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offset shock hardware

lawmanlawman Posts: 6,868
edited August 2012 in MTB workshop & tech
Any suspension experts out there have any idea what kind of difference offset shock bushings make to the performance of your frame, aside from geometry tweaks? I've heard they can mess with leverage ratios and curves etc? is this true?

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  • nicklousenicklouse Posts: 81,520 Lives Here
    Yes.
    As there is an offset force in a circle they will rotate in the DU bush. This is not a bad thing as this is what it is designed for. But it is still more movement than was designed.

    Leverage ratios will change as the effective mounting point changes as the offset bush moves. So therefor so will the rest of it.

    Note these changes will be smallish so will not be that noticeable to most. I am more concerned about the wear that has been added.
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  • lawmanlawman Posts: 6,868
    Ok, so it's not as bad as I've heard then. What do you mean by wear, more wear on the bushings?

  • DodgeTDodgeT Posts: 2,255
    Anybody got any more info on these? Considering a Burgtec offset bush to slacken the enduro a touch, as opposed to the £200 angleset.
  • bails87bails87 Posts: 13,317
    I think Northern Monkey had some....and they broke.
    MTB/CX

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  • DodgeTDodgeT Posts: 2,255
    Anybody running one? Any comments?

    Unless someone shouts up with something like "fit one and you'll die" i'm going to get one ordered and fitted next Friday and then hopefully see what difference it makes.
    Just need to find the geo specs for the frame (spesh enduro expert 2011) to make sure I don't slacken it too much.
    Looking at the specs, current HA is 66.5 deg. Drop it a degree??

    edit to add.. just read this;

    What do these do exactly?

    Compress your suspension; you'll notice your bike gets lower and slacker as the shock shrinks in length. This is what these bushings effectively do. By offsetting the hole in each bush, you can shrink the shocks e2e (eye to eye length) by as much as 7mm. This will usually give a 1-1.5 degree head angle change and lower the bb substantially too


    So, it reduces your travel, which may not be ideal if i'm wanting to do this for using the bike for DH.

    Or does it, as someone says this on another forum;
    As your rear end compresses it increases the head angle, so offset bushes will move the position of the shock so your rear end will sit lower but still give you the same amount of rear wheel travel through the shock.
  • mrmonkfingermrmonkfinger Posts: 1,452
    DodgeT wrote:
    So, it reduces your travel, which may not be ideal if i'm wanting to do this for using the bike for DH.

    Not correct. You still get full travel* - providing your frame has enough clearance.

    You might want to double check that with the shock fully compressed before you start riding off 10' drops...


    * yes, full travel might have altered a tiny bit because of the changed geometry.
  • bails87bails87 Posts: 13,317
    I think this is how they work....

    The shock normally mounts in the centre of the hole in the frame/linkage that the bushing is in.
    Draw two circles on a bit of paper, so the centres are 100mm apart.

    When you put the offset bushing in you 'offset' where in the the frame the end of the shock is fixed, it's no longer in the centre of that hole in the frame. So draw another two circles of the same size (draw round a coin or something) where the distance from the centre of one circle to the far edge of the other is 100mm. The circles are closer together. If those two circles are the mounting points for the shock you should be able to imagine what will happen.

    It has the same effect as running more sag, except you've still got the same amount of travel, so it might be that things start bashing into each other, as the shock with normal bushings would bottom out before it does so with an offset bushing.

    I think.....
    MTB/CX

    "As I said last time, it won't happen again."
  • getonyourbikegetonyourbike Posts: 2,804
    I don't know about your question but I'm getting a set for my Spicy. It's currently at 67 degrees, so I'll be looking at 65.5-66 degress with the bushings. I can always only run one if it's too slack. Personally, I'm just as interested in dropping the BB as slackening it off.
  • Mine siezed after about 30 seconds!

    had to spend another £20 getting them removed and replaced!
  • DodgeTDodgeT Posts: 2,255
    I think the easiest solution is going to be just get another bike.. The c456 is going to have to go to make way for a proper downhill bike.
  • stubsstubs Posts: 5,258
    Mine siezed after about 30 seconds!

    had to spend another £20 getting them removed and replaced!

    A mate tried a set on his bike and they lasted a lot longer than that. They lasted at least 10 minutes till the first bomb hole and collapsed and bent the lower mounting bolt. They were machined out of an alloy that seemed to be 90% cheddar cheese, luckily for me as I was the one who removed the remains with a Dremel.
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  • getonyourbikegetonyourbike Posts: 2,804
    Good job I'm ordering ones made of brass then.
  • yeah, I had brass ones.
  • cooldadcooldad Posts: 32,904
    yeah, I had brass ones.
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  • stubsstubs Posts: 5,258
    Good job I'm ordering ones made of brass then.

    Personally I would go for a good grade Stainless Steel set if such a thing exists.
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  • DodgeTDodgeT Posts: 2,255
    I was going to get the burgtec titanium ones.
  • personally, I wouldn't recommend offsetbushings.com

    Lots of people do rate then so maybe i git a Friday job.

    They're brass which is good, but the finish isn't great. Lots of burrs on both the brass and mounting kit which meant they didn't fit together great.

    needless to say, siezed within 30 seconds.

    I'd happily try again, but I'd spend more for higher quality.

    Be aware of some though, they use harder metals (one lot used steel!!) and they wear the shock mounts!
  • getonyourbikegetonyourbike Posts: 2,804
    I was going to order from offsetbushings.com but if that's the case them I'll get them from someone else.
  • DodgeTDodgeT Posts: 2,255
    @getonyourbike - the ones I was thinking of getting were (as said above) the titanium burgtec ones, from goldtec/betd. However, i'm probably not going to bother now, as my ideas with the bike has changed - I think..

    See, i've got a 2011 enduro expert and a C456 with 150mm revs. Thing is, they're too similar capability wise. My usual riding is places like Lee Quarry, Gisburn, Llandegla, Peaks, not to mention lots of playing around on jumps n stuff and to be fair, they both are excellent in all those places.
    More recently, i've started to do a lot more DH riding, not crazy stuff, but love Stile Cop, loved Antur Stiniog and I want to do more of this kind of riding. So I thought the best plan would be to make some slight changes to the enduro (like the HA / offset bushes) to make it a bit more suitable for DH stuff.
    But then I think, why make the enduro into a DH machine, when it'll never be a proper DH machine. So, I reckon the most sensible thing would be to sell the C456, keep the enduro as the multi purpose tool it is and then get a proper DH bike for doing, well, DH.

    Anybody want to buy a C456 :)
  • getonyourbikegetonyourbike Posts: 2,804
    I've just ordered some Burgtec ones. :)
  • I've just ordered some Burgtec ones. :)

    Could you let me know how you get on? Still interested in trying them as they made a noticeable difference to the feel of the Canyon.
  • getonyourbikegetonyourbike Posts: 2,804
    Yeh, no problem. I'm pretty sure it'll be easily noticeable because my bike has 6mm bolts, so I'm looking at 1.5 degrees and half an inch of BB drop.
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