Limiting travel on Roco's - thicker top out bumper?

Discussion in 'Downhill & Freeride' started by Kanye West, Jan 22, 2008.

  1. Kanye West

    Kanye West 220# bag of hacktastic

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    My objective is to make my frame lower and slacker. I have a 9.5" Roco WC on it at the moment. I am considering picking up a 5th in a 9"x2.75" and doing the shim mod on it to slack the bike out/lower it as a secondary shock or experimenting with a thicker top out bumper (1/4" - 1/2") under the piston head in the Roco damper the next time I rebuild the shock. Has anyone done this with a Roco or any other shock? What supplier would have this and what are the dimensions/part #?

    This is for an R9 by the way. It's a couple years old and the geometry has been tweaked on the newer models to be a degree or so slacker, and my BB can never be too low.
     

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  2. davep

    davep Turbo Monkey

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    Should work well on the roco as the damping is speed sensitive not position sensitive...although you might have to go up in spring rate.

    No one is going to have an off the shelf part to shim down a shock. You will just need to find something to fit behind the piston that will fit and not interfere with the compression shims on the back of the piston.

    If you have not already, go to windwave.uk and find the roco rebuild manual they heve. It has lots of good info.
     
  3. davep

    davep Turbo Monkey

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    Those may work^^...but that is not what he wants to do. Adding to the b/o bumper will not shorten the shock and thus will not lower the bike. You need to add a top out bumper on the inside of the shock.
     
  4. Cave Dweller

    Cave Dweller Monkey

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    I have shortened my avy by 1/4 inch. I put a spacer inside the shock between the piston and end of shock body so that it can extend the last 1/4 inch. The part was made by avy, not sure it would fit the roco
     
  5. vitox

    vitox Turbo Monkey

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    i dont think the avy spacer will fit a roco as it has a small step on the end to avoid it sliding up and down the shaft

    anyhow, i shortened a roco for an urban race using a plastic spacer inside, no problems but it was used for a limited time only so i wouldnt know about the long term durability of it, it works perfectly though.
    i think i used 1/2" ID and 17mm OD.
     
  6. toodles

    toodles Turbo Monkey

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    A standard DU bush has the correct ID and OD for what you want to do. Dunno if it's worth a shot. You'd have to make sure it didn't cover the rebound port on the shaft.
     
  7. Kanye West

    Kanye West 220# bag of hacktastic

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    Good idea! Unfortunately I'd probably want it to be rubber if I were going to take that route, or at least find some way to get a rubber O-ring around the end.

    Vitox - Did you notice any harsh topping out with the plastic spacer? Was there any wear or cracks on it when you removed it?
     
  8. sriracha

    sriracha Monkey

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    why not just run more sag and call it a day?...then you'd have a bit more negative travel also.
     
  9. vitox

    vitox Turbo Monkey

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    hack

    no problems at all
    setup worked perfectly for the time it was used and i have done similar mods to other shocks like rcs and 5ths and no real problems.

    the DU trick sounds good but theyre so thin and slippery id prefer a snug fitting plastic spacer.