Honest suspension/shock setup question from a hack

Manifesto · Apr 2, 2011

i was having the same problems with the rear end of my bike, except its a 9 inch travel dh rig. Greased up the bearings, swapped the D.U bushings for RWC Needle bearings and moved to a Titanium coil on my DHX. Even though I do run a stiff sag(20-25%) it feels like supple and snappy. When hiking the bike I can see the suspension taking up the chatter on the ground, it's deffinetly worth the money(alot of money for the Ti Coil)

was around 60 bucks for the needle bearings from RWC, and around 230$ for the titanium coil. Well worth the purchase

Jm_ · Apr 3, 2011

Blatent, you "love" the single pivot suspension, yet you are saying that it's harsh with a variety of shocks? That seems contradictory. It seems like you are trying all sorts of stuff to try and like it, but usually it's harder to optimize a "multi-chainring" bike as a single-pivot, and the lack of a linkage is going to contribute to that choppy feeling no matter what kind of shock you put on there. It's not apples to apples when comparing the suspension of a DH bike to that of an AM/FR bike. The type of rising rate that is found on most linkage-bikes is just impractical to replicate on a non-linkage single pivot from all the bikes I've tried. Lots of things have tried to band-aid this, but in the end you're not going to have that real soft initial travel without making some other huge sacrifice.

Let me put it this way, I remember not too long ago I demoed a Bionicon bike with a VERY similer shock/suspension/swingarm setup. This bike had 8" of travel. It was equipped with an air shock. This bike felt like it had LESS ability to suspend and absorb the features of the trail than my 6" RFX (horst link w/DHX shock). That is quite dramatic when you consider that the bionicon had 2" more travel, but it was severely limited by the single pivot suspension and air shock.

Honestly, good luck. I don't expect you'll get that SP morewood to perform like your el guapo did in the suspension department, although I know suspension can work quite a bit better than the el guapo even. The sharp-edged bumps are the problem with that kind of design, but there are a few out there that can deliver in that area and more.

What is it that you really like, the geometry or the suspension? You took a lot of flak, and it is pretty crappy to jump on someone's post like they did on mtbr when you posted (maybe it's the local love of Titus), but it seems like you're running into a dead end?

I'll say that my old 66 RC2 is no match for my rear avalanche chubbie (RFX). The chubbie is way better and rides way higher/firmer while still reacting to the sharp hits like butter. The 66 dives a lot more and is somewhat unbalanced with the rear. Maybe RC3 is better, but my avalanche rear shock simply outclasses anything I've tried. The real high/low circuts allow a pretty good overall compramise. It's interesting to try new suspension types though, as there are ones that give just as good if not better a feel now without the expensive rear shock. I like the avalanche suspension so much though that my DH bike is going to have it on both ends next week. The way the suspension reacts is just amazing and so stable, and as you go faster/hit choppier stuff it just seems to get smoother. That is what I like about it.

I'd say if the DHX didn't bring you close to what you thought was pretty damn good, it's not going to work out.

buckoW · Apr 3, 2011

Try a more progressive shock like an RC4. Close the bottom out chamber to help the bike ramp up a little more. You need a sick shock tuned for you and your bike to get the most out of a single pivot.

slyfink · Apr 3, 2011

how about a Monarch Plus RC3 direct from Push? a quick chat with them should get you a good understanding of whether it would work?

jekyll991 · Apr 3, 2011

Someone chime in if there are actual negative effects on the shock, but have you tried reducing the pressure in the air chamber? My commencal supreme (linkage driven single pivot - very progressive) came with a DHX 3 was the same way when I first rode it. I dropped the psi down to 75 and it felt much better, maybe try 100-125psi since you're much heavier than I am.

It will void the warranty if you go below what's written on the shock, but I haven't had any problems caused from running such a low pressure yet.

Jm_ · Apr 3, 2011

dbozman said:
JM/Others: If I wasn't clear the first time, let me restate. The geometry of the Morewood is what I love. Fairly certain I never said that I "love" single-pivot designs.

blatentfrommtbr said:
First off, after using a vairety of 'modern' suspension designs, I like the single pivot

You also said there is some feedback in the granny ring, I agree that it may not be an issue for you depending on where and how you ride. Idk, it seems like you are "trying" to make this bike work for you. Many of us have been there, making major modifications to our bikes to try and get them to work better. In the end will it perform like you want? Based on what you are complaining about, I'd say probably not, as these are the traits that are usually inherent in that setup. Again, the dynamics of the DH bike and the am/fr bike are different. You aren't pedaling in the same way on both, the smaller front ring that you are in/using on the shova, the harsher the suspension is going to be as the pedaling tends to lock out the suspension.

