'02 R6 and gold valves

Oh. I misunderstood. I thought you meant the Ohlins valve body had some inherent engineering advantage.

OK. I think that's a given. It would be silly to expect an Ohlins stack to perform properly on an RT valve or an RT stack on a stock valve.

Is that right? Then how am I able to restrict the flow by reducing the discharge orifice with a valve? A smaller or larger bore hose is just a "thick" orifice (non-adjustable valve) with differing values for frictional losses. Isn't it?

In the same line of thought. What if I think of the adjustable damping bypass as a hose. If I reduce the size of that "hose" by screwing in the adjuster needle will I still get the same flow if the pressure behind the orifice remains the same (same damper rod velocity/displacement)?

 

I think it does if you are looking for a certain type of damping.


I am not sure I follow you on the other part. You seem to be talking about the bleed circuit and not the pistons. In that case yes you are correct.

The amount of oil that is dislaced in the cartridge when the fork compresses will be the same (relativley) whether you have RT or Olins pistons. The oil moving through the pistons however will move at different velocities depending on how the pistons are made. The shims only take that oil and deflect it to alter the rate at which the fork moves.

 

Change "deflect" to "alter the orifice size/flow rate of the valve" and I think we're on the same page

 

But you are not changing the orifice size or flow rate. The size of the holes and how much oil the piston flow will remain constant. The altering of the flow happens after the oil passes through the piston.


BTW stop making me think......you are hurting my head.

 

I think I am changing the orifice size. The valve body and shim stack function together as a....valve! The shims act to control the flow rate (alter the effective orifice size) depending upon velocity of the piston through the fluid (or the fluid throught the valve).

Going back to your original point, however: It occurs to me that Ohlins may have a somewhat different philosophy than RT regarding valve design which is easily summed up.

RT prefers the shim stack restriction to account for most of the damping. Ohlins may craft their valve bodies such that the fixed orifice (the valve body) accounts for a larger percentage of damping at higher velocities. In essence, a particular design may rely more on traditional V2 orifice damping at the high end of the velocity curve. This might be used to good effect for specific applications. The RT approach does, however, offer greater versatility, specifically the ability to tune the "same" valve for a greater range of conditions by altering the shim stack.

That's my theory but I'm willing to change it!

 

I can see your point and as far as controling the flow goes we may just be arguing semantics.

I do not necessarily agree that RT offers greater versitility though. I think that each piston allows you to control different damping better. I think that the Ohlins valve lets you tune for high speed damping better and RT does the same for low speed.

 

That would imply larger orifices in the Ohlin's piston preventing V2 from becoming the primary damping effect, thereby allowing you to tune with the valve stack. Is that the case?

 

Actually the holes in the Ohins pistons are much smaller.

 

OK. So my revised theory is: The Ohlins piston is designed more specifically for the application, relieving the shims from responsibility for as much of the high speed damping thereby making tuning the shim stack less critical and therefore "easier".

Interestingly it does bring up the specter of V2!:wow:

 

Why do you say that?

 

quote:
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Originally posted by Strick
I think that each piston allows you to control different damping better. I think that the Ohlins valve lets you tune for high speed damping better and RT does the same for low speed.
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'Cause, I would think that the larger ports would cope with higher shaft speeds better.










Don't make me post a "rolling eyes" smilie to get you to answer...

 

Look I am not smart enough to outline any type of technical reason.

I am basing this on what I have seen and felt. I personally think that the Ohlins pistons control the quicker fork movement in high speed damping by controlling the velocity better. The RT pistons seem to just let a flodd of fluid to pass on high speed movement which makes it harder to control with the shim stack.

 

LOL, good enough reason for me. Thanks.

 

It sounds like the valve may have used a partially preloaded shim stack. The fix might have been to eliminate the preload and substitute a stiffer high speed stack.

 

I agree. I am not saying that you can not tune a RT fork to get better high speed damping, just that I think it's design lends itself better to low speed.