Powered by Outside

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

PB Forum :: Freeride & Slopestyle
Pros 'n' cons for Foes 2:1 suspension system
Author Message
flag yroger
Posted: Jun 10, 2009 at 10:52 Quote
Unhallowed wrote:
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.
no those are air curnutt
flag Royston
FL
Posted: Jun 10, 2009 at 10:53 Quote
I take back what I said about the stiction reducing.
flag Unhallowed
Posted: Jun 10, 2009 at 10:53 Quote
yroger wrote:
Unhallowed wrote:
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.
no those are air curnutt
I've seen coil with external, as well as air.
flag t3aSeR
Posted: Jun 10, 2009 at 12:42 Quote
Muttley wrote:
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.
Because you get two kind of friction: your static friction coefficient and your kinetic friction coefficient, with the KFC SFC. Meaning that the faster the shaft speed, the less friction. It's basic physics.
flag Muttley
Posted: Jun 10, 2009 at 12:43 Quote
Great, im talking about initial stiction. e.g, the one that causes a harsher ride on small bumps.
flag z-man
FL
Posted: Jun 10, 2009 at 12:44 Quote
Unhallowed wrote:
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.
this is wrong, no curncut has an external reservoir. they have valving that honda developed for its MX bikes it there that is far, far more sdvanced then anything. (my old head mechanic was one of the lead engineers for foes a while back) he knew everything about them.
flag Muttley
Posted: Jun 10, 2009 at 12:45 Quote
No.....several of the Curnutt airs have external Res's
flag ctd07
Posted: Jun 10, 2009 at 12:46 Quote
CBA to read back, but if this is a discussion over Curnutt shock s having more stiction.... they will have less than a conventional shock:

1. they use better quality seals intended for dynamic applications, not cheapo static seals - so they'll have less friction & stiction.

2. as the shocks have a larger stroke [low leverage ratio], the internals are under much less pressure, so the sealing doesn't need to be so crazy tight, again meaning less stiction & friction.

To Muttley: Stiction and Friction are proportional to each other, where stiction is high, so will friction be! If curnutt shocks have lower friction, they will also have lower stiction.
flag z-man
FL
Posted: Jun 10, 2009 at 12:47 Quote
Muttley wrote:
No.....several of the Curnutt airs have external Res's
only the air shocks, im talking the XTD
flag t3aSeR
Posted: Jun 10, 2009 at 12:48 Quote
From previous post: "with the KFC smaller than the SFC". Sorry the 'smaller than' symbol didn't work.
And the initial breaking of stiction will be when you climb on the bike. After that the shock will continue moving(i.o.w the KFC will be used as stiction). Don't tell me that a shock will be static at any point on a dh track (except in the air of course).
flag t3aSeR
Posted: Jun 10, 2009 at 12:49 Quote
ctd07 wrote:
CBA to read back, but if this is a discussion over Curnutt shock s having more stiction.... they will have less than a conventional shock:

1. they use better quality seals intended for dynamic applications, not cheapo static seals - so they'll have less friction & stiction.

2. as the shocks have a larger stroke [low leverage ratio], the internals are under much less pressure, so the sealing doesn't need to be so crazy tight, again meaning less stiction & friction.

Stiction and Friction are proportional to each other, where stiction is high, so will friction be!
Exactly, and your kinetic friction is always less that your static friction.
flag scrippsranchDJ
Posted: Jun 11, 2009 at 2:30 Quote
t3aSeR wrote:
What about shaft displacement?

What do you mean? The shock compresses, and the piston at the end of the shock rod plunges through the shock oil.

The piston has holes with adjustable size or adjustable number of holes, so you can change rebound/compression speeds. The resistance of oil movement is how you create damping for your bike.(common knowledge, just putting it out there)
flag t3aSeR
Posted: Jun 11, 2009 at 5:30 Quote
scrippsranchDJ wrote:
t3aSeR wrote:
What about shaft displacement?

What do you mean? The shock compresses, and the piston at the end of the shock rod plunges through the shock oil.

The piston has holes with adjustable size or adjustable number of holes, so you can change rebound/compression speeds. The resistance of oil movement is how you create damping for your bike.(common knowledge, just putting it out there)
When the shock compresses the shaft that moves into the shock displaces a certain amount of oil. Thats why you get reservoirs and internal bladders or pistons. Thats what I want to know, how does the shock compensate for this displaced oil. And I think I've already got an answer, apparantly it's got a internal piston. I'm not asking anything about the adjustments and valving and shit.
flag almightybenners
FL
Posted: Jun 11, 2009 at 7:00 Quote
one main disadvantage of the curnett shocks is how good they... are if that makes sense?
they perform so well most forks can't keep up with them and they're bikes feel wierd becasue of this (i say bikes ive only ridden an XCT5) but it had van 36's on it and they were completey outpaced by the AIR shock on the rear. they only fork that can match their shocks is there own which is like a 250mm travel fork that only comes on one of their bikes.
so basically in conclusion the 2:1 shocks are amazing but there too good atm so just get an rp23 or monarch until they bring out a shorter travel fork.
flag geo100
Posted: Jun 11, 2009 at 8:49 Quote
This may help some of you to see what a Curnutt Air looks like inside, (1.45 min into video). freecaster.tv/1000006/1005798I have been riding Foes/Curnutt for over 4 yrs. I will tell more later
photo

3340197

photo

2821072

 


Copyright © 2000 - 2024. Pinkbike.com. All rights reserved.
dv56 0.169164
Mobile Version of Website