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Rebound Speed - Slow Recommendation from Push

Pslide

Turbo Monkey
Why would you not agree with this? If the tire is leaving the ground from a drop like that, you will be losing traction on trail chatter(roots, rocks, high speed repetitive hits). Definitely one of the first suggestions I ever learned on setting up a dh bike.
I don't think that a drop test correlates at all to actual performance on the trail - not in my experience at least.

You can set up a DHX to not bounce in a drop test, then stick a CCDB and it will bounce. Now go ride them on a trail. No correlation.
 

djjohnr

Turbo Monkey
Apr 21, 2002
3,017
1,719
Northern California
I don't think that a drop test correlates at all to actual performance on the trail - not in my experience at least.

You can set up a DHX to not bounce in a drop test, then stick a CCDB and it will bounce. Now go ride them on a trail. No correlation.
Agreed, it's not highly effective. If anything setting up your bike to not bounce when you drop it is more a function of very light low-speed compression. On the Vanilla RC's I had the curb test was fairly important, however the rebound adjusters on the DHX/frame combos I've owned have allowed me to run faster rebound rates without bucking on high speed events. I still do a drop test when I first set-up a new shock/frame just in case, but it hasn't proven to be an issue in a long time.

The only place that I've found to be 100% effective for setting up rebound (or compression) is the trail; ideally a section with some braking bumps, a rock garden and a drop.
 

davep

Turbo Monkey
Jan 7, 2005
3,276
0
seattle
Why would you not agree with this? If the tire is leaving the ground from a drop like that, you will be losing traction on trail chatter(roots, rocks, high speed repetitive hits). Definitely one of the first suggestions I ever learned on setting up a dh bike.
Umm NO...

When is the last time your bike went riding without you??

The mass, and thus reaction of the entire damped oscillating system has changed. How the system reacts with a mass of 40lbs for example has just about nothing to do with how that same system will react with 200lbs (not to mention that the additional weight is in itself independantly oscillating and damped from the original system (bike).

In mathematical terms, the differential equation that describes a damped harmonic system contains a term (omega) that is dependent on the mass of the system. If you change the mass of the system, you change the solution to the equation (not to mention the stacking or two semi-independant systems like a rider on a bike..that would be quite difficult to model would not be consistant from event to event and would not be consistant from rider to rider or bike to bike due to the nature of active/reactive human input).
 
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rockofullr

confused
Jun 11, 2009
7,342
924
East Bay, Cali
lol, using rules of thumb like "the drop test" or "the curb test" just cause some guy told you to is the best way to set up your suspension wrong.

When you hear pros talking about getting there suspension dialed they always talk about trail testing. There is a reason for this.
 

profro

Turbo Monkey
Feb 25, 2002
5,617
314
Walden Ridge
Umm NO...

When is the last time your bike went riding without you??

The mass, and thus reaction of the entire damped oscillating system has changed. How the system reacts with a mass of 40lbs for example has just about nothing to do with how that same system will react with 200lbs (not to mention that the additional weight is in itself independantly oscillating and damped from the original system (bike).

In mathematical terms, the differential equation that describes a damped harmonic system contains a term (omega) that is dependent on the mass of the system. If you change the mass of the system, you change the solution to the equation (not to mention the stacking or two semi-independant systems like a rider on a bike..that would be quite difficult to model would not be consistant from event to event and would not be consistant from rider to rider or bike to bike due to the nature of active/reactive human input).
Very well put. A little to much information for those without engineering degrees. But the first paragraph explains it well.
 

Kanye West

220# bag of hacktastic
Aug 31, 2006
3,741
473
The bounce test is useful for determining how quick the back end will kick back or comply when you're skimming over braking chatter with the back end topped out. You don't always have weight on the pedals in that case. Ideally, yes, in reality, no. It's a good way in some shocks to see how the top-out rebound is (basically what the shimstack does when the needle port in the shaft gets covered up by the seal head).

Setting the needle position in any variable-fixed orifice setup whether it be a spring/needle or shimstack/needle, the needle basically acts like a timing switch for the shimstack - the more closed off it is, the sooner in the F vs. V curve the "knee" occurs where it digresses to the shimstack/spring. That's a pretty crude approximation, but it's a convenient simple way to think about it.
 

