cny-bikeman

I don't really see how a video will prove or not prove a bad rim. I think your tension results and inability for any procedure to get it right is sufficient. But it's your time, so go for it.

As to the multitude of posts trying to solve the probem:

Yes, no rim is perfect, those rims may have problems in general, the OP may have done something incorrectly, etc. etc. All true but all ignores the horrible tension readings when he had the wheel fairly true. There is no way I can see that he could have that kind of variation, a reasonably true and round wheel, and the problem not be within the rim itself. Having a hop at the seam can not only affect round but also the entire wheel structure, including true, as all of the components interact with each other. I'm going to give this thread a goodbye, best of luck to the OP..

mrrabbit 

Still waiting for the OP to check the 286.00 spokes in relation to their nipples...

=8-)

blaronn

Spoke lengths look good. When tension is high the deepest 286's are about halfway extended into the screwdriver channel.

2nd attempt at truing is complete. It seemed like things were going really well this time until the DS tension increased over 90 or 100. From that point on it seemed like I was just going back & forth between true with uneven tension and wobbly with even tension. Maybe I should have been making even smaller changes at that point. Right now tension is semi-close but there's around 0.61mm (.024") of lateral wobble.

Before evening tension out this last round tension looked like this...

DS (kgf) NDS (kgf)
..113.......57 <-- 1st spokes clockwise of valve hole, looking at it from drive side
..113.......56
..103.......58
..117.......67
..127.......60
..148......~34
...76.......62 <-- 76 is adjacent to the seam
..105.......96 <-- 96 is adjacent to the seam
..138......~45
..124......~42
..109.......56
..106.......68
..117.......60
..117.......52

Note: In my OP I listed NDS spokes going counter-clockwise rather than clockwise as I do here.


I think I'm going to set this aside for a day or two and work on front wheel #2, then come back and try this wheel one more time (yeah, maybe a waste of time if the rim is bad but I'm sure to learn something from it).

mrrabbit 

1. As it stands now, your tension looks to be in the ballpark...I wouldn't push it any further. Just finish truing...drive side when tensioned and with wheel dished determines non-drive final result.

2. Make sure when you stress relieve using the squeeze method - do so for two complete rotations each time - not one. Else you will be truing "ghosts". It take one rotation to "relieve" and one rotation to "settle" in order to determine the success of a truing/tensioning cycle is at in the "true" sense.

Did you pop a spoke out and test the thread+nipple limit? That's is what tells you how far a spoke can go before running out of threads.

Your numbers do hint at a rim with a seam that falls outside even "borderline" quality.

=8-)

neurocop

Well, the OP states he used 286 NDS and 290DS...could that be the problem? I recently built a wheel for which the on-line calculators gave the the correct lengths but attributed them to the wrong side of the rear wheel (I built it correctly using the shorter spokes on the DS. If this is the case, it would explain the screwy tension problem.

mrrabbit 

I think it was just a typo on his part...

However, the calculator calls for 284.50 - 285.00 after adjustments for the drive side - he went with 286.00 which is cutting it pretty close. One thing that happens when you run out of threads after a tension cycle where everything seems to be fine...

...is that after a stress relief cycle you find yourself truing the same spots all over again. (Similar behavior occurs in an over-tension condition...)

This is why I've suggested a thread and nipple test...

Not saying I'm right...just pointing out a possibility...there's some indications to support it.

=8-)

BikeWise1

I don't know if anyone has mentioned it, but if you can true a wheel with aluminum nips with a screwdriver, your spokes are too short. Nipple failure is far more likely when the spoke does not pass fully through the nipple.

mrrabbit 

So what did you do with Edco 10mm brass nipples in the early 90s? Throw them away?

=8-)

BikeWise1

Aluminum ≠ brass.

blaronn

Really?!? To me those tension numbers look slightly worse than the original tension numbers, albeit higher across the board. DS is still all over the place (76-148).


Yep, I've been using that approach since you mentioned it the first time. Thanks for the tip!


I just checked on a spare spoke. The threaded end goes ~2mm past the end of the nip. None on the wheel came anywhere close to that.


