Metric shocks – why the fuss

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  • Metric shocks – why the fuss
  • SOAP
    Member

    Why are there no Metric coil shocks for sale is a better question.

    mickmcd
    Member

    is a metric shock not an imperial shock divided by 25.4?

    Premier Icon teethgrinder
    Subscriber

    Pissing about with ‘standards’ again.

    swoosh
    Member

    What’s all this current fuss about metric shocks?

    I understand that it’s the eye-eye measurement rather than the shock stroke but why does it being metric make a difference? I don’t understand why the unit of measurement makes it a better shock. The metric shocks appear to be longer which improves the compression rate or something like that but why didn’t Rockshox and Fox just make their previous shocks a little longer?

    What’s the big deal? Is it that important? Is a 2018 bike without a metric shock such a problem?

    Premier Icon nickdavies
    Subscriber

    Search on here, Benpinnick posted a while ago with quite a good explanation of how they were a benefit on a similar thread, probably find the topic from his username.
    Ok, granted he’s bird cycles so vested but it seemed like a good explanation to me.

    Premier Icon sr0093193
    Subscriber

    Gotta find someway to make up for the losses on all those warranty reverbs and creaky pikes *not cynical*

    P-Jay
    Member

    Couple of things:

    1) the name is stupid, they’re no more metric than my 200mm x 57mm.

    2) The timing of the initial release was stupid. They announced it on the last day of March on Pinkbike, but because of the timing of the release lots of readers didn see it until the 1st of April “metric shocks” seemed classic Pinkbike April Fools.

    3) it’s another SRAM ‘innovation’ which just so happens to make existing Bikes seem obsolete, like Boost etc. If you’ve got an ‘old fashioned’ imperial frame you can no longer buy that Canecreek you’ve always wanted.

    4) the tone of the announcement was ‘aggressive’ the first one was basically – right, as of NOW, we’re not making ‘imperial’ shocks anymore, which means any frame maker that wants to run our stuff OE they need to change their design now, which of course means frames are now Metric or Imperial, or in other words – Fox or SRAM, PS were taking Canecreek, DVO, X Fusion and Manitou with us.

    5) the advantages are ‘dubious’ to most, the point is a longer eye 2 eye for the same travel to allow more room for fancy suspension stuff, pretty much what piggy back shocks have done for 15 years or so.

    All water under the bridge now I guess, the actual shocks are meant to be good, and Fox have quietly released a few ‘metric’ sizes.

    I wouldn’t loose sleep over having an imperial or metric frame.

    Premier Icon colp
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    mikeyd – Member
    Bush lapping

    I seen those videos.

    mindmap3
    Member

    Think P-Jay nails it; SRAM are gits for introducing silly standards and forcing them onto the market. But, the Americans seem to lap it up and love the ‘innovation’. SRAM have nailed some stuff like their 11 speed drivetrain but other stuff seems a bit forced and rushed.

    Premier Icon jimplops
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    I just find it ironic that an American company has decided to make a metric shock.

    pitchpro2011
    Member

    It’s actually not a silly standard, our trail bikes have got more and more travel and got stiffer and stiffer.
    The 200×57 shock length has the same eye to eye measurement as shocks we used to use for trail riding. Basically it’s flexy causing unreliability issues on some suspension linkages. The new standard allows them to fix the issue and it was an issue, if you ever had a cc inline on a stiff long travel frame you’d know this.

    Premier Icon chakaping
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    Yep, silly name but actually a good idea.

    Only ridden one RS Super Deluxe but it certainly felt more impressive than the equivalent current Monarch Plus.

    nickhit3
    Member

    I seen those videos.

    😀

    PJM1974
    Member

    Because we can’t have a single month go by without some marketing arsehole somewhere deciding that we need a new standard.

    Premier Icon hatter
    Subscriber

    It was more to do with the emergence of all the smaller rear shock brands (DVO, Bos, Cane Creek, FAST etc etc).

    Retooling your entire shock line-up for the new standard is chickenfeed for RS but it’s going to ruinously expensive for these smaller guys with much lower volumes.

    This leaves them with the choice; they either don’t do it, which will leave the OEM market entirely for the big guys, or they have to put their prices up to cover the costs, making them uncompetitive.

