BG2 With out a picture, guessing here, when you say rim gone, this is just a wobble, not actually pushed through? is the wobble at the rim joint? can you not re-true to remove the wobble?

I understand your answer and the difficulty about the wobble, but my that's something for later as far as i'm concerned.

What bugs me the most is what the reason is and why it happened.

What i noticed after things happened was that some spokes where more tight and others where much more loose.

Is it possible to give me an answer on that one.

Using a VAR dishing tool I've had since the 70's, I look for wiggle at the ends or daylight at the center. +/- .025"? I don't think that tolerance is relevant

"No way did i use to much pressure as i'm light build, but where the spokes not tight enough (i used 120/130 kg on the rear)." you wrote.

From my albeit limited experience.. your tension exceeded the limit of the rim. 130 kg is 286 lbs of force.. and this well over the specs of many alloy rims. Your rim sounds like it's loosing it's shape reacting to the high tension it's under... then applying the stress of testing shows that.. with the shape being compromised.

We hear and read of all this high tension in spokes.. but very seldom is specific data given. I haven't seen tension specs listed on rim maker's site to date... either. Likely a anti-lawyer measure.. can't blame them. So the newcomer to wheel building does same... learns by experience.

Seems to me hub flange width.. the wheel's lateral stability factors in with a rim's tension limit. For that matter I guess lacing to some extent too.

What I'd suggest a useful discussion.. input... would be how much NDS tension is needed to prevent elbow breaking.. given of course good lacing & attention to detail. I well know the refrain for butted spokes.. but I'm thinking of a straight gauge build. I've tried to put together some data per rim deflection & elongation of spokes under tension.. vs the load carried. I'm not seeing their worth under heavy loads and wide dished wheels..... ie butted spokes. I'm sure this will bring a chorus of 'worked for me'... but a few samples isn't always so reliable.

Some comments:

1. Wasn't aware that someone "owned" the outside pulling spoke method by "name". It's simply "outside pulling" or "inside pulling". No one owns it, nor does anyone have a patent on it as far as I know.

2. ALL spokes will fatigue if left in an under-tensioned state. Cheap, standard or entry-level spokes will snap at the heads sooner. Quality spokes such as DT, Wheelsmith and Sapim will take a while longer. But eventually it'll happen.

3. Most machine-built wheels can be turned into decent wheels - most shops just don't care to bother anymore. Buyer beware...

=8-)

+1

The results as you describe them are about what you'd
expect from failure due to over tensioning.

It is often correctable by running around the whole wheel
again and backing everything off by half a turn, then
truing up again being careful not to reach the same
tensions that caused the failure.

Respectfully yours,
Mike Larmer

p.s. The tensions you describe are not unreasonable and very
similar to what I usually try for in my own wheels, so I
understand your frustration in this case. Just one other
time when the magic didn't work, I guess.

I had spoken to very well known wheelbuilder who writes commercially on this subject and after explaining my situation he gave me a advice on the 120kg (= 22 nm). However i'll have another go an go lower to around 100 kg (19/21nm) and see if that helps.

I also checked with similar wheels with the same rim and # of spokes and it also came around the 120 kg or between 20 to 23 nm.

I have however a 1.8 mm radial wobble wich in my eyes is too much so i have another go tomorrow and see what happens.

It's a difficult situation realizing theres no specs from the makers on this subject for all good reasons as explained.

Nevertheless i appreciate everybody's contribution on this subject.

In my case.. going to those tension level's with a BMX hub of more narrow flange width added to my problems. 23-24 'Park' on the DS.. 19-20 NDS worked.. 24-25 DS and I was surfing those waves.. :). I believe that rim could have been taken higher with a wider flange. Yet that Champion rim wasn't as thick in the base section as the few I've done since. Dimension variables definitely affect tension limits and outcome.

25 'Park' is 121 KgF...for a 14 gauge spoke.

I'll check to the experienced who can build wheels sans a tension meter.... I believe I could now too given the experience of half a dozen wheels or so. Yet the Park meter has been a great learning tool... and I wouldn't be without it now.

I built a wider dished wheel for a winter rider... just adding more spacer on the DS. It's rare for me to break a spoke after riding on my LBS made wheel. Want to see the effects of this tension ratio first hand.. and how to tweek it... staying at the wide dish. Albeit this is my backup wheel... I'll get it on soon and rattle across all these spring roads.. such as they are.

Hardly. A brand new Spin Doctor or Minoura truing stand can be had for $70-$80. For traditional wheels the Jobst Brandt tensioning method achieves the same uniform high tension as a tension meter (I checked the last rear wheel I built and found 110kgf and better than +/- 5% on the drive side). You can just flip the wheel to check centering. I'm a tool geek and never bothered to buy a nipple driver since a screw driver with a piece of tape to count rotations works great. That's about $70-$80 in tools.

Where a shop won't re-use spokes because you might blame them for failures due to spokes fatigued from a bad previous build, you can which saves $24.

So you save $74 in parts and labor for the first rim replacement, which is the same you spent on tools.

My time is a worth a lot more than a bike shop would charge me, but it's enjoyable, guarantees my wheels will be built correctly, and if I really needed a wheel replaced by tomorrow I could.

There is no more dished, less dished, wider dished, narrower dished, etc...

Either the wheel is dished (rim centered between the ends of the lock nuts) or it is not. Of course - many folks casually will throw in the word "dished" in place of describing offsets when chatting - but if you are going to be a wheelbuilder - try not to do that.


=8-)

OK. So.. one is just MORE dished. Which.. is what I meant. :thumb: Now I know.

Being a 'spoke threader' apprentice (just past newbie stage).. I assume all of them run in the center. The more spacer one puts on the left the less the dish angle is... that is the nature of my 'speriments. Got a hair of an idea-er how to keep the heads from rattling when loose....... :crash:

Oh... 50 here today.. what a NICE ride. I mean VERY enjoyable.

Mr. Bunny:
What happened to Vietnamese New Year?
Is it over now?:D

Regards,
Mike Larmer

I dunno! I'll have to ask the wife...however it seems odd that she's being awfully nice to the cat considering she's not a cat person.

Should I be concerned?

=8-)

Cats.... grrrrrrrrrr. Used to have TWO here.. one went out via old age. The other one just "disappeared"....

HER family hinted at my connection to that event for yrs... I never.. I mean I never.........

:rolleyes:

If you were stress relieving there is a better way to do it. Grab parallel spokes on either side of the wheel and squeeze them as hard as you can. This temporarily over loads the spokes to their yield and removes the built up stresses.