Oops. Typo on my part. It should've read 286 DS and 290 NDS.


DS spokes couldn't be turned with a screwdriver at the end. NDS spokes still came close to the end so I think I'm okay there, especially since they'll just have 50-70 kgf (assuming I can manage to clean things up a bit).

mrrabbit 

Yes...you're all over the board...but higher overall. Most if not all are at or above 100...quite a few in the 110-115 range...go ahead and count the 109 as one of 'em.

Dunno what to do about the one really high spoke and the one really low spoke - without the wheel being in my hands.

Wrap it up - i.e., no more tension cycles.

Wouldn't hurt to email Velocity your number chart and ask 'em if what you have is normal...get their opinion?

Who knows, maybe they won't like the results either?

=8-)

Tunnelrat81

It looks like you have a 'wave and rebound' effect near the seam. Is it possible to massage the high and low tensions near the seam between each other on the same side? This may be something you've tried, but most of the reading that I've done simply teaches the basic "loosen left, tighten right" with no mention of more dynamic ways of distributing the tension between adjacent, same side spokes. Rather than just working on the DS and it's opposing spoke, I've had success with same side adjustments that are able to bring the tension numbers closer without effecting the rim trueness.

An example being a spoke on the DS that's 20 kgf lower than I'd like, with the adjacent same side spokes being right where I want them. Despite the fact that I'd rather not mess with the "perfect" neighboring spokes, you can leverage them against the one spoke in the middle. You'll often get a tiny tension decrease in the two neighboring spokes, and a significant increase in the problem spoke between them. The rim stays right where it is, and the balance has improved greatly.

I agree that this might just be a bad rim, and would definitely contact Velocity with what you've found. But if it was me, I'd continue to eliminate all other possibilities before giving up on it. The struggle can sometimes blind you to things during the build, and once you eventually find them, this wheel might come together nearly as easily as the others. Good luck.

-Jeremy

blaronn

Yep, I'd agree. Tried massaging but no change.

I decided to give it one more try from scratch so I tore it all apart last night and remeasured the spokes to make sure I didn't have an odd sized one in there somewhere. Everything looked good.

I laced it back up and turned all nips so the threads just barely disappeared. No dishing or truing done yet. Dial gauge said there's 0.098" (2.49mm) lateral wobble at this point. Not that it'll necessarily tell much but here's a video of it --> https://youtu.be/9Mzy3o1iYf8.

I plan on tensioning/truing much slower this round to see whether I can conquer this beast. If not it's time to escalate this to the LBS wheelbuilder and/or Velocity.

thirdgenbird

subscribing.

i am about to embark on my first wheel build and my spoke choices looks to replicate yours. 28h, 2x, revolution with alloy nipple drive side, and competition with brass nipples drive side.

i hope you get this all sorted.

blaronn

By the way, I built up the 2nd A23 front wheel a couple days ago with no issues, so that's three good A23 rims for sure. Hopefully this rear wheel will work out too.

mrrabbit 

Extrusion-wise the rim seems fine...

However I think I saw what amounts to be a non-straight seam...can be sure because of the lack of light.

Hold a straight edge ruler against the sidewall of the seam on both sides - take well lit closeup pics...

Make sure to hit the "rose" or "flower" button or menu feature so your camera knows it's taking a closeup picture.

If a gap appears between the ruler and seam - that means bad seam.

=8-)

blaronn

I tried but couldn't get a good photo. There is a slight gap though. The seam is definitely imperfect but I think the question is how "bad" it has to be in order to be not acceptable (especially in Velocity's eyes).

I detensioned the wheel one more time and tried again but came up with the same results. Took it to the LBS (with even tension and 0.95mm lateral wobble) and a tech did a quick truing job on it to the point where he was satisfied . It now has about .029" (.74mm) lateral deflection at the seam. Vertical deflection at the seam is about the same. The rest of the rim (apart from the seam) is within .022" (.56mm) laterally.

