the valve body that isn't shown on the CAD section views.
380230
380231


Any questions? No? Okies.
 

dazz

Queen Karen of Ballarat
I wish I:
1: Understood any of this
2: Could notice the benefits.
Basically the oil goes where the red arrows point. Biggest mistake people make is not realising that the arrows will vaporise when exposed to light, so they open up the forks for a bit of diy, but don't know about the arrows. When they put it all back together the oil doesn't know which way to go with the arrows gone and so the fork won't work correctly. This is the reason suspension tuning is often considered a "black art".

I'm thinking I should join the mtbr debates, I reckon they'd benefit from my knowledge.
 

moorey

with a big stick
Basically the oil goes where the red arrows point. Biggest mistake people make is not realising that the arrows will vaporise when exposed to light, so they open up the forks for a bit of diy, but don't know about the arrows. When they put it all back together the oil doesn't know which way to go with the arrows gone and so the fork won't work correctly. This is the reason suspension tuning is often considered a "black art".
380239
 

link1896

Is not a gynaecologist but will look at your fork
Well then, since nobody asked! Here's my description of how the HC97 functions, enjoy.

Essentially all dampers work by controlling the flow of oil through an orifice or orifices. Designers have come up with all kinds of different designs that control how much oil flows through the holes depending on either how fast the fork is moving, or how far into the stroke the fork is, or both.

With that out of the way, let's get onto the HC97 circuits:

Starting with Low Speed Compression damping
View attachment 380221
When the fork moves in compression, the piston (which has the rebound valve in it that also functions as a one way valve) pushes oil up the middle and past the orifice that I've circled in orange. The blue needle valve can be adjusted in or out to alter the size of the orifice and voila, you have achieved low speed damping. The oil then just flows out of the assembly through ports in the side (see photos below) where it makes it's way to the other side of the piston. Boom, simples right?

The magical High Speed Compression damping
View attachment 380225
So the thing with the LSC damping described above is that the size of the orifice is fixed by the position of the blue needle valve and does not change once set which is all good while you're cruising along the trail running over small bumps and what not, but wait, whats that ahead? A big root sticking out from that tree right across the middle of the track! You're too late to bunny hop over it and plow straight into it at full speed! Fully puckered, white knuckle death grip and eye's shut, dead sailor here we come right? With your life flashing before your eyes thinking 'is this it?' HSC damping flies into action to save the day!!!!
When the piston moves so fast that the LSC valve cannot flow enough oil to keep up, the pressure builds up and pushes the high speed compression valve (dark grey disc) open against the spring. This allows additional oil to flow through the damper during high speed impacts resulting in the fork absorbing the impact of that tree root, phew. The white knuckle terror is over and you open your eyes again wondering what miracle of magical divine intervention just saved you from certain death. The extra oil flow through the HSC valve joins up with the flow from the LSC valve and heads off to report for rebound duties. The operation of the HSC valve is changed by adjusting the pre-load on the spring. This is achieved by turning the large (outer) adjuster knob which rotates the whole LSC valve assembly inside the fork, winding the pre-load nut down onto the spring.


Here you can see the port in the side of the valve body that isn't shown on the CAD section views.
View attachment 380230View attachment 380231

Any questions? No? Okies.
Now let’s simulate that in shim restackor, looking at the flow losses. Most, not all, off the shelf solutions are not flow optimised, no one has time to deburr the parts, looking to minimise process time when making 10,000 piston heads a day on a cnc machine in Taiwan.
 

Shredden

Knows his goats
Appreciate the discussion of the suspension gear. Will be looking at the upgrade early in the new year (will also coincide with the forks being due for a service) so will read back over this thread then!

Added some pics of my new gravel bike too (are they allowed here? :oops:)
 

Ultra Lord

Hurts. Requires Money. And is nerdy.
Appreciate the discussion of the suspension gear. Will be looking at the upgrade early in the new year (will also coincide with the forks being due for a service) so will read back over this thread then!

Added some pics of my new gravel bike too (are they allowed here? :oops:)
That’s a sick gravel bike.
 

Shredden

Knows his goats
Have had the Rune for a year now and been loving it. Did a big service over the past few weeks with some cool upgrades - keen for the maiden voyage this weekend. Also bought a motorbike which is heaps of fun.

Bike upgrades:

- ZEB Ultimate 170mm forks (more travel, better damper and air spring).
- 200mm dropper (more travel).
- 220mm front rotor and matching rear 203mm rotor (bigger).
- 30mm rise bars + rental grips (higher).
- 2 new tires (grippier).
- XT chain (more shiny).
- SLX 10-51 cassette (bigger).
- 165mm XT cranks (shorter)
- Spank Oozy pedals (thinner).

IMG_6069.jpeg
IMG_3761.jpg
 
Last edited:

Ultra Lord

Hurts. Requires Money. And is nerdy.
Have had the Rune for a year now and been loving it. Did a big service over the past few weeks with some cool upgrades - keen for the maiden voyage this weekend. Also bought a motorbike which is heaps of fun.

Bike upgrades:

- ZEB Ultimate 170mm forks (more travel, better damper and air spring).
- 210mm dropper (more travel).
- 220mm front rotor and matching rear 203mm rotor (bigger).
- 30mm rise bars + rental grips (higher).
- 2 new tires (grippier).
- XT chain (more shiny).
- SLX 10-51 cassette (bigger).
- 165mm XT cranks (shorter)
- Spank Oozy pedals (thinner).

View attachment 392360View attachment 392359
Fuck yeah moto!
Do a sick cunt ya burnout
 
Top