Seriously, if you can't get it to feel at least somewhat decent with a DHX, then it's not going to get better. The DHX is decent, something like the RC4/Avalanche/Vivid coil would be a bit better, but I don't think you're going to solve your problem with other air shocks.

Being "honest", I can't honestly say that any of my non-linkage driven single pivot bikes were anything but harsh compared to the same-travel linkage driven single pivot bikes. I can also honestly say that with the DH bikes that I've owned, "virtual" or "FSR" type pivots don't really net you a huge benefit, as compared to an AM/FR/XC type bike. Yes, those are incredibly overall statements, but so far they've held up pretty well. Good luck.

jwick · Apr 3, 2011

Just a thought, but is it possible the DHX4 is tuned for a different bike's leverage ratio giving you some harsh ramping? Aside from having some aftermarket custom tune, i would just try reducing the air in the piggyback and turn off any propedal. You say the dhx is used... Is it possible it's in need of an oil change/rebuild?

There you go buddy, more questions for ya... sorry no real answers here

freeridefool · Apr 3, 2011

Being a scaled down version of the Izuma doesnt mean a whole lot. The one shova I rode was harsh on the little stuff... but I never even turned a dial on it as it wasnt my bike. Im not a huge source of advice on the subject but give push a call and get their thoughts on the matter... or morewood.

demo 9 · Apr 3, 2011

Only watching from the outside, but i get the impression you dont want to hear what JM is saying. I happen to agree completely with him,and i think you should really reconsider what he is saying. I get the impression your defensive on your bike choice, and i dont necessarily blame you.($$$) I think its really worth considering if its the right bike for you (and whatever you choose to do with it) A DHX is a pretty good shock, sure it can get better, but i doubt that you will totally solve the problem with a RC4. (placebo effect?)

The shock hardware wont help your ride, it will just quiet the bike down if it rattles, i dont think that is your problem. Either way i wish you luck, but i am not so fast to jump on the DHX being the problem

freeridefool · Apr 4, 2011

demo 9 said:
Only watching from the outside, but i get the impression you dont want to hear what JM is saying. I happen to agree completely with him,and i think you should really reconsider what he is saying. I get the impression your defensive on your bike choice, and i dont necessarily blame you.($$$) I think its really worth considering if its the right bike for you (and whatever you choose to do with it) A DHX is a pretty good shock, sure it can get better, but i doubt that you will totally solve the problem with a RC4. (placebo effect?)

The shock hardware wont help your ride, it will just quiet the bike down if it rattles, i dont think that is your problem. Either way i wish you luck, but i am not so fast to jump on the DHX being the problem

Cant believe I agree with demo 9. Good job d9

And unless your shock hardware or pivot bearing are so bad that **** is falling out it wont make very much of a difference.

slowitdown · Apr 4, 2011

freeridefool said:
Cant believe I agree with demo 9. Good job d9.

for sure

I'm clearly not a suspension expert. I want a shock that complements the 66 (which I really like), that rides relatively high in its travel, that has some form of "platform" for pedaling, is decently plush and complements the simple suspension and geometry that I love on this frame.

dboz,

It's been a long time since I rode a Marzocchi fork -- a 2004 888 whatever the top model was -- but my recall is that Marz are so supple in initial travel that they simply cannot ride tall in their travel unless you eliminate all the initial suppleness. Is that still true? If so then IMO you're not going to get a rear shock that feels the same yet rides high in its travel... and you're definitely not going to get it in an air shock.

I think you should listen to Jm.

I also think you should spend some time focusing on your riding, and not on what the bike is doing. This thread kinda smells like a lot of hot air (e-riding, e-speculation, e-pseudo-engineering) serving as a placeholder for riding, rather than an honest description of a true bike function problem and an attempt to fix it.

Gotta watch out for the urge to follow the InterWebToobz MTB herd, who love to pretend at insider technical knowledge by throwing around terms and speculations about how this or that might change their ride. Learning how to ride a bike better should always be the starting point for improving one's ride experience... not suspension upgrades or bike bling. Once you have enough saddle time you will realize this.

demo 9 · Apr 4, 2011

dbozman said:
I've ridden my Izimu on these same trails (same suspension, different shock) and was very happy with the suspension performance. Therefore, it seems to me that I have an issue with suspension/shock setup.

Not to point out the obvious (or not so obvious?) The bikes may be closer than a demo 9 to a V10, but still worlds apart. See not all single pivot bikes are the same, even if its the same brand and same acronym. (EX; spesh demo 8 is NOT an Epic or bighit) There are so many variables going from bike to bike, even sometimes generations of the same bike.

