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Post by pjax on Apr 20, 2007 23:36:59 GMT 8
OVERVIEWThe bike: excellent components spec, decent construction, looks fast standing still Performance: sluggish on road, but performs extremely well on trails FSR: quite an overhyped technology and dubious marketing. The thing is, even though a bike has the FSR linkage, it will not guarantee "isolation from pedalling forces" "maximum pedal efficiency". It might. But most of the time it doesn't. Although, with the system, it does enable designers to manipulate the instant center and create a non-circular axle path. IN-DEPTH REVIEWThe Stumpjumper FSR comes from the line of Stumpjumpers - the first production mountain bike. Building up on its name, Specialized gave some Stumpjumpers rear suspension and brought us the Stumpjumper FSR. The BikeBike as tested is a 2006 Stumpjumper FSR (base model) with the shifter, brakes and RD upgraded to Shimano LX. The bike was used for more than a year. Specialized did a great job spec'ing their bikes. The base model comes with Fox fork and shock, Avid BB7 brakes and Mavic 317 rims. I did change the rear tire because 1) there is little clearance between the tire and frame (the tire is really fat) 2) I ripped the tire's sidewall. Specialized tires are notorious for frail sidewalls. Finally, all I could say is that that the bike is well built. No annoying flex. No stubborn parts. No chipping paint. After a year of weekend riding abuse, the linkage did develop play but nothing an allen key and grease couldn't fix. Not to mention it looks really cool and aggressive. The performanceThe Stumpjumper FSR (up to higher models without Brain) features a proprietery shock called the Triad. This shock is built specially for the Stumpy as you can't buy a Triad shock elsewhere. As the name suggests, the Triad has three settings - lockout, propedal and open - learning from the finicky Septune shock of the previous Stumpjumpers. The Septune had four more settings than what most riders needed (with 7 settings). Simply twist a lever on the Triad to one of three positions to select a setting. You can even switch settings on the fly. Kinda like the RP23. LOCKOUT: Fox shocks are notorious for "pogo-ing" while locked-out. In this setting, the shock is stiff and locked, but not completely incompressible. The suspension tends to compress a little with each pedal stroke. It's quite annoying when mashing the pedals on road. And the bike still won't feel like a hardtail. OPEN: this is the most plush setting, and this is where you will realize how much of a joke FSR marketing is. Set the lever to this OPEN position, get on the bike then pedal hard. You will SEE and even FEEL the shock move by about a fifth of its stroke. Think about it: if Specialized claims that FSR technology "isolates pedal forces", then why do they spec their bikes with platform shocks, more so with inertia valves like the Brain? The OPEN setting is suited for the downhill runs. It's so plush, in fact, that it feels like there's no rear tire! It eats ruts and rocks too well that I feel as if my rear tire is constantly slipping. That's quite a compliment really. Although be careful about sudden climbs on downhill runs. The open setting is highly inefficient at pedalling and will disadvantage you on the climb. PROPEDAL: I use this setting 98% of the time. This setting activates the badly needed pedalling platform of the shock. It definitely improves pedalling efficiency but at the expense of not being as plush as OPEN. Pedal bob is minimized, but however, still noticeable. There is about half a centimeter of shock activation under really hard acceleration and it feels quite mushy under normal pedalling. It's definitely not as nimble as a hardtail. But what the stumpy lacks in nimbleness it makes up on the trail. The stumpy bores you when you're on the road heading for the trail. But as soon as your front tire hits dirt, rocks and roots, the bike transforms. You stop hating the bike for being so sluggish and start to praise it for excellent bump absorption and handling. It's a trailbike and trail riding is what it does best. The FSRMountain bikes have smudged the term "four-bar linkage". Technically speaking, VPP ( Santa Cruz, Intense), Maestro (Giant), dw-link ( Iron Horse), faux-bar (Da Bomb, KHS, Kona, sobrang dame pa), QUAD-link (Marin), FSR and a whole lot other acronyms ARE in fact, four-bar linkages. What makes them different is the pivot locations. For example, if you move the chainstay pivot on a Horst/FSR bike closer to the