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I don't understand suspension, does it need to be hydraulic?

TeachTeach Posts: 386
edited January 2012 in MTB buying advice
I have an old bike with good old fashioned spring suspension.
I've read lots and lots on the internet and it seems to move you towards hydraulic or pneumatic suspension, but there do appear to be occasional problems with pressure etc.
This is a quote from MBR.
Scratching around for ways to make the Lapierre perform even better, I also became fixated on changing the fork. The RockShox Sektor Solo Air wasn’t holding me up enough in turns or in the mid-stroke, so SRAM kindly switched the internals for a coil-sprung unit. The performance boost was and is impressive — just make sure you go for the extra firm option if you’re around 75kg or the sag will be too much, and if you’re any heavier than this, think again.'

I appreciate the choice could be rider specific, but why would you swap to coil sprung. It seems like a move backwards or am I missing something?

Posts

  • supersonicsupersonic Posts: 82,708 Lives Here
    Springs can be coil or air, dampers are usually hydraulic.

    Not sure why the air wasn't holding up as well, springs are linear, while air usually ramps up a bit - you can always add more air. But I think that problem is lack of low speed compression damping.
  • ilovedirtilovedirt Posts: 5,798
    edited December 2011
    I'm generalising massively here, but air sprung forks/shocks tend to have less small bump response and can feel a little notchy in their travel, and can also ramp up quite a lot in their travel (IE, the more you compress, the harder the fork/shock becomes to compress further). However, this isn't true for all forks/shocks, they're improving all the time, and it's equally easy to make a censored coil shock as it is a censored air shock etc. Air shocks/forks are lighter though, and tend to be more tuneable (and more easily tuned) as you can very finely tune the air pressure, and do it almost on the fly as well. To do this with a coil shock, you have to replace the spring... To give you a (very) basic idea of how they work...

    Also yeah, as super said, damping circuits are usually hydraulic.
    Damping (if you're not sure) basically controls the way the fork reacts. So you have rebound damping which controls how fast the fork rebounds to full travel, and compression damping, which controls the resistance to the fork being compressed (on the motion control damping on rockshox forks, full compression damping basically locks the fork out).

    Then you can have high/low speed compression damping to control fast hits on the trail (bumps, drops etc) and low speed controls how high the fork sits in the travel under the riders weight/brake dive etc. Then you can have beginning/end stroke rebound damping as well. That's all getting quite far into that sort of thing though! :)
    Production Privee Shan

    B'Twin Triban 5
  • TeachTeach Posts: 386
    Thank you. That's what I roughly thought. Air sprung forks are the way to go.
  • nicklousenicklouse Posts: 81,520 Lives Here
    Not always.

    And if you want damping that worksite tends to be hydraulic.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • mak3mmak3m Posts: 1,394
    lets say if someone *cough* of a more cuddly build was looking for forks

    would it be better to A go with air sprung forks you need to save all the weight you can, or B a coil fork with a hefty spring
  • nicklousenicklouse Posts: 81,520 Lives Here
    mak3m wrote:
    lets say if someone *cough* of a more cuddly build was looking for forks

    would it be better to A go with air sprung forks you need to save all the weight you can, or B a coil fork with a hefty spring
    Makes no difference.


    Usage has more effect as does make.

    I am not small and use both. But it depends on the bike.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • ilovedirtilovedirt Posts: 5,798
    Yeah, doesn't really make a difference, I just wouldn't buy a flexy XC race fork if you're of a slightly larger build.
    Production Privee Shan

    B'Twin Triban 5
  • RockmonkeySCRockmonkeySC Posts: 15,247
    Thank you. That's what I roughly thought. Air sprung forks are the way to go.

    No. Most DH & freeride forks run coils because they perform better although they weigh a little more. I have ridden a air sprung Rockshox Totem & the coil version & the coil is far better. Air springs ramp up too much so it's difficult to get a good set up which will work through the whole stroke. I run coil sprung Rockshox Domain & Lyrik and they are both amazingly good. Far better than my mates air Lyrik.
    Coils are also more reliable.
  • Do DH forks use coil rather than air because weight is less of an issue in DH - gravity taking its effect an all?

    I presume 'better' is very subjective and depending on the type of riding you do.
    Riding a Merida FLX Carbon Team D Ultralite Nano from Mike at Ace Ultra Cycles, Wednesfield, Wolverhampton 01902 725444
  • on longer or rougher DH courses, air shocks heat up and it can affect the damping.

    Weight isn't an issue, consistent performance is!

    Air forks aren't as supple at the beginning of the stroke and can suffer from more stiction.
  • RockmonkeySCRockmonkeySC Posts: 15,247
    I would use air on a light weight xc bike where actual suspension performance doesn't matter too much but weight does matter & coil on anything which will be taking big hits & needs the better control to keep the bike balanced & the wheels on the ground.
    Rear shocks are a bit different. Air gives better control when climbing to stop the rear bobbing when pedalling I would only put a coil shock on a bike which is purely for downhill or freeride. I do have a coil shock on my Reign X though but the rear suspension set up on that bike is so efficient that it even climbs well with 170mm of coil sprung goodness.
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