[General Lee]

At your size, with that spring you should not be bottoming it.

At my size (245) with a 500 on a VPF (granted diff suspension, but has a higher leverage if anything) I rarely see bottom (1-2x a big ride/mountain day) with ZERO compression/propedal clicks, and the bottom out half way in.

Something IS wrong with the shock!(or u r really 300lbs)

some impacts will bottom out a shock no matter how over-sprung it might be. Your classic 'g-out' is a fine example: as the term implies gravity is making you heavier, and in turn making the force of the impact much greater. A heavier spring does little in this situation, only a change in damping will have much effect. However, tuning damping solely for such an event would not give you very nice handling characteristics the rest of the way down the hill.

G-outs are not the only example and different bikes, in combination with different compression settings, shock characteristics, and rider position will bottom out hard in some unexpected places now and again. no design is going to handle every possible scenario.

I'll hazard a guess the shock is 100% okay. There is also the distinct possibility that the particular bike might not be the the best choice for the kind of riding being described, or that the rider is doing a poor job compensating for his suspension's limitations, i.e trying to let the shock do all the work.

also, the comment in bold is what i was referring to earlier when i said bottoming gets a bad rap. On any given run I probably bottom out my Sunday a minimum of 6-10 times, and that's a conservative estimate.

I'm bowing out of the conversation at this point as discussing suspension on RM is like teaching the blind to juggle.

 

[Fonzie18]

Hmm, I'm gonna go with Lee on this one. It sounds like everything is a-ok with the shock.

I notice I bottom out a couple of times during a run ect. ect...

With my suspension set up "correctly" or as I like it, I can make the bike bottm out pretty easily if I choose to. That is to say, if I go out and "goon ride" (

) or pre-load, put excess weight over the rear or the front end in the right spots...the bike will bottom.

 

[Huck Banzai]

some impacts will bottom out a shock no matter how over-sprung it might be. Your classic 'g-out' is a fine example: as the term implies gravity is making you heavier, and in turn making the force of the impact much greater. A heavier spring does little in this situation, only a change in damping will have much effect. However, tuning damping solely for such an event would not give you very nice handling characteristics the rest of the way down the hill.

G-outs are not the only example and different bikes, in combination with different compression settings, shock characteristics, and rider position will bottom out hard in some unexpected places now and again. no design is going to handle every possible scenario.

I'll hazard a guess the shock is 100% okay. There is also the distinct possibility that the particular bike might not be the the best choice for the kind of riding being described, or that the rider is doing a poor job compensating for his suspension's limitations, i.e trying to let the shock do all the work.

also, the comment in bold is what i was referring to earlier when i said bottoming gets a bad rap. On any given run I probably bottom out my Sunday a minimum of 6-10 times, and that's a conservative estimate.

I'm bowing out of the conversation at this point as discussing suspension on RM is like teaching the blind to juggle.

I agree overall, I expect my suspensiojn to bottom, and if it isnt it usually goes hand in hand with not using full travel in general. If you're bottoming 6-10x in a run, that is definitely too much IMO, unless its megavalanche/2hr runs or all you do is plow endless rock gardens. I might up my figure to 3-4x a DAY, 1-2 was a bit conservative.

Bottoming is normal, as you state - tuning to prevent bottoming would compromise the bike significantly, making the suspension less capable in almost every other way!

However a 145lb rider on a 500lb spring, maxes compression and bottom out with 150psi -- this shock shouldnt even use full travel for this guy. Just about any calculator would put this guy on a ~300lb spring, 500lb is the heaviest rate they offer for a bighit from factory. Now add the fact that I am riding a DHX with a 500lb spring on a similar leveraged bike at 245 and the incongruity grows.

 

[General Lee]

I agree overall, I expect my suspensiojn to bottom, and if it isnt it usually goes hand in hand with not using full travel in general. If you're bottoming 6-10x in a run, that is definitely too much IMO, unless its megavalanche/2hr runs or all you do is plow endless rock gardens. I might up my figure to 3-4x a DAY, 1-2 was a bit conservative.

to the contrary, rock gardens and high speed stutters use little travel as you are skimming over the top of them. quickly dropping the rear wheel into dips or ruts in the trail, landing into braking bumps or right on a rock, and even some corners will bottom a bike out fairly easily. usually at pretty slow speeds too as rider weight is often more exagerated than when going fast. i.e. your weight is heavily on your feet rather than spread out. Most factory DH bikes can be bottomed by the rider w/out even bunny hopping on flat ground. however, at speed those sort of impacts disappear.

