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Discussion Starter · #1 ·
Hey guys.

Just got a irt for my dorado, what a difference! Use to run about 70 psi now i am running 52 main 87 irt which seems plush and supportive, but always after more.

Lots of info on mezzer and mattoc, but can't find a lot on what dorado people like.


Fresh service, burnish, full mrd kit, maxima plush and motorgliss.

About 185 geared up, i want that baja truck plush, but stay up nice and high in the steeps.

Recently went to 52 89irt, stayed up a lot better but starting to feel a bit harsh mid stroke, don't know yet what the sweet spot is for ratio between the 2 chambers...

Any help would be appreciated, kinda a coil guy, so maybe i am after a plushness you can't get with air.
 

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Happy to help, I've math modelled out the Chambers.

What coil rate are you looking for or how much do you weigh?
 

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I haven't seen those ones, so no idea =)

For 43lb/" try 90/150psi.

I'd recommend that when you connect the pump allow it to sit in to travel about 10mm before you disconnect the pump.

This slightly overpressurises the negative chamber and makes it more plush.

1946748
 

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Just saw you ran 52/89!

Checking on my phone so easy to miss stuff.

Off stock settings, that equivalent of mid/soft for a 110lb rider.....
 

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Discussion Starter · #6 ·
I haven't seen those ones, so no idea =)

For 43lb/" try 90/150psi.

I'd recommend that when you connect the pump allow it to sit in to travel about 10mm before you disconnect the pump.

This slightly overpressurises the negative chamber and makes it more plush.

View attachment 1946748
I have deff done the pump trick to make a bigger negative....

I feel like those pressures would be incredibly stiff though.

I really feel i am in the ball park just the balancing between the two to get what i am after
 

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Well you like it extremely soft, what sag does that give you?

For you weight stock settings are.
85/105 soft
82/122 normal
90/150 firm.

So you're right that my settings would be firm =)

Your pressure vs 43lb/"
1946819


Those pressures come out at about 25ln/"

1946820


You either like your pressures really soft or your guage is way off...

Either way your ratios seem pretty good. About 50% extra in irt is a good start.
 

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So my calculations had both static and dynamic. Dynamic is when the air heats from fast compression so it pushes the rates higher. Reality is in between the two calculations depending on how fast it compresses and how much heat it loses.

I've got 70/110psi mapped out. Static it does bottom out around 25lb/in in the mid-stroke (90mm compression). It is firmer at the start and end. Starts at 40lb/in and finishes around 60lb/in.
Dynamic those same pressures come out a hair above 40lb/in.

The last time I rode an 36mm IRT Dorado I was using 60/120psi. I'm low 70kg range and this was too progressive for me. 70/110 looks like a better fit.
My current Dorado is a 2022 Expert model without IRT.
 

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I originally mapped out isothermal, adiabatic and a 'hybrid' based on motorcross.

Judging based on feel the static felt pretty close, Wheras the hybrid and dynamic were way off.

Vorsprung allegedly has a clever hybrid model based on actual bike data. Presumably you could do that easily on your fancy dyno Dougal?
 

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I originally mapped out isothermal, adiabatic and a 'hybrid' based on motorcross.

Judging based on feel the static felt pretty close, Wheras the hybrid and dynamic were way off.

Vorsprung allegedly has a clever hybrid model based on actual bike data. Presumably you could do that easily on your fancy dyno Dougal?
My spring tester is slow and does isothermal well. I haven't tried to run an air spring on my dyno yet. I do have a Deluxe rear shock setup as a dummy (destroyed damper) that could do that.
 

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Discussion Starter · #12 ·
Hmmm this is all very interesting, previous dh fork was a Manitou Travis that i had shim stack dialed to perfection! I rrode it with a firm Travis spring that i don't remember the rate... Felt great, and tuned it was very plush, stayed up in the travel and rarely a harsh bottom out... But i know firm was too soft for most people.

I think my riding style is extremely light, prob from to many years rocking a hardtail i really absorb the trail with my body..

My pump is a brand new cane creek digital, not sure but assume should be some what accurate.

Running 54/87 is the only way i can get full travel, even off about 6 foot drops with no bottom out feel just see the travel o ring at the bottom..


Does elevation change air pressure in relation to stiffness?
 

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So no noticeable effects at those speeds.

How fast does the dyno go?
Hopefully the dyno doesn't move at all. I would hate to see someone try to catch one moving at 800mm/second.
 
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So no noticeable effects at those speeds.

How fast does the dyno go?
That's noticable change, but not huge. I need to run it faster.
Max speed is tied to stroke. I can go 50mm stroke on that shock which will limit me to a bit over 1m/s.

I can go 3m/s on a 150mm stroke. I haven't needed to do that yet.

Hopefully the dyno doesn't move at all. I would hate to see someone try to catch one moving at 800mm/second.
It hops around a lot at 2m/s!
 

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Discussion Starter · #17 ·
Well just got back from a bike trip, almost 70 000 feet of descending in 5 days.... Spent quite a bit of time playing with the fork...

I ended up really likely 57 main, 80irt, no detectable bottom outs, stays up high in the travel and pretty active over the small bumps..

I feel the fork has to much hsc for me, ended up with one or two clicks at most depending on trail... About 7 clicks lsc.

Not sure if it's worth playing with the compression shims?

One thing i noticed was on day 4 the damper side really built up a lot of pressure when checking the trail side relief... Usually every 2 or 3 runs it would feel stiff till i bleed it..

Any idea why? Oil breaking down?
 

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One thing i noticed was on day 4 the damper side really built up a lot of pressure when checking the trail side relief... Usually every 2 or 3 runs it would feel stiff till i bleed it..

Any idea why? Oil breaking down?
Yeah those open bath dampers gas out when the oil gets worked. Before the TSR caps were available that would blow your seals.
 
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