Here is the current tension:
DS (kgf) NDS (kgf)
..109.......61 <-- 1st spokes clockwise of valve hole, looking at it from drive side
..131.......61
..128.......57
..120.......57
..116.......70
..115.......73
..150.......52 <-- 150 is adjacent to the seam
..130.......46 <-- 46 is adjacent to the seam
..115.......66
..118.......72
..128.......62
..143.......52
..112.......62
..134.......62

Note: All spokes listed going clockwise as viewed from DS.

Definitely better tension numbers than any of my attempts although I was always trying to get maximal trueness whereas he was shooting for "good enough" (which resulted in a compromise somewhere between ideal tension and ideal trueness).

It's pretty clear to me that this rim isn't at the level of the the other three A23 wheels I just built up, so my question to all you veteran wheelbuilders out there, is whether this trueness/tension is within your standards and whether you'd you call this an acceptable rim?

mrrabbit 

I'd say the drive side is now slightly overtensioned on average. But on the bright side, the NDS benefitted a little as a result.

How long will the drive-side holes last before cracks start to appear? Dunno...

Clearly, not the best of the A23s ended up in your wheel. Probably a wheel that can be ridden.

Here's what I would do though:

Ride the wheel. Over the next few months, keep an eye on the non-drive spokes noted "46" and "52". If any of those spokes keeps coming loose on you - requiring repeated re-trues - call Velocity and insist on a replacement. Use the record you've created here with your charts to make your case.

The problem with rims that have bad seams and bad extrusions is that they undermine the ability to build a stable and reliable rear asymmetrical wheel. The better the consistency and quality of the rim - the better the looser non-drive spokes hold up. Typically these imperfect rims do better in symmetrical setups...

=8-)

well biked

My opinion is that the DS spoke tensions are higher as a whole than I would call acceptable. This is just an opinion, others may chime in and say they've done the same thing and had no problems. But I have never tensioned spokes as high, overall, as you have on the DS rear. But then again, as mrrabbit points out, bringing the wheel up to such a high tension seems to have helped the balance of tension on the NDS.

I also think that since you've very meticulously built and rebuilt this wheel, and you've determined that the rim is clearly not as good as others of the same make and model that you've previously built with.......I think it would be fair to say you've determined that this is a defective rim. The bottom line is that you're clearly not completely satisfied with it or we would not still be talking about it, and it's not like you haven't tried, using sound techniques, to make it right. I think it would be fair to try and get it replaced as defective.

Or, as mrrabbit says, ride it awhile and watch it, and make a further determination later. I have a feeling that you like your wheels to be round, true, and require little or no maintenance, like most of us do, and that this wheel is going to be problematic if you do use it.

Good luck with it, whatever you decide-

cny-bikeman

You said earlier that you hoped you would learn something from this by continuing to work on the wheel. I really doubt you learned that much except that trying to correct a rim that on its face appears defective is futile. As I said in my first post, your initial tension results clearly pointed to a seam problem. You then built other wheels with almost identical specs and the same process without incident. I believe you did more than enough early on to show a problem. Getting something warranteed is the simplest when you have done the least to confound the situation.

If do you try to get it warranteed at this late date it is not appropriate or helpful for you to call the manufacturer. Even a retailer would not do so typically unless they were getting no satisfaction from their distributor, and that is unlikely.

Unless one is a professional wheel builder (who would also contact their distributor) the correct step is to contact the business from whom you purchased the rim. There is no reason to "insist" at this point. Show them your initial tension results and those after rebuild attempts and you should have no problem. The number of defect claims on any item is low, and it's much easier to warranty the item, especially one of relatively low cost, than to quibble.

The shop would typically exchange your rim for a new one, inform their distributor of a defective rim receive credit on their account. The distributor then does the same with the manufacturer. That way everyone in the chain knows of problems that may be systemic, the distributor and retailer only lose incremental costs, and nobody has to ship an individual rim directly to you.

I was a service manager for 12 years and owned a mobile repair and sales business for 10 years, and never had a problem with honoring of defect claims. I never had to call a manufacturer, except for bicycles. That included rims with exactly the problem you had, and in many cases during a time before our shop (or many at all) had tension guages.

