Proflex Elastomer Fix

proflex0.jpg

I’ll be honest, your best option is probably to buy new elastomers from this guy. His elastomers will make your Proflex fully functional again. Proflex was bought out by K2 some time ago, and official replacement parts, if you can find some, are probably hardening or rotting themselves, so it’s best to go through an outside source like Rapid Descent or similar to get the newest product possible since elastomer’s shelf life is only about 4-5 years tops.  edit: Rapid Descent no longer sells these, try here instead. Also David E has another great Elastomer fix, which I wrote up here. Anyways, I’m trying to illustrate how to at least get one of these bikes back on the road and functional until your new elastomers come in. I pulled my Proflex 656 out of the garage one summer night in 2004 and rode it around the block, to find that something was wrong. My elastomers (shock absorber/springs) had turned to the consistency of cheesecake and had been squished out of their usual location. This wouldn’t be an issue if it didn’t cause the bike to sit unusually low, and the piston in the rear didn’t push through to block the tire tread. So the bike has been in storage now, unusable, for five years and finally last week someone at a bike shop reccomended something to me I’d never thought of before. – using old bike intertubes wrapped around the piston to emulate the elastomer.

Here’s a brief photo essay of what I did, and shockingly enough, it works rather well. I’ve only put about 5 miles on the design, but I don’t see any immediate failure points. Travel distance is only about 1/2″, and can be adjusted an extra 1/4″ by removing one of the zip ties.

Your elastomer may look something like this. At 80 degrees this stuff is like play-doh, but at 70 it’s more the consistency of gouda cheese. I’ve heard stories that this stuff can harden, but I find that a little hard to believe.

proflex1.jpg

You can cut it out with a butter knife. It really does look like cheese! My cats kept trying to eat it while I was working.

proflex2.jpg

First start by taking some old inner tubes and cutting the valve stem out.

proflex3.jpg

Next up, match the innertube to the piston and start wrapping. What seems tedious at first actually goes by very quickly, since the tubing is thicker than you realize. Make sure the tubing lays flat so the final product won’t shift under your weight. You’ll probably need 8-10 wraps for the rear end, and if you have a Girvin Vector 2 front shock like me, 6 or 7 wraps for the front.Note that the innertube isn’t wide enough to fit the entire gap. If you pop wheelies or do anything extreme the piston is going to slide a little bit but there isn’t any issue unless you’re doing advanced technical trails.

proflex4.jpg

Secure the innertube with zip ties, one on each end at minimum, and for additional stiffness or durability, add one or more zip ties in the middle.

proflex5.jpg

Final product, rear (I realized I had a flash function on my camera phone)

proflex6.jpg

Final product, front:

proflex8.jpg

The final product doesn’t give you much travel, perhaps half an inch, but if you’ve picked up one of these bikes 2nd or 3rd hand only to find that regular spring shocks don’t work well on this bike, this will at least get you out on the road, and provide a little bit of travel. This is a Proflex 656 and to the best of my knowledge the only 656 I’ve ever seen with a Vector 1 front shock. I think this is a 95 or 96 model that was the store demo on sale at the time (in 97 perhaps?) for $680. While pricey by today’s standards Proflex, bikes are great bikes. This bike has been in the Cascade Mountains, the Olympics, Moab Utah, and numerous places in Texas and has never let me down (except the elastomer of course). If you ever come across one on craigslist give it a try, you might be suprised.

This entry was posted in Mechanical. Bookmark the permalink.

50 Responses to Proflex Elastomer Fix

  1. callum says:

    cool! I’ve also seen other materials used: a guy in the Caribbean used wood!!! modern elastomers shuld last more than 5 years so long as they don’t get any oil based products on them.

  2. GG says:

    Thank you! Easy fix. I’m back on the trails. . .

  3. Rick Hawkins says:

    A twist on this idea. I actually got my idea from this post. Anyway what I did was to get a truck inner tube and I cut out 1.6 inch O.D. by 0.5″ I.D. disks (about 50 will do) and stacked them up. I am a heavy guy (230 pounds) and this size worked very well. Reducing the O.D. would be recommended for lighter riders.

  4. admin says:

    That’s not a bad idea. Are you punching a hole in the middle, and then cutting a slit between the outside and the hole? Otherwise you have to completely disassemble the rear suspension, which is, to put it mildly, a huge pain in the ass. What works brilliantly about this is there’s no disassembly/reassembly required.

  5. Rick Hawkins says:

    Well, no, I did not cut a slit. Dissassebly is not that bad. Only requires removing the wheel and one bold.

