Help with Rotoflex Bearing Preload

[BiTurbo228]

Hi guys,

First off a happy belated new year! I have been chugging away but managed to melt my camera (I'll explain later, good lesson from that) so tricky getting photos for updates.

Down to brass tacks, I'm sorting out the rotoflex bearings so I can fit all the rear suspension and get it down on its wheels for the first time in nearly 4 years! I know shimming's pretty critical on these to preserve bearing life, so I thought I'd see if anyone has any pointers (already tried searching but couldn't find anything).

I think I've managed to get the first side to where it needs to be, but I'm not sure. It's all fitted up dry, shim in place (with a shoulder filed into it so it'll sit flush on the Canleys CV axles), torqued to 90lb-ft. There's no discernible movement in the hub, yet it rotates freely. However, at some points during the rotation when I try shifting the hub about there's the occasional faint knock (despite there still being no movement).

So, question is. Is that where it needs to be? Not sure if that constitutes 'no play' or whether I'm looking for something where there's not anything discernible at all.

I haven't yet pulled it back apart again to try and see if I can get a measurement of spacer-to-bearing with a straightedge and feeler gauges (couldn't get a measurement before building it up as the spacer/shim seems to be a press fit into the inner bearing race).

Also, surely if you set up the preload perfectly with new bearings it'll loosen up slightly as they bed in. Is that takne into account or will I need to look at it again in a couple of hundred miles?

[Dogsbody47uk]

THey are not pre-loaded! They have to be set up with minimal play. See Canley Classics Technical archive for instructions. Cheers, Dave.

[BiTurbo228]

Yeah looked through the archive and found that they're not preloaded (just easier to say 'setting rotoflex wheel bearing preload' than 'setting rotoflex wheel bearing lack of any preload at all'

I suppose the exam question is what contitutes minimal play? Am I lookong for the faintest of clunks over the whole travel, or no clunks but no binding either?

I know what I really should do is get a proper dial gauge...

[Dogsbody47uk]

I believe about .0015 to .0025 inches is desirable, but if anyone knows better, please say. Cheers, Dave. For anyone who thinks I've put the decimal point in the wrong place I mean one and a half thousandth of an inch to two and a half thousandths of an inch.

[BiTurbo228]

Gotcha, thanks if my maths are right I think you've got it right!

Something that's interesting if you're doing it by feeling for play rather than a dial gauge is that the fore-aft play seems to disappear before the side-to-side play.

Edit: re-reading the Canley's instructions they do mention that you should feel VERY slight play, but no end-float so that makes sense that it disappears first.

Now I'm just left with general unease as to what constitutes 'VERY slight play' but we'll see how it goes!