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.

Vs

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

Surely if it were better 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 200×57 – 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.

216×63 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 200×57 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.

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.