I noticed recently some play in the lowers of the front suspension of my fun bike (NEX 25). The way to notice it was the following:
- locking the suspension
- blocking the front wheel with the brake
- moving the bike back and forth
At the level of the dust caps, a 0.5-1mm movement can be seen and at the level of the wheel, it's about 5mm, in the opposite direction (difficult to capture in a video). It looks like the lowers are rotating around a axis located at mid height.
I initially though about the slider sleeves being worn out, which would be possible, given the bike has been used quite a lot in dusty environments, so I replaced them (myself, along with the dust caps).
Before changing the sleeves, I also checked with the two other bikes at home that have similar suspension: one with a more recent version of this suspension (that has 30mm stanchions instead of 28mm), and another one with a 15y old SR-Suntour NCX fork (1 or 2 ranges higher than NEX). Both are working smoothly, and have a bit of play (maybe 1mm at the bottom). But for these bikes, the stanchions surface is smooth and undamaged.
So I'm wondering about the origin of this play:
- maybe it's normal, it's a cheap fork, with lower tolerances than a high end one. This bike is on the unlucky side of the spectrum, and the other one with a NEX on the lucky side.
- the surface damage on the stanchion surface seems too superficial, and not really localized at the level of the sleeve, but more at the dust caps, that has no 'mechanical' role to cause that amount of play.
- or when remounting the fork, I missed one step (seems unlikely, given the simplicity of the fork).
Could it be another explanation?
EDIT: added some pictures
Side by side comparison, look at the nut of the QR release, the pictures have been taken by mounting my phone on a Quadlock mount, so relative to the wheel, the phone is at the same position
State of the stanchion, front side