In short, it is entirely possible to bottom out a dozen times on a run with a shock that is set up spot-on. This doesn't, however, mean that the back of my bike feels like is being ripped off every 100 feet.

 

[Huck Banzai]

Very assumptive, yes I can bottom my bike in the parking lot with little effort. But I see I am not going to get anywhere here.

Bottom line, there is definitely something wrong. This is NOT normal considering the shock, bike and spring rate. Endless rationalization will only delay the inevitable realization. But once again, I digress.

 

[General Lee]

Bottom line, there is definitely something wrong. This is NOT normal considering the shock, bike and spring rate. Endless rationalization will only delay the inevitable realization. But once again, I digress.

I seriously question the ability of the general RM community to describe, assess, diagnose, of otherwise evaluate a shock's performance or integrity without physically testing it themselves.

from the original poster's own admission:
1) "I'm bottoming riding gnarly solid rock garden/lava flow"

2)"I can assure you, nothing is wrong with the shock. It performs WONDERFULLY... until I really start pushing it hard... and even then it's still good, it just happens to be bottoming."

3)"The trail has gnalry ledged rocks and G-outs, probably similar in force values as 4-8 foot drops to flat, except that the energy spikes and you continue bouncing your way down the trail. My last crash involved me bottoming both ends (05 888rc custom valved sprung for a 170 lb rider) 3 times in a row causing my back wheel to gradually raise up placing me in a nose manual until I flipped over the bars."


This will bottom out almost any bike pretty hard. I'd say you have 2 options: learn to control it betters(skill), or slow down. And, at by the logic of some on this board, your fork is clearly broken too


And stated by his friend:

1)"i was literally right behing Cory when he last crashed and saw exactly how it happened, he was in a good position on the bike, but all of the sudden he was up on his nose and then on his face...
the problem section consists of about 4 consecutive 1'-1.5' ledges that have downhill sloped landings and lead up to eachother with about 10' or less in between... you hit these going problably around 20-25mph and they are easy to flow into and are not punishing on any shock BUT his!"

2)"but one thing to consider though Cory, you DO have a 24" wheel in the back..."

Sorry, I'm not sold on blaming the shock. Chalk it up to the characteristics of the trail, the bike being used, rider technique, and quite possibly that 24" wheel . . . .

again . . . juggling and the blind.

 

[Huck Banzai]

Fair enough, I appreciate a good response versus an attack!

Understood, but really, I can be a beast sometimes, and have a VPFree (same travel and leverage ration, different stages, BUT a known falling rate.) and have trouble with the idea that I dont have this issue with lighter settings and an extra 100lbs.

Of course the communication is an issue, and honestly I havent given that as much consideration as I might have, and actually overlooked the fork comment.

How do you explain the incongruity? 100lb difference in rider weight otherwise very similar setup. It does seem as if he must just be holding on and blasting with little finesse witht he info posted so far.



Does the bighit have an extreme falling rate or something? Excessive rebound damping and packing up?

 

[General Lee]

How do you explain the incongruity? 100lb difference in rider weight otherwise very similar setup. It does seem as if he must just be holding on and blasting with little finesse witht he info posted so far.



Does the bighit have an extreme falling rate or something?

1)You own completely different bikes, which makes any comparison essentialy meaningless if not downright impossible.

2) The trail and speed he's describing, if accurate, will bottom most properly suspended bikes. At least i know mine would get thumped and I'm a light, smooth, pro on a Sunday so nothing out of the ordinary there.