bottom bracket rather than the rear axle, you get VPP. FSR is Specialized's name for suspension with the "Horst-Leitner link" of which they own the patent to. If your bike has a four-bar linkage with a pivot on the chainstay (NRS, Ellsworth, Da Bomb, Titus), it has paid Specialized money You might have encountered a Specialzed advertisement where they claim that the FSR has a "vertical axle path". VERY NOT TRUE. In fact, since the chainstay pivot is very close to the rear axle, the axle path is very circular (you can see that the axle path is centered very much on the main pivot). The axle path is almost the same as a single pivot bike, varying by only millimeters. While there may be bogus marketing, the Horst link CAN make a difference. By moving the chainstay pivot farther from the rear axle, the axle path can change significantly. This is the case with the Giant NRS. notice that the rear axle path has no obvious "center" More so, the addition of pivots enables the designer to tweak the INSTANTANEOUS CENTER (IC) of the linkage. Not to be confused with the CENTER OF CURVATURE (CC) of a point, IC refers to a rigid body. In the case of FSR, this is the entire seatstay, where the axle is. Ellsworth capitalized on this and treated the IC as a "moving pivot" and tracked the "pivot on the chain line" thus the ICT "instant center tracking" patent. PS: I find it hard to express my ideas verbally. I understand that some things that I say may be quite unclear (I'm an engineer not a journalist ). So if you find some things that I say hard to understand, tell me and I'll clarify them
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Post by Dragunov on Apr 21, 2007 17:48:09 GMT 8
pjax! i think you should be a bike magazine editor with all those knowledge about full suspension! too complicated for me to understand but i want to. for me, the only test i do is the "seat of the pants" test or in short, ride it ;D Btw i like the color of your stumpy!!!
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Post by mountguitars on Apr 21, 2007 19:52:30 GMT 8
pjax,
are you sure you wrote all of this? if you did, its one awesome piece brad.
although specialized might've started or opened a can of worms, that doesnt mean they're good at it. through further research and development, some bike companies have flourished like giant and ellsworth by having their own way of doing things but using a common base: specialized technology.
and you're right. if their rear suspension is far superior than others, why use shocks that have pedal efficient platforms/features. a good example is giant's NRS. just apply the right amount of air and voila. no bob. but then again, its not vertically compliant as how you describe your stumpy.
that's what i thought with the stumpy as well. looks like a single pivot to me. but then again, i've never tried riding one so i could never express how it feels.
so after your review about FSR suspension, how do you find your stumpy? scale of 1-10, as 10 being the highest, how would you rate your experience with your stumpy?
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tutubing kalye
Urban Assaulter
daddy, paglaki ko akin nalang bike mo ha?
Posts: 96
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Post by tutubing kalye on Apr 21, 2007 19:54:11 GMT 8
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Post by pjax on Apr 21, 2007 22:27:04 GMT 8
@dragunov: i'd settle to be a magazine contributor. i'd do it for free ;D ahem siklista mag ahem ahemmountguitars: yes i wrote it. biking and engineering is something i'm very passionate about. it's based on some stuff i learned in school (ES12 dynamics of rigid bodies ;D) and personal experience. when we're in tight twisty rough singletrack i'd give it a ten. when we're on wide xc-ish roads i'd give it a 5. overall, meh, 7. i'm all for the ultra-efficient marvel of engineering bike. this one just isn't. @tutubing kalye: reading articles like that is exactly why i bought the stumpy. and how WRONG that article is. as i have quite experienced, oh boy. even when locked-out, pedal force causes the rear suspension to compress and don't get me started on the "BRAIN" inertia valve. i have never tried it yet, but don't you think the suspension will be a little too late at times? the brain inertia valve will turn on the shock only when it is movedwhatif you're going smoothly on road then you run over a square-edged bump. before the shock is "turned on" to absorb the bump, the "brain" has to move first. so you have to feel the bump before the shock activates.