LambMan

Chimp
Jul 13, 2009
46
0
ATL
Umm NO...

When is the last time your bike went riding without you??

The mass, and thus reaction of the entire damped oscillating system has changed. How the system reacts with a mass of 40lbs for example has just about nothing to do with how that same system will react with 200lbs (not to mention that the additional weight is in itself independantly oscillating and damped from the original system (bike).

In mathematical terms, the differential equation that describes a damped harmonic system contains a term (omega) that is dependent on the mass of the system. If you change the mass of the system, you change the solution to the equation (not to mention the stacking or two semi-independant systems like a rider on a bike..that would be quite difficult to model would not be consistant from event to event and would not be consistant from rider to rider or bike to bike due to the nature of active/reactive human input).
I'm not trying to say that is the only way to set up a bike. I think it should be obvious to just about anyone that testing on a trail is the best/only way to get it exactly how you want it. My understanding was that the "drop test" was a decent place to start from. You obviously know a lot about suspension, but my goal is to be able to set my bike up without getting all mr. wizard on it. I guess I assumed that if the suspension doesn't react how you want it with 40 lbs, it will be worse with 200. I understand that this assumption may be terribly wrong.
 

PUSHIND

PUSH Industries (Duh)
Dec 5, 2003
221
251
Colorado
Setting the needle position in any variable-fixed orifice setup whether it be a spring/needle or shimstack/needle, the needle basically acts like a timing switch for the shimstack - the more closed off it is, the sooner in the F vs. V curve the "knee" occurs where it digresses to the shimstack/spring. That's a pretty crude approximation, but it's a convenient simple way to think about it.
:thumb:

Ok, I see were your going here. It makes sense to me when I think of the avy independant hi/low comp adjuster and how it works.....Basically they are not totally independant and do affect each other if the setting are too fasr off.
If I am reading this correct, what your saying is that once the shims deflect/open, they stay open until the rebound stops<IE next compression stroke> Am I correct in how I am readig that?
It is different than this. The shims don't stay open, but rather open and close depending on the velocity that the suspension is moving at and where the external adjuster is set.


That's true for compression, but for rebound (which is what we were discussing) from my understanding the return velocity is defined by the spring. And in that context (again, specifically for rebound damping), end-stroke rebound is the same as high speed rebound, because that is where the spring will return at its fastest.
If you're using the top four inches of travel going over successive brick shape/size obstacles in the trail you also need the high speed rebound circuit to be functioning. In this scenario the suspension is also reacting to the bump input on compression. By describing the rebound as beginning or ending stroke you would be defining it as position sensitive, not velocity sensitive. Now, that being said, you're correct describing the springs role in rebound damping and the generalization that you need the fork or shock to react quickly from deep stroke impacts to get it ready for the next obstacle.

Darren
 

leprechaun

Turbo Monkey
Apr 17, 2004
1,009
0
SLC,Ut
If you're using the top four inches of travel going over successive brick shape/size obstacles in the trail you also need the high speed rebound circuit to be functioning. In this scenario the suspension is also reacting to the bump input on compression. By describing the rebound as beginning or ending stroke you would be defining it as position sensitive, not velocity sensitive. Now, that being said, you're correct describing the springs role in rebound damping and the generalization that you need the fork or shock to react quickly from deep stroke impacts to get it ready for the next obstacle.

Darren[/QUOTE]

last summer i spnt a day at Keystone (huge laps!) testing the rebound speed of a CCDB. I have a Pushed ROCO WC tuned for my Giant reign X (170mm travel 3:1 w/400lb spring) to use as a starting point. Fresh off a broken arm and wrist i was wanting to see if it was possible to run the damper buck proof but still track the ground well.

I tried to run the high speed rebound all the way in and the low speed in roughly 1/2 way-where i usually run it. I figured it might track chatter and slow down in g outs, or when i use my highly evolved technique of casing jumps. In the parking lot doing the endo-then slam your ass on the seat technique the rebound was not crazy slow. It seemed normal, and actually not that slow. Armed with my CCDB tool i hit the gondola only to get rattled so bad in the first 2 minutes i had to stop to see if my bike was still intact! I hadn't even hit any jumps or G outs yet, just rocky singletrack. My feet were numb.