3)The big hit is really not a pure dh bike, and from what i've seen with 24" wheels they transfer your weight to the back when a 26" is used in the front.

no doubt, a change in damping would fix the problem, but at what expense? Of course this does nothing to address riding style and what this particular individual possesses in their bag of skills that may or may not be partially the root of his problem.

cheers

 

[Huck Banzai]

similar leverage rates and travel do indeed make a basis for comparison, far from impossible. It will not match point for point, but there are fundamental similarities and the consistency of a little thing called physics. This isn't an effort to tune them to the same performance, but to shed some light on a fundamantal performace 'issue'.

I'm a heavy, smooth, non-racer that is very fast and ride some very rough terrain and dont have these issues.

Maybe the 24" is the critical component, but the leverage ratios being identical combined with the repeated 100lb weight difference just dont add up. I know several people (3) with big-hits, 1 of whom is a fast/rippin/psycho and this just isnt an issue.

So its either the rider or the shock, and as quick as you are to dismiss the shock as an issue, I am not, and think you are idealizing.

I've been working with suspension, riding, tuning and wrenching for a long time, and while I am no Dave Weagle, I have a pretty strong grasp of performance and tuning and this does not make sense.

So now Im back to getting nowhere.

lmao

 

[Huck Banzai]

I give up, and leave it to the OP to choose his own path.

Either he is a complete hack who's style is massively whack,

OR his shock is busted.

Im sticking with #2 with possibly a small portion of #1 tossed in for good measure.

 

[General Lee]

similar leverage rates and travel do indeed make a basis for comparison, far from impossible. It will not match point for point, but there are fundamental similarities and the consistency of a little thing called physics. This isn't an effort to tune them to the same performance, but to shed some light on a fundamantal performace 'issue'.

pivot location and axle path make a difference; and leverage rates are not constant. as i'm sure you know a 9" travel bike with a 3" stroke shock does not automatically have a 3:1 leverage ratio at all points in it's travel. Additionally the big hit has 3 mounting positions on the frame and 3 on the swingarm (his happen to be in the highest leverage ratio setting). So no, you cannot really compare your 2 bikes in anything more than a cursory way.

So its either the rider or the shock, and as quick as you are to dismiss the shock as an issue, I am not, and think you are idealizing.

Not too quick; i did a little digging trough the original posters previous posts and vids. From the photos it would appear his weight is greatly shifted to the rear, over the back tire. Let's just say I'm not sold on the shock being the culprit. I think he's learning how to set a bike set up properly and this is part of that curve. http://ridemonkey.com/forums/showthread.php?t=180701


over and out

 

[Huck Banzai]

pivot location and axle path make a difference; and leverage rates are not constant. as i'm sure you know a 9" travel bike with a 3" stroke shock does not automatically have a 3:1 leverage ratio at all points in it's travel. So no, you cannot really compare your 2 bikes in anything more than a cursory way.




Not too quick; i did a little digging trough the original posters previous posts and vids. From the photos it would appear his weight is greatly shifted to the rear, over the back tire. Let's just say I'm not sold on the shock being the culprit. I think he's learning how to set a bike set up properly and this is part of that curve.

over and out

Well - disagreements abound. Excellent!

Add that I'm also 6'8" and you can presume my wight bias is more 70/30 than the standard 60/40 (even in XL / 21.5, the bike is 'technically' too small for me.)

 

[FactoryCostcoDH]

Ok so I believe I've made up my mind. I'm going to put heavier oil in both ends and back the compression out, see how everything feels, and if I don't like it, I might just try for a lighter spring rate with the same oil. I really do appreciate the suggestions even though I sound completely against all of it. I barely get a chance to ride anywhere else because I don't have my own car yet, so that's why I'm so insistent on keeping my bike set up the way it is. If all else fails, I guess I'll just have to slow down.

 

[cheetaprowlerDH]

hahaha, slowing down is against that trails' name!!! and YOU made it up! lol

you'll figure it out man, you know what you want and i'm personally sure you'll get it down...
it is still so interesting how that section is always the only place you ever complain about your shock, the rest of the trail you always brag about how smooth and awesome your suspension is... and on every other trail we've ridden.

we should work on getting the helmet-cam set up on the frame focused on the suspension... then we could really see what and where it happens... we just need one first i guess

 

[Huck Banzai]

now you're talkin!