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Post by mountguitars on Apr 22, 2007 13:05:48 GMT 8
@dragunov: i'd settle to be a magazine contributor. i'd do it for free ;D ahem siklista mag ahem ahemmountguitars: yes i wrote it. biking and engineering is something i'm very passionate about. it's based on some stuff i learned in school (ES12 dynamics of rigid bodies ;D) and personal experience. when we're in tight twisty rough singletrack i'd give it a ten. when we're on wide xc-ish roads i'd give it a 5. overall, meh, 7. i'm all for the ultra-efficient marvel of engineering bike. this one just isn't. @tutubing kalye: reading articles like that is exactly why i bought the stumpy. and how WRONG that article is. as i have quite experienced, oh boy. even when locked-out, pedal force causes the rear suspension to compress and don't get me started on the "BRAIN" inertia valve. i have never tried it yet, but don't you think the suspension will be a little too late at times? the brain inertia valve will turn on the shock only when it is movedwhatif you're going smoothly on road then you run over a square-edged bump. before the shock is "turned on" to absorb the bump, the "brain" has to move first. so you have to feel the bump before the shock activates. wow, that's what i was going to say. folks who buy specialize bikes take the time to find out about what they're going to buy becoz these are expensive as hell. and as such they take pride, owners of specialized bikes. but unfortunately, not everything is true on print and online resources. specially bike mags nowadays, i think specialized owns a big chunk of stocks of the most prominent bike mags nowadays that's why when they review specialized bikes, all praises kagad, hehe ;D. that was meant as a joke. ;D in your case though, its not difficult for you to say that specialized sucks in a way even if you spent a fortune to own one. some folks just swallow their pride or just rely on what's said on print and on the internet. im hell proud of you brad. not that im saying that specialize sucks. im pround of you becoz you expressed how you feel even when i think you're up against a wall of critics and die hard specialized fans. but dont worry, i know some guys who dont like specialized. in fact, one of our moderators hate specialized, hehehe. ;D you're not alone in short, hehehe. rock on brad!
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Post by fattire on Apr 23, 2007 1:44:59 GMT 8
pjax, thank you for calling a spade what it is even if if you own one, just echoing what the mountG had said. you keepin' it real, brad!
remember guys, all bikes are good, in whatever form, they all pay back the rider: health, stress-relief, untainted recreation, and most of all as mother earth's most obedient child.
here's the part that i'm not going to be preachy and guess who that spesh-hatin'-mod is:
1. that mod don't have money to buy spesh 2. that mod rides a kona
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Post by pjax on Apr 23, 2007 11:07:02 GMT 8
it's not a total lemon. what bugged me are their false advertising claims. not the bike.
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Post by grnhrnt on Apr 23, 2007 15:32:43 GMT 8
Pjay,
Nice observations. I'm sure your right as far as the engineering is concerned, try adding a little air in the rear shock, 5 psi at a time to get the the right pro-pedal feel, the "open" setting will likewise improve.
I don't think the Triad is a proprietary shock, In fact I'm almost sure its a Fox. It was re-introduced in the '06 line because the septune just had too many settings. This is what i have on my stumpy and only use three settings, 1, 7 and open. I think the triad is the better rear shock because of the lock out feature. It acts like a hardtail (which will also throw you off if you hit a bump) when engaged. Climbing efficiency is greatly enhanced. Propedal is the middle ground where the rear shock has more resistance in the initial 1/2 in. then opens when you hit a large bump.
Inspite of all the great features of Fox shocks and Fox, there is still a lot to be desired and thus the existence of the company "PUSH INDUSTRIES". This is an aftermarket company that further tweaks the already fantastic shocks and forx of Fox and makes them perform even better. Check out their website (google 'em).
The stumpy is probably one of the better bikes out there and they have had this technology way before the other bike brands incorporated them in their frames. You know what I mean you ride one!
see you in the trails!