Long story short- there are high rebound shaft speeds over brick sized rocks and holes even if you are still in your first half of the travel. Until then i thought for sure that the rebound was only seeing the spring but i was wrong. At least with that shock. It seems that parking lot testing is only useful for low speed adjustments, and ya just gotta get out on the trail to see how the HS circuit feels.

I haven't found the ideal setting yet, but it's really good now. I kept speeding up the high speed until my bike felt normal again. Since then i've been playing with the low speed more. No doubt the valve spec in the Pushed Roco was just right and it took me about 2 minutes in the lot to get it set and never had to play with it again.

I think if i play with the CCDB long enough i can find ultimately the best setup, it just takes a lot of time.

I've also found that many of the current high production shocks are still too heavily shimmed on the rebound forcing you to run fast rebound damping to get the bike to track the ground. So it's either get a shock with 2 way tuneable rebound (assumig it works like it should) or have a tuner that knows what he's doing to valve it correctly. I struggled with two different 2009 bikes with "rough" handling only to find out the rebound shims were the culprit. If your bike has 1 or 2 clicks where it feels good then it's probably heavily shimmed and won't let the oil flow when it's turned up. If there are a few useable clicks that offer gradually more damping then it's doing it's job!
 

djjohnr

Turbo Monkey
Apr 21, 2002
3,017
1,719
Northern California
If you're using the top four inches of travel going over successive brick shape/size obstacles in the trail you also need the high speed rebound circuit to be functioning. In this scenario the suspension is also reacting to the bump input on compression. By describing the rebound as beginning or ending stroke you would be defining it as position sensitive, not velocity sensitive. Now, that being said, you're correct describing the springs role in rebound damping and the generalization that you need the fork or shock to react quickly from deep stroke impacts to get it ready for the next obstacle.

Darren
:lighten:

Ok, I think I know where I've been seeing this wrong -

- Rebound velocity is not only a function of spring force, but also the shape of the backside of the bump (ie square vs round), similar to compression.

Is this right?
 

MDJ

Monkey
Dec 15, 2005
669
0
San Jose, CA
:lighten:

Ok, I think I know where I've been seeing this wrong -

- Rebound velocity is not only a function of spring force, but also the shape of the backside of the bump (ie square vs round), similar to compression.

Is this right?
Gurp, you're trying to hard. Just pretend to understand like the rest of us.:D
 

Jm_

sled dog's bollocks
Jan 14, 2002
18,999
9,660
AK
Fresh off a broken arm and wrist i was wanting to see if it was possible to run the damper buck proof but still track the ground well.

I tried to run the high speed rebound all the way in and the low speed in roughly 1/2 way-where i usually run it. I figured it might track chatter and slow down in g outs, or when i use my highly evolved technique of casing jumps. In the parking lot doing the endo-then slam your ass on the seat technique the rebound was not crazy slow. It seemed normal, and actually not that slow. Armed with my CCDB tool i hit the gondola only to get rattled so bad in the first 2 minutes i had to stop to see if my bike was still intact! I hadn't even hit any jumps or G outs yet, just rocky singletrack. My feet were numb.
I guess you figured it out, but that's quite the polar opposite of how you'd achieve the result you want. A lot of times the rebound adjuster on an OEM shock is a bit too "overall" in terms of affecting high and low speed circuts, but if you are adjusting just a high-speed circut, then too much rebound is going to mean massive packing and super-harsh action. I think the context of this thread is to try more low-speed rebound, IF your damper is of decent design and allows for this without severely impacting the high speed.

I think it's pretty difficult to impossible to activate a high-speed rebound circut by just slamming on the bike in a parking lot. Or to explain better, I can't make my avalanche rebound "fast" in the parking lot, it's always going to have more low-speed rebound than some other shocks when you back it off fully, and in that respect it seems "slower" in the parking lot, but at speed the high-speed rebound does it's job magically and allows it to keep up with arizona super-chunk riding.
 

bobsten

Monkey
Oct 23, 2008
240
0
rain rain go away
I am trying to remember where Malcom (Cane Creek) suggested where I should ride my Morewood Izimu armed with a CCDB, I sold the CCDB last week so I can't go look at it.