(1 more post! YES! jk!)

 

[DirtyMike]

I would suggest at this point, before changing any oil, Call up fox tech, and ask them wher to set your shock up, the more I read whats going on, the more I think The shock just isnt set up properly, Maybe too much air, maybe the bottom out is too far in, Maybe teh rebound is just a little too fast for this particular spot, but like others said, you cant adjust for one spot when its perfect for the rest of the trail. Call fox, tell them your weight and bike, listen to what they say for the settings, then try it again, For your weight, your really not going to be happy with a heavier oil. You might find the rebound your looking for, but your going to ramp the compression to fast, and that will make it feel like it is bottoming alot more

 

[FactoryCostcoDH]

now you're talkin!

(1 more post! YES! jk!)

Haha don't get your hopes up yet I'm pretty sure I'm going to like the stiffer suspension. It'll probably be a while, but once I get everything tuned where I want it, I'll give you guys an update. I might have to do as Bryce said and get a video of the suspension working, going through 80-90% of the travel on the 500lb, 15wt, 125psi DHX

 

[FactoryCostcoDH]

... For your weight, your really not going to be happy with a heavier oil. You might find the rebound your looking for, but your going to ramp the compression to fast, and that will make it feel like it is bottoming alot more

dude. no... I'll make a gentlemen's bet with you that I will be much more satisfied with the heavier oil. Just trust me for a sec, the shock isn't anywhere near overly stiff. Could be a little undersagged, but definately not spiking in the compression. We're thinking on opposite ends of the spectrum here. I know what "I" am fast on, as opposed to somebody else. And don't worry about the suspension setup, that is completely out of the question, I know how to fine tune a shock (everything except for maintenance). Coming from a motocross background, I know what overly stiff suspension is, and my shock isn't there yet

 

[DirtyMike]

Well thats your call, I run 5w oil though for myself and I weight in at about 250 with gear. But hey, thats al R+D really is though right? Trial and error, post how it feels at least, like someone else said, its really hard to say for sure without having the bike here.

 

[cheetaprowlerDH]

without crazy technology, some true computer nerds and extremely expensive equipment, it is alomst impossible to say what is happening here with the information provided FOR SURE, but the good thing is that an oil change is not a huge project and is reversible and 100% changeable, so its really the best remedy for the immediate situation...
kinda my tired 2cents on the resoloution test...

 

[FactoryCostcoDH]

Alright, now that I've made up my mind for the moment, I need to know whether I should take the bike to the LBS and have them put in the new oil, or if it is simple enough to do at home. My dad and I are very mechanically capable, however, we both don't have much experience with suspension (maintenance that is). As long as we don't need any special tools, I'm sure we can take care of it here. Now if it is possible that anyone can give me a rundown of what needs to be done, or at least re-direct me to a thread with such information, that would be great

 

[allsk8sno]

odd enough i find my dhx allittle over damped and want to go lighter with the oil, i also bottom it sometimes on things i don't think i should but its more g-out stuff, and where can i get a better bottom bumber?? i've seen some mx ones but they are like 30 bucks!

 

[Jm_]

Alright, now that I've made up my mind for the moment, I need to know whether I should take the bike to the LBS and have them put in the new oil, or if it is simple enough to do at home. My dad and I are very mechanically capable, however, we both don't have much experience with suspension (maintenance that is). As long as we don't need any special tools, I'm sure we can take care of it here. Now if it is possible that anyone can give me a rundown of what needs to be done, or at least re-direct me to a thread with such information, that would be great

Cool, well, you have to drain the oil from the shock by opening the resivor up usually, but you gotta remember to depressurize it first. Then you can work the correct volume of fluid back into the damper, set the floating piston height, and recharge with air.

 

[CKxx]

I would let someone with experience change the oil. That way you eliminate another possible variable (n00b mistakes) from the diagnosis of your shock's problems.

 

[General Lee]

Cool, well, you have to drain the oil from the shock by opening the resivor up usually, but you gotta remember to depressurize it first. Then you can work the correct volume of fluid back into the damper, set the floating piston height, and recharge with air.

no, no, no. Until you actually know what you are talking about please don't give sh*ty advice or tech. help to people who don't know any better.

