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Discussion Starter · #1 ·
I've been peering at them recently, still pondering about new frames.

Basically though I'd love to see pics of any ones people have, or any opinions/recommendations. or even just a list of known ones tbh.

I know orange, morewood and yeti make them, anyone else?
 

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How are you defining single pivot? If it's just simple swing arms then Sinister, certain Nicolais

If you're looking at linkage driven as well, then Commencal, Trek, Diamondback, Scott, Kona, Cannondale, GT, Gary Fisher and Tomac.

Do yourself a favour and get a demo ride on an Orange 5 or Alpine 160 depending on what you had in mind.
 

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Discussion Starter · #5 ·
What difference is the between linkage ones and simple ones? I know obviously one has a linkage and the other doesn't but what effect does this have?

I've never been overly keen on the heckler. Not sure why just a gut thing, but I've found a trail centre near me that has a orange and santa cruz demo fleet, which has both the 5 and heckler. Was planning on giving the 5 a go anyways but may as well try the heckler whilst I'm there.
 

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I'm still trying to wrap my head around this but this is what I understand so far.

Simple single pivots have predictable characteristics based on spring rate, and shock/pivot placement. They typically suffer from brake jack and pedal bob (dependant on front chainring, pivot placement and of course how you pedal).

Linkage driven single pivots incorporate more pivots between the shock and swingarm to vary the spring rate through the stroke changing the way the bike behaves throughout it's travel.

It helps to try to visualize how the linkage moves as the bike goes through it's travel

Simple:



Linkage Driven

 

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A rocker arm linkage thing can add stiffness, and change the spring rate. On the downside, it adds complexity and more pivot points.

A simple single pivot may not need a change in spring rate or increased stiffness, so you can't say that a linkage is a superior design necessarily.
 

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There are also faux bar designs, like Kona or Ventana, and the seatstay pivot is supposed to help with brake jack.

They are also called single pivot designs (one pivot determines the wheel axle path).
 

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Discussion Starter · #9 ·
Well I want something which is as predictable and informative as possible. I love my chameleon for those reasons. It's just so precise and I know exactly what my wheel is doing. I geuss I won't get quite the same level through a FS, but I need something for multi day epics, and i'm just not sure the chameleon will cut it.

I've never quite understood what brake jack is. Also why does it occour? I can understand pedal bob fine, both what it is and why it happens, but never really got brake jack.
 

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Dheorl said:
I've never quite understood what brake jack is. Also why does it occour? I can understand pedal bob fine, both what it is and why it happens, but never really got brake jack.
Look at the picture of the Santa Cruz above. the brake caliper is attached to the swing arm. When you brake, the force from the wheel is transfered to the swing arm. this force is downward on the swing arm, tending to extend the shock. this force is opposite the force of hitting a bump, which would be upward on the swing arm. The result is that the suspension is stiffer when the brake is applied than when it is not. This is because the bump force has to overcome the opposing downward force from braking, before the shock starts to compress.
 

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Discussion Starter · #11 ·
If a big enough brake comes along to overcome the braking force will the brakes still work fine though?

Do all single pivot bikes have brake jack?
 

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Dheorl said:
If a big enough brake comes along to overcome the braking force will the brakes still work fine though?

Do all single pivot bikes have brake jack?
The brakes always work fine, you can lock up the wheel or modulate the brakes the same as any other bike. The effect is on the suspension, not the brakes.
I have a Santa Cruz superlight (same suspension as the heckler). I don't mind the stiffening effect during downhill braking. In fact, I am used to it and don't notice it.
Imagine you are blasting down a rocky downhill, and your front and rear suspension are soaking up the bumps. you need to slow down so you start braking. You would notice that your rear suspension would feel a little less plush, with the wheel bouncing over bumps a little more instead of absorbing them as if the brake were off. It's a subtle feeling. No big deal.
With multi pivot bikes, you can also have brake induced suspension stiffening, but the extra pivots allow some of the brake force to result in rear triangle deforming, rather than opposing the shock movement.

Brake "jack" refers specifically to the feeling of the shcok being extended when the brakes are applied, reducing your sag and jacking you up. I have never noticed that feeling on my superlight.
 

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Discussion Starter · #13 ·
I kinda like the thought of brakes stiffening slightly under braking. May not work as I think it will but hopefully the weather will clear up and I'll find out soon.
 

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smilinsteve said:
Look at the picture of the Santa Cruz above. the brake caliper is attached to the swing arm. When you brake, the force from the wheel is transfered to the swing arm. this force is downward on the swing arm, tending to extend the shock. this force is opposite the force of hitting a bump, which would be upward on the swing arm. The result is that the suspension is stiffer when the brake is applied than when it is not. This is because the bump force has to overcome the opposing downward force from braking, before the shock starts to compress.
I think you have this opposite. When the brakes are applied, the force tends to compress the suspension.
 

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Bubba74 said:
I think you have this opposite. When the brakes are applied, the force tends to compress the suspension.
Ditto. Brake jack is a compressive force.
 

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Brake jack is extension of the shock, brake squat is compression of the shock. Both will stiffen the suspension. Brake jack stiffens the suspension by applying a force counter to the bump force, and brake squat stiffens the suspension by compressing the shock and reducing the amount of travel remaining.

But I think you are right, the force I described on the Santa Cruz example is a brake squat force. Brake squat often results in rear shock extension anyway, because of momentum, weight shifting forward during braking, and fork dive, so that the front goes down, feeling like the back goes up.

Most bikes have brake squat, not brake jack, and I think that's true whether it is single pivot or the more complicated design.
 

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We're thinking of the same thing, just calling it different names. Either way, wanna see it in action? Throw your bike in a stand, pedal it hard, jam the rear brakes. Voila. Brake Jack/Squat.
 

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smilinsteve said:
Brake jack is extension of the shock, brake squat is compression of the shock. Both will stiffen the suspension. Brake jack stiffens the suspension by applying a force counter to the bump force, and brake squat stiffens the suspension by compressing the shock and reducing the amount of travel remaining.
I stand corrected about the terms. BUT, very few single pivot bikes, if any, have brake jack. The majority suffer from brake squat.

Thanks for clearing up the terms for me. :)
 

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Discussion Starter · #19 ·
Although this discusion has helped, I was wondering if there were any other brands that I've missed, I think I'd rather have just a straight single pivot. So far there is...

SC hecklet
Morewood
Orange
Sinister (although I can't seem to get them in the UK)

Any others?
 

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+1 on the sinister, I would sell a kidney before this bike. It's so verstile with several different setup options. I have seen them setup as everything from XC rides to mini-dh monsters. You can order direct from them or there are probably a few floating around used.
A bit of sinister love:
 
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