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Post by fattire on Apr 23, 2007 20:01:55 GMT 8
Inspite of all the great features of Fox shocks and Fox, there is still a lot to be desired and thus the existence of the company "PUSH INDUSTRIES". This is an aftermarket company that further tweaks the already fantastic shocks and forx of Fox and makes them perform even better. Check out their website (google 'em). sir ramon, i agree with these statements: "great features of Fox shocks" (and forx) "there is still a lot to be desired" with all due respect boss ramon, PUSH will do what they claim they can but i do not believe they can do marvels on them fox shocks and forx that we can't do ourselves. this is just me but it is an enigma for me that they are "renowned" and "respected" ("my fox got PUSHed!") for doing something to fox stuff that the owners/riders can do themselves: read the manual and tune the d@mn thing! there's even this snippet about a rider who bought a fox forx online and had it shipped DIRECTLY to PUSH and another rider dissed him bigtime that he didn't even tried the fork. i'm siding with the rider who dissed. here's my bottomline: if you're a pinoymtbiker with endless bike money and you opted for your fox to be PUSHed at an instant, it's your right. but if it's the pinoymtbiker that tossed and turned at night, raised that cash for 6 months, should've sent panganay to college, but desired to have your fox forx PUSHed, let me not describe the bike inferno of that pinoymtbiker. again sir ramon i say this things with all due respect; the exaggerations are only for humor. my statements are to be taken with a grain of salt as i have not tried having my suspension PUSHed so i will never know the difference. mine's a conclusion based on online info that i think makes sense and also from credible inside source that sadly cannot be divulged here but can be shared during trailside chats... my humble, offtopic (somewhat related, ok?), 2 cents peace po sir ramon, see you during the 24 hours race
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Post by pjax on Apr 23, 2007 21:08:45 GMT 8
@grnht i just keep the bike at the recommended sag point. i like it plush. i tried adding more air but i didn't like it. plus it felt like i'm riding really tall. and it still bobbed the TRIAD is a joint effort between FOX and SPECIALIZED. it's proprietary. It's distributed ONLY by Specialized I considered PUSHing the TRIAD shock once. but their website claimed that I will lose the three settings if I have it PUSHed. plus it's so d@mn expensive and yeah. like i said. it's not a lemon. i just want to point out the false advertising claims. it's a trailbike and trail riding is what it does bestOT: sir ramon! we frequent the "porto" trails over at daang hari. when'll you be riding down south again? maybe we can arrange a group meet ride, with us the San Pedro "SPOKE" Riders. We'd like to know the sweet fire road that connects Davilan w/ the langgam/porto trails.
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Post by grnhrnt on Apr 24, 2007 17:03:25 GMT 8
Hahahaha... You guys!
Just like buying a stock car and modifying it. There are qualified tuners and then there are qualified tuners hehehe... Push Industries did the math for you. I agree we can do it ourselves because what it involves is re boring of ports and valving. But hey, why re-invent the wheel. Just during lunch my younger kid was trying to convince his friend he had over for lunch to try the onion rings i brought home, his friend wouldn't touch it an said he hated them, to which my kid said, "Hey, don't knock it till you've tried it. they're really good." I think this is the better attitude. problem is, its going to cost you to find out.
Yo Pjay, we've been doing long rides to palace in the sky reverse the past four Sundays. Last Sunday we modified our long Sunday rides and went down and up talisay. Haven't been doing the langgam trails of late. would pass by paliparan just to get to maguyam. sometimes we pass thru maguyam trail to get to sta rosa. So I actually am not familiar w/ the davilan trails. But I have your no. so i can text you to invite in our rides. Doing San Mateo this Sunday to track read for the race on the 6th of May. Your free to join up.
Owen, see you in La Mesa for the 24!
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Post by pjax on Apr 24, 2007 20:12:09 GMT 8
i'm fishing for comments. isn't anyone going to comment on the software i used to display suspension parameters? look at it. it shows the instant center, center of curvature, axle path, pedal kickback, chain growth, leverage ratio... it's free too
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jakob
XC Rider
Posts: 103
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Post by jakob on Apr 25, 2007 11:35:43 GMT 8
so what software did you use? do you think it's pretty accurate?
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Post by bongjumper on Apr 25, 2007 20:46:03 GMT 8
Very long review with a back up of high tech software... thanks for that Pjax... I also like FSR design. but not the specialized brand...
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Post by pjax on Apr 27, 2007 22:42:49 GMT 8
the software I used is called linkage. the pictures above link to their website. there are three versions of the program: a FREE personal version with basic features like the ones shown in the picture, a commercial version with some added functionality, and a professional version which has a feature that let's you design your own bike (i like that ;D)
why wouldn't it be accurate? all you have to do is to input the bike dimensions and the software will do the rest. the personal version comes with a library of existing bikes. PLUS you can also access the online library where you can download bike files made by the linkage community. most of the bike files are created using the bike manufacturer's claimed dimensions.
check it out. they've got Ellsworths, Santa Cruzs, Giants, Intenses... actually i can't think of an FS bike manufacturer that's not in the library.
