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Discussion Starter · #1 ·
A. Should the shock mount hardware be fixed and the bushing rotate freely around the axle/pin?

-or-

B. Should the axle pin do the bulk of the rotation, and the eyelet bushing aid in rotation by having a little bit of give?

I replaced the air canister on my frame with a CC DBCoil IL. The front hardware is 25mm, rear 35mm. As far as I can tell the spacers are on correctly, I pushed the axle/pin through the bushing myself, and there is no play in the system.

The problem is if I torque the mounting bolts >2-3nm (leaving one end of the shock unmounted to check rotation/play) the shock has barely any movement. It feels like the axle/pin is completely fixed the DU bushing has a lot of friction. With both ends mounted there is a noticeable click as the bike goes through its travel

If I do 1-2nm then the shock will rotate much more freely and there is no click feel/sound. But I'm worried this maybe too loose.
 

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The axle/bolt/pin should be fixed and the DU bushing or plastic bushings rotate about the axle. That is the function of the DU busing or tan plastic bushings. There is usually some friction that can be felt. The typical spec for a shock pivot bolt is 10-15 Nm. Stick with the torque specified torque for your frame.
 

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Discussion Starter · #3 ·
The axle/bolt/pin should be fixed and the DU bushing or plastic bushings rotate about the axle. That is the function of the DU busing or tan plastic bushings. There is usually some friction that can be felt. The typical spec for a shock pivot bolt is 10-15 Nm. Stick with the torque specified torque for your frame.
Ok cool, that makes total sense. It's probably user error on my part, or spacing/fit issues. Thanks!
 

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You are not doing anything wrong. You have just discovered the inferiority of shock bushings. The bike industry considered them "good enough" for decades but have finally come around. Note how many rear shock yoke/clevis mounts there are now, as well as bearings mounted in the rocker arms where the shock connects. I hope it's not too presumptuous to think that our shock eyelet needle bearing kits helped to move the industry forward on this.

One of the main problems is normal machining tolerances. Shock eyelet bores have a normal range of variance. Some bushings systems have decent rotation, but the same system in another shock is very tight. Many times the fit between bushing and thru-pin or reducers is so tight that the pin spins against the rocker arms and wears away metal.

On the end of a shock that remains fixed throughout the travel range, a bushings system is great. For shock ends where lots of rotation takes place inside the eyelet, a bearing system is far superior. You don't have to take my word for it, though: https://forums.mtbr.com/shocks-susp...earing-kit-awesome-998670-5.html#post14055720
 

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Discussion Starter · #5 ·
You are not doing anything wrong. You have just discovered the inferiority of shock bushings. The bike industry considered them "good enough" for decades but have finally come around. Note how many rear shock yoke/clevis mounts there are now, as well as bearings mounted in the rocker arms where the shock connects. I hope it's not too presumptuous to think that our shock eyelet needle bearing kits helped to move the industry forward on this.

One of the main problems is normal machining tolerances. Shock eyelet bores have a normal range of variance. Some bushings systems have decent rotation, but the same system in another shock is very tight. Many times the fit between bushing and thru-pin or reducers is so tight that the pin spins against the rocker arms and wears away metal.

On the end of a shock that remains fixed throughout the travel range, a bushings system is great. For shock ends where lots of rotation takes place inside the eyelet, a bearing system is far superior. You don't have to take my word for it, though: https://forums.mtbr.com/shocks-susp...earing-kit-awesome-998670-5.html#post14055720
Hi Chris, Thanks for your reply! I have been eye'ing your kits for years now. I've always been too lazy to figure it all out- until now.

When I was pushing the pin through the DU bushings on my new coil shock I just kept repeating to myself "there is no way this is going to rotate freely". When mounted to the correct torque with one end of the shock unmounted it takes a considerable amount of force to rotate the bushing on the pin. Luckily it is a coil shock and works well enough, but I am starting to notice some wear and tear on my frame mount.

So now is a good time to revisit the RWC kit. Question, my frame spec is 35mm for the rear mount. The RWC kit is 35.56mm. Is that the correct one? thanks!
 

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Hi Chris, Thanks for your reply! I have been eye'ing your kits for years now. I've always been too lazy to figure it all out- until now.

When I was pushing the pin through the DU bushings on my new coil shock I just kept repeating to myself "there is no way this is going to rotate freely". When mounted to the correct torque with one end of the shock unmounted it takes a considerable amount of force to rotate the bushing on the pin. Luckily it is a coil shock and works well enough, but I am starting to notice some wear and tear on my frame mount.

So now is a good time to revisit the RWC kit. Question, my frame spec is 35mm for the rear mount. The RWC kit is 35.56mm. Is that the correct one? thanks!
Sometimes the manufacturer's number is the actual spec, sometimes they round up or down. What is the frame?
 

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Really? I went off this chart:
View attachment 1248109
I see. The link I followed from Google went to the Murmer 29 "custom," which has a different chart. That accounts for the discrepancy. Your quick ruler measurement seems to confirm the larger gap as well. Based on the design of the rear triangle, I would go with our 3556 kit. The 0.56mm difference will not be an issue.
 

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Discussion Starter · #11 ·
I see. The link I followed from Google went to the Murmer 29 "custom," which has a different chart. That accounts for the discrepancy. Your quick ruler measurement seems to confirm the larger gap as well. Based on the design of the rear triangle, I would go with our 3556 kit. The 0.56mm difference will not be an issue.
Yeah the steel frame has some flex/character to it anyway haha. Thanks for your help, placing order!
 
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