High speed rebound was suggested to be run almost full open and Low speed rebound was suggested to be about 4-6 clicks from fully open (there are like 24 clicks in the shock I had, might be more now). So it seems like Cane Creek is suggesting contradicting settings to PUSH.

Or, I'm an idiot.
 

Kanye West

220# bag of hacktastic
Aug 31, 2006
3,741
473
I am trying to remember where Malcom (Cane Creek) suggested where I should ride my Morewood Izimu armed with a CCDB, I sold the CCDB last week so I can't go look at it.

High speed rebound was suggested to be run almost full open and Low speed rebound was suggested to be about 4-6 clicks from fully open (there are like 24 clicks in the shock I had, might be more now). So it seems like Cane Creek is suggesting contradicting settings to PUSH.

Or, I'm an idiot.
That sounds dangerous...
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
If you're using the top four inches of travel going over successive brick shape/size obstacles in the trail you also need the high speed rebound circuit to be functioning. In this scenario the suspension is also reacting to the bump input on compression. By describing the rebound as beginning or ending stroke you would be defining it as position sensitive, not velocity sensitive. Now, that being said, you're correct describing the springs role in rebound damping and the generalization that you need the fork or shock to react quickly from deep stroke impacts to get it ready for the next obstacle
I didn't say it wasn't velocity sensitive, the way I see it, this just happens to be one occasion where velocity sensitive damping also happens to be position sensitive (because the shaft speed depends on where it is in the travel, assuming a linear coil spring). Regardless of obstacle, what is it that can cause the shaft to travel in the return direction (rebound stroke only) apart from the spring itself? I might be missing something here, but it'd be great if you could be clearer on what other factors affect the return speed of that stroke.

I disagree when you say that you "need" any circuit to be functioning, as high-speed damping just refers to a regression in an otherwise progressive (i.e. ported only) damping curve. To me your post suggested that you "needed" the shimstack to start flowing oil and that's why you recommend running more low speed damping, but to me that doesn't make sense:

As shaft speed increases, the shims will start opening (and if the damper is tuned right, this will happen at the correct speed) to allow more oil flow area... why do you need to enforce more low speed damping to make the stack open earlier?

The way I see it that should be controlled by amount/thickness/diameter of shims, and preload on them, rather than increasing low-speed damping beyond the desired amount (and from the posts earlier in this thread that seems to be the case).

Thoughts? I'm open to correction here, obviously I don't do this stuff for a living. :)
 

Viv92

Monkey
Jan 31, 2009
204
0
Australia
This speed/position sensitive thing with rebound damping has always confused me. Say you squash over the lip of a jump, your shock will rebound very fast because there is nothing for the spring to actually push up, then if you compress your shock to the same amount, into a g-out or something, you are still pushing the bike down as you are going up the other side of the g-out even if the spring force is rebounding your shock, but your shock is going to be rebounding a lot slower.

Am I right or am I thinking about something wrong?
 

Capricorn

Monkey
Jan 9, 2010
425
0
Cape Town, ZA
udi: increasing low speed damping allows less oil to bypass the shimstack, so on bigger hits, with more oil available, the pressure increases quickly enough and sufficiently so that your high speed damping comes into play.
At least that's how i understand it.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
capricorn -
The shimstack will open on bigger hits anyway, it's really not that complicated. The only thing a shimstack does is flex as shaft speed increases to provide more port area for oil to travel through, you shouldn't have to change whatever low speed settings you are comfortable with to allow the high-speed curve to work as required - I believe the whole point of (good) suspension tuning is to avoid things like that, where you have to make significant one-thing-for-another sacrifices.

viv -
That makes sense to me, but if you consider each of the scenarios you gave, the position sensitivity argument still applies. If you come off the lip of a jump, the shaft speed will still be highest when returning from deeper parts of the stroke as opposed to shallower parts. Sure, overall the shaft speed is higher than when the bike is weighted, but the shaft speed from deeper in the stroke will be higher still, than from a shorter way in. It's the same story for the g-out, yes overall the shaft speed is lower, but from a position perspective, the same variations apply.

