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Discussion Starter · #1 ·
Hi alltogether,

this is my first post in this forum. Normally I am reading/writing in german (vintage) bike forums. But I couldn't get the help I need so I am trying my luck here.

I have a Rockshox Mag21 fork for my Specialized S Works Mtb. While rebuilding it, I did not only want to change the seals and O-rings, but I also would like to adapt it to my rider weight (~62 kg). Rock Shox has a nice manual, which I tried to attach here.
Following this manual I should choose the following setup:
  • softer valve spring (25lb)
  • no "valve spring preload", so no washers under the vavle spring
  • compression bleed hole with 1,5 or 2mm (depending on cross-country or downhill use)
  • no rebound bleed hole or 2x1,0mm (depending on cross-country or downhill use)
I have the disassambled fork here on my work bench (see pictures below). No coming to my problems... :oops:;)
  • Do you agree with the proposed setting? any propositions?
  • How do I know which valve spring I have? I should be able to check that by compressing the spring. The manual says there is a 25lb and a 40lb spring - but which length change should the spring make under this weight?
  • Honestly: I do not understand where the compression or bleed hole(s) should be.
  • what does this sentence mean (from the manual): "valve plates are a tuning variable. The .005” relief step machined into plates used from 1994-97 improves small bump response"
Thank you very much for your patience and help - I am looking forward to your comments!

Felix

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· Registered
Joined
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1 Posts
Hi alltogether,

this is my first post in this forum. Normally I am reading/writing in german (vintage) bike forums. But I couldn't get the help I need so I am trying my luck here.

I have a Rockshox Mag21 fork for my Specialized S Works Mtb. While rebuilding it, I did not only want to change the seals and O-rings, but I also would like to adapt it to my rider weight (~62 kg). Rock Shox has a nice manual, which I tried to attach here.
Following this manual I should choose the following setup:
  • softer valve spring (25lb)
  • no "valve spring preload", so no washers under the vavle spring
  • compression bleed hole with 1,5 or 2mm (depending on cross-country or downhill use)
  • no rebound bleed hole or 2x1,0mm (depending on cross-country or downhill use)
I have the disassambled fork here on my work bench (see pictures below). No coming to my problems... :oops:;)
  • Do you agree with the proposed setting? any propositions?
  • How do I know which valve spring I have? I should be able to check that by compressing the spring. The manual says there is a 25lb and a 40lb spring - but which length change should the spring make under this weight?
  • Honestly: I do not understand where the compression or bleed hole(s) should be.
  • what does this sentence mean (from the manual): "valve plates are a tuning variable. The .005” relief step machined into plates used from 1994-97 improves small bump response"
Thank you very much for your patience and help - I am looking forward to your comments!

Felix

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Hello Felix I can help you with all your Mag 21 problems. It's too much to write it all down here. Just send me an email to [email protected]
Then we can change phone numbers and I will send you the information you need to setup the Mag 21 properly to your weight specifications. You can also make a tuneup to 63mm travel. I will tell you also how to mix the fork oil close to manufacture settings.
Greetings Jürgen
 

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As the Rock Shox expert at the bike shop in high school... F Rock Shox. They recalled/bought up all of the Mag rebuild kits from the bike shops as they launched the Judy forks...obsolescence. I was forced to ride one of their forks with my 2020 Fuse Expert, never planned to use more of their garbage, regardless of the new management over the years.

My 1994 Mag 21 in the original box. My 1992 Mag 20 was stolen with my ride to class Haro Thanksgiving weekend 1998 at Western MI U.

Hopefully a third party has come up with service parts. I'm leaving my dinosaur in the box.
 

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Discussion Starter · #4 ·
Hello Felix I can help you with all your Mag 21 problems. It's too much to write it all down here. Just send me an email to [email protected]
Then we can change phone numbers and I will send you the information you need to setup the Mag 21 properly to your weight specifications. You can also make a tuneup to 63mm travel. I will tell you also how to mix the fork oil close to manufacture settings.
Greetings Jürgen

Thank you - email is sent! :)
 
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