OzVMX Forum
Clubroom => Tech Talk => Topic started by: Gerard De Ruyter (Twistandshout) on October 17, 2008, 09:57:09 am
-
I'll start by saying I haven't got a pic of this but will try to find one. A recent US dirt bike mag had an article in it about a new design for front forks which sounded quite naff. Springs at both ends! ie, you have a chrome slider in the 'middle' of each fork, with fork legs at both ends of it, and with springs at both ends too (enclosed within each leg).
The lower leg/spring has lesser spring rate, to absorb small bumps, while the upper is for big bumps. when fork hits a small bump, only lower gets activated. when hits big bump, lower moves then upper. benefit? the lower finishes first and can start to rebound sooner and independently, keeping wheel in contact with ground more.
no independent testing has been done yet, but the develop reckons it gives you front end grip and ride like nothing else. they reckon give it a few years and they'll all have em (ie, his registered design.....). sound alright?
-
Pics please , quick , quick ;D
-
Seems interesting, thinking outside the square. Give us pixies.
(http://i323.photobucket.com/albums/nn458/mx250syd/needpics.gif)
;) :D ;D 8)
-
i knew i was right to plead no pic up front ::)
will scan and upload over weekend.
-
OK, here's a piccie:
(http://www.ozvmx.com/images/forum/forks.jpg)
-
Its the inside I would like to see ;D
-
i saw that article wierd looking things
-
At its simplest, it sounds like an elaborate way to fit dual-rate springs.
At the most complex, it sounds like variation on a KTM PDS set up.
I reserve the right to be completely wrong, depending on what's inside, but based in the information at hand....
-
yes dual rate but each can move independent of the other. i like it! its a bit like the first suzi full floater design, with the spring compressed at both ends....except different....
-
What is the difference when you compress the different ends ? I glad to learn something.
-
well they're on different ends of the bike, silly. ;D ;D
ummmm.....different also....because....there's two springs in there, at both ends of the slider....so can move independently of each other in response to different whacks....unlike the 'floater where there's one spring squished at same rate at both ends.
-
HMmmmmm, please tell me more ???
-
Walter , I can hear your brain ticking . gimmme gimmme a look inside ;D
At a guess it has one spring with dampers top and bottom
-
Asimilar idea was tried back in the day with a small leading link on the frunt of the forks?Nothings new :D ;D
-
I've got a new idea myself. It involves a slider inside a slider inside another slider and uses 3 sets of springs. A soft spring to soak up the small bumps, a stiff spring to soak up the big hits and a medium spring to soak up the medium bumps.
Don't bother trying to order any though as I'm already working on another new idea that involves four springs and.......
;D ;D
-
Always busy Ross.
You want something "special" made?
I thought you only owned Montessa's ;D
-
Makita make bikes now???
-
the bike that chippies choose to ride
-
i think the idea behind those forks was to achieve 2 sets of preload so as when a seto of whoops is hit the is still some shock left after the first whoop
-
Walter,
I seriously doubt there's any diff compressing two springs at diff ends, unless theres two diff dampers in there too.
Otherwise it seems to me to be the same as two normal split-rate springs but w a whole lot more unsprung weight.
Perhaps you can have 2 sets of preload, but you've still got more unsprung weight to deal with.
-
the guy reckons he built it cause arm pump was killing his racing, and reckons using this fork, he gets arm pump no more, like zero pump, ever. how handy would that be?
-
The only advantage I can see , is that you could play with the two different springrates for different tracks and weather conditions . But how many will go that far ?
-
After the work week from hell I finally have a chance to follow this.
Walter, I owe you an apology, I'll get in touch probably tomorrow as I've got a "dinner party" to go to. Just what I need!
I can't see what these double forks could do that normal forks couldn't.
Two spring rates? put two springs in normal usd forks.
Two damping rates? halve the damping chamber size and use two of them. But a well designed shim stack should do the job or you could use, as Nathan said, a PD style set up.
What I can see is two more seals, a I understand that modern seals are prone to leakage.
Two more points of movement, sliders, tubes etc. This give would give less rigidity and there would be, I imagine less overlap between the inners and outers.
The guy's done a great job and I love this type of engineering but I can't see too much advantage to it.
Having said all that I'd still love to see what's inside!
-
Brent you covered most points , but you just never know . Maybe we will hear more of it.
We recently played with water shocks , perhaps thats crazy too :D. But I remember when we made the first Hi Low Speed shock for road racing ( Glenn Ritchards)and the Ohlins camp told everyone there is no need for such thing ....