Rear Wheel dishing

[mrcpea]

Just rebuilt the rear wheel in the Dawes Galaxy. The rear dropouts are in alignment as I checked using Sheldon Browns "string" method on his site. The spoke length is I believe correct as I use this http://leonard.io/edd/

When the wheel sits in the frame, the rim is central (equal distance from each stay)
BUT, when I measure the dishing with my dishing tool, it's quite a bit out, i.e. the distance from each lock nut is a different measurement on each side in relation to the rim!
The rim and hub are what came off (weinmann rim and maillard large flange hub 120 OLN)


Riding the bike, you'd never know until you measured the dishing!
Does this matter? and will spoke tension stay or will spokes brake?

Any thoughts from the experts will be most welcome.

Cheers

Richard

 

[cce]

it's fine. I assume the wheel is less dished than might be considered correct, this actually makes for a stronger wheel - a front wheel has zero dish

 

[mattr]

Flip the wheel and see how the dish looks with the wheel in the other way round.

 

[foz]

Are you sure the wheel is in straight? Just because the rim is centered between the stays doesn't mean the axle is at 90' to the frame.

 

[NeilM]

it's fine. I assume the wheel is less dished than might be considered correct, this actually makes for a stronger wheel - a front wheel has zero dish

+1

 

[mattr]

FWIW while an undished wheel is stronger, unless the back end of the frame is designed to take an undished wheel, it'll make the bike handle like a dog.

 

[hamster]

But the frame must have been aligned for undished as the wheel is central.

I suspect that the frame has been widened at some stage and done by making an offset (dishless) rear. It's a good modification to make for a touring bike.

 

[mattr]

But the frame must have been aligned for undished as the wheel is central.

except the dropouts are aligned according to the OP. So somethings crooked somewhere!

 

[torqueless]

I don't consider myself an expert, but hopefully this is relevant and useful to somebody:

Frame alignment depends on many things- Usually, as far as the rear triangle goes, you ideally have a pair of chainstays of equal length emerging at the same angle (both in plan and profile) from a bracket shell which is at 90 degrees (both in plan and from the front) to the bike's usual direction of travel. From this you hope to have a pair of dropouts ideally parallel to eachother, and equidistant from the ground, the bottom bracket axle centre-line, and the centre-line of the bike itself.

Nothing on this earth is perfect, so there are tolerances involved, and part of the measure of a frame's quality is how close to perfection this alignment/symmetry is. It is usually close enough for practical purposes, and when it is, a 'perfect' wheel, with it's rim centred exactly between the axle locknuts, will sit exactly central between the stays, exactly behind the seat-tube. Reversing the wheel in the dropouts is the acid-test- any asymmetry will be doubled.

For those of us without a large collection of high quality close to perfectly symmetrical frames, and close to perfect wheels to swap between them, it makes sense to be aware of the (hopefully minor) alignment imperfections of the one frame you do have, and fine-tune your one rear wheel with spoke-key and axle spacers so that your rear rim follows the same track as your front rim, hopefully on the centre-line of the bike, equidistant between the stays on both sides. Always bearing in mind your chainline, too. And of course, with horizontal dropouts, this all depends on keeping the rear axle in it's proper orientation at exactly 90 degrees to the bike's usual direction of travel.

Never take anything for granted with frame alignment- check everything as best you can. For example, the brake-hole on the bridge on one of my frames is off centre by maybe 2mm. If I was unaware of that, it would be a false datum point for checking alignment, and a nightmare for centering the rear wheel. That same frame also once had it's bottom-bracket shell replaced. I never rode it afterwards because I took the trouble to check if the new shell was in alignment, and found that it was significantly out of alignment- probably far enough out to Fk up my knees- so I had to have the shell replaced again by someone else, and that first guy is getting no further custom or recommendation from me.

 

[mrcpea]

Many thanks for everyone's input, I really appreciate it. I'll have more time at the weekend, so will check the axle is 90' in relation to the frame, then I'll turn the wheel around in the bike & see what it's like then.
All suggestions and advice are much appreciated

Richard