[jsma09]

It's impossible to generate no damping from mid-valve

Should most of the damping be generated from the base-valve?

 

[reo-fahrer]

What's the benefit of keeping the mid valve damping low instead of balancing it with the base valve?

in my experience, it's difficult to balance midvalve damping between "has a reasonable amount of lowspeed damping" and "doesn't spike on highspeed", so the easiest approach is to simply design the midvalve as a check valve with minimal amount of damping forces. Besides that, external adjusting midvalves could be difficult, especially with LSR and HSR adjusters already sticking out of the lowers.

 

[Dano91]

@reo-fahrer why doesn't this apply for shocks as well? afaik, midvalves there produce significant amount of damping force

 

[bad mechanic]

in my experience, it's difficult to balance midvalve damping between "has a reasonable amount of lowspeed damping" and "doesn't spike on highspeed", so the easiest approach is to simply design the midvalve as a check valve with minimal amount of damping forces. Besides that, external adjusting midvalves could be difficult, especially with LSR and HSR adjusters already sticking out of the lowers.

I was asking because Avalanche puts a mid valve in everything they can. However, that kind of makes sense because they have the expertise to balance it correctly, and they're custom valving it so it doesn't need any external adjustment.

 

[upsha]

I was asking because Avalanche puts a mid valve in everything they can. However, that kind of makes sense because they have the expertise to balance it correctly, and they're custom valving it so it doesn't need any external adjustment.

Custom base/mid shim stacks + new mid valve piston is the key here.

If the mid valve is “low flow”, the orifice could generate more pressure difference than the base valve shim stack at high shaft speed. The only thing a tuner can do to balance the pressure is to put a even stiffer base valve, and could be too much total damping for a given rider.

 

[CaveGiant]

Didnt say its not a good fork, but he should also mention that its part of the products he selling like any other company (or their workers) that advertising products in this forum.

Yeah you're completely right.

Dougal should put something under his posts so you know he owns Shockcraft and lists what brands he supports.

Something like this for example....

Owner of www.shockcraft.co.nz, Mech Engineer, Tuner, Manitou, Motorex, Vorsprung EPTC, SKF, Enduro

 

[Dougal]

Should most of the damping be generated from the base-valve?

Depends on a dozen factors. Midvalve has a lot of "accidental" damping that you can't control because it sees the highest oil velocity in a fork by a long shot. If that accidental damping gets higher than base-valve at high speed you've got cavitation issues.

in my experience, it's difficult to balance midvalve damping between "has a reasonable amount of lowspeed damping" and "doesn't spike on highspeed", so the easiest approach is to simply design the midvalve as a check valve with minimal amount of damping forces. Besides that, external adjusting midvalves could be difficult, especially with LSR and HSR adjusters already sticking out of the lowers.

Indeed. A midvalve that looks totally fine on a dyno at 1m/s can be a serious problem at 3-5m/s (RS Charger).
I've got a series of design rules that I apply as best I can to existing hardware to solve harshness issues.

@reo-fahrer why doesn't this apply for shocks as well? afaik, midvalves there produce significant amount of damping force

Shocks run slower, with about a magnitude more damping force, put a lot more stress on the oil and have IFP pressure to help with cavitation. The design rules and goals basically invert between fork cartridges and rear shock dampers.
Try to apply one to the other and the result will really really suck.

I was asking because Avalanche puts a mid valve in everything they can. However, that kind of makes sense because they have the expertise to balance it correctly, and they're custom valving it so it doesn't need any external adjustment.

Avalanche dampers are open bath which means the oil is mixed with air and compressible. They need the mid-valve to create fast damping response. Without it you get a big lag and hysteresis before damping forces can build due to compressibility.

The same compressibility means you can do things that would be harsh on a cartridge damper but end up cushioned by the aerated open-bath oil so aren't harsh.
Same with cavitation and oil ingestion. Cavitation is cushioned and not a big issue, oil ingestion is part of the design.

 

[bad mechanic]

Avalanche dampers are open bath which means the oil is mixed with air and compressible. They need the mid-valve to create fast damping response. Without it you get a big lag and hysteresis before damping forces can build due to compressibility.

The same compressibility means you can do things that would be harsh on a cartridge damper but end up cushioned by the aerated open-bath oil so aren't harsh.
Same with cavitation and oil ingestion. Cavitation is cushioned and not a big issue, oil ingestion is part of the design.

Are those issues in a fork?

Is weight the only reason manufacturers don't use open bath dampers?

