Front wheel centering / build

silva

Senior Member
Location
Belgium
Question: I noticed that when I flip my front wheel, rim brake pad at one side touches the rim, implying that the wheel is asymmetrical. Why is that?
 

Gunk

Veteran
Location
Oxford
It just means that the adjustment cones for the wheel bearings are not exactly centred, so it’s pushing the wheel over to one side very slightly, nothing to worry about.
 

Ajax Bay

Guru
Location
East Devon
A properly trued wheel will not exhibit this. This observation implies that your wheel needs slight adjustment to pull the rim into dead centre, irrespective of whether the hub is exactly centred on the axle (so I dissent from @Gunk ).
When finishing a wheel build it's standard practice to flip the wheel round in the jig to check this.
If the difference is marginal, it's probably not worth worrying about, but I bought a bike once (still have it - 40,000km later - but replacement wheel now) the rear wheel of which was about 4mm out from centre. Correcting the inadequate dishing was quick and easy.
 
OP
OP
silva

silva

Senior Member
Location
Belgium
If I can assume that the hydraulic brakes mounts sit centered on the frame, then I'm basically steering a wheel that sits at least 3 mm outside the forks center. I do feel an instable riding behaviour: it's hard to stay on a road line, especially when the bikes rear rack has no weight / luggage on it. When I rode the bike after picking it uw new, it even felt so unsafe that I went back with it, but the dealer said no idea. When I later on went to shop to buy some stuff, I put it on the rear rack and all of sudden that unstable riding experience became alot less worse.

But what I know specifically want to know is why. Is there any possible reason to actually build, on purpose, a front wheel offcenter? A specific goal / application? A reason why a front hub doesn't sit in the center of the dropouts?
 

Ajax Bay

Guru
Location
East Devon
Possible reason for deliberate off-centre build? None I can think of. Will cause some additional tyre wear.
Exact centering of the hub doesn't matter as trueing the wheel will compensate for any small anomaly (rim brakes).
You do seem a magnet for problems with this new bike.
 
OP
OP
silva

silva

Senior Member
Location
Belgium
Possible reason for deliberate off-centre build? None I can think of. Will cause some additional tyre wear.
Exact centering of the hub doesn't matter as trueing the wheel will compensate for any small anomaly (rim brakes).
You do seem a magnet for problems with this new bike.
Well the front wheel does sit offcentre, as the brake pad hit (a plain block - cannot move the wheel) when flipmounted proved.
There is not any sign of additional/special front tyre wear visible.
But my rear tyres clearly wear out of centre towards the drive side. A month or so ago I flipped the tyre in order to wear the other side of the middle more - the difference is quite big, about 2 mm.

And it's not that the new bike attracted problems, it was delivered as such. :-)

I'm trying to find an explaining storyline for this offcentre mounted front wheel.
To add some info: the fronts hub is a Son dynamo. The same frame is also used for disc brakes, and also 2 tyre widths with as max 62 mm.
 

Ian H

I am an ancient randonneur, & I often stop for tea
Location
Dumnoniorum
If, as you flip the wheel, the rim is equally off-centre either way, then the wheel needs centring. If the rim sits centrally one way and off-centre the other, then it's been built to accommodate and out-of-true fork.
 

Nigelnightmare

Über Member
If, as you flip the wheel, the rim is equally off-centre either way, then the wheel needs centring. If the rim sits centrally one way and off-centre the other, then it's been built to accommodate and out-of-true fork.

Or spaced wrong at the cones/locknut.
 

Ian H

I am an ancient randonneur, & I often stop for tea
Location
Dumnoniorum
Or spaced wrong at the cones/locknut.
Except he states that it's a SON hub.
 
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