My DIY RockShox Indy XC Elastomers on the cheap!
#1
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My DIY RockShox Indy XC Elastomers on the cheap!
Hey gang,
I picked up a nice 1997 Specialized Rockhopper late last year and when I tore down the forks one of the elastomers was shot so I started looking and boy was that a frustrating experience. One shop in NM sells a new (suspect NOS) pair for $55 plus shipping. So I started measuring and searching on density and firmness and determined that solid polyurethane rod in the 50A durometer range would be idea and a solid rod that is 3/4" thick and at least 10" long so I can make a pair by cutting it. Well, even then there really wasn't anything economically available so I started a conversation with a poly ebay seller "kpreneurethane" and he hooked me up with a 24" 50A solid 3/4" dia poly rod for $37 shipped (took 30 days). Here's how that turned out:
I picked up a nice 1997 Specialized Rockhopper late last year and when I tore down the forks one of the elastomers was shot so I started looking and boy was that a frustrating experience. One shop in NM sells a new (suspect NOS) pair for $55 plus shipping. So I started measuring and searching on density and firmness and determined that solid polyurethane rod in the 50A durometer range would be idea and a solid rod that is 3/4" thick and at least 10" long so I can make a pair by cutting it. Well, even then there really wasn't anything economically available so I started a conversation with a poly ebay seller "kpreneurethane" and he hooked me up with a 24" 50A solid 3/4" dia poly rod for $37 shipped (took 30 days). Here's how that turned out:
#2
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Interesting! I am looking forward to your long term impressions. I seem to remember my original elastomers came in a three part stack with three separate densities.
I replaced my elastomers with Speed Springs when the elastomers failed years ago. The springs are still going strong. I don't know if they're available anyplace anymore.
I replaced my elastomers with Speed Springs when the elastomers failed years ago. The springs are still going strong. I don't know if they're available anyplace anymore.
Last edited by mtnbud; 02-10-21 at 02:17 PM.
#3
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Wow, great fix.
I’ve actually been looking for those springs mtnbud mentioned for a while now. Last saw them on eBay three or four years ago but they seem to have vanished off the face of the earth since then.
Might have to go with that same fix if I can’t find the springs. My concern is durability, tho.
I’ve actually been looking for those springs mtnbud mentioned for a while now. Last saw them on eBay three or four years ago but they seem to have vanished off the face of the earth since then.
Might have to go with that same fix if I can’t find the springs. My concern is durability, tho.
#4
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Wow, great fix.
I’ve actually been looking for those springs mtnbud mentioned for a while now. Last saw them on eBay three or four years ago but they seem to have vanished off the face of the earth since then.
Might have to go with that same fix if I can’t find the springs. My concern is durability, tho.
I’ve actually been looking for those springs mtnbud mentioned for a while now. Last saw them on eBay three or four years ago but they seem to have vanished off the face of the earth since then.
Might have to go with that same fix if I can’t find the springs. My concern is durability, tho.
#5
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Interesting! I am looking forward to your long term impressions. I seem to remember my original elastomers came in a three part stack with three separate densities.
I replaced my elastomers with Speed Springs when the elastomers failed years ago. The springs are still going strong. I don't know if they're available anyplace anymore.
I replaced my elastomers with Speed Springs when the elastomers failed years ago. The springs are still going strong. I don't know if they're available anyplace anymore.
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Not the only one who converted to Speed Springs. My old threaded fork, with springs, is somewhere buried up in my shed. Getting the non-specific elastomer thru ebay was a good idea-and probably easier (and less expensive) than finding a "genuine replacement" part.
#7
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Again stock elastomer in this RockShox Indy XC was 113mm...figure it might have been 115mm new, cut first pair at 116mm and they work great, but cut the second pair at 122mm and installed...BAM! Nice, tight and firm just how I like it!
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This is interesting. I thought the point of the old MCU (multicellular urethane, not Marvel cinematic universe) is that the open cell foam gave it damping just like a sponge. If it's not foam isn't it just a bouncy ball?
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#9
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Best I can gather is for the slight improvement on compression dynamics you give up a whole lot of durability. Polyurethane 40-80A durometer was still used in these shocks back then because it performed near as well as MCU and was more common material (used in industry bushing fab a LOT). Can I tell the difference in performance?...no, the shocks seem to function a hell of a lot better with these poly elastomers. But yeah MCU was the premium material, it's just once the outer shell was compromised it starts to disintegrate quickly.
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I did once replace some MCUs with elastomers that I think were poly.
Did not work all that great. Super bouncy. Also felt like the spring curve was much sharper.
The fork was some late 90s Manitou.
Maybe they work better in some forks than others.
#11
Constant tinkerer
Nice work! A bit off topic but are there replacement bushings available for these? They wear out, causing wobble in the fork (rocking under braking like a loose headset) which only gets worse over time.
Everyone in the world seems to hate these forks but I love mine. I put a NOS Indy on my main MTB I built up a few years ago. They're lighter than just about anything and they work great, IMO.