I apologize in advance if i butcher this or explain it wrong, but this is how it was explained to me, and it made sense. All bikes with rear suspension have a leverage ratio. *typically* DH bikes tend to have high to low leverage ratios. This is because if you break you shock into 3rds you get the following

(assuming a 3.0 stroke on the average DH bike with 8-9 inches of travel)

lets assume the first 3rd of the shock is for sag and really light bumps ("leaving" or "floating" the ground)

the 2nd 3rd of the shock is probably more used for real bumps, rocks, light jumps, generally everything you see on the trail.

the last 3rd is usually for G-outs, big jumps, drops ect.

IMPORTANT, this is only how the shock is generally designed, the shock doesnt know the bike its going onto, or how it works.

The more travel you can squeaze into the first 2/3rds of the shock-the better it can ride-TYPICALLY. Frame designers know this, and use this to help their design ride better.
(think of the opposite, hardly any sag, and when you bottom out you find 4-5 inches in the bank you can never get to unless you huck to flat=BAD)

Here is where it gets a little tricky, the reason the leverage ratio starts high and tapers off is because if it was straight the whole way, your 9 inch travel DH bike would only use 6 inches of travel for most of the bumps (big generalization) If you have it how it currently is, the bike can use 7 or 8 making it smoother. (yes you loose a little bit on your major G out, but you wont notice 2 inches on the back end as much as you will on the front end of it.)

Above is *probably* very similar to how your izumu was designed (big blanket statement) I cannot speak for the other bike, but if its not a DH bike, its probably way different. And no matter what you do, it may be tough to get to act the same. I learned this the hard way a few times wondering why i coudlnt get my AM/SS bikes to act like a DH bike with less travel. They have different leverage curves and goals in their design.

So you know, it is possible you will love the bike with a new shock, i had a jedi with a DHX and i was pretty happy with it, very happy with it. The next year i got the same jedi, but it came with an elka (more open than a DHX) The jedis have a "hump" in the shock curve that used to "line up" poorly with the DHX and cause it to spike, running the elka doubled the ride of the bike. *please do not take that as a positive reason to disregard what everybody says and buy a new shock. That said, if you want a new shock, dont let us stop you, but i still get the impression that you are trying to "convince" us (maybe yourself?) that a new shock will fix it. & it might, im not scientist over here, but do more research on the frame design, because a single pivot isnt just a single pivot.

demo 9 · Apr 4, 2011

dbozman said:
I appreciate that. Both the Izimu and the Shova have a reported 2.7:1 leverage ratio. The Shova has 7 inches of travel and the Izimu 8.2. For all intents and purposes (far as I can tell), they're fundamentally the same bike.

I'm open to most suggestions about "fixing" the issue. I already own the DHX, so financially I'd rather make it work. If there's a magic bullet out there, though (which I suppose was ultimately the idea of the thread), I'd consider it.

They are probably very similar, i just do want to point out the small differences can make huge differences (look at BMX bikes!)
That reported leverage ratio is kinda useless, its just travel divided by shock size. (demo 9 has 3.0, but its not a straight line, its 4.0 tapering to 1.0 *or w.e) as per discussion above.

Silly question, are you sure you have the right spring?

Push can probably custom valve the shock to act however you want, but its costly and takes a small bit of time, that said, you still fixing a problem that doesnt necessarily exist.

Inclag · Apr 4, 2011

I'm going to hop on board with most all the other posters and suggest you look long and hard at the bike. I'm in a scenario where I have a non linkage drive single pivot trail bike which I'm more or less stuck with for the time being. The geometry and fit is a hair wonky, but that will and is currently being sorted out.

However, one thing I am sure of is that the rear suspension performance is not and will never perform in the manner that I would like and have been accustomed to on other bikes. Which isn't to say that the suspension holds me back or ruins my ride, far from it, but I'm not going to spend extra money to custom tune or by an aftermarket shock that will make the performance marginally better. I know many people here geek out about their bikes and make claims that the parts they run make such noticeable improvements and are leaps better than their 1 year old obsolete parts. Hell, go back 4-5 years and follow till now the reviewing and whoring of bikes and parts from certain posters on this website and you would think that based on where they came from to what they are riding now that by farting on top of their seat it would provide enough propulsion to climb Mt Kilimanjaro or drop the Eiger North Face.