I've rebuilt a few dhx's in the past year and tell you that opening the reservoir and draining the oil will accomplish next to nothing except drain a small percentage of the shock fluid and probably leave a nice void in the fluid behind. changing the fluid requires taking the shock apart from the reservoir AND the head seal, and filling if from the piston end.

Much as i'd love to tell this guy how to take his shock apart step-by-step to "fix it, i'm not. it isn't broken and whatever he thinks he is going to "fix" by changing the oil is beyond me.

learn to tune it, and adjust your technique. that is really all that is going to help. try running your shock in a lower leverage setting on the big hit, and def. ditch that 24" wheel.

 

[cheetaprowlerDH]

My desired settings were out of the possible tuning range so I just put in heavier oil to broaden the range of adjustment. And I would love to get a 26" in the back but there are other things that need to be dealt with first and I don't have the money.

So after doing a few searches, I decided the procedure seemed easy enough and I went ahead with changing the oil on both ends. The fork was really straight forward and I had no issues. I ended up putting 5wt in the rebound side and 15wt in the compression. After that I still had plenty of time so I decided I'd do the shock as well. It was generally pretty easy, but I had to re-do the rebound shim stack because the heavier oil was causing the shock to be too slow. That took me a few tries to get the right tuning range, but in the end it all worked out great. It feels really nice bouncing up and down on the bike and both ends are well balanced. Now I just need to replace my broken derailleur hanger and I can ride

Should have a report by sometime this week

 

[cheetaprowlerDH]

oops, wrong user

 

[dw]

Are you sure youre not getting a mid to late travel spike and possibly confusing it for a bottom out? Anyone who rode an M1 back in the day will remember this FSR trait.

 

[FactoryCostcoDH]

Nah, that would make sense, but I know it wasn't a spike. I shouldn't have any issues now with the heavier oil. It still feels plush enough when I have it set at 75 psi and when I really want the extra stiffness I can just crank up the propedal. Thankfully enough I was able to figure out how to work with the rebound shims stack as well because now the adjustment range is perfect, where I won't have the shock packing up or feeling like a pogo stick. It matches up with the 5wt rebound in the fork very nicely. Like I said, I'll give you an update as soon as I can ride

 

[General Lee]

Nah, that would make sense, but I know it wasn't a spike. I shouldn't have any issues now with the heavier oil. It still feels plush enough when I have it set at 75 psi and when I really want the extra stiffness I can just crank up the propedal. Thankfully enough I was able to figure out how to work with the rebound shims stack as well because now the adjustment range is perfect, where I won't have the shock packing up or feeling like a pogo stick. It matches up with the 5wt rebound in the fork very nicely. Like I said, I'll give you an update as soon as I can ride

crank in the pro pedal for more stiffness? my, you really do need a crash course in what the adjustments on your shock are for and what they actually do. adding pro-pedal--low-speed compression blow-off--will do nothing to stop bottoming or make the suspension stiffer. the bike might ride higher in its travel but it will still take the same force to bottom it out, all the pro-pedal does is increase the force needed to move the wheel in the first place, it does not make the suspension stiffer overall. a properly set up dh bike shouldn't really need any pro-pedal. most of the racer-boy types have it fully open or have gone so far as to have it removed.

adding heavier weight oil is also a bad idea, as your shocks stock piston and free-bleed holes are ported specifically for th stock oil. if you want the shock to ramp up you need to make an adjustment to the shim stack itself. the shock is designed to run on the lighter oil. of course it feels "plush enough" if you are just pushing on it our bouncing around because the oil isn't being required to flow through the shims or various ports with much speed or force. see if this helps you understand what i mean: imagine you just filled a syringe with water and pushed down on the handle. it come our very easily right? now do the same thing only this time slam the plunger down on a table as fast as you can. doesn't work so well does it? the water can't escape fast enough. rebound is not the only thing that makes a shock pack up, overdamped compression circuits will do it too. basically the shock will feel fine just bouncing around or pushing on the seat, actually riding it at speed is an entirely different scenario.

seriously, i think what you are experiencing is the limitations of the suspension system; something that is by no means limited to your bike or shock--I'm feeling like a broken record on this point. somehow i think if you decided running peanut butter in your shock would work you would do it. and you'd come to the conclusion that it feels great simply because you want to believe it.

