|   How Much "Plushness" is Lost w/ Stable Platform Shocks... | Zag
Oct 17, 2002 2:17 AM | | More specificially, how much small bump compliance is lost with the new generation of stable platform shocks (i.e. Romic, 5th Element, Curnutt, etc.)?
I can see where a long travel "freeride" bike such as the Bullit or Uzzi SLX would benifit from such a shock, because with such a bike you are most likely much more concerned with big hit performance, rather that small hit sensitivity.
But how about a short travel trail bike? It seems like there is generally a tradeoff between efficiency and comfort. I you increase the travel you will increase the comfort and decrease the efficiency (for any one design). The new generation of shocks use more sophisticated damping to provide a stable pedal platform, which allows for more travel and softer springs while still retaining the pedal efficiency of shorter travel conventional shocks. However, there is still a "threshold" that must be overcome before the shock will move. Does this make the shock less senstive to small bumps, or does the longer travel and softer spring make up for this?
In general terms, I am trying to choose a FS frame, and am trying to decide how much travel I want. One of my primary goals, is comfort at slow to medium speeds on rough rocky/rooty trails. Big hit performance is of no concern what-so-ever. A small amount of suspension activity (or bobbing, or whatever it's called) while seated does not bother me at all. However, I find it very bothersome when standing, so I want something that does not wallow around in it's travel excessively while standing and sprinting or climbing (and I don't want to have to concentrate on pedaling circles while I am standing, I just want to hammer away).
So, my main question is this. Will I get better small bump sensitivity with 4" of travel and a conventinal shock like the Fox Vanilla RC (i.e. a Turner XCE for example), or something with more travel, say 5", and a more sophisticated shock (i.e. an Ellsworth ID or Turner 5 Spot)?
If the conventional shock with 4" of travel will provide more comfort than would then newer design with 5", then my decision is easy (and I am asking this question now, partially because the XCE may not be available all that much longer). The only reason I would consider 5" of travel is for the extra comfort. If I won't get that, then there is no reason for me to lug all that extra weight around (not to mention the problems caused by the slacker geometry). |
| Romic on a Truth | Steve from JH
Oct 17, 2002 7:55 AM | | When I first put on a Romic I did a kind of test. There's a place I ride to run my dogs that is flat but very bumpy. There are some dikes built up from river bottom rock where you're continuously bouncing from one baseball to softball size rock to the next. It's just rock--no dirt. I repeatedly rode over a section at different compression knob settings, from all the way open to all the way shut. I concluded that I couldn't tell any difference in the way the bike swallowed the bumps. A blind test, where somebody else set the knob and I didn't know the setting, would have been better, but I was by myself (except for the dogs).
When riding on smooth pavement the difference in pedal bob from the two extreme settings is quite noticeable. Also on a good dirt road I noticed once that with the knob all the way shut the bike was harsh over little rolling dips and wrinkles. And with it all the way open it wallows too much at speed in rolling dips and g-outs. I suspect that it's better not to set it too far shut when climbing very steeply at walking speed if there are roots or rock steps to go up. But for moderate to high speed cruising over small sharp bumps you don't seem to give up any "plushness" with the valve shut down.
As for your statements about giving up efficiency for comfort with longer travel, I think you know where I stand. I'm quite convinced that there's no loss of efficiency (energy in vs. energy out) from pedal bob that's caused entirely by up and down movement of the rider. It's bad for traction when the going is steep and the surface poor and it limits your top cadence when pushing a big gear while out of the saddle. But it doesn't waste energy. |
| I am probably not using the term "efficiency" correctly... | Zag
Oct 17, 2002 8:49 AM | | So how fast were you going in your test? I am not much of an adrenaline junky myself. I just like to get out in the woods and explore, so I spend most of my time riding at a relatively casual pace, but over fairly rough ground. I spend a lot of time riding over 2"-6" roots and rocks at about jogging speed. If I could, I would like to improve suspension performance in this situation, without adding a lot of excessive out of the saddle bobbing.
Efficiency is probably not the correct term for me to use here. At least I am not using it the same way as you are. I don't really care about lost energy (in this case). What I am really trying to say, is that I want to get as much comfort as I can (for low to medium speed hits), and yet I don't want the bike to bob excessively during out of the saddle pedaling. It's not that I am concerned about losing energy, it's just that the movement really bothers me and I don't enjoy riding as much (it doesn't really bother me when seated, just when standing). My Rocky Mountain Element bobbed so much during out of the saddle pedaling, that I stopped standing and spent all of my time in the saddle. However, I don't have that problem at all with my Dakar.
So, when I used the term efficiency in my initial post:
"It seems like there is generally a tradeoff between efficiency and comfort. If you increase the travel you will increase the comfort and decrease the efficiency (for any one design)."
I was trying to find a concise way to say:
"It seems like there is generally a tradeoff between travel and how much suspension movement you get with each pedal stroke (for one thing, you can run a softer spring). If you increase the travel (and reduce the spring rate) you will increase the comfort level, but also increase the amount of suspension movement you get with each pedal stroke (for any one design)."
Perhaps I should have used the term "bobbing" instead. But there seems to be some disagreement on what "bobbing" means as well, so I tried to find a different term.
