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Storia dyno plot

Flo33

Turbo Monkey
Mar 3, 2015
2,135
1,364
Styria
When buying a Storia the customer receives a sheet with a checklist of stuff done with the shock, QC stuff and all. Last week I had the idea of asking the marvellous EXT comp if they would be willing to share the dyno plot listed on said sheet of my custom built Storia shock I bought with my Titan last year. Turns out they were. Now I got the plot but am not really understanding all of it.
It's a Velocity-Force diagram picturing runs with two different settings. The blue one with 14 out of 14 clicks of HSC, 12 out of 12 clicks of LSC and 7 out of 8 clicks of LSR, the brown one with 10 clicks of HSC, 0 clicks of LSC and 0 clicks of LSR. This means one run nearly fully open and one with a bit of HSC and fully closed LSC and LSR.

image.png


Comp is in the top left quadrant, rebound in the bottom right. Here's my interpretation. The different LSC settings are visible at the low speeds from 0 to about 25 mm/s resulting in different gradients. The change to HSC can be seen in the different force values at which the first kink appears and the damping force curve digresses meaning the shims start to lift. What I don't understand is the second kink appearing at around 250 mm/s and the different gradient in that mid speed range between 25 and 250 mm/s. At higher speeds both lines are parallel again. I always thought that the preload of the base valve shim stack only affects the threshold force or needed pressure to get the shims to lift. When I come to think about it, there may be a crossover stack or something. But then again it wouldn't explain the different gradient. Or would it? :blink:

I asked EXT about it but I guess the language barriers netted in a not very satisfying answer.

So, anybody got some ideas? Calling out on all the usual suspects but not exclusively @Kanye West @englertracing @tacubaya @buckoW @Udi maybe even @Steve M rises from the ashes.
 

Jm_

sled dog's bollocks
Jan 14, 2002
20,065
10,628
AK
Well, I definitely felt a hard "kink" for any sharp-edged/HS impact.
 

Kanye West

220# bag of hacktastic
Aug 31, 2006
3,767
501
First, that is a very smoothed/normalized data set. Not necessarily a bad thing for distribution purposes.

Knee(s) in a curve means that the valve has just opened up or it's a transition from one circuit to the next basically. Rebound is more simple, so it would go needle flow, shim cracking open, then shims wide open and letting that port breathe more fully. Unless they have rebound metering back through the compression adjusters (not super likely), you're looking at a force representation of the mechanisms on the main piston only, which are the ones just described.

Compression side has a bit more going on with two sets of valves opposing each other in the main chamber, but same thing applies.

.5m/s isn't real fast. I expect there's more going on further up the curve. But it demonstrates that the adjusters function competently, which is more than most major brands can show.
 

Flo33

Turbo Monkey
Mar 3, 2015
2,135
1,364
Styria
Thanks for your reply and explanation @Kanye West . So basically there are just a few data points resulting in that specific curve. Side or back bleed is very unlikely, EXT uses balls as check valves in the main piston and in the base valve for that matter. Would surprise me if they make such an effort on the comp side and then ignore it for the other way.

Fully agree with you with the level of information you can get especially compared to other players in the market. And as you said, the adjusters definitely work.
 

Jm_

sled dog's bollocks
Jan 14, 2002
20,065
10,628
AK
Thanks for your reply and explanation @Kanye West . So basically there are just a few data points resulting in that specific curve. Side or back bleed is very unlikely, EXT uses balls as check valves in the main piston and in the base valve for that matter. Would surprise me if they make such an effort on the comp side and then ignore it for the other way.

Fully agree with you with the level of information you can get especially compared to other players in the market. And as you said, the adjusters definitely work.
You can have your balls removed. EXT offers that.
 

madpharma

Chimp
Oct 16, 2018
55
33
I bought an Arma v3 for my dh bike last month and im really impresed with the performance. Coming from a dhx2 2021 and a Öhlins in the previous bike, I feel that honestly is the best shock I ever had.

It came with two dyno plots too, pre and post tuning it for my bike and weight. Ill try to take a photo and upload it to show you.
 

Carraig042

me 1st
Apr 5, 2011
766
373
East Tennessee
I find all this interesting, my storia didn't have the graphs with it. Is that new? They did have great customer service though when they exchanged one of the two springs.
 

madpharma

Chimp
Oct 16, 2018
55
33
Yes I bought it new, spoke to the distribuitor filled their sheet and in a Week I had it im my bike. Top customer service.
A friend bought one v3 last year and broke ir in the eyelet, In 3 days had another one brand new posted under warranty.
 

Jm_

sled dog's bollocks
Jan 14, 2002
20,065
10,628
AK
Yes I bought it new, spoke to the distribuitor filled their sheet and in a Week I had it im my bike. Top customer service.
A friend bought one v3 last year and broke ir in the eyelet, In 3 days had another one brand new posted under warranty.
Who did you buy from?
 

Flo33

Turbo Monkey
Mar 3, 2015
2,135
1,364
Styria
I find all this interesting, my storia didn't have the graphs with it. Is that new?
I received mine after writing and asking about it. madpharma had his reshimmed, I guess that's why he received the plots as sort of documentation/proof of work when his shock was returned.
 

Jm_

sled dog's bollocks
Jan 14, 2002
20,065
10,628
AK
I bought it from the Spanish distributor.

My friend who bought it last year, got sent the graphs too, but I guess its like a proof of work from the reshimming to the weight and bike.
The reason I ask is buying from the US distributor and getting it tuned didn't work well for me, but the difference could be the distributor.