    Premier Icon deadkenny
    Subscriber

    I just assumed it was a Euro thing and after Brexit we’d get our imperial shocks back 😀

    At a very basic level a metric shock can just be a longer travel imperial one with a travel reducing spacer. It’s just putting the same stroke shocks in longer bodies and for convenience they’ve made the numbers metric round properly in metric system. This means you need a long thin shock which fits better in more designs than a short piggyback one, and those that it doesn’t can have a trunnion mount rather than eyelet.

    Retooling your entire shock line-up for the new standard is chickenfeed for RS but it’s going to ruinously expensive for these smaller guys with much lower volumes.

    I’d actually guess at it being the other way around.

    Cane Creek will just tweak the numbers in the CAD package and hey presto a metric shock pops out of the CNC machine. They might in the future optimise the design of their inline shocks for it, but it’s not a big deal really (except for Cane Creek who struggled to come up with a reliable way to package the DB design in an inline shock so they probably quite like the idea of more room).

    RS, FOX etc use forged parts (which are cheaper to mass produce) and do require actual tooling which is replaced regularly so a change to it isn’t a novel cost.

    JackHammer
    Member

    On a similar note what is trunion mount and why do i need one?

    On a similar note what is trunion mount and why do i need one?

    The shock mount appears to go through the air can instead of being on the end.

    More space for air/dampers and stuff above the bolt and bearings rather than bushings.

    JackHammer
    Member

    Ahhh I had failed to notice that. Magic.

    Premier Icon dangeourbrain
    Subscriber

    Is it just me who finds it far too coincidental though that they managed to do 190/40 & 190/45 followed by a 20mm jump in eye to eye to 210/50 & 210/55 but some how couldn’t get five or ten mm more stroke from a 10mm increase in eye to eye for 200/50 or 200/55 which would have managed a whole load of “legacy” frames? (Same could be said for several other sizes too)

    The new tech maybe a good thing but people have done bearings for eyes perfectly well with old eyelet sizes and increased internal room surely just needs you to not do a few of the old sizes (190/57 say) and stick to ones which do give you enough internal room.

    The new sizing really does strike me as forced obsolescence much as i hate the phrase (and I’d be reluctant to use it about a lot of the “new standards” which at least on paper can be made to look partly sensible)

    The new sizing really does strike me as forced obsolescence much as i hate the phrase (and I’d be reluctant to use it about a lot of the “new standards” which at least on paper can be made to look partly sensible)

    Yea, but, no. Shocks are fairly serviceable/rebuildable, and for the majority probably the thing on the bike least likely to ever be replaced. And I suspect that the likes of Cane Creek will continue to offer the full range of sizes, because their market is the minority of people who do swap shocks, whereas RS/Fox are almost entirely geared up to providing what the OEM’s want.

    So it’s not going to make old frame’s obsolete.

    It is cutting down the number of (air) shock bodies they have to make from 7 to 3 though. Given the hoo-har over three wheel sizes, imagine if they’d gone the other way to 7 shocks!

    Premier Icon dangeourbrain
    Subscriber

    Point taken.

    P-Jay
    Member

    Is it just me who finds it far too coincidental though that they managed to do 190/40 & 190/45 followed by a 20mm jump in eye to eye to 210/50 & 210/55 but some how couldn’t get five or ten mm more stroke from a 10mm increase in eye to eye for 200/50 or 200/55 which would have managed a whole load of “legacy” frames?

    Nope, the truth is, they could have just made new sizes – there are already different shocks with the same eye to eye with different strokes etc.

    What they wanted was a gimmick, a line in the sand that says ‘old tech / new tech’ this gave them a sense of obsolescence to sell to customers and a chance to stick the boot into Fox and Marz. It’s not the new tech that annoyed the Brits (as the North Americans seem to love anything new) it was the marketing BS that came with it.