Note, that I am not saying that I disagree with you regarding you view on efficiency. Recently, I bought a Jamis Dakar. Overall, I really like the way it pedals. The only time I am bothered by the "bobbing" is when pedalling at a high cadence in a big gear. I seem to hit the resonant frequency of the rear suspension, because it starts ocsillating quite a bit (probably partially due to the terrible RST-22 rear shock, which looses all of its damping in the first 1/4" of its stroke when pedaling along like this). I thought of our previous discussion, so I tried a little (very unscientific) experiment. I unclipped from the pedals, and tried to move my legs at the same cadence. Sure enough, the bike bobbed just as much (at least I could not tell the difference) without my feet even touching the pedals. Apparently, most of the bobbing was not caused by chain tension, but was caused by the up and down motion of my legs, as you described. So, in this case, the bobbing is not a loss of efficiency. However, it still bothers me. I suspect that a shock with better damping, could eliminate this bobbing all together.
I figure that I am probably annoying some people with all of these questions. I know, that how much bobbing is deememd excessive is a relative term, and is largely a personal thing. I really wish I could test ride some of these bikes, but I really don't see how I can. To make a long story short, I was transferred to Norway on a job assignment 2 1/2 years ago. I will be here for another 1 1/2 years, and there is a lot of really good trail riding here (lots of XC ski trails). However, mountain biking is really not that popular, and there simply are not any long travel or "high end" bikes available for test riding. There are some small importers of high end bikes, but they don't stock any bikes. On top of that, bikes are incredibly expensive here. A frame that costs you $2000 in the states, costs me $2700 here (with shipping, duty, taxes, etc.), so I can't really afford to buy something and then decide it's not for me. I probably should just wait til I get home, but I have been drooling over all the bikes that have been released over the past 3 years, and am suffering from serious bike lust. On top of that, I have a 40 minute commute to work that consists largely of technical single track, so I can ride every day. Chances are, when I get back home, I will be limited to weekends. Anyway, I think I am rambling... |
| A mutt of an answer... | Tscheezy
Oct 17, 2002 2:11 PM | | Here are some excerpts from a review of the Uzzi SLX from mountain bike. The Uzzi is a totally different beast than the XCE or 5 Spot, but the shock behavior may transfer a little.
"Now, about the shocks. With the Fox Vanilla RC, you get the ride you expect. The bike is ridiculously plush and supple, and basically swallows everything. Climbing and sprinting is a bouncy experience, which is no surprise on a bike with six to seven inches of travel... it feels like it's all spring. In corners, the bike never settles down completely, and will wallow and bounce. When pedaling through rough sections, the bike will kick the rider off the saddle occasionally. The bike is much easier to bunny-hop with the Fox, and generally has a more playful feel.
Put the 5th Element on and the SLX has a more stable, planted feel. The wallowing-in-corners sensation disappears, and there's hardly any kicking when pedaling through the bumps. The shock also removes about 95% of the bouncing that goes along with pedaling the SLX.
It doesn't have the same suppleness on small bumps, but it has a nicer finish on the big hits. Bunny-hopping the bike with the 5th Element is much tougher-the bike wants to stay on the ground. You trade the playfulness of the Fox for speed and stability-even though you're going faster, the shock lets it feel like you have more time to guide and control the bike. Huckers will appreciate the ability to increase progression without having to jack up spring rate and screw with the bike's smaller-bump performance.
Spend some time thinking about what ride traits are important to you before you make your shock choice. The easiest way to explain it is like this: For bigger hits and higher speeds, you want the 5th Element, no question. If you hold a plush feel and comfort above everything else, get the Fox."
Obviously the XCE pedals extremely well (I have one and it is the best pedaling full bounce bike I have ever sat on- compliant and efficient and no bob). I don't know about the 5 Spot, but it is safe to say it will behave the same, with a little more travel. The difficulty is in applying the shock behavior from a bike which desperately needs some squish-reduction like the Uzzi to a bike which does not need any squish-reduction like the Turners. Apparently the pedal-filtering shocks feel a little "dead" and less supple and may hurt your type of riding if being able to bunny hop the bike is important. Others would rather sacrifice that for a very level, controlled ride. It's all personal preference. You sound like the Fox Vanilla type, though, because you don't mind some suppleness in the suspension, and the Turner's linkage design itself eliminates all chain-torque bob. Read the XCE reviews and those with Romics love them, and those without love the bike too they and don't complain about any extra squish.
tscheezy |
| A mutt of an answer... | Zag
Oct 18, 2002 8:04 AM | | Thanks for the info. Yeah, I have read that review, and several others like it. Most of the reviews are for long travel freeride types bikes, that's one of the reasons I am wondering how well the new shock work in shorter travel applications. Up until now, I was not interested in any of the longer travel bikes, because the geometry was really too slack for my tastes. However, the 5 Spot looks like it might make a decent trail bike, so now I'm not so sure. I suspect I am more the Fox Vanilla type. I just don't want to limit my future upgrade path. I guess maybe I need to give the guys at Turner a call and see what they have to say about it. I was hoping to get a bit more feedback here, but it looks like no one wants to play. Or, maybe no one knows the answer. |
| Still plush on small bumps | Benno
Oct 18, 2002 7:03 PM | | I've got a 5th element on my heckler single pivot, I find that small bumps are absorbed fine. As I understand it small bumps are at a higher 'frequency' than pedaling forces. What the 5th element suspension resists are slower movements of the suspension, like pedaling or, in an offroad race car, cornering. Rather than being a force threshold (smaller forces are ignored, large ones activate the shock), its a speed threshold (fast bumps activate, slow movements don't).
The NRS is definately of the 'force threshold' variety - locked out on the smallest bumps, activated on bigger ones. Comparing the heckler with my NRS, the heckler has a bit softer pedaling feel, but I don't think its soaking up pedaling energy. The NRS just has that 'locked out' feeling like a hardtail. Riding across slickrock terrain on the heckler I can just cruise along where I would have been worrying about picking my line on the NRS. Small bumps are erased. Hope this helps! |
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