Obviously in that context it'd be important to make sure your settings didn't cause hindrance at either extreme. :)
 

MarkDH

Monkey
Sep 23, 2004
351
0
Scotland
Just a thought from someone who doesn't know much about suspension, but is shaft speed on rebound also affected by the momentum of the rear wheel and swingarm? So in the example above of going off a lip, the rebound circuit may not have as much spring force to deal with when it gets nearer to full extension, but it still has to work against the momentum of the wheel? If this is the case, perhaps the shaft speed will be slower nearer full extension, but relatively not as slow as it would be if you were simply considering spring force vs. damping force on an isolated shock?

Just thinking out loud. :)
 

djjohnr

Turbo Monkey
Apr 21, 2002
3,017
1,719
Northern California
Viv + Mark - That is about what I'm thinking. Although as Udi points out the affects would be greatly magnified as you get further into travel and spring force increases.
 

Commencal-guy

Monkey
Nov 25, 2007
341
0
Massachusetts, US of A
So on an easier note...

What's the ideal set up for a shock with High and low speed compression?

Do you want more Low speed and less high speed to prevent the fork packing
or is it the reverse? less low speed rebound and more for ending stroke to prevent bucking?
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
I think the general consensus on compression is definitely easier / more commonly agreed upon, very basically I think this is what you want:

- Enough LSC to stop excess dive in corners, g-outs and steeps but:
- Not so much LSC that the damper can't move very slowly without damping (=SPV=bad)
- Low enough HSC to ensure that the damper is not spiking on bumps, but:
- Enough HSC (which is usually applied in the form of spring preload on a shim) to make sure the compression damping isn't regressing too quickly, because that tends to mean the damping disappears when you really need it (really aggressive corners for example).

Excessively low spring rates + excessive damping to compensate will also result in a bike that feels more "dead" so it's worth keeping that in mind if you like your pop, because any sort of damping generally reduces that.

That's my best 12:40am sum up. :)
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
Unless of course you meant "a shock with high and low speed rebound", in which case everything that has been discussed so far still applies - just that you're lucky enough to actually have external control over those elements.

On a shock without separate adjusters, the single adjuster usually just controls the low-speed bleed, and tuning beyond that involves getting to the internal stack.
 

leprechaun

Turbo Monkey
Apr 17, 2004
1,009
0
SLC,Ut
Udi,
I think that tuners like Darren, who have tuned cars and motorcycles, like a good bit of LSR to keep the action from feeling too loose, sloppy, vague etc. It seems like many pedal bike riders start at the other end, going as soft, squishy and fast as possible rather than controlled as possible without feeling harsh. This may still be from having shocks over the years that just didn't track the ground when slowed down. In my experience, riding a motorcycle with too little LSR makes the bike feel like its levetating and floating above the terrain without the feel and grip. On a 250lb bike it is a dangerous and scarry feeling.

I remember my karpiel with 1999 Risse dampers, i would drag my brakes the whole way down a run because if i let off i felt like i had zero traction. If i turned up the rebound it would pack up though so i dragged the Hayes mags till either they overheated or my arms failed! Might have been a gazzy 3.0 related problem though! Haha!
 
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Kanye West

220# bag of hacktastic
Aug 31, 2006
3,741
473
In my experience, riding a motorcycle with too little LSR makes the bike feel like its levetating and floating above the terrain without the feel and grip. On a 250lb bike it is a dangerous and scarry feeling.
Amen to that...
 

dsb18292

Chimp
Mar 24, 2009
68
0
Have other people found that the suggested rebound setting from Push was relatively slow compared to what they normally run? Results?
I had an air shock and an air fork tuned by Push this last year. Both came back way slower than I would have liked. In the rear I found that I could adjust to the slowness. On the fork though I ended up running the external adjustment full open. To Push's credit both shocks worked well. I never felt a loss of traction or control. At high speed both were phenomenal.

