A friend at the LBS is thinking of building up at 27.5 HT and wanted to try out the XX1 so I lent him my rig and he gave me one of the hire bikes to try out, a mid range 29er Scott Spark. After the ride he was impressed with the bike and the XX1 and he will probably go with 1x11 set up ! He did however point out a few things wrong with my bike. Loose headset, rear brake judder and the rear frame had a lot of play in it ! I was aware of the brake problem as the rear rotor is slightly warped and needs replacing. I hadn’t noticed the headset had a slight amount of play in it but that was a quick fix.
Rear frame triangle !! So after close inspection there was a lot of lateral movement in the rear frame. By a lot I mean about 2-3mm in the Top tube pivot and slight movement in the seat stay to linkage pivot. I checked the torque on all the bolts and all seemed in order. (I did snap a bolt head whilst re-torquing the seatstay to suspension linkage, pay attention to torque settings ! LOL
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With the reoccurring theme of trashed bearings I decided to strip down the suspension linkage and chainstay/seatstay pivots and check them out.
Before I built up the IP-036 whilst waiting for parts I stripped the frame, greased the bearings and re-torqued all the pivot points to make sure they would last. This seems to have worked as all parts were in near perfect order. Some of the black paint had worn away from the bolts and spacers but nothing to worry about. The only wear I could see was on the spacers and on the non-drive side to the Top tube pivot point. This is probably accounting for the lateral play.
Edit: The aluminium is worn, there is a slight 'dishing' to the face of the pivot housing !
The only bearing of slight concern was in the seatstay/chainstay pivot. Basically this bearing sits in a recess within the chainstay and the recess was filled with dirt/grime so if you ride in the wet/wash regularly the bearing will always sit in gunk ! The bearing moves freely but is starting to discolour. The amount of movement that this bearing goes through I doubt I would ever notice if it was seized so I don’t suggest everyone goes tearing it out to give it a good clean as it’s a real ball ache to get back together !!
I took this foto after I had cleaned most of the crap out and decided to mention it on here !
So happy with everything working as it should I addressed the lateral play with some shims. I added one 8 x 14 x 0.3 shim in the seatstay to suspension linkage on the drive side. Then ended up with six 12 x 18 x 0.3 shims to the Top tube pivot point (Three on each side sitting between the bearing face and existing spacer)
Picture of shims and existing washers/spacers.
Without the back wheel on and rear shock attached I pushed, pulled and twisted the frame as much as I dared looking for movement. There is now almost no play in all pivot points , I doubt whether all play in this linkage could be removed completely.
For reference the bearings in the:
Seatstay to chainstay (x2) were 698RS.
Seatstay to Suspension Linkage (x2) were 698RS
Top Tube Pivot (x2) were 6901RS
I didn’t remove the BB pivot as when all the other component were off it cycled freely with no play. (And I couldn’t be bothered removing the cranks, rear brake and derailleur with cabling ! ) I suspect the bearings there is also 6901RS !