Tyres, Brakes and Suspension » Front wheel bearing spacer

Just about to fit new bearings to the front wheel.
It appears that the spacer that is fitted between the two bearings is longer than the distance between the two lands in the wheel hub that the outer part of the bearing race would stop/land on.

If I pull in both bearings by squeezing on the outer races, the inner races will be stopped by the spacer before the outer races but up on the lands. This means that inner races will have a sort of pre tension pushing out aganst the outer races via the ball bearings.

any thoughts please

Are you fitting "like for like " identical bearings? i.e. BMW supplied rather than any other manufacturer. If you can confirm they are the same size and shape, with all dimensions then I would think it's going to be o.k.
The inner race are pressed against the spacer, the outer are contained by the wheel, any 'float' is the space for the ballbearings between inner and outer parts. Getting the wheels loose enough for rotation but tight enough for handling is why I would only use original OE bmw units

30 x 7 bearings if I remember correctly.

Yes. I am fitting the same size bearings as I removed. You are correct the tolerances within the bearings should determine any lateral endfloat of the wheel on the spindle.
New bearings:-
47.00mm OD
25.00mm ID
12.00mm Width

The space/distance between the two larger diameter landing faces inside the frontwheel hub for the outer race of the bearings to be "pulled up" onto are 104.50mm appart. That is the dimension between the nearside to offside, or left to right of the two faces inside the wheel hub.
The hub spacer which will rest upon the inner face of the inner race of the bearings has faces 105.00mm appart. It is 105.00mm long
For assembly, first of all, pushing against the outer race of the bearing, I pull in the righthand bearing (opposite the ABS sensor wheel) and pull the outer race hard against the landing face inside the wheel hub. Then I pull in the second bearing, again using the outer race to pull it in. (On the other side)
The inner race will first come up against the spacer and then the outer race will be pulled in a futher 0.50mm before the outer race seats against the landing face in the hub. There will now be a side load (left to right/right to left) on both of the deep groove bearings. The side load on each bearing will be equivalent half of the extra 0.5mm that the outer race was pulled in. These bearings do not usually have to withstand a side load.

I can;
1. Try to pull in the second bearing so that the inner race just kisses the spaces
2. Remove 0.50mm from the space and pull up the bearing hard against its hub landing
3. Fabricate a 0.50mm spacer to be paced between the outer race and hub landing
4. Another option

In the end I received some advice from BMW UK
Fit the Left Hand (ABS sensor side) bearing first and seat the outer race against the land in the hub.
Install the spacer and fit the Right hand bearing seating it against the spacer. They use a puller that sits on both of the races and so does not impart any end load on the bearing.

Screenshot 2025-07-10 212636.png - Bild entfernt (keine Rechte)
Screenshot 2025-07-10 213930.png - Bild entfernt (keine Rechte)