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  1. #1
    Trail Ninja
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    VPP leverage ratio curve, and resulting susp feel?

    It seems that the typical trail/AM VPP leverage ratio curve (shock rate) is regressive-progressive (falling-rising rate). So it starts out stiff, gets softer, then harder again. This accentuates the spring rate curve of air shocks, which are stiff-soft-stiff, with a "hammock" shaped curve. The V-10 and Intense M-series DH bikes have a progressive/rising rate curve, so they are an exception.

    I'm trying to understand the system by looking at the forces chart (wheel rate). Assuming a 40:60 front to rear weight distribution, a 165 lbs rider with 30% sag on a Nomad (v3/Newmad) would need to put an additional ~100 lbs of force on the rear to move it from 30% to 66% travel, but needs significantly more than 300 more lbs on the rear to bottom it out, how much more depends it having Vivid or Monarch Plus (note these are forces on the rear, which is 60% of a force applied to the BB, landing with both tires). Pretty much something that a monster hucker (or someone who cases a lot of jumps) would be happy on and one that looks like it's a good candidate for a coilover.

    In comparison, a 165 lbs rider on a 5010 with 30% sag, would need an additional ~80 lbs on the rear to move it from 30% to 66%, but an additional ~160 lbs to go from 66% to bottom out (340 lbs total on the rear, or 3.4 Gs worth with stock air shock).

    Looks like the Bronson is probably the 2nd "plushest" out of the Santa Cruz line, following the TB LTc, for those looking for comfort rather than big hit performance, seeing how they require the least amount of force to go through their full travel, yet with minimum wallowy feel. The TB LTc has a lot more chain growth and kickback, leading to more pedal reactiveness, while the Bronson has a minimal amount of it, making it more active than the TB LTc.

    Just making observations based on paper. I haven't demo'd a 5010 nor a Newmad. Basically wondering why Santa Cruz's is the opposite of what many other top rated designs are like, mimicking some modified single pivot leverage curves (ex. Yeti 575). I was under the impression that the opposite of Santa Cruz's curve was the more preferred choice, to make an air spring more coil-like. I suppose in the end, the shock's spring rate and damping tune and well how it mates with the suspension matters more than the suspension design itself.

    Can any owners confirm that a wide range of sag feels ridable (as low as 15% to 55%), with consistent pedaling characteristics that don't change dramatically? I predict this due to how "flat" the forces curve is around the 30% sag point (550 N, +/- 100). I also predict that as long as the chain growth/kickback is low (well under 15 degrees, in middle ~32t ring), that it's also very active and sensitive, assuming a similar flat forces curve around the sag point.

    I kind of envision an ideal Santa Cruz owner as one that prefers a stout rigid frame, equipped with an old Cadillac's suspension to make it feel like they're on a cloud, using up a lot of travel easily in early to mid-stroke, but takes big hits well, and accelerates without bouncing from the rear sinking and front tilting up. In contrast to a rider that likes his suspension to react predictably and proportionately to the hits they're taking. I suppose the former uses suspension liberally, while the latter keeps quite a bit in reserve except in the most consistently chunky of courses. My thoughts are basically turning into guessing what real world riders want and what are their trails like. I can see a lot preferring the former (SC style) for typical hiking trails, and the latter appealing to those that ride purpose-built trails. Is there a point between linear/coil-like and wallowy, that is much more preferred than coil-like, ignoring the other air vs coil differences?

  2. #2
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    I know nothing of the subject but would enjoy learning more. Where did you find the information about leverage ratio curves and spring rates of shocks? How about the forces chat you mentioned?

  3. #3
    Trail Ninja
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    For starters:
    Joe's Corner | Santa Cruz Bicycles

    Once you know how to interpret things better:
    Linkage Design: Santa Cruz

    Note that Joe uses a shock rate curve, which is basically a leverage ratio curve flipped upside down. His "wheel rate" is essentially the forces chart (what you get when you combine leverage ratio curve + the spring rate curve of the stock shock).

  4. #4
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    Quote Originally Posted by Varaxis View Post
    For starters:
    Joe's Corner | Santa Cruz Bicycles

    Once you know how to interpret things better:
    Linkage Design: Santa Cruz

    Note that Joe uses a shock rate curve, which is basically a leverage ratio curve flipped upside down. His "wheel rate" is essentially the forces chart (what you get when you combine leverage ratio curve + the spring rate curve of the stock shock).
    Thanks for the links. I've been to Joe's corner before, when those articles were written. It didn't mean much to me then. I'm hoping that after two physics classes, statics, and dynamics I'll get more out of it this time.

    Being able to read, write, and speak Spanish used to be a useful skill, now Google does or for you with a click of a button. Who needs a brain?

