856 Rear pivot bolt tightness

[paulspro]

Hello. I just replaced the seal and bushings on my 856. There is a sticker where the pivot meets the bike frame that says DO NOT OVER TIGHTEN. I put blue threadlocker on the bolts and tightened them until I felt resistance in the pivot. I am still worried that the bolts may drop on the trail during a ride. Any thoughts or experience with this out there?

[w2zero]

You have the threadlock in there so they won't fall out on the trail.  My manual said that you tighten the bolts evenly until the swing arm still drops, just barely by its own weight.

[pczeilon]

+1
That's exactly how it's done.  FYI, Loctite 290 is made for locking already assembled items & does an excellent job in applications such as this where you want to "fine tune" & then lock something down.  You'll be just fine with the blue though.

[fyrstormer]

I take the approach of tightening them evenly until it supports its own weight, then I back them off a bit at a time until it no longer supports its own weight. I do the same with the upper shock pivot and the strut pivots, prior to bolting the shock and the strut together. My frame is 14 years old and I haven't had to replace the nylon bushings yet, so I think that means my approach works.

It should be noted that you do this WITHOUT THE WHEEL ATTACHED, just in case you were unsure.

EDIT: I've taken apart and put back together a lot of things, and I've never actually seen a bolt fall out as long as it was fully inserted and tightened even a little bit. The only bolts I've seen fall out were ones that were finger-tightened or not even fully inserted. Don't worry about it.

ANOTHER EDIT: I don't use Loctite. It annoys me to have to fight with fasteners to get them loose. I rationalize it like so: if I had to remove a fastener in the first place, it's because the device needed servicing, so by not using Loctite I'll worry enough about it that I'll service it again before too long, instead of forgetting about it and letting it wear out again.

YET ANOTHER EDIT: Actually, I do use a threadlocker on some fasteners that repeatedly self-loosen, but I use superglue instead of Loctite. Why? Because when I loosen the fastener again, once the superglue snaps loose, the fastener backs out very easily instead of fighting me like Loctite does.

[Colin]

The official K2 Tech force instruction sheet "RK002 World Cup Pivot Rebuild Kit" states:

10.To adjust the pinch bolts properly, detach the seatstay from the swingarm. Hold the swingarm up and tighten the pinch bolts evenly. The pinch bolts should be tightened until the swingarm (with the rear wheel installed) falls slowly downward when released.

I follow it. with one addition, I tighten one side until I get the correct "slow fall" then back it off 1/4 turn and adjust the other side to get the same fall, then re-tighten the first side the 1/4 turn and check the fall is still correct.

Fyrestormer: If the adjustment works better for you without the wheel then so be it, but I just thought I'd quote the "official" instruction, which works well for me and like you I have a 14 year old "World Cup" Bike (XP-X) that, also, has never needed new bearings.

Link to the full Instruction:
http://idriders.com/proflex/coppermine/albums/userpics/10284/856_RK002_rebuild.pdf

P.s. I use Blue loctite.

Each to their own.........!   <GRIN>

Regards,
Col.

[fyrstormer]

I used to do it with the wheel installed. Then I realized I was introducing a lot of unnecessary stiction into the rear suspension by cinching down the pivot clamps until they could support the weight of the swingarm and the wheel, when it provided no useful benefit to do so. All of the pivot components are solid matter, meaning once the clamps have been tightened enough to close any gaps, there is no more "slop" that can be eliminated from the system by tightening the clamps further.

Also, I have concerns that the nylon bushings could deform (even if just a tiny bit) as a result of tightening the clamps more than the minimum necessary amount; the holes that the bushings fit into were milled to be round when the clamps are loose, meaning that tightening them causes the clamps to ovalize more and more as you tighten them. That could cause uneven wear on the bushings over time, and if I can avoid ever having to replace a single frame component on this bike, I'd prefer to do so.

[paulspro]

Wow! Thanks everyone for the excellent advice. I double checked and they are just tight enough to allow free movement, without the wheel. Kept the threadlocker blue in just for insurance. Been out on a couple of rides and nothing has dropped off yet. I'm about to change from 15w oil to 30w. The rear feels a little bit springy. I have the Cor spring replacements on the back. Thanks again.

[fyrstormer]

Do you have an ODS shock? I assume so since you're talking about changing the shock oil yourself. If you have the cash, consider getting an NR-4; it's awfully nice to have a true 3-way adjustable coilover on the back. It even feels significantly better than the NR-2 I had before, because the NR-2 didn't have adjustable compression damping. My pedaling got noticeably more efficient when I was able to minimize pedal bob with a fully-adjustable shock.

[paulspro]

Hey fyrstormer. I do have an ods on the back with the Cor spring. Unfortunately a new shock is not in the budget. I do have a 300 lb spring coming and am fiddling with oil weight to fine tune the shock as best I can.