    Their type of ‘aggressive innovation’ stops riders doing what they’ve done for years, incremental upgrades – you might buy a new fork one year, a new set of wheels the next, new drivetrain etc and come year 3 throw the lot on a new frame. It’s harder and harder to do that now – most riders are only a bike or maybe 2 into the shock that was 650b (even that seems to be on the ropes now) only to find if they want to upgrade their forks they need a new front hub at least, if they want to upgrade their drivetrain they need a new rear hub, and if SRAM and the others had stuck to their initial plans if you wanted to upgrade the shock to a 2017 one, you’ll need a new frame because they seemed to go out of their way to ensure nothing was cross compatible.

    Premier Icon andybrad
    Subscriber

    the bushing overlap thing.

    Just a thought but while that would potentially make the shock stiffer its not the shocks job to keep it stiff? Thats the frame isnt it? and if you then have a larger surface area of bearing isnt that more friction?

    Premier Icon dangeourbrain
    Subscriber

    its not the shocks job to keep it stiff?

    No but they’re being “compromised” by stiff (boosted, through axled…) frames transferring the force to the shock. Dt fixed the problem with fancy spherical bearings ages ago on normally sized shocks.

    and if you then have a larger surface area of bearing isnt that more friction?

    Less than a similar area on a bushing I’d guess.

    Premier Icon spawnofyorkshire
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    @ P-Jay – You ok hun? Need a hug?
    You seem quite irate about this

    P-Jay
    Member

    @ P-Jay – You ok hun? Need a hug?
    You seem quite irate about this

    Better now thanks, I just enjoy a rant is all.

    Tom_W1987
    Member

    Dragon, stiffer links mean that the shock should be put under less bending forces… surely? Not more.

    Note, its only ever really been RS shocks with their piss poor tolerances that have ever suffered from this.

    Tom_W1987
    Member

    This means you need a long thin shock which fits better in more designs than a short piggyback one, and those that it doesn’t can have a trunnion mount rather than eyelet.

    But piggyback shocks are better packaged surely, with less length mass is better centred and standovers can be made to be lower.

    Note no GP bike or MX bike e has ever been fitted with an inline shock for packaging reasons.

    But piggyback shocks are better packaged surely, with less length mass is better centred and standovers can be made to be lower.

    Only on frames with vertically mounted shocks and fairly open front triangles, which isn’t all of them by a long way. If you look at the lengths the standard shocks grow by ~10mm which is barely going to be noticeable in the frame design anyway. The trunnion mount shocks are ~15mm shorter than the equivalent imperial versions. And they still make piggyback versions, just the inline versions will get some of the benefits.

    Note no GP bike or MX bike e has ever been fitted with an inline shock for packaging reasons.

    Not sure what your point is, the Ohlins GP shocks are hardly what you’d describe as neatly packaged. And equally, they’re not trying to make one shock fit many frames, they’re making a bespoke shock to fit a frame design, which would be an even bigger compatibility nightmare which seems to be most peoples gripe with new stuff.

    Tom_W1987
    Member

    There’s still a piggyback there though isn’t there!? Some people here have in the past been arguing that longer inline shocks make more sense for packaging reasons.

    Only on frames with vertically mounted shocks and fairly open front triangles,

    Which, shock horror – are most of the decent bikes out there. But now we have frame manufacturers pointlessly stuffing elongated shocks vertically into their frames – and then having to introduce another standard…trunions to claw some of the standover back.

    WHOOOOO PROGRESS GUYS! See any trunion mounts on the Ohlins shock….oh right…no…..motorsports doesn’t do stupid bollocks to the same degree as MTB.

    And in regards to the metric piggybacks – aren’t the new RS Deluxe piggybacks simply there for heat dissipation – unlike every other motorbike shock in existence where a lot of the damping is offloaded to the piggyback? So again, you’ve added length for something that could have just been done by simply adding a proper reservoir.

    All to make up for crappy frame design and piss poor manufacturing tolerances! WHOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO! We’re all winning though guys, all this innovation is great – it’s improving our bikes so much.

    Premier Icon konanige
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    I had trunnions on my Morris Minor, progress eh!

    Premier Icon yoshimi
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    Sorry for the hijack, but this seems like a good place to ask my question –

    Are Fox volume spacers 10.8cc and 7.6cc volumes in cubic centimeters? So with one of each of these spacers I’ve got 18.4cm3 of volume spacer?