Check out an Ellsworth ICT bike to see the instant center actually tracking the chain line (it really does).
check out the S-shaped axle path of VPP bikes (they don't look significantly s-shaped though).
check out the leverage ratio of Foes bikes.
check out chain growth and pedal kickback
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Post by grnhrnt on Apr 28, 2007 11:50:43 GMT 8
pjay,
I stand corrected on the triad. fox only does them for stumpy's so in effect they are proprietary. Keep up w/ the reviews they're great and saves us the time to do the research ourselves. hehehe...
Are you joining any of the upcoming races? Men's health xc race in san mateo and the 24 hr in la mesa.
See you in the trails!
Ramon
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Post by Onie on Apr 28, 2007 13:40:24 GMT 8
Good for you, Pjax! Cuz you are an engineer as well as a bike enthusiast. Got some background with dynamics of rigid bodies...
Props to you for that unbiased review of Stumpy.
Got that Linkage as well. But only the Demo version. Quite a helpful proggy... Like you said, all you have to do is just enter the variables... Guess, yours would be the commercial version?
Let's say if we let you choose which "One bike to rule them all"... which yields a great ride and efficiency... Or at least the bike company that's true with its claims (get away with super-hyped tech & marketing BS)... Then what's it going to be?
TIA!
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Post by pjax on Apr 29, 2007 0:35:09 GMT 8
if you let me choose the "one bike to rule them all", i'll design one myself. i'll try experimenting with keeping the instant center some distance above the chain line for some "anti-squat" action... or have a single pivot bike with the pivot exactly at the bottom bracket to ELIMINATE chain growth... just thinking out loud but nah i don't have the resources to build prototypes. so i guess i'll try out a DW-LINK bike first, cause Dave Weagle is a real mechanical engineer. he even logs on to forums with the nick "_dw". ask him on the forum and he'll reply (i tried it). he's a REAL person, not like the mysterious engineers of other bike manufacturers. next on my list would be an Ellsworth, cause the ICT does make sense. although i think they forgot to consider a certain "factor" in their design cause Ellsworth bikes do bob, although ever so slightly. Don't believe Ellsworth if they say the ICT is "100% efficient on every gear blahblah...". that's just impossible then perhaps a maestro bike. if I see a platform shock on a bike i won't buy it.
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Post by Onie on May 1, 2007 20:14:57 GMT 8
i'll try out a DW-LINK bike first, cause Dave Weagle is a real mechanical engineer. he even logs on to forums with the nick "_dw". ask him on the forum and he'll reply (i tried it). he's a REAL person, not like the mysterious engineers of other bike manufacturers. then perhaps a maestro bike. if I see a platform shock on a bike i won't buy it. Keywords: DW-link; MaestroMy bets are same as yours... Hmmm... except perhaps that ICT thingy. Ellsworths have a myth and you won't find many Ellsworth riders saying bad things about their bikes. Same with Mercedes drivers who pride their German cars... Well, those may be good cars but not better than several others too. Kid you not, one of the main reasons I roll on a DW-LINK'D bike is I wanted a rig that minimizes brake jack. Gone are the days of skidding, the rear end binding up, wondering how to dive into a corner, how early to brake, how late to brake, etc... since almost 2 years coming off from a no-resonance system. While the brake jack issue may have been an important feature to me, I believe Dave Weagle himself hit the nail on the head. DW bikes exhibit a unique blend of superb traction, controlled decending, efficiency, activeness and a simplicity (regarding set-up) that no other suspension design can match! A paradox (to my part) that I'd be using Tony's... Those that ride, know! Subsequently, you must invest with the bike that best suits your needs. Thank you again for your time, Pjax! & more power! Reason for editing: Re: quote--retained only some pertinent excerpts from Pjax's...
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Post by pjax on May 4, 2007 0:43:40 GMT 8
you're on a dw-link bike? then switched to an ellsworth?
