[broke(n)]

Having acquired a 2010 Boxxer Team (and provided it with some lubrication so it actually works) I'm wondering about tuning the Hi/Lo speed rebound.

Firstly does anyone know if the adjustment is actually speed sensitive or is it position sensitive? The speel on the RS website talks about controlling rebound from the first 25% of the travel with the low speed dial and the rest of the travel with the high speed dial. This seems a more position sensitive approach.

I would have thought that a speed sensitive system would have the low speed rebound regulating the start (and/or "small" rebound strokes between consecutive compressions) of the rebound stroke with the high speed rebound regulating the end of longer rebound strokes, yes (or no)?

More importantly, what do you adjust on the trail to achieve what. In the past I would have slowed down the (1 and only) rebound adjuster to remove the high speed "chatter" through the bars that (I believe) overly fast rebound results in.

I would have thought that the LSR adjuster would be the most appropriate adjustment, especially over smaller bumps, to do the same (as above), but to stop everything feeling "whack" should I slow the HSR too? If so, buy how much? (e.g. 1 click HSR per click LSR)

In contrast, if I follow the RS guide literally, rebounding from anything deeper than the 1st 25% of the stroke (which would be most bumps as I run 30% sag), is controlled by the HSR.

Thoughts?

 

[Udi]

In terms of rebound, speed sensitivity = position sensitivity. That is, low speed rebound directly equates to beginning stroke rebound, and high speed rebound equates to end stroke rebound. This is because unlike compression, the spring determines rebound speed, and that also means there is a defined upper limit on rebound speed.

Personally I run the rebound on the front as fast as comfortably possible (quite fast) and then set the rear a little slower than that to prevent bucking etc.

I don't think chatter is a result of fast rebound like you say. There is probably some other cause for that - tyre pressure, excessive compression damping, stiction in suspension, you name it.

Generally you want the LSR on the faster side to allow the suspension to respond to (and recover from) bumps quickly, but a little more HSR to stop the suspension bucking you from impacts that push the suspension deeper into its travel (lips of jumps, hard fast cornering, etc).

Personally, I've found that holds true for the rearend (if you're lucky enough to have LSR/HSR adjusters on your shock), but on the front, I prefer it to be closer to linear, or even slightly the opposite. I'll explain why, because this is just my opinion. While at the rear rebound has a big effect on bucking, the front doesn't suffer from this nearly as much, so the rebound speed can afford to be faster from deeper in the stroke. On the other hand, most forks don't have the hydraulic topout mechanisms that most shocks do, so you do need just enough LSR (= early stroke rebound) to stop it topping out harshly. Obviously not too much for the reasons given in the above paragraph.

Anyway with the reasoning out of the way, I think rebound damping is often a fairly personal thing, so apart from the basic principles of "as fast as comfortably/safely possible" and "slightly slower on the rear than the front", you can figure out what works best for you with a bit of experimentation.

 

[broke(n)]

We'll have to disagree about overly fast rebound reducing handlebar "chatter/patter" (run the same bit of rough trail with fast and then slow rebound and tell me there's not less feedback through the handlebars...)

I get that the rebound stroke is driven completely by the spring, but (surely) rebound speed, even from deep in the stroke starts off slow, and is consequently regulated by the LSR adjuster (provided it is a speed sensitive set up)? Or is the amount of time spent at "low speed" deep in the stroke so small as to be unimportant?

Anyone know what Cane Creek say about the HSR/LSR adjusters on their rear shocks?

 

[Udi]

Well "overly fast" is pretty subjective, I mean by definition if anything is "overly" anything, then it's a bad thing (for whatever reason). But having relatively fast rebound shouldn't increase chatter, if anything it should allow for less transmission to your hands because the suspension can respond to bumps rather than packing up over them (and sitting deeper in the travel than it should).

Obviously any damping circuit will start in the low speed region and then only if shaft speed is high enough, will extra port area open (via shims, springs, whatever). But I think the amount of time spent in that region is negligible / insignificant (from a deep stroke rebound, for example) so I think you're wrong in thinking that you should be taking that into account with your tuning.

That's not to say that there isn't overlap between LS/HS adjusters - because obviously the size of the port will determine how long the damping curve will progress for before starting to regress... but beyond that consideration, I think you've got the wrong idea.

So ultimately, I'd recommend tuning rebound just how I described earlier (on a position = speed basis) - and apparently rockshox feels the same way and even gives you a range of stroke where each adjuster applies most.

 

[slowmtb]

In terms of rebound, speed sensitivity = position sensitivity. That is, low speed rebound directly equates to beginning stroke rebound, and high speed rebound equates to end stroke rebound. This is because unlike compression, the spring determines rebound speed, and that also means there is a defined upper limit on rebound speed.

Personally I run the rebound on the front as fast as comfortably possible (quite fast) and then set the rear a little slower than that to prevent bucking etc.

I don't think chatter is a result of fast rebound like you say. There is probably some other cause for that - tyre pressure, excessive compression damping, stiction in suspension, you name it.

