Metal Working! Fitting, Machining, Welding, Sheet and General Metal Fab

link1896

Mr Greenfield
Incorrectly Functioning Penis
Now now, no judgement around here. I’m sure life still has meaning and purpose. Or so they tell me.


The IFP, internal floating piston, is the most popular method to seperate the gas from the oil in a damper. The oil needs to be pressurised so it doesn’t cavitation during fast strokes, sit back down komdotkom.

Say you’re landing the bike from a big jump, the shock is slammed hard to full stroke. The shaft speed is very high. The shock’s damper provides some energy absorption via damping, aka resisting the pistons travel through the oil. What we call compression damping. The oil’s viscosity works in conjunction with the compression circuit to provide this resistance. When oil cavitates, it changes state from liquid to a gas. Gas has a fraction of the viscosity of oil.

Now on the rebound stroke, the spring or air can is providing maximum rebound force. The rebound damping circuits job is to slow this down, so we don’t have a pogo stick. If the gas pressure on the ifp wasn’t there, the oil wouldn’t be pressurised, and again we’d have massive, temporary viscosity loss due to cavitation, and a pogo stick.

Here is a cutaway of an old RP23 shock, with the IFP circled.

The IFP fjohn860 is talking about wasn’t in the damper side of a shock, but for a dual air chamber setup in forks. Instead of volume reducers, you can run a slave air chamber. The IFP separates the high pressure and low pressure air chambers. The main chamber, in the fork stanchion can be set at a lower pressure, for better coil like feel. The air chamber is set higher, becoming an influence on the air spring force, as the fork goes deeper into its travel.


Check here for a lovey little animation.


 

Ultra Lord

Hurts. Requires Money. And is nerdy.
Now now, no judgement around here. I’m sure life still has meaning and purpose. Or so they tell me.


The IFP, internal floating piston, is the most popular method to seperate the gas from the oil in a damper. The oil needs to be pressurised so it doesn’t cavitation during fast strokes, sit back down komdotkom.

Say you’re landing the bike from a big jump, the shock is slammed hard to full stroke. The shaft speed is very high. The shock’s damper provides some energy absorption via damping, aka resisting the pistons travel through the oil. What we call compression damping. The oil’s viscosity works in conjunction with the compression circuit to provide this resistance. When oil cavitates, it changes state from liquid to a gas. Gas has a fraction of the viscosity of oil.

Now on the rebound stroke, the spring or air can is providing maximum rebound force. The rebound damping circuits job is to slow this down, so we don’t have a pogo stick. If the gas pressure on the ifp wasn’t there, the oil wouldn’t be pressurised, and again we’d have massive, temporary viscosity loss due to cavitation, and a pogo stick.

Here is a cutaway of an old RP23 shock, with the IFP circled.

The IFP fjohn860 is talking about wasn’t in the damper side of a shock, but for a dual air chamber setup in forks. Instead of volume reducers, you can run a slave air chamber. The IFP separates the high pressure and low pressure air chambers. The main chamber, in the fork stanchion can be set at a lower pressure, for better coil like feel. The air chamber is set higher, becoming an influence on the air spring force, as the fork goes deeper into its travel.


Check here for a lovey little animation.


Brilliant explanation.
You should start a weekly “learning things with link” thread.
 

Jpez

Down on the left!
Brilliant explanation.
You should start a weekly “learning things with link” thread.
If you’ve got the patience or intelligence of which I lack both Steve from Vorsprung does brilliant YouTube vids on all sorts of nerdy suspension topics. I try but just glaze over by the halfway point or I learn something new but because my brain is only so big when something new goes in something old goes out.
Definitely worth a look though.
 

Ultra Lord

Hurts. Requires Money. And is nerdy.
If you’ve got the patience or intelligence of which I lack both Steve from Vorsprung does brilliant YouTube vids on all sorts of nerdy suspension topics. I try but just glaze over by the halfway point or I learn something new but because my brain is only so big when something new goes in something old goes out.
Definitely worth a look though.
Yeah and it translates well to moto, I forward vorsprung vids to mates all the time rather than try and explain compression/rebound etc.
 

Haakon

Keeps on digging
Not my own work, but had a duct piece made up. Not entirely to spec sadly and I’m going to have to rethink my attachment strategy somewhat but they refused to remake it the way I asked which was … disappointing…

I gave them the internal dimensions and asked for insulation which I assumed would go on the outside. Leaving me the full 40mm on the turnout at the end to attach to the timber frame it’s going into. But they put the insulation on the inside, robbing me of 25 of the 40mm for the turnout. Not ideal…

oh well, I’ll make it work with only fixings on the sides… Also, who knows if rockwool insulation is a good idea for inside a duct…? Feels like a dodgy idea, spreading fibreglass dust through the system!

edit - insulation seems legit. Odd. The perforations are a neat idea though making it act like a muffler. Mildly annoying they didn’t want to own their error, but I’ll live. Was only $360 which felt reasonable given the work that appears to gone into it.

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