SortaGrey

How common is it to build rims by design with over 110 kgf?

'25 Park' is one of my homespun reference pts... using 2.0's the Park deflection scale states 121 kgf. That is tight... saying the least. My first new rim build would not handle '25' DS and went "waves".. flipping to the side to 'semi pretzel'. Turned out a good learning experience with a nice finish at 19-20 NDS and 23-24 DS using the Park scale. I found/learned a relative tension limit of the box type rim of that weight/profile.

Which goes to my inquiry: these deep aero and new generation heavy duty rims.. what is too much tension? I read 150 in this thread example and have to think that's one lot of stress on the rim hole........ for the long term. [?].

eddy m

What you haven't posted is the direction and pattern of the deflections. If the wheel is over-tension it's possible to have a wave pattern of lateral errors. Maybe that exacerbates the error at the seam.
You also didn't indicate whether the large deflection at the seam is towards the drive side or the non-drive side.
That looks to me like the rim is bent a little at the seam away from the freewheel side. If that's the case, you might correct it by bending it a little, or by rebuilding it with the rim reversed so that it bends towards the freewheel. that would put the low tension spokes on the drive side, which won't hurt anything, and the high tension spoke on the non-drive side, which actually makes the wheel better.
You could also check the rim by laying it on a flat table, and measuring it for roundness before you build it.
Depending on where you bought the rim, the best solution at this point might be to get the dealer to replace it.

em

blaronn

DS (kgf) NDS (kgf) Deflection
..109.......61.....0.011"/0.28mm <-- 1st spokes clockwise of valve, looking at it from DS
..131.......61.....0.013"/0.33mm
..128.......57.....0.015"/0.38mm
..120.......57.....0.013"/0.33mm
..116.......70.....0.014"/0.36mm
..115.......73.....0.011"/0.28mm
..150.......52.....0.000"/0.00mm <-- 150 is adjacent to the seam
..130.......46.....0.022"/0.56mm <-- 46 is adjacent to the seam
..115.......66.....0.025"/0.64mm
..118.......72.....0.021"/0.53mm
..128.......62.....0.015"/0.38mm
..143.......52.....0.009"/0.23mm
..112.......62.....0.007"/0.18mm
..134.......62.....0.006"/0.15mm

Deflection = Distance from the point of the rim that is furthest toward the NDS side.
Note: All spokes listed going clockwise as viewed from DS.

Correct. The seam currently deflects toward the NDS side.

I'm not about to try bending the rim. If it's that bad I'll just get a replacement rather than risk damaging it further or voiding any warranty.

Bingo! That's where I'm headed at this point.

3alarmer 

Mr Bunny can tell you a lot more on this, because he's done a lot
more of them than I ever will. Briefly, the guys who make these have
somehow decided that high count spokage = bad (all that windage
and air resistance) and low count spokage = good (it's all about
aero, doncha know).

Since nothing in life is free, there is some fallout from this decision.
Fewer spokes mean the remaining ones need to pull higher tensions,
unless the rim is so beefy as to be unmanageable. These rims also
are often (not always, depending on material) considerably heavier
than a comparable older style rim, so a lot of your rotational mass
gets moved outboard.......also not ideal for a bicycle wheel.

You may already know all this. I cannot answer your actual question,
because it is my impression (I may have read it earlier on some
occasion in a thread here...possibly by Rabbit) that the manufacturers
are deliberately speccing too low a tension for a durable wheel in
order to limit their own liabilties (i.e. "How tight did you say you
made it ? Sorry, you voided the warranty.)

Thus the wheelbuilder's classic conundrum....how tight is tight
enough to make a durable wheel without voiding the rim warranty.

Personally, I think Velocity rims bite the big one, but nobody cares
what I think........probably just as well.

ultraman6970

Sincerely I wouldnt bother no more, u wont notice if the wheel is weird while riding anyways, and yes the wheel is rideable 100%

Happy u know how to lace wheels and truing too, you will save a lot of dough doing this stuff yourself