[jaks]

My Instinct C70 has had a knocking ever since it was new and I've traced it to the front shock mount. I can put my fingers in that area and feel it moving around (and hear it knocking) when I lift the bike off the ground.

At first I thought it was because the Fox shock eyelet bushing was out of tolerance based on what I read on mtbr, but after I bought a new set of bushings, I realized the bushing ID is probably where it should be at 8.03mm (using digital calipers). I then took a look at the shock bolt OD and it measures 7.94mm, which I'm guessing is smaller than it's supposed to be.

Can I ask someone to measure their front shock bolt OD just so I can verify that my shock bolt OD is smaller than it's supposed to be (and know what the "correct" OD is)? It should be the same bolt used across all recent Instincts, Altitudes, Thunderbolts models... Thanks!

 

[RaymondC]

Mines 7.94 as well and I have no noise. I suspect yours may not be tight enough or there is some other problem.

 

[jaks]

Interesting, thanks. I did use a torque wrench to tighten to 70in-lbs as per spec. Mine is clearly moving around though - it makes sense given the .1mm clearance between the bolt OD and bushing ID. It's more of a mystery why yours isn't moving and knocking like mine.

 

[enonnaig]

Interesting, thanks. I did use a torque wrench to tighten to 70in-lbs as per spec. Mine is clearly moving around though - it makes sense given the .1mm clearance between the bolt OD and bushing ID. It's more of a mystery why yours isn't moving and knocking like mine.

Did you ever get this issue fixed? having the same thing happen to mine

 

[rockyuphill]

Anyone suffering the knock, check to make sure that the conical washer #55 is in place, a friend's Altitude C50 was missing the washer from new and there was a lot of knocking noise even with the bolt torqued to optimum.

 

[enonnaig]

Anyone suffering the knock, check to make sure that the conical washer #55 is in place, a friend's Altitude C50 was missing the washer from new and there was a lot of knocking noise even with the bolt torqued to optimum. View attachment 1931470
View attachment 1931470

should that go on the inside or outside of the mount? hard to tell in the diagram

 

[Ben39]

should that go on the inside or outside of the mount? hard to tell in the diagram

From the left: conical head screw, washer on the outside, then shock mount with shock upper eyelet, then screw from the outside right.
Nothing but the upper eyelet of the shock will fit inside the mounting tabs.

 

[enonnaig]

Definitely don't have that washer on my frame...

 

[Ben39]

Definitely don't have that washer on my frame...

Check this out, photos taken during my Slayer wrenching session today.