Whilst swapping wheels on my X1, I found the front wheel bearings shot. It didn't bother me cos the wheel was scuffed and I was putting another one on...
Last week I decided to try my new scales out and weigh a set of cast wheels, a set of PMs and a set of Dymags. To make it fair I removed the tyres and the bearings...
On closer inspection, the centre spacer for the cast wheels (with the shot bearings) looked like this:
Why??? Look at the wall thickness at the ends...
The spacer is a 25mm OD tube with a 17mm ID, but there is a 8mm deep 20.5mm counterbore each end...
...so the minimum area is 161mm^2... And it got crushed, probably by a gorilla with a big spanner...
Obviously the wheel can't go back together again like this, especially because, and get this, the distance between the bearing shoulders is measured as 75.3mm but the length of the spacer was measured as 74.1mm, so crushing, either with worn bearings or in damaging the bearings, has occurred...
The solution...
Well, the bearing itself, a 6204...
...has an inner race ID of 20mm and an OD of 29mm, so it would make sense to have a spacer to suit those dimensions, cos any increase in area, as in the central part of the standard spacer, will do nothing to help the ends...
Best I could come up with was 30mm OD and 20mm ID.
On the contact area of the bearing, this gives 346mm^2 area, 2.15 times the minimum area of the original spacer. This means the spacer can withstand over twice the load of the original spacer (assuming the same material - 6082T6) without deformation. Not that it will need to cos we will be sensible with the torque wrench...
Big length of tube ordered, Length will be 77mm, non-disc side bearing in first...
Question is, how many more crushed spacers are there on UKBEG front wheels? Let me know if you want a spacer made up...
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5 please, recent fecked bearing and trashed spacer.
..................He was caught in a trap