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Post by pjax on May 7, 2007 22:05:02 GMT 8
let me just add: i'd really like to try out the "virtual link" sonix bikes. it's got the main pivot on the chainstay so there's no chain growth. It's almost a URT bike. the bike i saw over at john wilkies got platform shocks though
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okidok
Bike Commuter
MiniMe
Posts: 67
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Post by okidok on Jun 20, 2007 9:50:04 GMT 8
The key word I guess in todays bike rear suspension is virtual pivot, almost all manufacturer claims they have the best virtual pivot system. I agree with Pjax regarding Haro Sonix, the pivot is in the BB thus no chain growth. Here are some analysis regarding different suspension system. Comments please agree or disagree. FSR MAESTRO, DW-link SC VPP Xtension PVP This analysis is done obviously by XTENSION on there 2008 XC frame. they claim that a pivot point that moves forward and upward is the most efficient.
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Post by pjax on Jul 7, 2007 15:44:50 GMT 8
can't see the pictures
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Post by Alphabolt on Jul 7, 2007 18:57:13 GMT 8
I 've tried the Ellsworth ICT design and I have to agree that it really works . Uphill biking is a bliss with it Same with the DW link ( is Maestro a DW link? Tried it as well...sweet) ...but I only tried the Ironhorse sunday..a DH bike that can climb well ...and that s saying alot for a Dh bike If I had the moolah...I'd buy an Ellsworth Epiphany (and change the rocker to a sturdier material..it breaks) and an IronHorse All-Mountain bike MK series The only beef I have with my Spez Enduro Pro is the "over-torque" uphill ride ... too forced ala HT. I prefer the relief of an Ellsworth at the same speed uphill Nice write up , PJ . you research gets better and better
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okidok
Bike Commuter
MiniMe
Posts: 67
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Post by okidok on Jul 14, 2007 15:27:09 GMT 8
Pjax, Like magic it appeared on its own. Glitch from my image host side. sorry,
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Post by boredmdmtber on Jul 14, 2007 17:32:43 GMT 8
sluggish on roads?
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Post by pjax on Jul 16, 2007 12:30:03 GMT 8
yes. i immediately feel the difference when i hop on my HT. you might say "who wouldn't? don't compare HT with FS", but you can actually see it bob.
i guess with the triad shock there's just too little "platform" or compression damping. and you can't adjust that. you only either turn it on or off.
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Post by boredmdmtber on Jul 16, 2007 13:10:31 GMT 8
Pjax, i have a PUSHed RP3 and PUSHed Fox RLC on my bike and i really noticed a difference esp. with the ProPedal settings. in my opinion its worth the money. my friends with older stumpys(prior to 2006) have had similar problems like u with their triads esp. the heavier riders. Some sent their shocks to PUSH and are very happy with the performance of their stumpys. i think it runs about $175 for their service. the alum Stumpjumper i demo'd with my son(with the triad shock) a couple of months ago climbed pretty well and didnt bob. the Sworks(with brain fade) i tested last year didnt bob either but still didnt react fast enough to bumps in my opinion( as Specialized claims they fixed ).
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JAM
XC Rider
Patience is a Virtue
Posts: 118
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Post by JAM on Oct 5, 2007 16:41:53 GMT 8
Sir Pjax, sorry this post came pretty late for the superb exchange of technical research and actual riding experience regarding the different suspension systems available in the market. Given your knowledge and expertise on this subject, just cant help but ask for your opinion regarding a different suspension system that is out in the world market (although I havent seen anyone using it locally yet) that claims to be both bob free and bump compliant without any dependence on a shock with SPV features. This is Felt Bicycle's patented Equilink system in their Virtue 1-4 line of XC/trailbike models. Im interested in getting your feedback on this especially since I already placed an order for it from Felt's dealer in Singapore. I will try to get the link of a video of one of its engineers explaining in laymans term the features of the equilink and why it works. But you can go to Youtube and search for Felt Virtue and Im sure the vid will come out. Though the Virtue frame comes with an RP23, Felt claims that you can use any shock without any stable platform or propedal features. In fact, they suggest to just turn-off the propedal setting. Hope to hear from you brad. Jam
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