So yes they were slower and no, it didn't cause any real issue. I have come to the conclusion that tuners have their preferred methods and if you stick close to their recommendations you will have results inline with the tuner's experience. Only issue is that sometimes personal preference gets in the way and it is hard to trust the tuner :rolleyes:
 

Pslide

Turbo Monkey
I am not a suspension guru, but from what I've heard about in off-road motorsport, you can either primarily control the vehicle dynamics through the rebound circuit (traditional) or through the compression circuit. Controlling through the compression seems to be a newer technology with the advent of high/low speed damping and finer tuning and analysis. In this case the shock will often have a "fast rebound" circuit.

You can read about "fast rebound" here: http://www.donerre.fr/innovation.detra.php?langue=en Donerre pioneered and patented it and BOS has a similar technology which may have been copied (they are were in a lawsuit over the technology). When you control the vehicle dynamics primarily off the compression circuit, the damper does a LOT more work, and therefore heat issues a bigger problem (at least in motorsport).

I would guess that Fox's strategy has and continues to be to use rebound as the primary dynamic control, whereas BOS and CCDB are designed more around compression control. But with so many adjustments, I think the line is blurred and most shocks fall in between (including BOS, CCDB, and RC4).

I personally think the compression control strategy with fast rebound is not a viable option for mountain bikes, it would certainly screw up the feel of the bike. So seeing a move back towards traditional rebound control (or a balance thereof) per the subject of this thread seems good to me.
 

Udi

RM Chief Ornithologist
Mar 14, 2005
4,915
1,200
FOX actually uses far higher levels of compression damping on the shocks they tune for the pros - I think a classic example of its importance for those in elite/pro categories, and a drastic variation on what they provide for the consumer. I don't really agree with the way they handle that (throwing a blanket, as such) but it definitely makes a point.

I think slower rebound is in fact the thing that lingers from the past (the opposite of what a couple of you are saying - remember: mtb isn't moto!), because good compression dampers are actually a very recent development in mountain biking, especially at the consumer end. Remember the marzocchi days? Most forks didn't even have a compression damper, and those that did provided very little. Rebound had to tread the line between stability and traction, and big compromises generally resulted from this. Motorbikes on the other hand run a lot of compression damping out of the box, so heavier rebound rates are quite acceptable there - I don't think it's a relevant comparison.

I only briefly skimmed the article, but it definitely highlights the biggest advantages of transferring some of that load to the compression damper: improving balance/stability without as much sacrifice in traction, and maintaining stroke position.

I think most dampers on principle still do have more rebound damping than compression, and I think that's fairly normal/correct (on my bike I think that still holds true, albeit just a little) - but in my experience, letting compression take care of stability issues, and letting the rebound damper do less - generally results in a bike you can ride faster and more confidently at the limit.
 

Pslide

Turbo Monkey
I think slower rebound is in fact the thing that lingers from the past (the opposite of what a couple of you are saying - remember: mtb isn't moto!), because good compression dampers are actually a very recent development in mountain biking, especially at the consumer end.
I would agree with this, but you have to consider the possibility that Fox had it right all along and that the new breed of highly damped shocks (in compression) is just a fad that may pass for the typical DH rider.

The exception would be the pros, who only want the fastest setup and don't care about the "feel" and liveliness of a bike - and this is where more compression damping seems to be the way forward.
 

djjohnr

Turbo Monkey
Apr 21, 2002
3,017
1,719
Northern California
As far as how you can have a high speed rebound event relatively shallow in travel -

Check this site out - http://www.myphysicslab.com/spring1.html

On the app, set Velocity to Y, Position to X, Drag to .99 and change lines to dots. Then release the weight from different lengths - specifically try full travel, 50% and 30% (our normal sag point).

As you can see, the mass is accelerating after you release it. It's not at full velocity instantly. If you were to set the knee for LS/HS transition at a velocity of 1, you could hit that knee starting from as little as ~20% spring travel.

If the ground is not falling away at the same acceleration rate or faster it will obviously reduce velocity. If that rate is slow enough you could keep that acceleration force below the knee even when starting from full travel.
 

