midstroke support...explain

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driftking

Wheel size expert
can someone explain to me midstroke support and its relation to HSC and LSC. I know what it is but how does it relate to the other adjustments. From what I have gathered from my RC4 midstroke is sort of support essential while HSC is more initial compliance not really a support adjustment.

Right now my boxxer R2C2 feels nice but while it uses appropriate travel in rock gardens as soon as I launch off into a rock gardens it likes to blow through its travel. HSC is fine as it uses the right amount when not launching. My LSC is also nice but due to the fork wallowing a fair bit in bigger holes I run it fairly stiff which takes away a little traction on the smaller stuff like corners. I can only think that I need some midstroke to help support the lsc and hsc. Is this a correct assumption?
Do I achieve this with shim stacks or am i looking at a custom damper

Settings
spring :yellow soft (63-72kg) the recommended was undersprung
LSC +10
HSC +8
ESR 14 from full slow (ESR 7 from fast)
BSR 17 from full slow (BSR 8 from fast)

Ideally id like to run slightly less LSC to get more traction early on but have more support midstroke so it doesn't dive too much, HSC I dont want to go too high to lose that initial compliance id like a little more sport.

i haven't really tested my rebound much so maybe that might help? I cant see how though given rebound doesn't offer any opposing force or resistance to compression.
 
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jrewing

jrewing

Eats Squid
dont know much more than it provides additional compression support when fluids going back thru the rebound circuit( compression stroke. Look up rebound separator valve on racetech.com...actually just go on that site. My friend runs seminars at greendale with Paul Thede once a year. Sounds like something you'd like.
 
D

driftking

Wheel size expert
.dan. said:
Why did you buy boxxers then? I've ridden boxxers, the midstroke support was never there. Get something with a speed senstive damper, a lot more midstroke support and more consistent feel.
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originally I wanted 40's then I upgraded to the teams from races for cheap and the 40's couldn't be matched and was another $750 ($500 more than my lbs retail hence the higher exchange price) so I didn't go down that path, the forks feel great don't get me wrong but not perfect or where id like them, I tried selling them but no takers so decided to just run them. If i had the money I would buy 40's but I don't so I'm hoping there is either an adjustment I can make or looking at the cheaper alternative than new fork and get it tuned.
 
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driftking

Wheel size expert
.dan. said:
There is a few companies that make aftermarket dampers that you can easily fit to boxxers. Avalanche make a really good one: http://www.avalanchedownhillracing.com/Rock Shox/Boxxer 35mm.htm Never used one of these aftermarket dampers, but only heard good things about them.
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Yeah almost every thread about boxxers has avalanche mentioned, I do love the idea but they only over one compression adjustment. not sure how that works out but not having separate LSC and HSC concerns me when it comes to fine tuning.. I will do some more research into this and maybe throw them a email with some questions.

Anyone who can go into details about the initial question and midstroke would appreciate it still.
 
muvro

muvro

Likes Dirt
I don't know how the boxxers work, but is it possible to run a thicker fork fluid, then run less LSC and HSC.
 
udi

udi

swiss cheese
You should possibly try the next spring rate up.

Also keep in mind the compression damper in stock guise is valved very lightly. Doubling up the stock shims and converting it to a regular pyramid stack (stock on 2011+ forks is a 2-stage design, which is stupid when preloaded by the HS adjuster) will give you more external adjustment range, and essentially bring the adjusters to life.

There are guides floating around on the net if you need help, be careful as it's a little finicky, and you may need to get / make some little tools to unscrew the shimstack. It's been a while since I've worked on one.

Get the spring rate right first though if it's too soft, otherwise it'll just be a web of compensation.
 
D

driftking

Wheel size expert
udi said:
You should possibly try the next spring rate up.

Also keep in mind the compression damper in stock guise is valved very lightly. Doubling up the stock shims and converting it to a regular pyramid stack (stock on 2011+ forks is a 2-stage design, which is stupid when preloaded by the HS adjuster) will give you more external adjustment range, and essentially bring the adjusters to life.

There are guides floating around on the net if you need help, be careful as it's a little finicky, and you may need to get / make some little tools to unscrew the shimstack. It's been a while since I've worked on one.

Get the spring rate right first though if it's too soft, otherwise it'll just be a web of compensation.
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Could I really need another spring rate up though? Already using the next rate and only getting 20%sag, I do consider myself a fairly fast rider but it seems pretty excessive to be using a rate for people 72-81kg? My main concern with doing that is I will loss inital compliance.i do have the other spring though so maybe I should test it.
 
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D

driftking

Wheel size expert
creaky said:
Call Aaron at NSD, explain and he will solve.
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That's my next move, I'll send him off an email today. Does my explanation make sense in my inital post?
I want to make sure what I'm saying makes sense so he knows what I'm saying.
 