Anyway, do what you want with it, or listen to some sound advice. either way you're the one who has to ride it so it's of no consequence to me if you muck it up. from your previous posts in other threads it seems you and your buddy are still sort of new to dh riding and technology so you're allowed to make your own mistakes while you figure it all out (97 cheetah frankenbike, RC motocross bars, 24" wheels . . . .); the rest of us sure did.

broken record again, but you've said time and again that the shock is working perfectly on everything you ride except this one section of trail. seriously, why do you feel the need to change anything then? you cannot and will not be able to tune if perfectly for everything, if you've got it set spot-on for 95% of what you ride then you are far ahead of what most riders would like to achieve. seriously, and with no disrespect, i think you need to learn to ride around the limitations of your bike. even the fastest guys in the world have to do it.

 

[Huck Banzai]

Are you sure youre not getting a mid to late travel spike and possibly confusing it for a bottom out? Anyone who rode an M1 back in the day will remember this FSR trait.

YAY - someone with (a lot of) clue(s)!!

My butt was done talking, others are still pooting.. SAVE THE WORLD DW..

heehee

 

[FactoryCostcoDH]

Yes I understand that propedal is all low speed compression but think of it this way. By adding more low speed compression the shock will begin to slow down faster before reaching the point at which the bottom out kicks in, thus causing less of a spike when it does. Almost like you would compare the compression feeling of an airbag vs a trampoline.

And I agree that I am still an amateur, there's no question in that. However there shouldn't be some standard that every rider has to follow to be considered fast. Some people may do better with wide bars, some might be better with soft suspension, others with stiff suspension. How fast someone is is completely determined by the rider, the bike only accents their ability which is what I am trying to do here.

 

[FactoryCostcoDH]

And look I know I'm sounding really defensive, but putting heavier oil in isn't a permanent modification. If it doesn't solve my problems I can always just take it out, put in 5wt oil again, and maybe even send it off to push. This is all just one big experiment to see if it works for me

 

[dhkid]

umm, dhx stock oil weight is 10wt, you will end up with far to little damping with 5wt. i have tried it and i am only 120lbs.

propedal and bottom out are related. its the same valve which controls them both. the boost valve is held close by the air pressure in the shox, but propedal is a spring trying to keep it open.

at low pressures, maybe 80 or so with the propedal set at minimum the boost valve is pretty much open, and as the shox goes deeper into its travel, the air pressure increases due to the oil displaced by the shaft. this in turn will put more pressure on the boost valve giving more damping the deeper in the travel the shox is.

so there isn't really a transition between pro pedal and boost vavle, its the same thing, just at different point in the travel.

propedal adjustments do actually effect the boost valve and how much bottom out resistance you will get, but air pressure will effect it far greater.



there is something else going on if you are feeling a spike and thinking that its the transition from pp to boost valve.

 

[FactoryCostcoDH]

I wasn't feeling a spike, so to say, but my conclusion about the propedal was all my own speculation.

When I was messing around with different shim arrangements I noticed that the propedal coupled with different amounts of air pressure would cause the shock to be much stiffer through about the first half of the stroke.

So in my logic, I would think that the PP would start the wheel decelerating much quicker before even reaching the point at which the pressure in the boost valve would ramp up significantly. Therefore allowing the shock to be sitffer but not ramp up too hard where it is uncomfortable.

