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  1. #1
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    Manitou suspension fork elastomers???

    I own four early-to-mid 1990s bikes with Manitou suspension forks (2, 3, 4 and Comp). I have been keeping them rolling with a collection of extra MCU elastomers I rounded up around 2000 when I realized there were going to be problems getting replacement parts. I have now run out of replacement elastomers and have even used aluminum spacers to substitute for some of the elastomer stack. Any ideas on a source of new elastomers? Elastomers are still very heavily used in industrial applications and I have even located a company that used to make them for mountain bike applications (http://www.kryptane.com/springs.htm). However, I haven't been able to find a vintage bike parts supplier that stocks them.

  2. #2
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    Order the elastomers from an industrial supplier

    Call the manufacturer and tell them you want to know who the local distributor is. They will give you a contact number. You may have to say you are calling from a company, in order to keep them interested.

  3. #3
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    Elastomers

    The forks are on ebay all the time and they sell pretty cheaply.
    Send the seller an email asking them to pull the elastomer stacks (an easy 30 second job on a Manitou) and tell you their condition.

    I believe there was also a spring conversion ????
    Wanted: Phil Wood front hub, one orphan WTB shifter mount.

  4. #4
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    Yeah, there were springs too. I have a set in my EFC. I keep looking for more but they don't seem to come up often.
    Quote Originally Posted by banks
    That is one big f'n dude!
    Yes I am!

  5. #5
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    speed springs , no damping though
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  6. #6
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    The speed springs work well, but they do not replace the top out and bottom out bumpers (which are a different size than the other elastomers). I could try to put together an order through our company (my boss is cool about such things) if there is enough interest. I've got a Manitou 3 I am trying to get going. I managed to fabricate either the top out or bottom out bumpers (can't remember which right now) but the bumpers are too big in OD to work for the other set.

    Outside!
    Mountain bikers, hikers and horseback riders are not the enemy. Bulldozers are the enemy.

  7. #7
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    They work well in the EFC because of the little damper in it.
    Quote Originally Posted by banks
    That is one big f'n dude!
    Yes I am!

  8. #8
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    Well, if you get a bunch made, I am sure they'd sell easily and frequently on ebay or mtbr.
    Wanted: Phil Wood front hub, one orphan WTB shifter mount.

  9. #9
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    Does anyone have an assembly drawing of a "Manitou 2" shock?

    Also, if someone has a photo of the elastomer bits that go in one of these early Manitou shocks, preferably with a ruler/scale for reference, I would be very grateful.?

    I'm an engineer by training, and a tinkerer by nature, with some experience with machining and laboratory molding of various silicone and urethane elastomer compounds. It might not be that difficult to make something up. It would also be helpful to get a sense of how "hard" these elastomer bushings are. Generally this property is measured on a Shore scale. The "D" scale is pretty hard, while the "A" scale would cover things like rubber bumpers, skateboard truck bushings, and skateboard/rollerblade wheels (75-95 ShoreA).

    Polyurethane rods, tubes and cylinders are also available from McMaster-Carr industrial supply in hardnesses from 40A to 75D and diameters from 1/4-3". If I knew where to start, with respect to length, diameter and hardness, it might be possible to put some of these old units back in action.

  10. #10
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    Quote Originally Posted by Staggerwing
    Polyurethane rods, tubes and cylinders are also available from McMaster-Carr industrial supply in hardnesses from 40A to 75D and diameters from 1/4-3". If I knew where to start, with respect to length, diameter and hardness, it might be possible to put some of these old units back in action.
    I used McMaster Carr PN 87235K111 "Black Polyurethane Tubing 1" Od, 3/8" Id, 6" Length, 40A Durometer (Same as 87235K11)" to replace the bottom out bumpers for a Manitou 3. They work fine for that, but they will not work for the top out bumpers becuase the OD is too big to fit inside the stanchions. I was unable to find anything on McMaster Carr that was the right size to replace the elastomers that act as the actual suspension springs. I don't have any data on the Manitou 2. Even the data I have (at home) on the sizes of the Manitou 3 elastomers is +/- 0.050" or more due to the difficulty of accurately measuring partially decomposed elastomers.
    Mountain bikers, hikers and horseback riders are not the enemy. Bulldozers are the enemy.

  11. #11
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    Outside:

    Thanks for the starting point. The durometer info is especially welcome. Have you ever seen or handled any original elastomer bumpers? Did the 40A tubing seem close?

    Since I have access to metal lathe, I can simply order up some smaller diameter rod stock, and bore a hole down the center, for the top bits. If I come up with something that works, I will post back.

  12. #12
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    Quote Originally Posted by Staggerwing
    The durometer info is especially welcome. Have you ever seen or handled any original elastomer bumpers? Did the 40A tubing seem close?

    Since I have access to metal lathe, I can simply order up some smaller diameter rod stock, and bore a hole down the center, for the top bits. If I come up with something that works, I will post back.
    The last time I rebuilt the fork when the original elastomers were still goodt was back in 1996. Unfortunately at that time I rebuilt both mine and my wife's forks using white lithium grease (which apparently is a bad thing). When I pulled the forks apart last year after a few years hanging in the rafters in the garage some of the elastomers had melted and the others had turned into some sort of clay like substance. The 40A tubing seemed to feel perfect for the bottom out bumpers and I replaced the other elastomers with the Speed Springs. I still need to figure out a way to reduce the OD of the 40A tubing for the top out bumpers for my wife's forks. I have a lathe, but I just haven't gotten around to trying it yet. The shop is in a bit of flux right now. I assume I would just need to grind a really sharp cutting tool to cut the urethane.

