Gimmie till tomorrow Jon and I'll hit you back
DSD RUNT?
- Thread starter slyfink
- Start date
After removing the tampon I gradually added oil and tried different pressures until I found a pressure/volume that works well. This is on my less fancy winter Sur-ron.
dual positive air chamber, now for shocks: https://www.pinkbike.com/news/first-look-the-new-chickadeehill-lfb6-shock-has-two-positive-air-chambers.html
retaliatory bad spelling rating!? cheap shot.. you have two conflicting verb tenses in an 11 word sentence... what did I spell wrong.
Swapped the 170mm piston for a 180 for the 38
Going to slap the secus in the 36 with a new foot nut and the runt is going in the 38.
Going to slap the secus in the 36 with a new foot nut and the runt is going in the 38.
only assholes use that in the first place.retaliatory bad spelling rating!? cheap shot.. you have two conflicting verb tenses in an 11 word sentence... what did I spell wrong.
Lmao that's funny, Diaz and I were joking about that..too...
The only conclusion I can see is catastrophe...lol they both attack issues from other ends which seems to nulify each other making it a weird wallow monster..
So maybe lol got nothing to lose...
At least for one ride
So bull did you do it?
We have all been eagerly awaiting results of the dsd secus test
We have all been eagerly awaiting results of the dsd secus test
Lol not yet...
Been a few years.
Winter suspension project time, so why not a Deep Dive on the RUNT?
I feel these 3rd air chamber setups offer a bunch of air spring adjustability and I have one in every air fork, including a Boxxer.
This one is for a Lyrik/Pike and is the same length as qty5 RS volume spacers. But with the 8mm hex in the middle of the RS spacers, and a slight OD difference, this RUNT takes up the same volume as just under 6 volume spacers with the flat piston, and just over 7 with the stepped piston that is extended 10mm. This is only at sag/ride height, the piston starts moving around 1/3 of travel depending on pressure difference between high/low chamber.
(Don't mind the outer finish, at one point RS changed the ID on Lyrik stanchions so I had to turn this one down a bit so that it would fit.)
A complaint about these is the progression of the 3rd chamber (RUNT) piston. It seems especially common for folks using them in shorter travel forks 150mm and under. I found this as well, so I bored a few pistons in order to play with the RUNT chamber internal volume a bit.
I didn't end up doing the smallest piston as the increase in volume was only 3%. No fancy tool paths, just a flat bottom end mill with a healthy corner radius on it. I left a 2.5mm wall, hopefully it will be strong enough (material is POM/Delrin).
The middle piston is the 10mm longer version and bored out will increase the internal volume of the RUNT by just over 8%. The tallest piston is 30mm longer and will increase the volume by 18%, but I don't think it will fit in the 150mm 2024 Lyrik I'm using. But we'll see....
If going from a fork with the factory setup of typically 1-2 volume spacers, the main chamber pressure would drop in order to achieve the same ride height/sag and the fork would get a bit more supple off of the top. Then the RUNT piston pressure can be tuned to adjust mid stroke to end stroke progression. I start with 175psi in the RUNT chamber before installation to make sure it does not effect setting the main fork pressure and sag.
The last time this was in a fork I found that if I set it up for linear support from mid stroke on (like a coil), it would get too progressive at end stroke. I had to compromise and lower the RUNT chamber pressure.
The goal is to have a higher RUNT chamber pressure with less progression than before. Cut weight from 12g to 7g as well!
Now just waiting for that $299 blow out Lyrik to show up.
Winter suspension project time, so why not a Deep Dive on the RUNT?
I feel these 3rd air chamber setups offer a bunch of air spring adjustability and I have one in every air fork, including a Boxxer.
This one is for a Lyrik/Pike and is the same length as qty5 RS volume spacers. But with the 8mm hex in the middle of the RS spacers, and a slight OD difference, this RUNT takes up the same volume as just under 6 volume spacers with the flat piston, and just over 7 with the stepped piston that is extended 10mm. This is only at sag/ride height, the piston starts moving around 1/3 of travel depending on pressure difference between high/low chamber.
(Don't mind the outer finish, at one point RS changed the ID on Lyrik stanchions so I had to turn this one down a bit so that it would fit.)
A complaint about these is the progression of the 3rd chamber (RUNT) piston. It seems especially common for folks using them in shorter travel forks 150mm and under. I found this as well, so I bored a few pistons in order to play with the RUNT chamber internal volume a bit.
I didn't end up doing the smallest piston as the increase in volume was only 3%. No fancy tool paths, just a flat bottom end mill with a healthy corner radius on it. I left a 2.5mm wall, hopefully it will be strong enough (material is POM/Delrin).
The middle piston is the 10mm longer version and bored out will increase the internal volume of the RUNT by just over 8%. The tallest piston is 30mm longer and will increase the volume by 18%, but I don't think it will fit in the 150mm 2024 Lyrik I'm using. But we'll see....
If going from a fork with the factory setup of typically 1-2 volume spacers, the main chamber pressure would drop in order to achieve the same ride height/sag and the fork would get a bit more supple off of the top. Then the RUNT piston pressure can be tuned to adjust mid stroke to end stroke progression. I start with 175psi in the RUNT chamber before installation to make sure it does not effect setting the main fork pressure and sag.
The last time this was in a fork I found that if I set it up for linear support from mid stroke on (like a coil), it would get too progressive at end stroke. I had to compromise and lower the RUNT chamber pressure.
The goal is to have a higher RUNT chamber pressure with less progression than before. Cut weight from 12g to 7g as well!
Now just waiting for that $299 blow out Lyrik to show up.
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Solid.
Will be playing with mine again soon.
Will be playing with mine again soon.
Still think these are one of the best upgrades to a fork...
Predictable and consistent.
Predictable and consistent.
@Redwood Mulch Chucker yeah those fox forks were dirt cheap...almost grabbed a few to strip and sell dampers and CSU as upgrades
Had a Runt in my trailbikes 150mm Avy Lyrik. The end stroke progression and subsequent rebound kick was horrid. Now snashpoted and much much happier. Anybody interested in the Runt inhabiting my parts bin?
(I will preface by saying 170 is as least travel I've used one in, so I can't comment on 150 and progression)
Coil will almost always rule the roost for sure ..I didn't notice a lot of end stroke kick in the 38. I Ran it softer and used the dampers to control stroke. Upped a couple clicks on HSR and it seemed to level well .
If I ran it higher psi I would notice it got aggressive near last 1/4 , wrists would feel it . But was able to control a lot with high pressure on runt.
Was also easier to balance with coil rear shock and runt...
I'm Ohlins on all 3 bikes and not going coil on them. I found my spot that works well on the bikes .small variance but balanced with rear...
I love coil forks that said... Always consistent top to bottom.
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The '24 Lyrik showed up, looks like RS increased the stanchion wall thickness yet again.
Now the stanchion ID is 29.9mm or so.
Little RUNT body goes back on the lathe to remove a bit more material.
Now the stanchion ID is 29.9mm or so.
Little RUNT body goes back on the lathe to remove a bit more material.
You've been dubb'edThe '24 Lyrik showed up, looks like RS increased the stanchion wall thickness yet again.
Now the stanchion ID is 29.9mm or so.
Little RUNT body goes back on the lathe to remove a bit more material.
Aluminum Mulch Chuker.
How much did you skim off the wall thickness of that there pressure vessel?
About .25mm this time, still plenty left.