Wheel bearing full-seating

[Guest]

So I'm replacing the wheel bearings on my 550 but I'm having trouble knowing what constitutes "fully seated".

I've been poring through the threads and found nuggets of info suggesting that the inner hub spacer links the two inner races of the bearings, essentially causing them to spin as one, that is acts as lateral support preventing the outer spacers from pushing too hard, but that the two bearings should lightly touch the spacer without being too tight.

The trick: I noticed that the inner hub spacer is actually longer than the distance between the two seats for the bearings. Thus, should the two bearings be firm against the spacer forming a tight unit, or loose allowing the spacer to free-float without touching anything?

[Billy Ricks]

Use your old bearing or a large socket to knock the new one in place. You'll feel when it seats. The inner bearing support is there to keep the bearings from binding and keeps the inner races stationary, they don't spin. Everything will snug up when you tighten the axle.

[derickson104]

That is solid information, and installing the bearings themselves I do not think will be a problem (they're in the freezer now). The problem is that it seems as though the bearings are seating against the inner spacer, not on the hub itself. If I drive the bearings, albeit lightly, as far as they go the bearings jam against the spacer to where they will barely turn by hand, and then only if both are spun at once. There is considerably more resistance than when the bearings were in the hub, but not pressed all the way.

It baffles me. There is no way the spacer grew, and should be to OEM spec, where it should snug against the bearings, right? I'm temped to file off the few thousandths on the spacer that pushes it against the inner bearing race. Anyway, unless someone replaced the inner hub spacer, I don't see how this could happen. Does anyone have any thoughts?

I ran across another thread dealing with this same issue, but no conclusion reached. Also, the bearing I removed was torn up (strands of metal in the bearing itself). Perhaps the bike just ran that way?

http://www.thegsresources.com/_forum/showthread.php?t=122154

[derickson104]

The insanity of this made me triple check the measurements. One bearing is in the hub. The distance from that bearing to the seat on the other side is 3.244 inches. The spacer measures 3.273 inches. A touch of calculus later, and we see that the spacer is .029'' longer than the gap between the bearing seats! Thirty thousandths is causing all this mess. Any thoughts?

[1074cm3]

don't worry, billy is right, you'll be OK. I just saw this question in the "service" section of Cycle World mag. a few months back. I'll see if I can find it.

[derickson104]

Please do. Probably there is no problem, but any additional info I can get would be brilliant.

[Dogma]

I just ran into something similar. I was able to seat both bearings (If you're driving them in with a hammer, you'll get a more solid-sounding thunk when you hit a seated bearing). I ran out of room to move the bushings outward on the fork, so I had to spread the forks a little to get the wheel in. The fork doesn't seem to be binding, but I have another set of bearings on the way.

At about $10 a set, I'd say don't be afraid to try another set if the rest of hte reassembly doesn't work out. I know I'll have another occasion to tear my front end down soon, so I get to check on my bearings again then.