  5. #5
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    If you think about it the biggest difference between small brands and big brands is that the big ones always try to get custom Shocks (Trek, Cannondale, Specialized, Scott...). Santa Cruz used to be a small brand but now they are "Huge" and I think they need to start working with custom shocks.

    Right now they can use the 2015 RS Debonairs and soon the new 2016 Fox Evols... They have won the "shock lottery" and they didn't have to do anything to get a couple of shocks that are almost custom made for them, but I still think there is room for improvement and they could do pretty cool stuff with custom made ultralight coil shocks... In the long run this can be very important too. Think about Specialized lossing their Pattent and being "humiliated" by a few small brands that are designing better FSR bikes than them.... Something like that could happen to Santa Cruz, but if they start messing with shocks they can keep ahead of the competition for a long time...

  6. #6
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    I'll bite...
    Here is some of my background. I've always been pretty interested the suspension curves and how they work with coil vs air vs custom tuned. I've ridden mostly FSR type bikes (Titus,Knolly) but I did have an older VPP bike (Intense 6.6) and a couple of solid single pivot bikes (Yeti ASR5, Evil Uprising). I've also ran all sorts of shocks including CCDB coil, air, Avy Chubbie, Avy tuned FloatX. I keep an eye out absorbing info on all the various suspension designs. DW-Link, FSR, VPP, DELTA, 4x4, and all the various iterations interests me for some reason. When the N3 came out I dug in and I found a lot of folks who hadn't ridden the bike crapping on it due to VPP's infamous falling/rising rate. I also found people who rode the bike were loving it. So after I killed my Uprising I went with the advice of some good friends and picked up a new Nomad with Vivid Air. I gotta say I'm pretty blown away by this bike. Super stiff, pedals great, flies great, absolutely gobbles the chunk.

    Now to respond to your post...
    I do prefer a stout rigid frame but I do not like "Cadillac-like suspension". My 6.6 had that kind of suspension and I hated it as it was basically a couch bike. The Nomad is not even close to that. The bike does erase the smaller hits but not at the expense of feel. It has a very coil-like feel to it in that it stays very high in it's travel w/o a hint of wallow. I find I have excellent feel for the trail and can pop it at will. I've hit some good sized drops to flat-ish landings and I have yet to clank it. I do see I'm using pretty much all the travel on the bigger hits but no harshness whatsoever. As someone who has always loved coiled FSR bikes for their plushness and lack of wallow, I can honestly say they nailed it on this one.

    I'm currently running the Vivid at 30% sag. I tried 25% and 35%. 25% was no good. I felt like I was getting bounced around too much and I quickly got rid of that. 35% actually felt really good but I bumped it up a little due to the low bottom bracket and how it reacts to rocky trail. It's hard to say how much of the bikes feel is the Vivid since it's the only shock I've ridden on this bike. My buddy had the Debonair on his and he liked how it felt but had some issues with it so he picked up an Avy Coil and really likes how that feels. I do think having a shock that's tuned for the VPP is important. If you read up on the interwebz lots of folks having to take extra time to dial in their CaneCreek shocks. As curious as I am to feel how other shocks would react to this bike I have no plans on swapping out the Vivid as its pedaling super nice now.
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  7. #7
    Trail Ninja
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    Reminds me of this article: RockShox Rear Shock Tuning Experience - Pinkbike

    Can't underestimate how essential shock tuning to fit the bike, intended riding style, and terrain is to the ride.

  8. #8
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    You guys sound real smart re: leverage curve etc., and I was wondering if you'd share your opinion regarding the following:

    I was planning on getting a Monarch Plus RC3 Debonair for my Santa Cruz 5010. I've been able to find it in L/L and M/M tunes.

    I've only just recently decided that Cane Creek's offerings are too expensive to buy, too expensive to service, and seem to still be having warranty issues (DB Inline specifically).

    But if you think the Monarch Plus RC3 Debonair is an inappropriate shock for the 5010's leverage curve, I'd be open to reconsidering a DB Inline.

    What do y'all think? Thanks!

  9. #9
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    {edited...realized it was not the right place for my question}

  10. #10
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    I've owned a blur XC catbon, blur 4x, Bronson, and now a 5010.

    Yep, the leverage curves are a bit different than non VPP.

    Yes, the VPP designs pedaling efficiency is quite sensitive to too little sag. To little and it squats (losing power to the shock) then you can add LSC, but it will then feel wallowy.

    If you don't want the Baja/Cadillac feel you either need a EVOL or Debonair can, or add a bunch of volume spacers.

    VPP shines out of the saddle accelerating, and in seated climbing.

    Is it possible the regressive rate at the beginning of the curve helps the wheel track better?
    Last edited by Grizzy; 12-10-2015 at 08:54 PM. Reason: Messed up

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