FS Linkage designs.. pro's/con's.
The Northern Monkey
Posts: 19,174
As the title really.... whats the main adv/disadv of some of the main linkage designs?
Also.. a pic of the linkage would be good... they all look the same to me!
think i've seen somewhere on the net with them all side by side but I have no idea where
Also.. a pic of the linkage would be good... they all look the same to me!
think i've seen somewhere on the net with them all side by side but I have no idea where
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looked in the tech links sticky?"Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Most suspension is a trade off between anti squat (the chain and drive forces opposing your rearward weight shift under acceleration and downwards force when stomping, causing bob) and pedal kickback, which is what happens if the wheel gets further away from the chainrings and the chain 'lengthens'.
More anti squat = more pedal kickback
Less anti squat = less pedal kickback, but more bobbing.
Is a basic summary.
A virtual pivot point bike will behave exactly the same as a single pivot bike if the vpp is in the same place as the single pivot (except under braking).
So the further the pivot is from the bottom bracket, the more the chain tends to lengthen, the more pedal kickback you get but they tend not to bob much ie a typical single pivot like a Heckler.
The closer the pivot to the BB, the less chain growth you get, less pedal kickback, but tend to bob more under power ie Trek and FSR.
Many VPP type bikes can have the pivot location change througout the travel, allowing different characreristics at different points.0 -
Or look in the stickies ;-)0
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have jsut looked in stickies.. didn't really get any of it
Whats with the magic link on kona's then? whats that preventing?
and DW link?0 -
Magic link physically alters the main pivot position an leverage ratio.
DWs page explains how it works well.0 -
the magic link is designed to change the geometry of the bike automatically isnt?0
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Yewah, sora turns into a shorter, steeper bike for climbing.0
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sheepsteeth wrote:the magic link is designed to change the geometry of the bike automatically isnt?
Kona's explanation
A hardtail is what you all need, or a dawes single pivot.
Now that we are strong ought to bear the infirmities of the weak and not to please ourselves. ROMANS 15:10 -
supersonic wrote:Yewah, sora turns into a shorter, steeper bike for climbing.
whats the dope link then for the stinkys and stabs? is that something to do with braking?0 -
it prevents brake jack0
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yeah, have a look on youtube, theres a couple of vids demonstrating it, funnily enough, all of the examples on youtube are done using FSR :? although they have removed the shocks to demonstrate the effects.
i might go and have a look to see if it happens to my bikes with the shocks fitted.0 -
would be interesting!
just been and had a look... tis pretty shocking! surely that'd just throw you over the bars?
whats stops other bikes being like this?0 -
i think the effect only really occurs with the shock removed and involves actually locking the rear brake.
ive never felt this effect when riding and believe me, i spend plenty of time on the brakes
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i just wondered what people thought of this. http://www.youtube.com/watch?v=5nGoqF7CNR8 do you agree/disagree?0
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im sure some of it is a bit overplayed, but fundamentlay its pretty much right i would imagine, well donr GT. infact, if i was goning to buy a FS it would be a i-drive 5 elite.racefaceec90 wrote:i just wondered what people thought of this. http://www.youtube.com/watch?v=5nGoqF7CNR8 do you agree/disagree?I like bikes and stuff0 -
I thought the GT video was so poor I emailed them to complain about it last week!0
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bigbenj_08 wrote:whats stops other bikes being like this?
Not a lot really. You can place the pivot concentric with the rear axle, so the brake should always be in the relatively same position.0 -
Trek and FSR try to minimalize braking influence with their designs - but to explain it goes into defining instant centres and so on.
Best way to think about it is this - on a four bar system each part of the 'floating' four bar has its own unique virtual pivot - so the caliper can be rotating around a different point to the axle! This allows the designer to somewhat independantly tune brake and drive forces in the same design.
Single pivots do not allow this. TREK ABP has the caliper on the floating part - Kona does not and which is why it has the DOPE system to imitate it.
Thing is, in use, can you feel it? We all move our bodies differently when braking and weight/unweight the rear sus in different ways.0 -
Ben none of it makes the slightest difference - if there was one design even marginally better than the others in real life scenarios, every manufacturer would use that. There are so many variables that are not constant in biking (mainly centering around the fact that we humans are extremely inconsistent) that worrying about the intricacies of modern suspension design is a pointless pursuit 0
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fun though. for me, anyway. any other engineers out there?Rock Lobster 853, Trek 1200 and a very old, tired and loved Apollo Javelin.0
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el loco pollo wrote:Ben none of it makes the slightest difference - if there was one design even marginally better than the others in real life scenarios, every manufacturer would use that.
That's clearly not true - some designs are obviously better than others.. what stops them all using the same designs are the patents.0 -
frogstomp wrote:el loco pollo wrote:Ben none of it makes the slightest difference - if there was one design even marginally better than the others in real life scenarios, every manufacturer would use that.
That's clearly not true - some designs are obviously better than others.. what stops them all using the same designs are the patents.
Or that some are better in certain areas. There's many factors that make a good suss design, chain growth, pedal bob, kickback etc. Some are better in certain areas (ie. idrive minimises pedal bob).What We Achieve In Life, Echoes In Eternity0 -
they all claim to minimise pedal bob and they all produce evidence to suggest they are the only system which does it. very little of this true.0
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I think Dave Weagle's website is best at explaining stuff.0
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We'd all be better off just getting out and riding our bikes instead of getting bogged down in the intricate minutae of x versus y.
I think I'll take my own advice, bye!0 -
Best way is to simply go and test. They vary in feel - a lot.0
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Cheers sonic, it is pretty good.supersonic wrote:I think Dave Weagle's website is best at explaining stuff.
Guess you might know the answer to this one though, i'm guessing the suss designs for short travel trail bikes and big hitting DHers is going to be different, so is the suss design on the carbon GT Fury different to that on the idrive/force bikes?What We Achieve In Life, Echoes In Eternity0 -
ok then, i'm sold! where do i buy a GT FS from???? :roll:
slightly more seriously.. who actually stocks GT over here, none of my LBS' seems to have any GT bikes (from memory){insert smartarse comment here}0 -
The Fury uses the same Idrive platform, just tweaked for longer travel.
The system does work well, I just think the video asks more questions than it answers.0