 

[Dougal]

Are those issues in a firm?

Is weight the only reason manufacturers don't use open bath dampers?

Issues in a what?

Weight is a big reason more manufacturers don't use it. Damping is a lot more consistent in a closed cartridge too.

Comparing a Dorado Expert and Dorado Pro damper on the dyno the Pro is firmer and dead consistent. They're the same damper except open bath vs IFP.

 

[bad mechanic]

Issues in a what?

Weight is a big reason more manufacturers don't use it. Damping is a lot more consistent in a closed cartridge too.

Comparing a Dorado Expert and Dorado Pro damper on the dyno the Pro is firmer and dead consistent. They're the same damper except open bath vs IFP.

Fork, not firm. Autocorrect got me.

 

[fatesjester]

@Dougal where did you learn all this? I see you're an engineer by trade/training, did you just nerd out on suspension early on and then follow through with the business or something else?

Always super impressed with your knowledge and sent plenty of customers your way back when I was in NZ.

 

[CaveGiant]

Fork, not firm. Autocorrect got me.

Weirdly I read it as fork... auto-correct-correct got me.

 

[jsma09]

Comparing a Dorado Expert and Dorado Pro damper on the dyno the Pro is firmer and dead consistent. They're the same damper except open bath vs IFP.

I’ve seen you describing the difference between these two as plush vs crispier. Isn’t the “plushest” of the two (open bath or in-leg open bath) probably more appropriate for the average Joe looking for a supportive yet comfortable setup?

 

[Dougal]

@Dougal where did you learn all this? I see you're an engineer by trade/training, did you just nerd out on suspension early on and then follow through with the business or something else?

Always super impressed with your knowledge and sent plenty of customers your way back when I was in NZ.

It's been an all consuming hobby for about 30 years now. I go a lot deeper into what makes things tick than most. I realised that in engineering school where others were just there to pass exams and I was there to mine everything I could.

I’ve seen you describing the difference between these two as plush vs crispier. Isn’t the “plushest” of the two (open bath or in-leg open bath) probably more appropriate for the average Joe looking for a supportive yet comfortable setup?

I don't use the word "plush". It might have been "softer". Crisp and comfortable aren't exclusive things.

 

[bad mechanic]

Weirdly I read it as fork... auto-correct-correct got me.

When you love bikes, everything looks like a fork.

 

[jsma09]

Crisp and comfortable aren't exclusive things.

But kinda go in opposite directions?

Anyways, just wondering from what you said if the open bath might be more comfortable overall.

 

[Dougal]

But kinda go in opposite directions?
Anyways, just wondering from what you said if the open bath might be more comfortable overall.

Crisp and harsh should not be confused. Crisp means everything happens when it should.

Crisp vs laggy damper performance isn't related to comfort. Comfort is determined by spring/damper rates and damper design.

A crisp comfortable damper is no problem at all. Neither is a laggy harsh damper.

 

[x-rated]

What Happens If you Push Rebound shaft below the Mark? There is a Mark about 3cm on the bottom. Rock shox Just writes, do Not go below that. I think i did and IT doesnt Stop to dump lol from the purge hole

 

[johnsogr]

I wasn't sure where to post this, but I suppose this thread is as good as any. I recently received a Dougal/Shockcraft tuned Charger 2.1 for my Zeb, mated to a Debonair+ spring w/ Vorsprung Secus. The fork was a Select model, so it came with the Charger RC, which is just awful. For comparison's sake, my other forks include a Yari w/ Avy Hybrid coil & Intend Edge w/ Avy cart.

I only have a couple of rides on the fork, but holy ****, it’s so much better. He shipped it with LSC essentially closed, and HSC open, and the only knob I’ve touched is rebound which I opened up just one click. I believe Dougal describes his tuning as “crisp” and I couldn’t agree more. It’s very supportive of jumps and absolutely stays high in the travel. There is no harshness as it comes alive in high speed rocky tech.

Compared to the Avy forks, I’d say his Charger 2.1, is, in his words, just more crisp. Avy, with the dials where I want them, is a bit more fluid & plush. I love them both and would highly recommend his tuned Charger 2.1 to any current Zeb owners.

Additional notes: 170 lbs, large Transition Sentinel

 

[x-rated]

why they went back to use suspension oil in the lowers? Is it because the seal head is like Fox much more open and too much oil from casting goes into the damper unit?
Also the amount of oil increased significant to 30ml.
And then why they changed it on air side also?