Outer Limits 4x4 Board

Hydrolic Twintube, Twintube with Nitrogen or Monotube
These or This?

Jonathan Ferguson wrote:Hydrolic Twintube, Twintube with Nitrogen or Monotube
These or This?

I thought you asking about DAMPER you cook in a camp oven

useless pad...

don't use em, shocks limit your travel... which is fine considering the lack of K's my 40 has done this year

Jonathan Ferguson wrote:Hydrolic Twintube, Twintube with Nitrogen or Monotube
These or This?

there are advantages and disadvantages to either type.

monotubes have in their favour a piston which completely separates the gas from the oil. they also dissipate heat well so are good for applications where there is a lot of high speed action. their downsides are are a reduced travel length for a given tube length, and susceptibility to damage - as the outer tube is the tube the piston slides inside, even a small dent can render them useless. due to their usually narrower caseing they will fit in places where it is difficult or impossible to fit a twin tube damper.

twin tubes have the advantage of maximised travel for a given shock length, but they are more susceptible to fade as (1) the oil and gas can mix fairly freely causing emulsification of the oil so reduced damping. (2) heat that builds up in the oil does not dissipate as easily as the damper is insulated by the outer tube.

foam cell technology combats the oil/gas mixing very effectively but it makes the heat dissipation problem worse.

a good compromise is the remote canister type shock which has some of the advantages of twin and monotube designs - they still have the susceptibility to damage of monotubes but they have the length to travel ratio of twin tube designs and the heat shedding capability and oil/gas separation of a mono.

does that help?

cheers

Brian

Twin tube with Nitrogen is the bet compromise even leaning towards plusses.

bazzle

bazzle wrote:Twin tube with Nitrogen is the bet compromise even leaning towards plusses.

bazzle

twin tube with nitrogen is the cheapest, most problematic twin tube design there is. why do you say they are a good compromise?

dumbdunce wrote:

Jonathan Ferguson wrote:Hydrolic Twintube, Twintube with Nitrogen or Monotube
These or This?

there are advantages and disadvantages to either type.

monotubes have in their favour a piston which completely separates the gas from the oil. they also dissipate heat well so are good for applications where there is a lot of high speed action. their downsides are are a reduced travel length for a given tube length, and susceptibility to damage - as the outer tube is the tube the piston slides inside, even a small dent can render them useless. due to their usually narrower caseing they will fit in places where it is difficult or impossible to fit a twin tube damper.

twin tubes have the advantage of maximised travel for a given shock length, but they are more susceptible to fade as (1) the oil and gas can mix fairly freely causing emulsification of the oil so reduced damping. (2) heat that builds up in the oil does not dissipate as easily as the damper is insulated by the outer tube.

foam cell technology combats the oil/gas mixing very effectively but it makes the heat dissipation problem worse.

a good compromise is the remote canister type shock which has some of the advantages of twin and monotube designs - they still have the susceptibility to damage of monotubes but they have the length to travel ratio of twin tube designs and the heat shedding capability and oil/gas separation of a mono.

does that help?

cheers

Brian

Sure does.

What exactly is 'Foam Cell' All I've come up with, is that it's a Multi-Viscosity Oil.

Foam cell is a very cheap and low tech way of manufacturing a hydraulic twin tube damper.

Instead of using high pressure gas to try and prevent the oil foaming, the gap between the inner tube and the outer tube of the shock contains a strip of high density foam, much like roll bar padding. The idea ( I believe) is that the foam traps the gas bubbles and reduces the formation of an emulsion.

I believe that these shocks are often padded with low pressure nitrogen so that the thermal expansion and corrosion problems of using air in the shock body are reduced.

Most "Quality" twin tube dampers use higher pressure gas and eliminate the foam cell. I guess this permits a greater volume of fluid/gas and provides more accurate damping rates as the oil/gas is not impeded by the foam as it moves around the shock.

Feel free to correct/flame me as appropriate if i'm wrong, but that's my understanding.

Cheers, steve

Gwagensteve wrote:Foam cell is a very cheap and low tech way of manufacturing a hydraulic twin tube damper.

Instead of using high pressure gas to try and prevent the oil foaming, the gap between the inner tube and the outer tube of the shock contains a strip of high density foam, much like roll bar padding. The idea ( I believe) is that the foam traps the gas bubbles and reduces the formation of an emulsion.

I believe that these shocks are often padded with low pressure nitrogen so that the thermal expansion and corrosion problems of using air in the shock body are reduced.

Most "Quality" twin tube dampers use higher pressure gas and eliminate the foam cell. I guess this permits a greater volume of fluid/gas and provides more accurate damping rates as the oil/gas is not impeded by the foam as it moves around the shock.

Feel free to correct/flame me as appropriate if i'm wrong, but that's my understanding.

Cheers, steve

no flames necessary

in a foam cell shock, the gas is encapsulated in the foam and therefore prevented from mixing with the oil. in a gas twin tube shock there is nothing to prevent the oil and gas mixing - so foam cell is an improvement on twin tube gas. a 100% oil filled foam cell shock can be run in any orientation but a gas charged twin tube must be run close to upright.

Ive buggered more foam cell shocks under hard abuse than Gas charged ones!!

Bazzle

What about the LTR? Monotube interior to prevent airating, remote canister to restore lost travel, outer shell to prevent damage. Bloody expensive also.

Slunnie wrote:What about the LTR? Monotube interior to prevent airating, remote canister to restore lost travel, outer shell to prevent damage. Bloody expensive also.

I made a dumb uninformed statement. see below message.

LTRs are twin tube. Normally mounted cannister end up, rod down.


Bazzle

bazzle wrote:LTRs are twin tube. Normally mounted cannister end up, rod down.


Bazzle

you're right. cross section in the ARB catalogue.


I retract my earlier statement.

Damn, I missed the slam.

I was just at Auto Alliance this afternoon, and the now have a Rancho pro shock or something. $440ea for basically the same as the LTR except it also has a 9 step damper adjustment! Only come in about 850 and 950mm open measurements though.