    Which, shock horror – are most of the decent bikes out there.

    Apart from Trek and Giant I’m actually struggling to think of many big brand’s that still build bikes like that, spesh and SC both mount them horizontally. And as I said, it’s actually 15mm shorter for the same stroke with the trunnion mount.

    aren’t the new RS Deluxe piggybacks simply there for heat dissipation – unlike every other motorbike shock in existence where a lot of the damping is offloaded to the piggyback? So again, you’ve added length for something that could have just been done by simply adding a proper reservoir.

    Well, no.

    The piggyback is just there to take up the volume displaced by the shock’s shaft.

    Ohilins TTX (and CCDB, and Romic and now Fox with the X2) works by cycling the oil through the adjustable damper and back round the shock (via the ‘twin tube’ to the other side of the main piston. Back in the Fox DHX5 and Vanilla RC days the compression damping was done by just damping the oil displaced into the pigyback, which is a poor design because not much oil floes into there relative to what the main piston forces through the damper in the TTX/CCDB/DPX2 architecture.

    The piggyback is and was always just a reservoir to absorb the excess damping oil (and helps with cooling). The reason shorter travels hocks don’t have them is there’s enough space in the damper itself to fit an IFP (which trunnion mounting solves for more shock sizes). Remember Romic? Their damper was very similar to the TTX design, but didn’t need a piggyback.

    Tom_W1987
    Member

    Back in the Fox DHX5 and Vanilla RC days the compression damping was done by just damping the oil displaced into the pigyback, which is a poor design because not much oil floes into there

    Not really the dhx5 had a ported and shimmed main piston as well. Its just the damping was more reliant on thr main piston, which is not always a bad thing because you can shim it – that can give better tuning options than preloaded valves.

    Twintubes have their downsides as well. For example, the outer tube ob a twin tube damper can act as an insulator. I belive that most of the WRC cars are on monotubes.

    Tom_W1987
    Member

    and if you do want some form of external adjustability, you eitger make room for it in the shock or locate the valves outside of the main damper body leading into the reservoir. Again, adding pointless height to the shock.

    Loads of companies are using vertically moubted shocks… Cube, Giant, Trek, Transition, Kona…. even the ones that are mounted horizontally will have less packaging issues from a smaller shock.

    Not really the dhx5 had a ported and shimmed main piston as well. Its just the damping was more reliant on thr main piston, which is not always a bad thing because you can shim it – that can give better tuning options than preloaded valves.

    The CCDB does as well (as did the Vanilla RC).

    The point was that the twin-tube design flows a lot more oil past the adjustable damper, so you get a lot more control. Whereas a single tube/DeCarbon design relies on displacement.

    Twintubes have their downsides as well. For example, the outer tube ob a twin tube damper can act as an insulator. I belive that most of the WRC cars are on monotubes.

    Yea, but McPherson strut’s have very low leverage ratio’s, it’s more analogous to the forks on a bike. With low leverage ratio’s and big shafts you can displace a lot of oil for damping.

    I never quite understood the heat argument with twin tube shocks, if anything the oil that’s just done the work in the damper (and therefore hot) being kept separate, then getting circulated round the outside should cool it. You get better cooling with one very hot part than with a larger area at a lower temperature. I guess you might get inconsistency with the damper sometimes drawing cold oil from the inner tube or hot oil from the piggyback or twin tube, but a twin tube will certainly be cooler overall.

    Loads of companies are using vertically moubted shocks… Cube, Giant, Trek, Transition, Kona…. even the ones that are mounted horizontally will have less packaging issues from a smaller shock.

    Yes, and the tunion shock is ~15mm shorter but still get’s ~10mm more useable space.

    Everything being equal you could now fit a 205*65mm shock in a frame that previously fit 200*57 (with some tweeks obviously). It has a bigger damper than an old 215*65 as well as longer stroke than the 200*57.

    Premier Icon dangeourbrain
    Subscriber

    Forgive my obvious question, largely as i think it’s me being dumb but…

    The trunion mount socks aren’t smaller surely? yes the eye to eye is shorter but you’ve got another lump of shock above the upper eye so suddenly your back to your original size so no more able to squash it in a smaller frame than before?

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