Steve M

Turbo Monkey
Mar 3, 2007
1,991
45
Whistler
With a square bump you get very short duration with very high velocity at the damper. With a lot of our setups that use a preloaded high speed stack, running the low speed bleed slower will allow the preload of the stack to be overcome more easily allowing the shims to deflect, therefore decreasing rebound forces and making the force curve more digressive.
I still can't see how running MORE damping through the LS circuit could possibly equate to a net total of LESS damping, for a given shim stack/preload configuration, it's simply not possible without severe transient effects in my opinion (I am open to being proven wrong, maybe you guys have verified this on a dyno or something). If you're trying to use the LSR to bring the HS threshold down to a lower velocity rather than a lower force I could see what you're saying, but otherwise I can't really see how what you're saying could be true.

If you like rebound slow/fast/whatever, fair enough. Usually I prefer rebound relatively fast, or at least I used to. When I did some blind-adjustment testing with a 40 and an RC4 a year or so ago, I found that the "optimum" settings I ended up settling on (not having any idea where the adjusters were, and not even bounce testing the bike between adjustments as they were all done by someone else without telling me what was being done) were slower than what I usually ran prior to that. Part of that was definitely to do with the 40's stellar rebound damping when compared to the Boxxer (even my home-modded damper, the rebound curve isn't that precisely tuned compared to Fox's). Since then I've slowed my rebound down a tad front and rear, and there is definitely a sweet spot as far as traction goes, somewhere between "really f**king slow" and ejector seat fast. One or two clicks (on almost any shock) slower than that point though and all of a sudden "planted" becomes "faceplanted".
 

MarkDH

Monkey
Sep 23, 2004
351
0
Scotland
Sorry for the thread bump, thought it would be better than starting a new one. This thread has some useful information and it's got me thinking about my suspension set-up. Does anyone have a link to any videos of front and/or rear rebound setup that are useful for downhill? I seem to remember Tim Flooks had one but I can't find it anywhere, it was good because he was actually showing you it on a DH bike (223 IIRC) with Boxxers and gave you a rough idea of where to start with it. I've searched Pinkbike and Youtube but found little of interest. I realise testing on the track is the only way to get it nailed, but a starting point would be nice.

Cheers
 

bullcrew

3 Dude Approved
No vids but I can say the slower feeling rebound on the vivid tracks WAY better than the fast set up I usually run. Only reason its slower then the norm is its a c-tune and rebound is off so its under its own valving that its rebound speed is at. Id have opened it up more if it was there but being I couldnt I rode it and Im not going to change as far as the feel Ill be doing the same set with rebound when the roco gets back.

Just my .02
I played with it a bit by adding more and it seems pretty spot on wide open with that tune on it, messed with the front fork to match and its pretty close now...
 

SylentK

Turbo Monkey
Feb 25, 2004
2,332
879
coloRADo
I think you're thinking of Dirt's Fundamentals. Someone already mentioned it in this thread.

The rough idea on where to start, according to Flooks, is to push down on your seat or handlebars pretty hard, then pull up really fast. You want to try to get the wheel in question off the ground before the suspension rebounds/tops out. It may make more sense after watching the vid. Someone in your group of riding "Bro's" probably has a copy. Just how fast it rebounds/tops out after you lift it is up to you. He recommends making the rear a bit slower than the front. That'll get you going for rebound. As we all know, compression is another story.
 

MarkDH

Monkey
Sep 23, 2004
351
0
Scotland
Ah, Fundamentals! Yeah I remember now, thought it might have been online or something, I can borrow the DVD off a mate, cheers. I remembered that tip of being able to get the wheel off the ground, but I couldn't remember if it was barely getting it off or quite a bit of lag, or how far to push down etc., hence I wanted to see a video. It would be interesting to see a video of a pro's rebound though, just to see if it is mega slow as this thread kind of suggests..

Bullcrew: I'm also running a Vivid on my Sunday. I can't remember exactly how many clicks I have but it's around half way, not particularly fast or slow. I slowed the ending stroke down by one click in the car park, and added on another half turn on my Boxxers, but it felt really dead and I found it hard to get it off the ground. I was really just wanting to have a blast in the woods that day so I turned it back to what I had it at, but I think I'm going to have to experiment with it properly. I think my forks are probably set up realtively fast but I've just got used to it.