FBinNY 

That's like asking an artist when a painting is finished.
Short answer is when I think it's about as good as it's going to get. These days it's generally well below 1mm, but I won't chase that ideal at the cost of a more sound wheel.



The longer answer is that it depends on a variety of factors. The biggest factor is the rim. BITD rim joints tended to cause stiff zones and local distortion which made getting that area better then 2mm difficult. These days rims are more perfect, but also stiffer, so resolving rim distortion is more difficult. So, I'm still limited by the rim, but there's more judgement involved, and I'll stop when I feel that the local changes to spoke tension are more than I prefer. There are also rim twists, so sometimes I'll have one area reading high on the right and another reading high on the left, so I have to find the best overall balance and quit.

As a general rule, wheels rapidly come to excellent alignment, and can be refined to better yet with only some minor quitting. Once I've done that, I don't believe that obsessing to chase perfection is warranted.

It's important to heed the advice for baking bread --- "don't overwork the dough".

Lombard

This is what Roger Musson says in his book "Professional Guide to Wheel Building":

Lateral trueness: 0.2mm
Radial trueness: 0.5mm
Dish: 1mm

That being said, equalizing spoke tensions is more important than getting a wheel to this trueness spec.

Kontact 

I've built plenty of wheels where the seam isn't detectable while truing. So it isn't always a problem.

Lombard

Can you name a few? I've never built a wheel where the seam wasn't detectable.

Kontact 

Kinlin, Hed Belgiums.

Taller rims act differently than box section rims around the seam, in general, because they can flex less vertically. It seems like the forces the forming process to be more uniform.

It doesn't matter - just something I've had occasion to notice.

Lombard

I've built with both of those. The seam is definitely detectable.

FBinNY 

Kontact 

Okay. Then I guess it didn't happen.

Lombard

It happened, you just didn't notice it.

Kontact 

There you go. My senses aren't as good as yours.

squirtdad

All of this reminds me i need to go to the garage to finish the radial of the wheel im building.... think I am close, i have one place where it is reverse hop....will check if this is at the seam. (ambrosio nemesis tubular rims ....la Reine du Nord)

Arthur Peabody

Did you build a wheel with it and ride on it? I've built wheels with bent rims, gotten them true and round and dished, but they didn't ride that way because they weren't uniformly strong, the tension on the spokes varied so much.

I build wheels with nothing but a spoke wrench and a handmade dish tool (a flat 1x1 and 2 wood screws). If I can't see a hop by eyeball I can't feel it and I'm okay. I suspect I'm probably advertising my incompetence rather than giving advice. I don't build wheels for other people.

zandoval 

No Arthur, I did not. I was too chicken. At the time I did not even have a spoke tension meter and I true my wheels on the bike as I don't have a stand. I probably could use the rim but I don't want to spend the time putting it together only to have it fail... Ha...

Steel Charlie

What's with that Park video saying don't lace the spokes?

cyccommute 

Not talking about “truing”. It’s the roundness where the pins cause a little bit of a problem.

Kontact 

I have built wheels professionally for years. Which you know. Please stop talking down to me.

"Truing" is also the general term for making tension adjustments on a wheel, not just lateral ones.

SJX426 

Picked up an old Bottecchia from about 1972. The rear rim had a "flat' spot causing hop.
Here is the gap compared to the rest of the rim.
P1030739 on Flickr

Applied some thought and tools.
P1030738 on Flickr

As the flat spot range slowly decreased, the spacing of the wood blocks were moved closer together until the gap was removed. See markings on the rim to locate the transition points.
P1030740 on Flickr

smd4

I have never "rounded" a wheel in my life. Is that really a term you prefer?

If not, stop being so obtuse. "Truing" as understood by 99.999% of the world's English-speaking bike mechanics, as well as every-day cyclists, applies both to the roundness of a wheel as well as lateral straightness.

Lombard

It's both.

cjenrick

What about balance?

Put your bike upside down and pedal like a mad man in high gear. I bet that wheel bounces around like a skeleton on a hot tin roof.

I wish the roads I ride on were good to +/- 1 mm. Especially the chip rock.

Kontact 

Bike wheels have so little mass that you can spin them to 30 mph in the stand and stop them by grabbing the tire. They will never be so unbalanced that they break contact with the road, so you won't be able to feel the balance vertically and you and the bike have too much mass for the wheel to affect the bike horizontally.

So wheel balance just doesn't matter.

smd4

Something I try never to do.

cjenrick

I can sure feel imbalance on high speed decents,

Maybe instead of worrying about perfect roundness you should worry about this:

"Main frame computer testing at McDonnel Douglas, has shown that just 3 grams out of balance will multiply 25 times at 25 mph and is exponential above those speeds to the point where a serious out of balance problem inhibits the forward speed of the bicycle and can make it impossible to control. At 25 mph, 3 grams out of balance will cost the rider 100 ft. per mile and at 40 mph, it is close to 500 ft. per mile. One national competitor brought his wheel set to me (Zipp) and I found that the front was 31 grams out of balance and the rear was 28 grams out. He stated he could not control the bike much above 30 mph on a decent. Putting the balancing weights opposite of the heavy point is not a balance in all planes and does not work. Most wheel manufacturers strive to ensure a balance as much as possible, but they cannot anticipate where the speedo magnet will go, nor how heavy the tube stem will be. Only one wheel maker (ADA)actually does it right and I helped design those wheels and bearings. However, not even Cees Beers (ADA) can anticipate how heavy the stem will be, so he does the best he can. Have been riding a racing style bike since 1962, and during the intervening years have found only one wheel was in balance after mounting the tire and tube. Most take between 3 and 7 grams of balance weights. Have found that carbon fiber wheels tend to be the worst offenders (along with solid rear wheels), with good rims (MAVIC) and good tires Vittoria and Conti Super Sonic tubes to be the least offensive combinations. Contrary to most who state that wheel vibration contributes to high speed castor shake, after extensive testing, have found this to not be true. A badly designed and matched frame/front fork offset is generally the culprit. The fork, with too much off-set sets up a vibration that twists the downtube radially and axially when a sympathetic vibration with the downtube is matched. This translates to a side to side shake of the head tube, then this translates to an axial motion at the top tube/head tube bearing and this becomes the motion at the handlebars. Proper wheel balancing cannot stop this combination, but improper wheel balancing will add to the problem. Have written and published many papers on bicycle wheel balancing, but withdrew the papers after I found out that several were charging for wheel balancing and several were unwilling to give me credit for the years of work that I had to do to perfect and make the balancing system repeatable (as in the current HPV speed record holder). I will answer questions, but will not respond to snide comments or trolls. If you live in the Chesapeake VA area, bring your wheels by and I'll balance them for you--free,

Kontact 

I guarantee you that I (and plenty of other cyclists) have hit 50mph on wheels with more than 3 grams of imbalance.

Do you actually believe this stuff? MD doing bike testing? Uncontrollable at 25mph??? Have you ever ridden a bicycle?

cjenrick

Everytime you quote a post you double the server space required
just post your response, any idiot will know what it pertains to

Have you ever lost a tire weight on your car? You get on the freeway and your steering wheel starts vibrating because the 3000 lb car is vibrating.
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