  6. scott says:

    Eureka! That is a great trick. Thanks for posting!

  7. ShaunOtter says:

    OK, so for these cut-out truck tire discs:

    How much travel do you seem to get compared to good-condition elastomers?

    How does it ride/feel compared to elastomers or Rapid Decents’ replacements?

    Thanks!

    shaunotter (aaaa t) ya h o o {do t/ c o m

  8. Maxim van Rijs says:

    Hi there,
    just wanted to let you know that I’ve just bought a second hand 753 with the rear elastomeer hardened! I couldn’t believe it either. All the second hand proflex bikes I’ve come across have always had blubber for elastomeer suspension, Its completely intact, no brittle or broken off bits and strangely enough functions perfectly. It’s hard enough to barely be able to push my fingernail into but still gives a good ride. If anything a little firm.
    Great bikes!

  9. Rusty says:

    Howdy;

    I used the original idea from this post, wrapping the tube around the bolt/post – except I used rubber tube clamps rather than plastic ties. I expected the plastic would break in the hot/cold here near Boulder, Colorado.

    I still had to remove the assembly to install new washer separating the original elastomer still intact and the new tube-omer. Removal not bad, as Rick found.

    I had to drain the goo from the tube I used, since that was the tube I had available.

    The rubber tube clamps (3 or them) are the flat metal ones where the tail screws into the head and tightens down.

    This 2nd hand (at least) Proflex Attack lives to see another day!

    Back on the trail in Colorado,
    Rusty
    rustycz at rtphokie dot org

    p.s. I was going to buy new ones from Rapid Descent and Callum but that shop closed down two days before I got there. So very glad I found this.

  10. admin says:

    The ties I used were the same ones I used to zip-tie my car’s rear bumper back in place, and never had any issues at 70mph in either 20 degree weather or 108 degree Texas heat. Plus they match the color of the tube :) Tube clamps make a good second option though. P.S. those zip ties are still holding strong on my bike. Glad this worked for you!

  11. justinchampaignil. says:

    thanks for the info !!i too have the same model.had it about 10years and i went to waka and came home to melted goo allover my ride,i was amazed and pissed!!best bike ive ever rode.

  12. Ronbo says:

    Hey guys,
    I’m crushed that I’m too late to get replacements from Rapid Descent and although I think this is a Great work around, is there going to be any other place to get elastomer replacements you think? Or how about some kind of spring replacements? I have two 756s with Girvin forks that I’ve had in storage since the nineties and are in MINT condition. I’ve finally gotten around to using them and now the only part on the bike that could really wear out I’ve waited too long to replace. Any thoughts?

  13. Thomas Anderson says:

    I weigh a little over 230 lbs. I would like to talk to Rick Hawkins about his fix dated May 25, 2009 at 12:51 am. How is this fix holding up? I have a 656 that still has a reasonably good elastomer, but I would like to be prepared. How do I contact Rick?

  14. Richard White says:

    This place in New Mexico has elastomers for all sorts of Proflex product, great idea on the inner tube though!

  15. lance says:

    I was going to do the tude thing and on my way to buy a bike tude I stopped at an auto parts store and I was looking around and found a shock absorbing bushing they have a few different size and they don’t have the same gurth but they are made solid rubber and they have ones that are stiff and one’s that are softer. The best part is it only cot me $10.00. I has worked so far. I hade to buy a pack that had one big one (3 in) and a pack that had two little one’s (1/2 in). Hope this helps if you proflex elastomer blows out.

  16. admin says:

    Hi Lance, Is the hole in the bushing about the right size? If it were too big I’d worry about it bouncing around too much. Do you have a part number you could share with us? Thanks for the great idea!

  17. David says:

    I found a fantastic fix for my Proflex rear shock. Go to your local Ace Hardware or plumbing store and ask for 1 1/2 inch test plugs, or they might call them pipe plugs. Take the wing-nut off, remove the bolt, then take the washers off from both sides. You should be left with a chunk of rubber that has a center hole that’s almost exactly the same diameter as the elastomer was. I used a little soapy water and mine slid right on the shaft the elastomers were on. 3 of these did the trick for me and it’s holding up just fine.

  18. admin says:

    Thanks David! Do you have any pictures (cell phone or otherwise) I could post here for others? I’m sure a visual aid would help them tremendously.