    Back in the day, there was some advertising to the effect that the Manitou bumpers were "microcellular elastomer". Is that the same thing as urethane, or did they do something special to it?

    Staggerwing as in Beech Staggerwing? A yellow one flew over my house about a year ago.
    Mountain bikers, hikers and horseback riders are not the enemy. Bulldozers are the enemy.

  13. #13
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    There were two kinds of elastomers. The first was plain-jane elastomers, then I think in 1995 the Judy came out and was the first or one of the first to use micro-cellular elastomers, or MCU's, which had little nitrgoen bubbles in them, which reduced weight, and made them less temperature-sensitive. They also were supposed to have better damping qualities.
    undefined Absolutely must have: Black Machine Tech Zeroflex brake levers (the ones with the rotating leverage adjuster)

  14. #14
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    Good stuff here guys.
    I'd love to get a Manitou 3 for my old Karakoram. Anyway, I have a Manitou 3 manual I can scan/copy/fax if anybody needs it.

    I also have some unused Manitou elastomers in my tool box. I'm not sure if they are from the old Manitou 3 or are from a FS Ti fork. I can take some pics / measurements if you'd like.

  15. #15
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    i have sourced some replacement elastomers and have been using/selling them for a while now (as in pic)

    if you guys can wait till tomorrow i can get you the original type measurements

    not sure of the originals durometer hardness , but the ones i get are equivalent to the yellow (in feel) and are 60shore hardness
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  16. #16
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    forgot to mention , the hole in the centre is larger then the originals , but they do work , and these are for the manitou 3/4

    the mani 1/2 were larger in external diameter , but the centre hole was the same as these (5mm)

    so they will fit in both , been using them in mani 1/2/3 and 4 for about a year

  17. #17
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    I have several new sets.

    http://geckocycles.com/some_old_stuff.htm
    For larger pictures.
    I also have a couple of crown assemblies 1.25" and 1.125" and 1" steerers
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  18. #18
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    If you can send me some sets of the elastomers, please PM me.

  19. #19
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    Manitou 2 elastomers

    Tested the Cane Creek Thudbuster elastomers for fit on a M2 bolt and they fit for I.D. and O.D. Three of these for each leg would do the job, the extra soft would be about right for a heavier rider. Since I did not test under compression don't know if they rub the sliders under compression, they are of a larger diameter than origionals.Tamer and others make replacement elastomers for their seat posts, another place to look - haven't tested any for fit.:idea

  20. #20
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    Quote Originally Posted by outside!

    Back in the day, there was some advertising to the effect that the Manitou bumpers were "microcellular elastomer". Is that the same thing as urethane, or did they do something special to it?
    There's solid urethane and Micro-Cellular Urethane with nitrogen bubbles manufactured in to them.

    The MCUs (foam urethane) first appeared in the Tange Struts/Anti-Gravity forks in late 1993.


  21. #21
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    Source for Manitou springs

    This guy can supply M2, 3, 4 & EFC springs (not elastomers): http://wings-suspension.de/springs_e.html. He'll let you know up front that it'll take 4-6 wks for delivery. I've bought three or four sets from him in the past and they do eventually get here.

  22. #22
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    Quote Originally Posted by plowak
    This guy can supply M2, 3, 4 & EFC springs (not elastomers): http://wings-suspension.de/springs_e.html. He'll let you know up front that it'll take 4-6 wks for delivery. I've bought three or four sets from him in the past and they do eventually get here.
    I tried for weeks to get something going with this guy and never had success. I probably have four sets of MI/MII's lying around here waiting for a viable option.

    Slimboy -- did you ever make that elastomer order?

  23. #23
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    joe steel = Slimboy -- did you ever make that elastomer order?

    will ba ordering more any time now , will mail you when they get here

  24. #24
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    Quote Originally Posted by outside!
    Back in the day, there was some advertising to the effect that the Manitou bumpers were "microcellular elastomer". Is that the same thing as urethane, or did they do something special to it?

    Staggerwing as in Beech Staggerwing? A yellow one flew over my house about a year ago.

    Microcellular just means there are bubbles in the elastomer. Sometimes, if we didn't properly de-air our 2-part silicone mixes, we would end up with bubbles. Makes for a softer, more compliant part. Since a lot of the off the shelf 2-part urethane mixes only go down to 50 Shore A, it would be an easy way to make something softer, and do it with less urethane to boot. The trick is finding a way to reliably incorporate a certain quantity of air, with a uniform bubble size. Of course, calling it microcelluar makes it sound all sexy and high tech.

    Yes, you have the Staggerwing reference correct. I don't own one, but I've seen more than a few up close, and it is perhaps the most beautiful of the production, classic aircraft.

    Thanks to all of the other that have contributed to this thread. Based on the photo on the wings suspension site, if looks like 1" OD x 4" L compression springs might be a place to start. There are many such animals in the McMaster catalog. Just as a WAG, I would thing something in the 100lb/in stiffness range might be close. Might have to order up some bits and start playing.

  25. #25
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    Quote Originally Posted by SLIMBOY
    speed springs , no damping though
    Any chance you can measure the length and diameter of the springs in that pack.

    There is a strong chance they are just reselling industrial die springs. There is a Raymond color code for these things and blue corresponds to "medium load."

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