Dishing a wheel

larkim

Ever since the bike arrived I've noticed that the front wheel is not correctly centred under the fork on my son's Nerve. I've not been concerned to do anything about it as the tyres he has run for most of the year have plenty of clearance.

However, now he's on slightly wider tyres and the clearance is tighter so it would probably make sense to get the wheel properly dished so that it centres correctly. (As an aside, I am surprised that Canyon supplied it incorrectly dished, as it is "true", so perhaps they have a batch which were all improperly dished?)

Not having a truing stand or a dishing tool, how feasible might it be to dish the wheel by eye simply by loosening all of the right side spokes say half a turn, and then tightening the left side by a similar amount evenly across the wheel, reviewing it for movement and then repeating (or undo-ing) as necessary until it has moved across enough?

Or would you avoid this sort of messing around as an amateur and just get the guys with the right tools to sort it out?

The Rookie

First off, make sure it is really a dishing issue, fit the wheel the wrong way round in the forks and see if its too close to the same side or now the opposite side.

Just dish the wheel in the forks (if it needs doing) measuring between the fork leg and rim (not tyre) and equalling it up both sides.

My front wheel truing stand is an old set of fork lowers!

larkim

That's a good shout on the lowers - I've now got a set hanging around which could do the job. Though I presume also I could simply put the bike up on the stand and re-dish the wheel in situ?

How could reversing the wheel help, not sure I comprehend that? The wheel definitely sits to the left hand side of the fork when viewed from above (i.e. closer to the disc side of the fork than to the non-disc side). Surely if I just turn the wheel around it must, by definition, now be closer to the non-disc side? Only if it was properly centred / dished would it show no difference either way around? Or am I missing something here?

The Rookie

If you reverse the wheel and it still sits to the left it's an issue with the fork and not the dishing.

For example some time ago RS produced a batch of SID forks with the lowers mis-machined and the wheel couldn't quite go in straight, 30 seconds with a round file (enlarging the dropout hole upwards slightly) used to fix it.

Have you checked the wheel is fitted correctly, no sillies like an adaptor not quite snug etc, I'm not sure what front wheel fitment you have.

larkim

QR / Reba forks so nothing complex. But I take your point about the fork etc. Though wouldn't that likely put the disc out of line with the calipers also? No issues there.

Wheel has been on and off many (many) times with the local thorns and the necessary repairs therein, and the QR lever is nice and snug.

Thanks as ever for help!

keef66

^ wot he said. It's just a quick way of telling if it's a wheel or a fork / dropout problem.

The Rookie

Have you tried refitting the front wheel, put some slight downward pressure on the front of the bike as you do up the QR, if the axle isn't sitting properly in the dropout it has the same effect, and yes I've seen that as well. No it would have very little effect on the disc, not enough to notice.

larkim

It's out by about 7 or 8 mm from centre so it would have an impact on the relative position of the disc.

Yes, I've tried refitting etc. We've had the bike for 18 months so it's not just a temporary misfitting.

The Rookie

Given the relative radius that would be less than 1mm at the disc and well within the ability of the slotted calliper mounts - so you still think it would be obvious?

Your choice but I really would try it first, or you risk screwing up a wheel and still not fixing the route cause, its only QR and will take about 20 seconds to try!

I find it very unlikely a wheel has been built with the dish that far out, miss-fitting seems most likely.

larkim

I think we're at cross purposes (and I fully accept I am likely the one misunderstanding!!)

Are you suggesting that if there is a burr on the fork lowers, and if that was on the right hand leg, sorting out that would have no impact on the disc position? That's true of course, but surely it would also cause the fork legs to toe into each other. They are true / parallel at the moment.

Now, if I were to move the centre line of the tyre / wheel by using spoke tension to shift that centre line, with no impact on the position of the axel in relation to the fork lowers, that clearly would have no effect on the disc position relative to the fork lowers / caliper?

As to whether we've got it fitted correctly, all I can say is that we've had that wheel on and off more times that I can care to remember, both fitted with the bike up in a stand and with downward pressure with the wheel on the ground. The result is the same, it sits offset to the centreline of the forks.

(Hopefully I'm not giving the impression of trying to be petulant - I'm well aware that countless posters on here post with what they think is a problem and it turns out it is something else again which only someone with experience might have picked up. I'm just trying to get across firstly that I am as confident as I can be that the wheel is properly fitted, and secondly a lack of comprehension on my part as to why I'm not understanding that issues with positioning in the fork itself would have a differential impact on the left to right position of the disc compared to the centreline of the wheel itself!)

Thanks as ever for your input Rookie - I do appreciate it!

[I've edited this post to remove a cockup I made in the description, so it probably makes less sense now than when I wrote it!)

keef66

So have you tried it in the other way round? What's the result?

The Rookie

You asked advice, I've given it, trust me it could be a fork issue and could well be the only symptom.

I'm not going to argue the toss over a 20 second test (when redishing will take much much longer) any more, It's up to you, but you've spent longer arguing it that it would take to do.

larkim

Sorry - yes - wrong way round shows dishing is out (tried that). Inserting / re-inserting shows no places where there is excess metal getting in the way.

I got distracted by the thought processes instead.

The wheel is definitely, definitely dished incorrectly.

The Rookie

Ok fair enough

larkim

So, back to the first premise - DIY or LBS?

The Rookie

I'd DIY it, but not everyone is comfortable doing that.

drlodge

As its the front wheel that suffers less stresses, I'd DIY it. You can always take it to your LBS if you screw it up.

I don't feel comfortable tweaking my roadbike wheels as they fairly expensive things and has drastic consequences if they fail. Having said that I did built a set of wheels in my yoof (27 1/4" steel rims) and they lasted OK. Try and get even spoke tension all round and a true wheel, that's all there is to it.

The Rookie

Changing the dish is fairly easy, first make sure you have no overtight or slack spokes, then go all the way round the disc side spokes undoing by 1/2 a turn, then do up all the non-disc by the same amount, repeat until it's right!

larkim

Cheers. I'll give it a go, what's the worst that can happen, eh!?

The Rookie

Worst that can happen, unless you go nuts, is paying the LBS the same as you would have had to anyway.

larkim

Eggzacly!