  19. Bill says:

    Great idea! What I did was disassemble the front and rear units, take out the old elastomer and then got the heaviest duty compression springs I could find at the local hardware store. I used springs 5″ long in the rear and pre compressed them for installation using 3 zip ties through the coils and working them righter and tighter while pushing down on the spring. For the rear I was able to put one spring inside the other, and the front just one. Then I coiled old inner tubes around the springs. Playing around with how many wraps I could ‘tune’ the suspension for my weight (225#). I wrapped them with electrical tape instead of zip ties, but to protect the tape I coated them with electrical joint water proofing ‘goop’ I have a can of in the garage. I figured it must be compatible with electrical tape if it’s meant to be applied over it, right?

    I found the springs were important because they make the suspension expand back to the expanded position, and the inner tube provides more resistance to the compression portion of the stroke.

    Thanks again, my old 656 has a bounce again and I’ve camouflage painted it to get ready for duck hunting season where we ride them in the refuges with our waders on, shotguns on a rack on the handlebars, and bag of decoys on our backs since it’s so much faster and easier than walking a mile. Until it rains and then all bets are off :) .

  20. Bill says:

    Here’s a link to test plugs, you can get the idea. That’s another great idea.

    http://www.huntingdonfusion.com/downloadfiles/expandableplugoverview.pdf

    If the link goes bad in the future, google “rubber test plug” or “expandable plug”

  21. bap says:

    Hey Bill, Do you have a photo of your setup with the springs? I would love to do something similar. I bought a 855 yesterday from a garage sale for $25 and the rear Elasomer has gone soft and I was looking around for a fix.

    Thanks

  22. Bill says:

    No, the project is done and the springs are now inside the tire tube wrapping.

    After taking the suspension apart with allen hex wrenches, I went to the local Orchard Supply Hardware store in San Jose knowing they have a great industrial/hardware dept with all kinds of springs for sale. I pretty much found the stiffest springs that would slide over the center metal piece in the shock, and was able to find one to fit inside a second for the rear, and a single for the front. It was interesting that when I got on the bike without the tubing as a wrapper, they immediately compressed to the bottom.

    Like I said, the tubing gives it compression strength and the spring expansion strength. That’s the best help I can be.

  23. Bill says:

    Let me add another, unrelated comment about the Proflex 656. I ride my 656 while waterfowl hunting in California state and federal refuges to get to the ponds to hunt. I brought my bike to hunt with my son, and unloaded it and my container of gear (waders, etc.) at the house he was renting and put it all in the middle of the front lawn to bring inside overnight, since he was living near the bars in town and I was afraid of anything in the bed of my truck being stolen.

    He backed his 1500 series pickup with bid mud terrain tire RIGHT OVER MY 656! The tire drove over the pedals and the seat. The seat was destroyed which I had to replace, I had to re-true the wheels and I used a heavy hammer to straighten out the one crankarm which was bent. But other than that- my 656 was driven over by a full sized pickup truck, and it rides perfectly after I made those repairs. The frame and suspension where not damaged AT ALL with that abuse. Pretty remarkable I think.

  24. sylvan says:

    so simple and yet so effective!
    You saved me a whole lotta ‘pleuros’,
    cheers

  25. Rick Meyers says:

    If anyone is in need of parts for a 626 drop me a line. I have a pristine one that I found off of CL that is too small for my wife. The front end of this is a thing of beauty! I appreciate craftsmanship and would love to pass any difficult to find parts to someone instead of selling it on CL and think of it rotting in someones back yard.

    RM

  26. Parker says:

    I used 2 springs off of 2 old steelcase swivel office chairs,,,,,worked like champs; front & rear…..

  27. Sherwin says:

    Thanks for your website, I recently purchased a proflex 954 off of craigslist and it had no rear elastomer at all. I had an old manitou fork stiff spring lying around and it fit perfectly over the piston. I then used your inner tube method to wrap the spring tightly and held it together with 3 plastic ties. Its perfect. You can actually adjust the travel pretty easily by turning the bottom disc. I do think the spring helps as described earlier by another poster.

  28. Craig says:

    I am looking for proflex shock elastomers – I have an 852 – any idea where they can be found in North America?

  29. Kevin says:

    If you have the money, Risse Racing makes a great damper for most Proflex bicycles. Even for the 656 and the Girvin fork.

  30. tok360 says:

    found a company that sells advertises elastomer parts.

    http://www.suspensionforkparts.net/eshop/index.php?_a=viewCat&catId=11

  31. Pingback: Proflex elastomer | Alleverythingr

  32. Kelly says:

    I found these guys a few years back and bought a spring upgrade kit from them. Talk to the owner Ryan and you will be blown away with how helpful he is. Takes calls night and day and will happily walk you through the installation. A+ shop if you ask me!