Everyone in the world seems to hate these forks but I love mine. I put a NOS Indy on my main MTB I built up a few years ago. They're lighter than just about anything and they work great, IMO.
#12
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Nice work! A bit off topic but are there replacement bushings available for these? They wear out, causing wobble in the fork (rocking under braking like a loose headset) which only gets worse over time.
Everyone in the world seems to hate these forks but I love mine. I put a NOS Indy on my main MTB I built up a few years ago. They're lighter than just about anything and they work great, IMO.
Everyone in the world seems to hate these forks but I love mine. I put a NOS Indy on my main MTB I built up a few years ago. They're lighter than just about anything and they work great, IMO.
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Nice work! A bit off topic but are there replacement bushings available for these? They wear out, causing wobble in the fork (rocking under braking like a loose headset) which only gets worse over time.
Everyone in the world seems to hate these forks but I love mine. I put a NOS Indy on my main MTB I built up a few years ago. They're lighter than just about anything and they work great, IMO.
Everyone in the world seems to hate these forks but I love mine. I put a NOS Indy on my main MTB I built up a few years ago. They're lighter than just about anything and they work great, IMO.
They don't list the Indy, but the Mag21 and RS1 are listed, so they clearly have ways of handling some pretty old stuff. Whether it is worth it is a different question.
An Indy is a fine shock if you suddenly find yourself in 1995.
#14
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The bushings and elastomers are different things, no? I haven't actually had one of these forks apart but it's my understanding that the elastomers provide the "springiness" (which could be a coil spring or air on other forks.) The bushings I'm referring to are what locate the uppers as they move up and down.
Best I can guess is what ever the part if it is like a dense rubber then poly rod in the ~ same firmness (duro) cut to the same dimensions and machined (drilled out etc.) as necessary might work?
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by chance did you ever see and blocks or brick shaped of similar poly. I'm looking for some to make an elastomer for a vintage Moxey Suspension seat post I recently bought. I need it to be 1.25 - 1.5" thick then at least 2" wide and at least 3" long.
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Thanks for the post and the video Roy!
I contacted kpreneurethane (Paul) and was able to procure a 3/16" inside diameter x 1" outside diameter x 12" long 60A polyurethane tube to restore my vintage '93ish Tai Huei MIT forks. I'll be sure to use a box cutter (and not a PVC pipe cutter) for size adjustments.
I contacted kpreneurethane (Paul) and was able to procure a 3/16" inside diameter x 1" outside diameter x 12" long 60A polyurethane tube to restore my vintage '93ish Tai Huei MIT forks. I'll be sure to use a box cutter (and not a PVC pipe cutter) for size adjustments.
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Don't think anyone mentioned this, but Suspension Fork Parts has specific elastomers for many fork models. I procured a set (about $50) for a '95 (AIR) RS Judy and they were of supreme quality. Plus the owner is available by email or phone.
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Suspension Fork Parts will sell elastomers identifying specific brands, offers a warranty, and also includes lubricant. The route I've chosen is more akin to DIY since no one sells anything specifically for the retro shocks (Tai Huei) on my two bikes, and I'm not particularly educated as to what will or won't work.
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Hey gang,
I picked up a nice 1997 Specialized Rockhopper late last year and when I tore down the forks one of the elastomers was shot so I started looking and boy was that a frustrating experience. One shop in NM sells a new (suspect NOS) pair for $55 plus shipping. So I started measuring and searching on density and firmness and determined that solid polyurethane rod in the 50A durometer range would be idea and a solid rod that is 3/4" thick and at least 10" long so I can make a pair by cutting it. Well, even then there really wasn't anything economically available so I started a conversation with a poly ebay seller "kpreneurethane" and he hooked me up with a 24" 50A solid 3/4" dia poly rod for $37 shipped (took 30 days). Here's how that turned out:
I picked up a nice 1997 Specialized Rockhopper late last year and when I tore down the forks one of the elastomers was shot so I started looking and boy was that a frustrating experience. One shop in NM sells a new (suspect NOS) pair for $55 plus shipping. So I started measuring and searching on density and firmness and determined that solid polyurethane rod in the 50A durometer range would be idea and a solid rod that is 3/4" thick and at least 10" long so I can make a pair by cutting it. Well, even then there really wasn't anything economically available so I started a conversation with a poly ebay seller "kpreneurethane" and he hooked me up with a 24" 50A solid 3/4" dia poly rod for $37 shipped (took 30 days). Here's how that turned out:
#20
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My son rides it every day to/from high school. They work like new ones. I would make them 1/4" longer, we now run the adjusters all the way tight. I think if they were a bit longer we wouldn't have them fully tightened. We also relieve them during long per of non use.
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I'm going to buy some for a retro mtb build I have going on (it's the first mtb I bought back in 2002) and just wanted to get something that wasn't too soft for my considerable heft haha
Last edited by JB450; 08-30-22 at 06:28 AM.