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  1. #1
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    Modernizing a Sherman build thread

    Hi,
    Wasn't sure where to put this, but I'm working on modernizing a manitou sherman for a future 650b bike, thought I'd put it here to help with the 660b popularity.

    I'm really only done the steerer, wanted that done first so if I fubar'd it I wouldn't have too much work or wasted money down the drain.

    I had a 1.5 sherman breakout for sale that wasn't getting any nibbles on PB, and I really like to tweak everything to my liking, so I figured why not see how light/modern I can make this old thing.

    I contacted manitou about getting a tapered steer tube, they weren't helpful in me getting one, or an air piston,but thats for later. They were polite, and said we don't recommend you doing any work of this sort, basically.

    So, long story short, I removed a tapered steer tube from an upper domain assembly I found on pb, cut the old one (sherman 1.5) out from the inside to avoid scoring from pressing it out. Froze the tapered steer tube, and a friend who works in the aerospace industry (more older stuff but still) provided a paste for pressing parts together (sleeve retaining loctite would also be a good choice) and we pressed it in.

    So heres a picture of what I believe is the only tapered steerer sherman upper.
    Attached Thumbnails Attached Thumbnails Modernizing a Sherman build thread-sherman-tapered.jpg  


  2. #2
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    Next on the list is to make a MARS air spring like the modern minutes have, which is to use an air spring on top of a short coil spring, to give the small bump sensitivity of a coil without a large weight increase. They do this by using a shelf to limit the air piston from over-preloading the coil spring, so the coil provides the first bit of travel until the pressure moves the air piston. Seems to me to be the best choice for an "all-mountain" fork.

    I've honed out the ridges and scratches inside the spring leg using an automotive brake hone, had to go from both sides. The piston is going to be made by a friend if I can't source a manitou minute air piston/or its the wrong size.

    The plan is to transplant as much of the new minute MARS spring as possible, and use a rolled up peice of harder plastic to make my air shelf from the lower cap to the piston. That, and playing with the length of the air piston/coil spring rod, should let me fine tune the ramp rate to my liking, which should be quite linear, if I can get it there.

    SO, provided that all works, and I get the air/coil spring holding air and providing a good spring rate, the last step is less work, more luck. Source a nixon 160 tpc+ damper cart. I've currently got a stanchion based tpc+ system, but with 150+ cc's of oil, and larger piston assemblies, I'm hoping to shed a couple grams from the damper side while I'm at it.

    Oh, and I've got a bored out hex loc on my current nixon I'll transfer over, but theres not much savings there. Goal is to turn an aprox ~2500g fork into the 2200 ish range while getting the best damper out there, and large tire 650b capable.

    Any suggestions/hints, info, questions?

    Yeroon

  3. #3
    Crazed Country Rebel
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    Quote Originally Posted by Yeroon View Post
    Next on the list is to make a MARS air spring like the modern minutes have, which is to use an air spring on top of a short coil spring, to give the small bump sensitivity of a coil without a large weight increase. They do this by using a shelf to limit the air piston from over-preloading the coil spring, so the coil provides the first bit of travel until the pressure moves the air piston. Seems to me to be the best choice for an "all-mountain" fork.

    I've honed out the ridges and scratches inside the spring leg using an automotive brake hone, had to go from both sides. The piston is going to be made by a friend if I can't source a manitou minute air piston/or its the wrong size.

    The plan is to transplant as much of the new minute MARS spring as possible, and use a rolled up peice of harder plastic to make my air shelf from the lower cap to the piston. That, and playing with the length of the air piston/coil spring rod, should let me fine tune the ramp rate to my liking, which should be quite linear, if I can get it there.

    SO, provided that all works, and I get the air/coil spring holding air and providing a good spring rate, the last step is less work, more luck. Source a nixon 160 tpc+ damper cart. I've currently got a stanchion based tpc+ system, but with 150+ cc's of oil, and larger piston assemblies, I'm hoping to shed a couple grams from the damper side while I'm at it.

    Oh, and I've got a bored out hex loc on my current nixon I'll transfer over, but theres not much savings there. Goal is to turn an aprox ~2500g fork into the 2200 ish range while getting the best damper out there, and large tire 650b capable.

    Any suggestions/hints, info, questions?

    Yeroon
    I've changed out steer tubes before without issue. I used sleeve retaining locktite. You should be fine. Just listen for creaks, and check for slop every now and again.
    Stupid, but sometimes witty. Occasionally brilliant. Slow and fat though.

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  4. #4
    MattSavage
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    This is kind of awesome...

    You should xpost this in the suspension forum.
    "I wrote a hit play! What have you ever done?!"

    Have Ashtray, Will Travel....

  5. #5
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    Will do, once i get more progress on it, right now I'm still waiting on some parts.

    Yeroon

  6. #6
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    I'm looking at a Gemini as a heavy duty trail / all mountain 650b project. How much room is there up front for 650b? Any photos? I can't find any online.

    I'm very curious to see how your project turns out!
    Looking for the person who tapped and pinned a set of Shimano A530 pedals - can't find the thread! Shoot me a PM. Thanks!

  7. #7
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    The manitou manuals state the same tire sizes/clearance as a nixon. From having both, the arch has the same room, it just extends back a bit more. It should clear a 650b with the same room as the nixon. Now crown clearnance i don't know, theres a couple different versions so it'd be best to check.

    Made backwards progress, ordered some parts from a new manitou and they don't fit, too big. Not much effort has gone into this lately.

    Yeroon

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