Easy stroke-indicating device for coil shocks.- Mtbr.com
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  1. #1
    No, that's not phonetic
    Reputation: tscheezy's Avatar
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    Idea! Easy stroke-indicating device for coil shocks.

    OK, so a lot of people are wondering how much travel they are getting from their coil shocks in terms of how much of the shock stroke gets used. Here is an easy to make coil shock travel indicator I just whipped up out of two CDs, an old spoke, two old alloy spoke nipples, and a cable slap donut. I used CDs because I wanted some stiff, tough, thin plastic and they were sitting around. I will be curious to see if they crack under load. There is probably more appropriate plastic out there...

    I grabbed a dremel and cut the center of the CD out to match the inside diameter of the coil, so it would seat nicely over the preload collar or on the lower spring support of the shock. I trimmed the outside down and left a tab sticking out to mount the spoke on. I made two of these. I drilled 2mm holes in each tab to pass the spoke through. The tab needs to be big enough and the hole far enough out to clear the coil plus a little extra in case the coil fattens under compression.



    I cut one nipple down and threaded it onto the spoke. I passed it through one of the holes and captured the spoke via the second nipple.



    I placed the disc down where the lower spring support on the shock would go and cut the spoke down so that it reaches approximately to top of the shock body's threaded section. I slid one of the discs onto the shock and onto the preload collar. I then slid the coil onto the shock, followed by the lower disc (being careful to thread the spoke into the upper disc's hole), and finally the lower spring support. I snugged the preload collar down being careful to keep the discs aligned and the spoke straight. It was very easy, and the spoke can be placed at any side of the shock provided the tabs don't interfere with the piggyback and the spoke doesn't hit the rockers when mounted on the bike.





    The spoke slides easily through the upper disc's hole. The disc pushes the rubber donut down the spoke as the spoke passes through the hole. The travel achieved is the distance between the upper disc and the donut.

    The system is independant of the bike's linkage parts moving or the eyelets rotating. It simply measures the distance the shock (specifically the spring) compresses. Simple. Light too at only 9 grams complete. The spoke also won't poke anything as it basically stays stationary as the rocker arms rotate down towards it. Just don't mount it upside down where it will try to stab towards the bb.

    My video techniques can be found in this thread.

  2. #2
    banned
    Reputation: Jerk_Chicken's Avatar
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    Good show!

    I have yet another idea that I simply have to find time to implement at this time. Hopefully next week I'll have pics up and running.

    What cds did you use?

  3. #3
    thats right living legend
    Reputation: blackagness's Avatar
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    Took you long enough.

  4. #4
    Just another FOC'er
    Reputation: .Danno.'s Avatar
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    Sweet! I've got to build one of those to get my end stroke set up correctly.

    Just by feel I can never tell if I've got too much ramp up preventing full stroke, or real bottom out.

  5. #5
    I dig trails!
    Reputation: Mr.P's Avatar
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    Brilliant! I love the re-use of the bike bits.

    Thanks for the write-up.

    P

  6. #6
    Bad Case of the Mondays
    Reputation: Jdub's Avatar
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    Quote Originally Posted by tscheezy
    OK, so a lot of people are wondering how much travel they are getting from their coil shocks in terms of how much of the shock stroke gets used. Here is an easy to make coil shock travel indicator
    Interesting idea, but I have to ask why a simple o-ring around the shaft wouldn't work? Would it just get burried in the bottom out foam pad thing (I'm sure there is a technical term for that thing but it eludes me at the moment)?

  7. #7
    Lay off the Levers
    Reputation: Bikezilla's Avatar
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    Nice. Ts McGuyver strikes again.

    Those CD's really didn't crack?

    Now could you invent a spring compression tool so I can add and remove my 800# spring w/o using 2-pairs of vice grips and risking life and limb?


    I was thinking of making a sag measuring tool the other day and was considering using a telescoping tube with a 5mm hex driver mounted perpendicular on each end. The idea would be to hold it in the bolt holes while sitting on the bike to measure sag. Now I'm thinking just use longer bolts with a nut near the end to replace the origs. But your fabrication is very elegant and far more useful since you can actually ride it and it'll weigh far less than the tubes and hardware I had in mind. Mee likey!
    Faster is better, even when it's not.

  8. #8
    Bite Me.
    Reputation: cutthroat's Avatar
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    That's scary - brilliant - but scary.
    When I see an adult on a bicycle, I do not despair for the future of the human race. ~H.G. Wells

  9. #9
    No, that's not phonetic
    Reputation: tscheezy's Avatar
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    Quote Originally Posted by Bikezilla
    Now could you invent a spring compression tool so I can add and remove my 800# spring w/o using 2-pairs of vice grips and risking life and limb?
    That's an easy one. It's called a "diet".

    I really don't know how long the CDs will hold up. They were really just employed for the prototype.
    My video techniques can be found in this thread.

  10. #10
    Team Blindspot
    Reputation: S-Works's Avatar
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    You've got waay tooo much time on your hands!
    Astigmatic Visionary

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