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PostPosted: Wed Jul 24, 2013 9:23 am 
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I tried


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PostPosted: Wed Jul 24, 2013 9:43 am 
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:facepalm:

Come on now Graham, play nice; the suspension is connected, it's an interesting comparison. I wonder if Muddy Fox tried linking it up the 2CV way around to see if it worked on a bike.. worth a try.


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PostPosted: Wed Jul 24, 2013 11:04 am 
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samc wrote:
:facepalm:

Come on now Graham, play nice; the suspension is connected, it's an interesting comparison. I wonder if Muddy Fox tried linking it up the 2CV way around to see if it worked on a bike.. worth a try.


Sorry. The abrupt nature of my reply was to do with it was being late and that I had other things to do. It was not that the History Man's 2CV comparison was not both interesting and relevant.

However, due to the very high centre of gravity of a bicycle, linking it like a 2CV throws up a some big issues with front and dive under braking and rear end squat when pedaling.

It can and has been successfully done on the Highpath built Toptrail, but only with the addition of a complex anti-dive front brake and an anti-squat rear drive chain.

Checkout the videos on the Toptrail site.
http://toptrail.co.uk/

Or here for technical info:
http://toptrail.co.uk/docs/MB_suspensio ... 050606.pdf


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PostPosted: Wed Jul 24, 2013 11:50 am 
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^ that's awesome! If they could make it weigh less than the Forth Bridge that'd be amazing, but I guess if it's sold as a DH bike it doesn't matter so much.

Be good to see it in comparison with a decent long-travel full suspension bike though, rather than the halfords nonsense and the ancient RTS they compare.


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PostPosted: Wed Jul 24, 2013 12:22 pm 
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Yes! A prime candidate for a monocoque carbon fibre structure. But this suspension system is more complaint then any others that I know of so, without a major re-tune, it is not really a candidate for big hits like those in downhill racing.

From what I understand from talking with its maker, is the it is more of an ultra comfortable, lazy man's trail bike, as the suspension does all the hard work for you. All the rider needs to do is pedal and steer. Whilst the "Interactive" design is all about improving rider comfort without wasting any pedaling energy in the process. Not unlike the later Renault Sport/Giant' NRS no sag suspension system.


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PostPosted: Wed Jul 24, 2013 12:26 pm 
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" . . to see if it worked on a bike.. worth a try."

Er, no! - not worth a try, because it can't possibly "work" - just as it didn't work on the 2CV, which was infamous for its instability.

I'm reminded of an in-depth technical article in 'Autosport' - a candid critique of the anti-roll function on F1 cars. It simply stated the scientific fact - "This is the opposite of what is required." - yet all the 'experts' still follow the same design convention!! Smart design doesn't need ANY anti-roll, because the car can't roll in the first place!!

So, every car on the planet (lacking 'active' suspension) suffers from an entirely unnecessary ride/handling compromise, which can be eliminated by simple passive designs that actually DO work.

Being charitable, I'd say that the Toptrail project is barking up the wrong tree. Being brutally honest, it's just 'barking'.

Two springs on a bike is plain wrong, just as four springs on a car is an unworkable design premise. The compromise is inherent and incurable. As my proof-of-concept car model demonstrates, if you separate the chassis levelling function from suspension compliance all the problems disappear. QED.

'Ringo' is right - that's the original. The 'avatar' I've posted on 'Disqus' is the original Intereactive Ultra. (learn spelling!)

Dave Smart


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PostPosted: Wed Jul 24, 2013 1:13 pm 
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Dave2020 wrote:
" . . to see if it worked on a bike.. worth a try."

Er, no! - not worth a try, because it can't possibly "work" - just as it didn't work on the 2CV, which was infamous for its instability.

You may be confusing the 2CV with the swing axles on the original VW beetle? The 2CV was only unstable when going backwards.
http://www.veoh.com/watch/v9148400QMrmcMzM

Dave2020 wrote:
I'm reminded of an in-depth technical article in 'Autosport' - a candid critique of the anti-roll function on F1 cars. It simply stated the scientific fact - "This is the opposite of what is required." - yet all the 'experts' still follow the same design convention!! Smart design doesn't need ANY anti-roll, because the car can't roll in the first place!!

So, every car on the planet (lacking 'active' suspension) suffers from an entirely unnecessary ride/handling compromise, which can be eliminated by simple passive designs that actually DO work.

Yes any car with a centre of gravity that is dissected by a plane that also passes through the centre of the wheel axis would not roll. However that means either very low slung car bodies as in F1, or very big wheels.
Dave2020 wrote:
Being charitable, I'd say that the Toptrail project is barking up the wrong tree. Being brutally honest, it's just 'barking'.

The Toptrail designer Adrian Griffiths, is a top automotive suspension designer. As such I think he deserves a more detailled critique than simply describing his design as "Just barking".
Dave2020 wrote:
Two springs on a bike is plain wrong, just as four springs on a car is an unworkable design premise...
I am not getting this. Surely most motorbike designs use two springs. And most car designs use four springs?


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PostPosted: Wed Jul 24, 2013 3:15 pm 
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"However that means either very low slung car bodies as in F1, or very big wheels." No it doesn't. F1 cars roll and wheel size is immaterial. You are confusing conventional design with sensible design. Smart design makes a 'tall' SUV with long-travel suspension AND zero roll. Read what I wrote:-

"separate the chassis levelling function from suspension compliance". It is impossible to do that on a car with a conventional four-spring design. With a single spring there would be NO ride/handling compromise. Simples.

"I am not getting this." You're in exalted company in that respect!! Aside from Adrian Griffiths, you can add Honda R&D, McLaren, BMW, Williams, Brawn, Mira, MGRover and a long list of other "top" automotive designers!

Conventional motorbike/car designs are built to the mantra of 'independent' suspension. That's their mistake. The model I built at the start of this century proves them wrong, but they can't believe their eyes, because it makes a mockery of their faith in the orthodoxy. They don't get it!!

Actually, most car designs (F1 included) have six springs, if you count the anti-roll mechanism. That's why they're unworkable. You'll often hear the frank admission that "The tyres have more suspension than the suspension".


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PostPosted: Wed Jul 24, 2013 3:19 pm 
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Total thread hijack!


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PostPosted: Wed Jul 24, 2013 3:22 pm 
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Saw notification and came for a look as I have a MF FS.

Not another poxy argument about bugger all. I must say getting fed up with all this all over the place. Humorous banter is one thing, but this isn't.


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