 

[General Lee]

you're propedal theory is interesting; but wrong all the same. it is a slow speed compression blow off. it simply increases/decreases the force needed to get the shock moving but it does not change the overall damping of the shock. as soon as you hit something hard enough to overcome the pro-pedal circuit the shock will react as if the pro pedal was never there at all. it will not control bottom out; it is intended to control pedal bob and slight compression due to changes in body weight (though a true low-speed comp. adjustment a la rockshox vivid would be better at the latter), hence the term "pro-pedal." yes, turning your propedal dial in may feel like it is stiffening your ride overall but in effect you are simply altering the ride height of your suspension as bumps try to overcome the propedal blow-off. it feels stiffer but what is happening in reality is you have compromised the shock's ability to absorb med. sized bumps while doing nothing to keep it from bottoming out. think of it this way: say bump forces range from 1-10. with the propedal dial you might be able to tune the shock so it remains firm on forces 1-7(hypothetically) so in effect you have lousy feeling suspension for the majority of the trail--this gives you the feeling of it being stiffer--but as soon as you hit a large bump (8-10), wham, the shock still bottoms out. and before someone feels the need to point out that you can, in fact, effectively lock out your suspension with the propedal valve that pretty much defeats the purpose of having 8" of travel. cranking it in anywhere beyond a half dozen clicks just isn't practical.

propedal is not meant as a bottom out control, that's that the big blue knob on the reservoir is for. it decreases the volume in the air chamber and thus ramps up slower or faster. heck, the propedal isn't even a true low speed comp. adjustment which is why many factory riders have opted to remove it altogether and make lsc adjustments internally, and why rockshox have opted for a real lsc circuit on their vivid line rather than a spring loaded blow-off valve.

again, learn what the adjustments on your bike are for and what they actually do. And keep in mind that there are maybe a dozen people on this message board qualified to discuss suspension in a proper, factual way. None of them has bothered to chime in here; maybe they've realized it's a lost cause.

carry on.

 

[cheetaprowlerDH]

(97 cheetah frankenbike, RC motocross bars, 24" wheels . . . .); the rest of us sure did.

would you like to take a walk in my shoes concerning that focking bike?!?!?!? yes, i know the bike was f-ed up, the bars are wide, and the frame WILL ONLY ACCEPT A 24" WHEEL, but before you go making solid conclusions about us, consider what limitaions we have and how few options there are for a couple of 16-17 year old kids who DH off of $120 or less per month.


i greatly appreciate all of your input to help our knowledge of suspension, there is no denying that- i'm essentially taking notes on what you are mentioning, but consider some things please, i'm not singling you out, but we dont comment on other peoples equipment making conclusions about them; if we do, we are trying to understand what their situation is so it can make sense.

 

[davep]

Many people have mentioned that you guys should learn more about the DHX (or other products) before deciding that you need to modify it in a way that you do not understand.

I am curious how the shock oil got re-bled, multiple rebound shim stack configs were tested (with a complete rebuild each time), and a concusion as to the benefit of this mod was made in one day????

Also, oil weights keep getting mentioned which is another 'red light' to signify that what is being done is not undertood by you guys. Oil weights mean nothing!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! What is the cSt of the stock oil ? what cSt did you put in? How did you make sure 100% of the air was removed? What IFP depth is propper for your length DHX?

With out the ansers to all of these questions, you are doing more harm than good by opening your shock. Not to mention that (like most people) you do not fully understand the adjustments of the DHX.

Many people have tried to help, you choose to not listen.

 

[General Lee]

would you like to take a walk in my shoes concerning that focking bike?!?!?!? yes, i know the bike was f-ed up, the bars are wide, and the frame WILL ONLY ACCEPT A 24" WHEEL, but before you go making solid conclusions about us, consider what limitaions we have and how few options there are for a couple of 16-17 year old kids who DH off of $120 or less per month.


i greatly appreciate all of your input to help our knowledge of suspension, there is no denying that- i'm essentially taking notes on what you are mentioning, but consider some things please, i'm not singling you out, but we dont comment on other peoples equipment making conclusions about them; if we do, we are trying to understand what their situation is so it can make sense.

no offense was intended. I know full well what it is like to be 17 and trying to scrounge together enough $$ and parts to keep a dh rig running (and it wasn't any easier in 1997 when everything we used was essentially beefed up xc technology). I was tearing apart rockshock super deluxes as far back as 1996 in attempts to get them working better. i did some whacky sh*t and was yelled at by daweson and jeremiah for it. I had no idea what i was really doing back then but i learned a lesson or two in the process. no unlike what you are doing now. lucky for you, we now have the internet (not so much for most uf us back then) and lots of people who can help take the guess work out of tuning. unfortunately the real guess work is figuring out who to listen to as everyone fancies themselves an expert even though they can't get the right pressure in their tires.

