[Closed] Metric shocks - why the fuss

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

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

Pissing about with 'standards' again.

Bush lapping

https://m.pinkbike.com/news/rockshoxs-new-super-deluxe-shock-first-ride-2016.html

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.

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

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.

mikeyd - Member
Bush lapping

I seen those videos.

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.

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

It's actually not a silly standard, our trail bikes have got more and more travel and got stiffer and stiffer.
The 200x57 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.

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.

I seen those videos.

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

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.

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.

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.

[img] [/img]

Ahhh I had failed to notice that. Magic.

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!

Point taken.

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.

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?

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.

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

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

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

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.

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.

[img] ?1460088654[/img]

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.

[img] [/img]

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.

I had trunnions on my Morris Minor, progress eh!

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.

[img] [/img]

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.

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.

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?

I may be wrong, but I thought the basic idea was that the trunnion mount allowed the shock gubbins to be moved upwards so that a longer shaft/stroke could be used for a given amount of wheel travel.

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?

You're right but spread the linkage/mount out and fill the dead space.

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/p>

Vs

[img] [/img]

I see that, but, other than a different linkage shape, what's the benefit?

Surely if it were [i]better[/i] to do a than b, they'd make all (fancy fandangled New metric) shocks like that rather than just some since it obligated designers to accommodate new "shapes" any how?

(And of course, back to the sizing thing, why not just make them the same e2e as existing shocks for a given stroke, rather than completely new sizes given the stroke vs e2e is clearly achievable because are now shorter for a given stroke?)

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.

Arent the tiny dampers in F1 monotubes?

How can you be certain of heat?

And don't longer shocks and longer leverage ratios introduce more friction into a shock? Not always helpful on an MTB where the weight isnt as high to overcome seal friction. Isnt that partly the reason why journos are gushing over girder forks, as they overcome friction by upping the leverage ratios? Wheres the tradeoff? I cant say that my DHX2 feels any better damped than my 36, despite the 36 having a 1:1 leverage ratio.

And don't longer shocks and longer leverage ratios introduce more friction into a shock? Not always helpful on an MTB where the weight isnt as high to overcome seal friction.

Lower leverage ratio's allow for lower pressures (both damping and air spring) which means lighter seals can be used, so less friction.

Isnt that partly the reason why journos are gushing over girder forks, as they overcome friction by upping the leverage ratios?

Are they? Lauf aside I've not seen any since the PRST-1 and Grivin 15+ years ago. They reduce friction because they separate the structural aspects from the damping. Bearings and pivots offer much lower friction than sliding bushings when side loaded.

Wheres the tradeoff? I cant say that my DHX2 feels any better damped than my 36, despite the 36 having a 1:1 leverage ratio.

See above, telescopic forks aren't all that great so you end up with six of one and half a dozen of the other.

The trade off is also weight, a 2:1 frame + shock will weigh more than a 2.5:1 design because the shock is 25% bigger.

Lowering the leverage ratio is almost always going to improve the damping control.

And of course, back to the sizing thing, why not just make them the same e2e as existing shocks for a given stroke, rather than completely new sizes given the stroke vs e2e is clearly achievable because are now shorter for a given stroke?

Because if you made a shock that shape it wouldn't fit anyway. The point is it's a better design, but requires a different frame design, and if you're doing that anyway you may as well simplify the lineup.

Ignore the word 'metric' that's just a convenient differentiator to the old imperial sizes. It's just a new/better shock design than the old eyeletted design, that isn't backwards compatible and just happens to be in metric sizes.

As I pointed out on the first page, the odds are you couldn't swap shocks between two existing frames anyway. There's only a small chance they'd be the same e2e and stroke, and an even lower chance they'd have suitable damping curves. The fact that the latest shock designs in the future might not be compatible with old frames is irrelevant, because few people are going to be spending £400+ on a shock for old frames, and those that do will probably still have the option of stuff like Cane Creek.

Ignore the word 'metric' that's just a convenient differentiator to the old imperial sizes.

That much i can follow! 😆

See above, telescopic forks aren't all that great so you end up with six of one and half a dozen of the other.

Despite the fact that Moto GP teams, works MX teams etc etc - with their huge budgets - all choose to stick with telescopic forks. Funny that. I believe that it's because telescopic forks tend to be stiffer and more reliable and an unpredictable, non linear axle path tends to **** with riders heads. Sure you can cut out brake dive mechanically, but dive actually seems to be useful to exploit anyway for making tight corners.

Again, my 36's don't spike anymore than my DHX2 200x57 - the damping in terms of feel in the real world is equal. The only difference is that the rear, for shock absorption has a more rearward axle path around the sag point - and the fork feels stickier because it's using a 1:1 leverage ration - irrespective of whether it's loaded or not.

216x63 was pretty much standard for Enduro bikes before Metric, so I am sure lots of people could swap their shocks. I can't imagine the difference between 65mm and 63mm in terms of damping, is worth a ****. Not compared to piston design, valving design and damper friction. And the 16mm of size difference doesn't seem worth much as the shock ends up being physically similar in length in reality anyway.

Sorry, I just don't believe that metric shocks were a good thing - that offer us noticeable improved performance. I think the gains are marginal at best.

It's just a new/better shock design than the old eyeletted design, that isn't backwards compatible and just happens to be in metric sizes.

Again, can someone explain to me why trunnion shocks aren't seen elsewhere on motorbikes? You make it sound simple, that it's just a better design - but the cynical part of me that knows that motorbikes have always and still are at least a decade ahead of the mtb world - are not behind the cycling world on this.

So why are you so upset that you can't fit one?

Rationalised in order to make production cheaper and maximise profit, anything else is just sales talk.

Again, can someone explain to me why trunnion shocks aren't seen elsewhere on motorbikes?

Possibly because they don't have the same packaging constraints.

As I understand it, the trunnion mounts allow the new airsping design to be accommodated on a shock that has a shorter eye to eye measurement while maintaining the stroke length. I've not checked this, but I assume the trunnion shocks will be the shorter ones. Or they can fit longer stroke shocks in a smaller space. The extra stroke appeared to have been used to improve the damper design.

It could all be made up, but the extra space allowed by the new dimensions makes it possible to produce a better spring and damper. Wheather many people can benefit from the improvements is a good question, but they certainly look different on the inside.

The extra stroke appeared to have been used to improve the damper design.

But yet they still failed to produce a better damper than either a 200x57 Ohlins or DHX2.

Possibly because they don't have the same packaging constraints.

They look like they have more to be honest, especially when you have to consider the effect of engine placement on weight distribution.

[img] [/img]

That is an impressive machine, but I feel compelled to point out that there is an awful lot more room for a shock in that bike than there is in any mountain bike I can think of.

You may have to accept that motorsport implementations of suspension will always be better than those in bicycles. There is more money involved for one thing.

Öhlins and Fox shocks may be better than those made by Rock Shox because they may be designed and manufactured by people who are better at what they do. This is good for you as it means you won't have to loose out when you don't by Rock Shox.

Motorcycle shocks are huge (and heavy) in comparison to any mtb shock

Yeah it's always a standard line when you get stuck into a corner
"BUT Motorbikes!!!!"
Given the performance from even the budget end of MTB shocks these days and the array of adjustment at the top end I've come to the conclusion that some people are never happy 😉

My bike has a metric shock, it seems to work.