  33. Kelly says:

    Sorry I did not leave their info http://www.nulifecycles.com go to the Proflex Kits Link

  34. robert says:

    where can i buy prosports kit

  35. robert says:

    where in australia i can buy the kit

  36. Aidan says:

    I used plaster of paris to take a mold of the elastimer and used spray rubber to fill, then slipped it into an inner tube works like new

  37. Craig says:

    I used body mounting material for auto body to frame. It came in a 24″ long stick. It was the right diameter and had a hole pre-drilled in it that was also the right size. I got it from 4wd.com. It’s supposed to be for a Jeep body.

  38. Fred says:

    It’s the body mounting rubber for thier fiberglass tubs. I work there and I’ve seen the stuff yet never thought of using it for my Proflex. Brilliant idea ! I’m at extension 895 if anyone wants to order it.

  39. Doc says:

    My shock exploded and I decided that urethane is so common that I should be able to build something that would give good travel. I didn’t realize how close I was to the solution until I took off my flip flops. Same material. I went looking for a 1/2 tube I could sharpen to cut holes and in a hardware store discovered urethane street hockey pucks, exactly what I needed. I’ll let you know how they stand up.

  40. mike says:

    I used valve springs off of a 350 chevy motor with some fender washers to take up the slack. This has been working like a champ on my Attack for a good 10 years. 250 lb rider.

  41. Alejandro says:

    Let me add another, uteelanrd comment about the Proflex 656. I ride my 656 while waterfowl hunting in California state and federal refuges to get to the ponds to hunt. I brought my bike to hunt with my son, and unloaded it and my container of gear (waders, etc.) at the house he was renting and put it all in the middle of the front lawn to bring inside overnight, since he was living near the bars in town and I was afraid of anything in the bed of my truck being stolen.He backed his 1500 series pickup with bid mud terrain tire RIGHT OVER MY 656! The tire drove over the pedals and the seat. The seat was destroyed which I had to replace, I had to re-true the wheels and I used a heavy hammer to straighten out the one crankarm which was bent. But other than that- my 656 was driven over by a full sized pickup truck, and it rides perfectly after I made those repairs. The frame and suspension where not damaged AT ALL with that abuse. Pretty remarkable I think.

  42. felony dui says:

    This post has helped me think things through

  43. Wayne Tessier says:

    My 656 sat for a few years till I installed Risse Racing shocks, I installed the Genessis shocks at 198.00 each………works perfect! Straight bolt in:)

  44. Wayne Tessier says:

    My 656 sat for a few years till I installed Risse Racing shocks, I installed the Genessis shocks at 198.00 each………works perfect! Straight bolt in:)…….have over 10,000 miles on the bike and just this past week had to replace the shift cables and housings because the cables wore thru the plastic housings along with a new cassette.

  45. Just do me a favor and keep writing such trenchant analyses, OK?

  46. Craig says:

    I needed a fix for my Proflex with Girven forks. I went to Lowes and purchased some solid rubber bushings in the hardware dept. They’re in the big pull out drawers with all the nuts and bolts. I used two per shock and had to cut them to fit but they work great. Total cost was about $5.

  47. Chris says:

    I recently came across an old dumped 656 Pro-Flex so decided to to do it up. When however it came to replacing the melted elastomers I decided I didn’t want to go down that route. This was because of cost (I’m from the U.K. and you can only get them from the States) and longevity. I therefore decided to put a spring in the Vector front forks but for the back I was in a bit of a quandry. I tired the inner tube fix but found it too hard so I surfed the web and decided to try neoprene washers, however when they turned up I found them to be a bit too hard for my liking as well so I then though about using soft neoprene instead . I had an old knee wrap that had cloth on both sides with neo’ in the middle. I cut these out and stuck them to the hard neo’ washers and hey presto! It works an absolute treat! You can “tune” the softness to suit your style by adding or subtracting how many soft washers you sandwich between the hard, and of course by the compression ring. Hope this helps.

  48. J. Todd says:

    Interesting discussions. I bought the elastomers several years ago and when they wear out I’ll be looking for another fix. I just returned from Crested Butte Co. where the riding can get technical and I’ve had a few endos.Part of the problem, which I am currently working on, is to lower the saddle enough. Therefore, I’m cutting down the seat post and also making an “adjustment slit” in it so I can get it as low as possible.

    Some blogs say to forget a Proflex because they are obsolete, but I still like the bike and if I want to ride the toughest trails perhaps I could rent a high travel bike for a day or two.

Leave a Reply

Your email address will not be published. Required fields are marked *

*

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>