keep something in mind, and again this is not meant as a jab at you, your bikes, or you ability: Your bike has it's limitations, there is no getting around it. it can only accept a 24" wheel, it's a few seasons old, it is not the latest and greatest in dh technology, and it is not designed originally to be a pure dh bike. so what, you can still rip on it. Greg Minnaar said recently that riders make the bike, not the other way around as so many people would like to believe. however, you have a very capable shock on the bike so consider, at least to some degree, if the sum of all these factors still means the shock is the root of the problem? all bikes have their limitations, you ride around them.

my final bit of advice, if you decide to take it, would be to get a lighter spring (and possibley mount your shock in a setting with less leverage. quality over quantity in the travel department), use the stock oil as you are pretty light, run the bottom out control all the way in, and use between 0 and 4 clicks of pro-pedal. then adjust the air pressure in the reservoir to see what happens. why a lighter spring you ask? becasue it will let you use a wider range of air pressures and when it does bottom out it will not rebound nearly as fast (the possible root of why you get front wheel heavy). seriously, the section of trail you are describing sounds like the sort of think that will bottom out most suspension unless it is tuned specifically for that one section. doing so, however, would give you an overdamped, chattery rider everywhere else.

the key to riding "around" the problem is knowing what your bike is going to do--be it bottom out like a ton of bricks or pitch you over the front tire--and be ready for it and learn how to ride through it. if it was a race course that's what you would have to do.

 

[FactoryCostcoDH]

you're propedal theory is interesting; but wrong all the same. it is a slow speed compression blow off. it simply increases/decreases the force needed to get the shock moving but it does not change the overall damping of the shock. as soon as you hit something hard enough to overcome the pro-pedal circuit the shock will react as if the pro pedal was never there at all. it will not control bottom out; it is intended to control pedal bob and slight compression due to changes in body weight (though a true low-speed comp. adjustment a la rockshox vivid would be better at the latter), hence the term "pro-pedal." yes, turning your propedal dial in may feel like it is stiffening your ride overall but in effect you are simply altering the ride height of your suspension as bumps try to overcome the propedal blow-off. it feels stiffer but what is happening in reality is you have compromised the shock's ability to absorb med. sized bumps while doing nothing to keep it from bottoming out. think of it this way: say bump forces range from 1-10. with the propedal dial you might be able to tune the shock so it remains firm on forces 1-7(hypothetically) so in effect you have lousy feeling suspension for the majority of the trail--this gives you the feeling of it being stiffer--but as soon as you hit a large bump (8-10), wham, the shock still bottoms out. and before someone feels the need to point out that you can, in fact, effectively lock out your suspension with the propedal valve that pretty much defeats the purpose of having 8" of travel. cranking it in anywhere beyond a half dozen clicks just isn't practical.

propedal is not meant as a bottom out control, that's that the big blue knob on the reservoir is for. it decreases the volume in the air chamber and thus ramps up slower or faster. heck, the propedal isn't even a true low speed comp. adjustment which is why many factory riders have opted to remove it altogether and make lsc adjustments internally, and why rockshox have opted for a real lsc circuit on their vivid line rather than a spring loaded blow-off valve.

again, learn what the adjustments on your bike are for and what they actually do. And keep in mind that there are maybe a dozen people on this message board qualified to discuss suspension in a proper, factual way. None of them has bothered to chime in here; maybe they've realized it's a lost cause.

carry on.

I apologize then for my misunderstanding. I am just not as familiar with the DHX in comparison to what I am used to tuning (motocross suspension). I guess I'll leave the shock at 75, back the PP all the way out, and turn the bottom out about 1/3 the way in. It actually rides about the same through the first 3-4" of travel but then ramps up more than before. Same with the forks.

I took my chain and broken derailleur hanger off today so I could hit the little urban style drops at the end of my street. Everything felt good so far and I am using full travel in the rear at 75 psi with everything backed out. The fork's also using about 6" out of 7 with the compression backed out