Replacing air for coil shock - sizing?

Beardface
Beardface Posts: 5,495
edited March 2011 in MTB workshop & tech
Hi all,

I've got a 2006 Spesh Enduro (entry model), with a Fox DHX air 3.0 shock, with measurements of 8.5 x 2.25 (216 x 58 ).

I've seen a DHX 5.0 Coil shock for sale, which has come from an S-works Enduro (2006 again), but measures 8.75 x 2.5 (222 x 65).

Clearly, these are different lengths etc... why, and will the Coil shock fit in my enduro, given the .25 increase in length and the .25 increase in stroke?

Bit hesitant about buying the shock if it's not going to fit properly.. would I need to buy a new shock/link plate if I was to get this coil shock?

Thanks in advance, appreciated :)
Stav

Comments

  • nicklouse
    nicklouse Posts: 50,675
    you need the same figures. or a new plate/rear end.

    why? they are different designs.

    and will the coil shock fit between the frame (diameter).

    would it give any more shock travel? well only if you can extend the rear sus any more than it is now.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Beardface
    Beardface Posts: 5,495
    Damn. I kinda had a bad feeling that may be the case.. ah well, thanks Nick, I knew you'd be along soon enough to help me out!

    Forum legend ;)
  • benpinnick
    benpinnick Posts: 4,148
    You might be able to get away with it - there's nothing to say it won't. I run a longer shock on my Specialized FSR (albeit a different suspension design than yours) than is the spec. Roughly the same difference as yours (.25 on stroke and length) and it works very well. This allowed me to bin the Triad and get a custom tuned RP2. What you need to consider is two things:

    1. Will the end (so fully compressed) of the stroke finish at the same point? This will prevent you damaging the frame with too much movement.
    2. As the shock is longer, will it fit when fully extended? I am guessing yes, but worth removing one bolt from the old shock and extending the suspension a little so you can judge whether it will fit.

    My gut feeling is that as long as the shock mounts are the same, it will work fine.
    A Flock of Birds
    + some other bikes.
  • benpinnick
    benpinnick Posts: 4,148
    Having just looked at the two frames online. I'm convinced it will fit ok (assuming the shock mounts are the same).
    A Flock of Birds
    + some other bikes.
  • Beardface
    Beardface Posts: 5,495
    Thanks Ben,

    I'll take that into consideration.. I thought it would fit ok, but I'm also kinda worried about messing up the geo?

    I think it's probably best for me to play it safe and get the same i2i length shock to replace.. a larger stroke (0.25") wouldn't make too much of a difference though I assume?
  • benpinnick
    benpinnick Posts: 4,148
    Its going to slightly alter the geometry (slightly steeper head angle + higher BB being the main things) but its not likely that you'd notice too much as its only .25" which really won't make a huge difference, 0.5deg on the head angle and a few mil on the BB I imagine.

    Also, if your bike runs longer than specified forks (I am guessing you'll have replaced them since 2006) your head angle will already be slightly slacker than intended. You also do have multiple shock mounts so that you could play around with it a little too. for example, if you run on the steeper setting now, why not add the longer shock and use the slacker head angle setting? That way you'll counter one with the other.
    A Flock of Birds
    + some other bikes.
  • Beardface
    Beardface Posts: 5,495
    Haha, the only thing that is original is the frame and shock these days, I'm running 140mm Fox RL's, so have upped the front by 10mm.

    Currently use the high BB shock mount, so assuming I use the other one (low BB) to counter the slight rise in length of shock?

    Cheers for the help again Ben, I'm a bit useless when it comes to changing shocks etc, not done this before :)
  • benpinnick
    benpinnick Posts: 4,148
    Exactly - you can play with the various options until you're happy. I recon it will work fine. Lots of people get a bit funny about changing shocks, but I've been doing it for years. While I cant comment on your frame, Specialized told me that my shock change wouldn't effect warranty either.

    Also remember that of the extra 0.25 inches, around 0.08 will be in sag, so your effective shock length change is even less.
    A Flock of Birds
    + some other bikes.
  • benpinnick
    benpinnick Posts: 4,148
    PS - Once you get it sorted we should hook up at Swinley for a ride so I can see how you're getting on with the new shock (if you're in N. Hampshire and not Portsmouth or somewhere like that).
    A Flock of Birds
    + some other bikes.
  • nicklouse
    nicklouse Posts: 50,675
    benpinnick
    often the rear sus will not extend any further so in that case you will be reducing the effective travel.

    it all comes down to the design.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • benpinnick
    benpinnick Posts: 4,148
    This is very true, however I can't see that being the case given the Enduro '06 design. Even worse is if the shock actually fouls the frame, which would be more common on a rocker/Faux bar design, or the common under-top tube designs that most bikes run now.
    A Flock of Birds
    + some other bikes.
  • Anonymous
    Anonymous Posts: 79,667
    Also bear in mind that the behaviour of coil shocks can vary dramatically from air shocks. If the frame is designed for one, it may be rather strange with the other.
  • Beardface
    Beardface Posts: 5,495
    benpinnick - I'm in Aldershot buddy, so not too far from Swinley :) Once I've worked out what I'm doing with this frame, I'll give you a shout.. only been to Swinley a few times, and couldn't find my flow, so would be good to go with someone that knows the routes!

    Yeehaa - True, I was of the thinking that the coil shock shouldn't matter too much, seeing as the Enduro is very similar to the SX Trail of that year.. I've seen a few other 06 Enduros with coil shocks sitting at my LBS waiting for a service, so know it can be done..

    Might just buy another frame.. lol, it's almost 6 months since I've had this one.. why change my habits now! :lol: