What makes a twin-tube shock better than a monotube, or visa-versa?

 

The following I found posted on another site;

Twin-tube Low Pressure Gas
A shock absorber or strut can be a low pressure gas, twin tube design. This basic design has not changed too much since the 60's, but there have been some refinements over the years. This design has some characteristics, such as a soft valving, and usually costs less to manufacture than a Monotube or Adjustable type shock absorber. They are usually pressurized with some Nitrogen gas, usually 100 psi or less. In this design the hydraulic oil and gas are mixed together in the same chamber, which, while dampening, causes some aeration/foaming. Monroe Auto Equipment, Bilstein, and KYB GR2 still make units like these.

Mono-tube High Pressure Gas
A shock absorber or strut can be a high pressure, mono tube design. These are a more modern type design, and have characteristics of their own. The monotube design allows them to operate cooler. Monotubes are under high pressure, from around 200 psi, to as high as 360 psi. The hydraulic oil and Nitrogen gas are in separate chambers, separated by a floating piston. This allows the shock/strut to function without any aeration or foaming. Monotube shocks usually have a stiff valving, and traditionally cost more to manufacture. They are also able to withstand more punishment, and offer higher dampening ability. (for instance, most racing shocks, from Nascar to Formula One, are of a monotube design). Great care and engineering is taken into consideration when manufacturing a monotube, and many have a very specific valving. This is years of racing technology adapted for street and off-road use. Some of the companies that make monotube shocks are Bilstein , Edelbrock, and KYB.

 

Generally, the monotubes are better shocks...and they resist fading better by design....as they dissipate heat better.

Bilsteins for example, have digressive valving, so that they do not need knobs or dials to adjust the compression or rebound valving...as the more sophisticated set-up allows the shock to adjust itself instantly to the terrain and vehicle automatically.

For easy pace/low speed situations, a twin-tube shock, properly valved, can do a perfectly good job....when the going gets rougher, and the pace increases to where the piston motion, which is absorbed and turned into heat, eventually overwhelms twin tube shocks before a monotube would be in trouble.

When a twin tube over heats, it fades/loses the ability to damp motion.

 

They are high pressure, mono-tube design.

 

yup, what he said and they work quite well

 

i like twin tube also because you can beat them up a bit and they will still work

 

Thanks for the responses. Right now I have Pro Comp Twin-Tubes. Already, my second one has busted (I hear the clicking). I take it easy when offroading and watch myself, their shocks just aren't doing it for my JK. So I'm looking into monotube Bilstein's or twin-tube Teraflex (only have a 2" BB).

So, thanks!

 

monotubes are high pressure like everyone has said and tend to ride alot stiffer. Monotubes are lighter and really were intended for "race" applications.

IMHO a good set of Twin tubes are great for our use.

David

 

So for a weekend offroader who uses his jeep as a DD which of these would be best? Bilsteins or rancho adjustable shocks with a 4" suspension that does mostly rock crawling and rocky hillclimbs

 

My answer is always the same. OME LT for that lift.

The Twin tubes in my opinion are a better ride for our use. If I was desert racing I would get a monotube.

David