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  1. #1
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    RS MC 3.1 on a 575

    I finally put together a working dogbone mount for the RS MC 3.1 on my 575. I promised Crisillo I would post a description of it, so here it is

    Initially, I bought some bearings to match the 12mm bushing in the RS eyelet, since the Fox is 1/2 inch. Enduro doesn't make bearings the right size, so I bought them from VXB. Enduro must make some hardy bearings, because the ones I tried would only last a few rides before falling apart.

    I should also mention that a simpler solution to the 12mm eyelet problem may be to just machine the RS eyelet to match the Fox bushing. The RS eyelet is also thinner than the Fox eyelet (12mm vs 0.5 inch), so I would still have had to find some thicker spacers. I tried something completely different, though.

    Okay, to begin I ordered the standard RS mounting hardware for both ends, 35mm for the dogbone end and 22.2mm for the frame end (sorry, no pic). The frame end mounted as expected.

    For the dogbone, I decided to try using plastic bushings from Igus. They were nice enough to send me some free samples. The ones I used were GFM-1214-09.



    To get the bushings to fit the dogbone, I made housings from some thick walled 2024 aluminum tubing. 3/4 inch X 0.095 inch wall is a standard size and matches the press fit bushing requirements. They are cut to 9 mm which leaves room at each end for the same spacers used on the Fox mounting. I should have taken these to work and cut them properly, but I wanted to ride the next morning. I chopped them up with a hacksaw and bench grinder



    Okay, so the bushings get pressed into the aluminum housing, and the housing is mounted in the dogbone. The flange on the bushing faces inward, with the outside of the housing flush with the edge of the dogbone.





    Despite my poor work with the hacksaw, the tolerances were very tight. The shock fits snug between the bushings.



    I had the same problem with pinch bolt torque as with the bearings in the Fox mount. If they are too tight, nothing moves, and too tight "feels" too loose. I probably should have used some Loctite between the dogbone and the aluminum housings to keep them from spinning. I marked them with a sharpie for testing, though, and they haven't slipped yet.

    I've ridden around 50 miles of relatively mild single track on this setup, so far. I've taken a few 3 foot drops, but mostly have kept the wheels close to the ground. I've taken it apart and inspected everything after every ride. The bushings are fine, there's no wear that I can see, and there's no play in the suspension.

    Note that I don't need any special tools to take this apart. There's no bearings press fit to the pin, so I just have to takeout the bolts and push the pin out with my fingers.

    Okay, how it rides...

    The RS will definitely accommodate heavier riders than the Fox. I have my pushed RP3 pressure set to 230 psi, and the RS pressure set to 115. I initially set the RS pressure at 200 psi, and it turned the 575 into a hard tail even with my 220 lbs crushing it.

    The RS gate setting has a much wider range than the RP3 Pro pedal, as well. My one complaint is that the gate is super dependent on the shock pressure. When I added 3 whole psi, my smooth ride became rough and jittery, and I had to screw around with the gate again to get things back to normal.

    I'm also using much less sag with the RS, less than 10% I think. Riding over rooty trail is still much smoother with the RS than with the RP3.

  2. #2
    Nightriding rules SuperModerator
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    Quote Originally Posted by belljeffw
    I finally put together a working dogbone mount for the RS MC 3.1 on my 575. I promised Crisillo I would post a description of it, so here it is
    wow... nice work!

    Thanks for taking the time to post back with the setup and your experience... looks promising.

    Please let us know on how it performs over long time (ab)use

  3. #3
    Nightriding rules SuperModerator
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    BTW, you were the one, that had the dogbone with the screws "on the wrong side", right? (the screws on your dogbone face towards the rear)

  4. #4
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    I kind of like these bushings. If this setup holds up, and if igus has the right size, I'm thinking of changing out all the bearings on my ASR-SL. It's had a slight creak since the day I bought it that I've never been able to locate.

  5. #5
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    Quote Originally Posted by crisillo
    BTW, you were the one, that had the dogbone with the screws "on the wrong side", right? (the screws on your dogbone face towards the rear)
    I don't think I've ever had the dogbone mounted backwards, but it does sound like something I would do.

    Wouldn't that prevent the shock from extending fully?

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