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Pros 'n' cons for Foes 2:1 suspension system

PB Forum :: Freeride & Slopestyle
Pros 'n' cons for Foes 2:1 suspension system
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flag Muttley
Posted: Jun 9, 2009 at 14:17 Quote
FOx went out their way and failed.


i kept my boxxer damn well oiled and greased, every month.

same with my 40, every 3-4 weeks, strip down, clean, lube.

Boxxer Obliterates it in tems of beginning stroke suppleness, the 40's a great fork, no denying, but the boxxer is a smoother unit.


Why do you think proprain have designed their Rage DH with a very high begging stroke ratio falling to a very low one?
flag sherbet
Posted: Jun 9, 2009 at 14:19 Quote
So the suspension ramps up? It's not uncommon. Makes it sensitive, yet firm when need to be. (Lol don't say it)

That being said, it's SPV that's behind the lack of sensitivity. Same issue fell on the dorado line,
flag Muttley
Posted: Jun 9, 2009 at 14:19 Quote
NObodys going to win here, lets leave it.
flag t3aSeR
Posted: Jun 9, 2009 at 14:24 Quote
Agreed, and if someone could answer me:

t3aSeR wrote:
z-man wrote:
yroger wrote:
I ride a foes dhs mono 2:1 and thust me you will never go back to other bike this is it the suspension is amazing 1/8 of a turn and you see the change
cruncutt shocks are second to none. it's MX technology, simply more advanced.
Just for interests sake, do Curnutt shocks (coil) have an internal bladder as none of the coil shocks have reservoirs?
flag nlitworld
Posted: Jun 9, 2009 at 15:43 Quote
t3aSeR wrote:
Agreed, and if someone could answer me:

t3aSeR wrote:
z-man wrote:

cruncutt shocks are second to none. it's MX technology, simply more advanced.
Just for interests sake, do Curnutt shocks (coil) have an internal bladder as none of the coil shocks have reservoirs?

Curnutt shocks don't use external reservoirs on their coil shocks because they have a huge amount of oil internally. It isn't necessarily an internal bladder, just a huge open volume of oil. It also makes a difference because on long runs where shocks would tend to heat up and lose dampening, theirs don't as easily.

Also as a side note, after having ridden on the Curnutt coil shocks (05 Fly), the Curnutt Air (08 Fly) and the Curnutt Air w/ reservoir (RS7), I really see no need to go back to coil even with no significant weight between the Air w/ reservoir and Ti Coil. Even the difference between my Fly w/o the external reservoir and my dad's RS7 with the reservoir is extremely noticeable. Kinda jealous actually. Small bump performance is significantly increased and the adjustability from very linear shock rate to very progressive shock makes fine tuning easy for every course.
flag t3aSeR
Posted: Jun 10, 2009 at 1:22 Quote
nlitworld wrote:
t3aSeR wrote:
Agreed, and if someone could answer me:

t3aSeR wrote:

Just for interests sake, do Curnutt shocks (coil) have an internal bladder as none of the coil shocks have reservoirs?

Curnutt shocks don't use external reservoirs on their coil shocks because they have a huge amount of oil internally. It isn't necessarily an internal bladder, just a huge open volume of oil. It also makes a difference because on long runs where shocks would tend to heat up and lose dampening, theirs don't as easily.

Also as a side note, after having ridden on the Curnutt coil shocks (05 Fly), the Curnutt Air (08 Fly) and the Curnutt Air w/ reservoir (RS7), I really see no need to go back to coil even with no significant weight between the Air w/ reservoir and Ti Coil. Even the difference between my Fly w/o the external reservoir and my dad's RS7 with the reservoir is extremely noticeable. Kinda jealous actually. Small bump performance is significantly increased and the adjustability from very linear shock rate to very progressive shock makes fine tuning easy for every course.
The shock should have some sort of reservoir or bladder, otherwise it will have a hydraulic lock. The amount of oil there is in the shock wouldn't matter, but oil needs to go somewhere when the shock is being compressed. Or am I missing something...
flag scrippsranchDJ
Posted: Jun 10, 2009 at 2:12 Quote
t3aSeR wrote:
The shock should have some sort of reservoir or bladder, otherwise it will have a hydraulic lock. The amount of oil there is in the shock wouldn't matter, but oil needs to go somewhere when the shock is being compressed. Or am I missing something...

Yeah you are missing something. The spring is on the outside, so the oil isn't being pressurized when the shock compresses(the oil is not being used as a spring). Inside the shock, at the end of the shock rod there is a plunger that has holes in it, based on how many holes are open and how big they are is how you can change your compression/rebound speed. The larger the oil capacity, the less likely the shock will become heated and lose damping performance. This also helps the shock performance stay consistent.
flag t3aSeR
Posted: Jun 10, 2009 at 2:56 Quote
scrippsranchDJ wrote:
t3aSeR wrote:
The shock should have some sort of reservoir or bladder, otherwise it will have a hydraulic lock. The amount of oil there is in the shock wouldn't matter, but oil needs to go somewhere when the shock is being compressed. Or am I missing something...

Yeah you are missing something. The spring is on the outside, so the oil isn't being pressurized when the shock compresses(the oil is not being used as a spring). Inside the shock, at the end of the shock rod there is a plunger that has holes in it, based on how many holes are open and how big they are is how you can change your compression/rebound speed. The larger the oil capacity, the less likely the shock will become heated and lose damping performance. This also helps the shock performance stay consistent.
What about shaft displacement?
flag yroger
Posted: Jun 10, 2009 at 4:40 Quote
photo

3487032

here a picture of the curnutt
flag t3aSeR
Posted: Jun 10, 2009 at 7:41 Quote
yroger wrote:
photo

3487032

here a picture of the curnutt
Exactly, now where does the oil go displaced by the shaft? Do they work like the Romics and the older vanillas with an internal floating piston or a bladder of some kind?
flag yroger
Posted: Jun 10, 2009 at 8:09 Quote
I think Its a internal floating piston
flag Royston
FL
Posted: Jun 10, 2009 at 8:37 Quote
Muttley wrote:
No, the reason their shocks are terrible on small bumps is that due to the leverage being so low, the force initially moving the shaft is smaller, which means stiction in the seals is amplified, resulting in the bike taking alot more force to literally work.
You are describing high ratio designs. With lower ratio, seal stiction has less effect and bump sensitivity improves. This is in theory, as in reality other factors will play a part also.
flag t3aSeR
Posted: Jun 10, 2009 at 9:50 Quote
yroger wrote:
I think Its a internal floating piston
Thank you, some sort of an answer!
flag Unhallowed
Posted: Jun 10, 2009 at 10:17 Quote
yroger wrote:
I think Its a internal floating piston
Some of them have an external mounted on the swingarm. But my guess would be that one is internal.
flag Muttley
Posted: Jun 10, 2009 at 10:40 Quote
Royston wrote:
Muttley wrote:
No, the reason their shocks are terrible on small bumps is that due to the leverage being so low, the force initially moving the shaft is smaller, which means stiction in the seals is amplified, resulting in the bike taking alot more force to literally work.
You are describing high ratio designs. With lower ratio, seal stiction has less effect and bump sensitivity improves. This is in theory, as in reality other factors will play a part also.

how could stiction reduce if less force is applied.

 


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