If you are really picky about your rear suspension and hellbent with keeping this frame (lets face it there are endless bikes that kick ass these days) just get your rear shock custom tuned which will band-aid as best as possible the issues you currently have with the bikes wheel-rate.

goodgrief · Apr 4, 2011

the source of the shock is what concerns me. trek get custom tunes for their bikes which are all linkage driven so i'd say it's quite likely to be the root of the problem. nobody else picked up on this?

lalocotequinta · Apr 4, 2011

Hey OP, I own an '05 Shova LT and love it. I have it set up with a Roco TST which when I first bought it I didn't like at all, blaming the bike and the single pivot design for the lack of responsiveness.
For the second season I decided to send the shock to Push Ind and what a difference it made.
Probably your shock was valved for it's original frame and that's why it may be difficult to find the sweet spot on your bike. I strongly suggest you to send the shock for a custom tuning, after that I bet you'll enjoy your bike a lot.

jwick · Apr 4, 2011

goodgrief said:
the source of the shock is what concerns me. trek get custom tunes for their bikes which are all linkage driven so i'd say it's quite likely to be the root of the problem. nobody else picked up on this?

That is what i was getting at earlier. moar shimz. I'd call Push or morewood directly and see what their thoughts were like someone else said. They'd have the best ideas on the specific leverage curve and the tuning required for any specific (DHX) shock. A custom tune is probably the best and least expensive route, imo. On another note, why not try a #450 spring. Cheap idea. You might just be fighting a slightly oversprung setup.

demo 9 · Apr 4, 2011

^ building upon that, according to push (when i pushed my dhx) all springs have a 15-20% leniency, so the 500 might actually be a 515 or w.e

Delimeat · Apr 4, 2011

Hey dbozman,

I read or original post but not all of the replies - sorry if this has been said already.

Getting an air shock with a proper lock-out or platform to ride like your 66 isn't really feasible. The 66 is very active... I see a Diverse shock being a good mate for it if you are looking for that sort of ride and want a balanced feel, but there is no lock out or pedaling aids on it. A Roco with the TST switch would obviously be a good match as well.

I've spent a bit of time on a Monarch equipped 5" travel bike and am loving it. It feels more active but at the same time much more controlled than some other options. Its tough to just go ahead and recommend a shock because they are usually tuned for the bike's leverage and the same shock can ride so differently on different bikes. Having said that, a bit of time tinkering with your RP23 may change your tune. If it has an XV air sleeve, slide it off and add something in there to take up some of the volume (I cut up an old water bottle to fit against the XV can's inner wall). This will make it ramp more at the end of the stroke, meaning that you could run a bit lower air pressure for better small bump compliance. No, it'll never match the Diverse (or any other coil) for sensitivity, but you should be able to get it working better and it does have ProPedal for the climbs.

There is no reason that you can't get your single pivot bike dialed.

Jm_ · Apr 4, 2011

dbozman said:
Thanks for all the input. It is true that I want to like this bike and make it work. I imagine that's accurate for most of us. Reality is, the Morewood just fits my body and my riding style perfectly. I don't feel like I'm being defensive about it; I got the frame for a song so I'm not economically tied to it.

I don't typically like JM's delivery, but I recognize his experience. The problem is, if you really read his replies (and I've read them carefully) they boil down to a treatise on pedaling characteristics and the associated harsh/choppiness.

For the record, THIS IS NOT ABOUT PEDALING

The lack of plush I'm experiencing is happening on descents regardless of whether I'm pedaling or not, regardless of which of my two front rings I'm in.

I've ridden my Izimu on these same trails (same suspension, different shock) and was very happy with the suspension performance. Therefore, it seems to me that I have an issue with suspension/shock setup.

Not trying to start arguments, just looking for some reasonable outside input. Thanks again.

I hesitated to add this earlier, but you seem to be driving the point. There is a reason these designs were referred to as "semi-active" back in the 90s. While it's a pretty crappy term, the idea is that your feet are on the pedals ALL the time, that creates resistance via the chain as the suspension tries to extend the chainline throughout it's travel. While certain bikes do use chain extension to control certain aspects, a high single-pivot is not designed in this way, not to mention that the lack of a linkage creates the leverage issues we discussed earlier. There may be ways to overcome some of this, I just think they may not be feasible given current technology and equipment.

What size chainring is on your DH bike? What size chainrings on the AM/FR one?

freeridefool · Apr 5, 2011

dbozman said:
Thanks again for all the ideas. I'll start with some simple stuff and report back (spring rates, air, propedal). When I took the shock off today the hardware in the back eyelet fell right out.

Even if that doesn't exacerbate the harshness, it certainly caused a bunch of clanking (which my mind could easily interpret as harshness).

JM: Both bikes have a 32-tooth ring.

32 on both bikes? Hmmm.

Honest suspension/shock setup question from a hack

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