31.5 forks, wheel centring issue

[Dave354]

Hi, I wonder if anyone has has an issue getting the front wheel to align exactly in the centre of the forks? I have assembled the rebuilt wheel with new bearings and axel. But it sits about 1.8mm to the left hand side ( the brake shoe side). The only way I can get it to centre is to shim between the fork leg and the brake hub. One tightened up it spins beautifully and is now centred, however i wonder why is like this?
Dave

[Duccout]

Hi Dave,

Is it the hub off centre or could the rim have been built out of line with the hub? This happened to me once when I had a front wheel rebuilt - when I fitted it to the forks the rim was off-centre. I took it back to Alf Hagon, whose guy had done the job, and Hagon, in his usual taciturn manner took it out the back and then ignored me. When I asked what was happening he told me that the builder was correcting it, which took about five minutes!



Regards,

Colin

[Dave354]

Hi Colin, thanks for your thoughts. The wheels were rebuilt by a very established wheel builder and on checking they do appear to be spot on centre. I’m wondering if the new wheel bearings are slightly off with the spacer… I will have to recheck the wheels for offset as they are on Borrani rims

With the shim to centre the wheel as it is I don’t think there will be a problem?

Thanks

Dave

[Duccout]

No, I can't see anything wrong with shimming the wheel.


Colin

[blethermaskite]

I think nearly every narrow case single I have ever owned or worked on has had a of shim of varying thickness between the fork slider and the wheel hub to get the front wheel spot on centre.
Cheers,
George

[Dave354]

That gives me so much confidence! Thank you

[blethermaskite]

Just be aware that the further you shim the brake plate from the fork slider (to centre the wheel) the engagement slot on the brake plate is being moved away from the stop lug on the fork slider, which can increase the slop in that area, I have often put a shim (if needed) internally on the axle between the brake plate and the hub bearing boss to minimise this, you could certainly put a shim in there around 1 to 1.5mm without upsetting the functional and cosmetic positioning of the brake plate in the hub. If this leaves your wheel less than .5mm off centre neither you or the bike will notice it
Cheers,
George

[Dave354]

Ah! Why didn’t I think of that! Thank you a better way to resolve the issue… spanner’s out tomorrow!

[kaysystems]

Further to this issue - Should the speedo plate and brake plate be flush with the wheel hub? Mine are both recessed a couple of millimetres. Putting a 2mm shim on both sides (on the bearings would solve this and centre my wheel.

David

[Dave354]

I’m not sure if they should sit flush? Mine also sit slightly below the rim of the hub. My issue was the centre of the wheel in relation to the centre of the forks. I think my issue stems from the seating of the wheel bearings and the spacer. If one bearing is seated slightly deeper than the other because of any issue with the spacer it will sit slightly off centre. Mine was only 1.5mm. I doubt it wold notice but shimmed against the brake side bearing inner race.

Regards

Dave