C

creaky

XMAS Plumper
driftking said:
That's my next move, I'll send him off an email today. Does my explanation make sense in my inital post?
I want to make sure what I'm saying makes sense so he knows what I'm saying.
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I'd just give him a call rather than email. That way he will be able to ask the right questions to know what you need in terms of damping mods.
 
udi

udi

swiss cheese
driftking said:
Could I really need another spring rate up though? I mean I'm 60kg already using the next rate and only getting 20%sag, I do consider myself a fairly fast rider but it seems pretty excessive to be using a rate for people 72-81kg? My main concern with doing that is I will loss inital compliance.i do have the other spring though so maybe I should test it.
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Sounds like you're okay on the spring front then, although if you're getting 20% I wouldn't have even considered the rate below that. Everything else I said will address your desire to run less LSC without losing support.

Midstroke is a blanket internet term to describe a whole host of things, but in reality, most dampers (virtually all modern fork dampers in any case) are primarily speed sensitive - thus there is no actual midstroke damping component that can be isolated. An air sprung fork like the boxxer air may wallow in the midstroke because of the air spring curve in that particular fork, but there's still no correlation to the damper.

A common setup mistake is running a lot of compression, particularly LSC, to control wallowing / dive when in actual fact the damper is valved too softly to provide adequate support. This results in higher levels of compression at low speeds than necessary - giving poor sensitivity, and often not really increasing support at all. The solution is to have a firmer stack so that the LS damping can be opened up a little (for better sensitivity, more liveliness), but once the shaft speeds cease to be super low (hitting a corner, landing, etc) the support kicks in.
 
D

driftking

Wheel size expert
udi said:
Sounds like you're okay on the spring front then, although if you're getting 20% I wouldn't have even considered the rate below that. Everything else I said will address your desire to run less LSC without losing support.

Midstroke is a blanket internet term to describe a whole host of things, but in reality, most dampers (virtually all modern fork dampers in any case) are primarily speed sensitive - thus there is no actual midstroke damping component that can be isolated. An air sprung fork like the boxxer air may wallow in the midstroke because of the air spring curve in that particular fork, but there's still no correlation to the damper.

A common setup mistake is running a lot of compression, particularly LSC, to control wallowing / dive when in actual fact the damper is valved too softly to provide adequate support. This results in higher levels of compression at low speeds than necessary - giving poor sensitivity, and often not really increasing support at all. The solution is to have a firmer stack so that the LS damping can be opened up a little (for better sensitivity, more liveliness), but once the shaft speeds cease to be super low (hitting a corner, landing, etc) the support kicks in.
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Thanks for that udi, I will look into changing my stack, hopefully it does give me the desired feeling.any reccomendations for where to start with the stack. Should I double is straight up.
 
Dymalla

Dymalla

Likes Dirt
udi is on the money, as usual.
A couple more thoughts on the subject.
You can deal with a BUMP INPUT in a number of ways using the same amount of travel

1 / soft spring, higher compression settings
2 / medium spring, medium compression settings
3 / firm spring, lighter compression settings

Given that these choices will use the same amount of travel for a given BUMP INPUT the difference is the BUMP RESPONSE TIME.
Option 3 offers the fastest response time providing the plushest ride and a higher ride hieght
To achieve this on a BOXXER

Option 1 / Spring side / throw all drop-stop stuff in the bin, fit red spring
Damper side / throw internels in the bin and fit AVALANCHE cartridge

Optio2 / Spring side / throw all drop-stop stuff in the bin, fit red spring
Damper side / MODIFY comp damper, lower comp settings, slightly higher rebound settings

MODIFY comp damper / As udi said, on early dampers the HSC adjuster preloads the face-shim on the HS stack making it useless
Remove HS adjuster and throw in the bin with drop-stop (forks are nearly 100 grams lighter now) and beef up HS stack
OR / Put a backing shim on the HS stack that the HS adjuster acts on alloeing the HS stack to transition to the adjuster preload

IF none of this works throw the whole lot in the BIN and be thankfull they won't sell you a new VIVID
 
udi

udi

swiss cheese
driftking said:
Thanks for that udi, I will look into changing my stack, hopefully it does give me the desired feeling.any reccomendations for where to start with the stack. Should I double is straight up.
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Doubling up each shim is a good start, and if the stack is not a straight pyramid (i.e. piston face > bigger shims > smaller shims), just reorganise it so it is - it'll make tuning simpler.

Basically you're just increasing the overall damping so you can use the adjusters to control where in the shaft speed range you use that damping, whereas when there isn't enough (stock), you're forced to wind the adjusters closed just to get *any* damping, and thus have little control over what shaft velocities it acts at.
 
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