Wheelbuilding - trueing a rim - more out of true than I expected

[alicat]

I'm swapping one rim out for another.

I've reached the stage of doing the first true. The wheel is more out of true (c.4mm) than I expected, especially when I took care to turn the spokes an exact number of time. Should I wind back a stage and repeat or carry on trueing?

I've had a few false starts. I got the wheel round and true earlier but hadn't taken enough tension out and this is another attempt.

Thanks for any advice.

 

[Ming the Merciless]

The trick with truing is not to try and get it perfect in one go. You just tackle the biggest wobble then next biggest. Bit by bit it gets more true till you are happy with it.

Unless the spokes are already wound up to tension you should be able to continue. But backing off and starting again isn't a problem either. Just take your time, and remember, don't make massive turns of the spoke nipples. Just a little at a time to get it better each iteration.

 

[alicat]

Thanks, @YukonBoy.

I suppose I was surprised that it wasn't truer to start with. Is 4mm within the realms of normal when starting to true?

The wheel isn't at tension so I will carry one.

 

[Ming the Merciless]

Depends how you started. I tend to break it down into lacing it up, bringing up to tension, then truing, stress relieving, final tension adjustments etc. When bringing up to tension first time I'm just bringing it up to a minimal tension that shouldn't take a wheel out of true.

I don't measure what the actual wobble is in mm. I just have feelers that I gradually bring in closer to the rim as it gets more true. You should alternate lateral (side to side) and vertical (roundness) truing corrections. Again little at a time not big adjustments. Don't forget to feather your adjustments.

 

[wisdom]

I have a back wheel that has developed an out of trueness.potholes are the culprit I think.
I dont have a wheel truing stand,and have never trued a wheel before.
Can it be done using the bike frame as a reference(using a pencil).And is it possible to do without wrecking the wheel.
I can do everything else on bikes but always looked at wheeltruing and building as sorcery.

 

[alicat]

Depends how you started. I tend to break it down into lacing it up, bringing up to tension, then truing, stress relieving, final tension adjustments etc. When bringing up to tension first time I'm just bringing it up to a minimal tension that shouldn't take a wheel out of true.

That's what I did. I didn't measure the wobble, it just looked bigger than I was expecting.

Anyway, I'm batting on and about to do a last check on the dish then stress relieve.

 

[Ming the Merciless]

It can look exaggerated when in a truing rig and close up. It's often not as bad as it looks.

 

[Ajax Bay]

Can it be done using the bike frame as a reference(using a pencil). And is it possible to do without wrecking the wheel.

Yes and yes (very difficult to 'wreck the wheel' btw). Worth getting the 'vertical' trueing right (and tight) first (ie getting the rim 'perfectly' circular in the vertical plane) and then trueing in the horizontal plane (ie between brake blocks equidistance from the centre line) by an iterative process (patience and the odd pause for beer).

 

[overmind]

Yes and yes (very difficult to 'wreck the wheel' btw). Worth getting the 'vertical' trueing right (and tight) first (ie getting the rim 'perfectly' circular in the vertical plane) and then trueing in the horizontal plane (ie between brake blocks equidistance from the centre line) by an iterative process (patience and the odd pause for beer).

Yes Beer is definitely a key ingredient. Beer is to wheel truing what yeast is to beer (in my opinion. )

 

[Blue Hills]

Don't forget to feather your adjustments.

Can I ask what you mean by this?

 

[Ming the Merciless]

Can I ask what you mean by this?

You find the biggest wobble in the rim and it is to the right. So you tighten the nearest spoke pulling to the left, a spoke attached to the left side of hub as you look at it. Lets say you tighten that nipple by 1/2 a turn with the spoke key. Then you want to tighten the left side spokes either side of that spoke, by 1/4 of a turn of their nipples. If you tighten the nearest by 1/4 turn then either side (attached to same side of hub) tighten by an 1/8 of a turn.

This is known as feathering.

 

[wisdom]

Update.
I asked if it was possible to make it worse.Well I thought I'd try and true the wheel.Found a broken spoke which was obviously the cause of it going out of true.
It was broken at the hub.Drive side but still on place.Casette off new spoke put in and wheel trued.Its a lot better as I did it on the bike I am well pleased.
Might look for a s/h truing stand in the future.

 

[SkipdiverJohn]

I've salvaged a 27" steel rim that had been crashed and was so far out the tyre was touching the frame at one point - on a 3-speed roadster with loads of clearance too. First off I brute forced it by lashing the rim to the frame with rope to stop it rotating then standing on it with size 10 boots where necessary. Once I had brutalised it down to just about 3/16" out of true I used the spoke key. I've got it under 1/8" out now so it clears the brake blocks but the spoke tensions are all over the place. Since the wheel was borderline scrap, I decided there was nothing to lose, but I am very careful not to kerb or pothole the wheel because I suspect it would be easily buckled again given the very uneven spoke tensions. It's only a low speed, local journey hack anyway.