Of course I suspected the brake to be rubbing or just misadjusted.
That didn't help.
Then I read Artefex's tip about not really tightening the axle bolt.
That worked to a certain extent: the wheel was turning better, but still not real smooth.
And I noticed a little bit of play in the front wheel, which disappeared when the bolt was fully tightened. But then the wheel did not turn freely again..
So I investigated further:
The two aluminium spacers on both sides of the wheel were not exactly flat faced.
So I carefully flattened the faces.
That did not make much of a difference.
Then I looked at he wheel and the bearings.
The bearings seemed ok. But then I noticed a spacer in between the bearings (inside the wheel).
This bearing was a little loose. It looked as if it was just not big enough to bridge the gap between the bearings.
I could push it from underneath and found quite some axial play.
The bearing in the front wheel, with the spacer behind it:
- spacer in wheel behind bearing.jpg (29.22 KiB) Viewed 5151 times
That would explain the problem:
When you tighten the axle bolt, the bearings get pushed against this centre spacer. But since this centre spacer is not big enough, the bearings are pushed inside too much. Then they are under constant sideways strain, and then they do not run freely anymore.
So I carefully got one bearing out (tapping on a metal rod placed on the hard metal center ring of the bearing, not on the soft metal dust cover with the abec markings!)
I took the spacer out, and measured its height to be 10.9mm.
The gap in between the spacer was 11.4mm!
I got a wider spacer from a toolshop, and cut and sanded it until it was the right height.
Front wheel with bearing and spacer next to it:
- spacer and bearing next to wheel.jpg (26.71 KiB) Viewed 5099 times
Old and new spacer:
- old and new spacer.jpg (13.07 KiB) Viewed 5138 times
The height is the thing that matters here. Th new spacer is a bit larger in diameter as well, but that's not the point.
(I got a hard nylon spacer. The guy in the toolshop said it would outlast an aluminium one, but I expect I'll need to replace it in the future..)
Then I inserted the new spacer, pushed the bearing in, and put the wheel, bolt, etc back on the bike.
Now I can tighten the axle bolt, and have a front wheel that runs really smooth, without play!
So smooth I even have to use the brakes!
This may sound funny, but until now I could just stop pedaling if I wanted to stop, and the bike would slow down quite quickly. But not anymore!
When you do this mod/repair, keep some things in mind:
-the spacer needs to fit around the axle bolt (M8), so has a hole measuring 8mm.
-the external diameter of the spacer must not be too large: it must sit against the hard metal inner ring of the bearing, so the outside diameter must not exceed 12mm, or it will rub against the soft metal dustcover of the bearing.
-one of my front wheelbearings came out real easy, the other one seems to be really stuck.
So if you don't succeed in gently tapping out one bearing, try the other.
-when you tap the bearing tap the hard metal inner ring (silvery) only, not the soft metal dustcover (marked with ABEC and numbers, brass coloured)
-your bike might have a perfectly fitting spacer, or need a different size spacer than mine: look and measure!
Job