Generally you want the LSR on the faster side to allow the suspension to respond to (and recover from) bumps quickly, but a little more HSR to stop the suspension bucking you from impacts that push the suspension deeper into its travel (lips of jumps, hard fast cornering, etc).

Personally, I've found that holds true for the rearend (if you're lucky enough to have LSR/HSR adjusters on your shock), but on the front, I prefer it to be closer to linear, or even slightly the opposite. I'll explain why, because this is just my opinion. While at the rear rebound has a big effect on bucking, the front doesn't suffer from this nearly as much, so the rebound speed can afford to be faster from deeper in the stroke. On the other hand, most forks don't have the hydraulic topout mechanisms that most shocks do, so you do need just enough LSR (= early stroke rebound) to stop it topping out harshly. Obviously not too much for the reasons given in the above paragraph.

Anyway with the reasoning out of the way, I think rebound damping is often a fairly personal thing, so apart from the basic principles of "as fast as comfortably/safely possible" and "slightly slower on the rear than the front", you can figure out what works best for you with a bit of experimentation.

x2 - chatter can be a compression setting thing so have a play in this area just to be sure.

 

[Kanye West]

I've found on super high speed stuff (40mph +) that the faster rebound actually can increase the transmission to your hands just because the wheel is coming back and hitting the rocks and edges that much faster. That rebound speed is pretty close to the limits of full fast though. It's much easier to notice an effect of packing with the slower rebound.

For high speed stuff I end up just going up a whole springrate to begin with and running almost no low speed compression damping and more high speed. For rebound I would keep it slower typically than I would on the slower speed stuff just due to a different riding style for each situation. When it really opens up I start attacking stuff with much slower deliberate motions much like I would on my dirt bike rather than picking sneaky little sniper lines everywhere in the tighter stuff. That said I end up setting up the suspension more for stability rather than tracking. At high speeds you aren't really "tracking" as much as you are just skimming and the bikes overall attitude becomes more critical. I usually set the rebound on the slow side so it packs up just a TINY bit. Usually not hitting tons of edges right in a row that would use up all your travel, and if your compression is tuned right and slows nicely on the high speed impacts you'll still have travel to use if you do get in that situation.

The spot I notice HSR coming into play the most is off of lips. It seems to be used a little bit on drops and landings and out of deep corners, but the wheel is still loaded on all of those, so the highest shaft speeds it would ever see on the rebound stroke would be near the end of the stroke right as it becomes unloaded. So I always tune the HSR exclusively for lift off jumps first, LSR for chatter where the wheel stays planted, then fine tune HSR for taller rocks where the wheel leaves the ground completely between hits.

 

[go-ride.com]

Having acquired a 2010 Boxxer Team (and provided it with some lubrication so it actually works) I'm wondering about tuning the Hi/Lo speed rebound.

Firstly does anyone know if the adjustment is actually speed sensitive or is it position sensitive? The speel on the RS website talks about controlling rebound from the first 25% of the travel with the low speed dial and the rest of the travel with the high speed dial. This seems a more position sensitive approach.

I would have thought that a speed sensitive system would have the low speed rebound regulating the start (and/or "small" rebound strokes between consecutive compressions) of the rebound stroke with the high speed rebound regulating the end of longer rebound strokes, yes (or no)?

More importantly, what do you adjust on the trail to achieve what. In the past I would have slowed down the (1 and only) rebound adjuster to remove the high speed "chatter" through the bars that (I believe) overly fast rebound results in.

I would have thought that the LSR adjuster would be the most appropriate adjustment, especially over smaller bumps, to do the same (as above), but to stop everything feeling "whack" should I slow the HSR too? If so, buy how much? (e.g. 1 click HSR per click LSR)

In contrast, if I follow the RS guide literally, rebounding from anything deeper than the 1st 25% of the stroke (which would be most bumps as I run 30% sag), is controlled by the HSR.

Thoughts?

Yes, the 2010 Boxxer rebound is a speed sensitive system. Basically it is the Mission Control compression system used in a rebound capacity. However, as UDI pointed out rebound forces are generated from your spring rate (and to some effect wheel weight), so the forces are generated by suspension position.

What is confusing is RS calling the LSR the "Beginning Stroke" and the HSR the "Ending Stroke" adjuster. Deep and Shallow might have been easier for the consumer to understand.

If you are getting HS chatter from not enough rebound then you are running it really fast. In most cases you adjust the LS to track the chatter bumps and the HS so the fork releases properly off of jump faces. A good way to set HS rebound is to find a smaller HS jump that you really have to compress the fork into into to keep the rear of the bike from kicking up at take off. If you have too much HSR the fork won't release quick enough and the rear of the bike will come up off the jump. This was a problem the older rebound system had.

I'm currently running 8 clicks of HSR and 1 - 1.25 turns of LSR (can't really feel the clicks on most LSR adjusters). I weigh 165 lbs and run 55 - 57 psi in a 2010 WC.