Wheel truing gone wrong
 

Per my other thread, I got a older bike and the rear wheel was very wobbly. I decided to try to true the wheel and it's gone very wrong. I have a stand and a Park meter (which I'm learning to use). I thought I could bring the tension down on all the spokes and then bring them back up to an even tension using the meter as a guide. I don't know what the proper tension should be and not sure how to find that info. But checking where it was it seemed like drive side were mostly 20 (on the meter) and non drive were 15. So I took everything down and brought the back to even 20/15 and my wheel looks like it's tacoed now. Then I tried to do both sides evenly and it still looks completely tacoed. One thing I noticed is that when I go through and adjust the tension that spokes I had previously brought to 15 are now close to 0 without me having loosened them.

Am I doing something wrong? I figured I could just try to get even tension and that would be a good starting point.

This "even tension" nonsense is what got you into trouble.

Even tension is desirable, but is not the key objective. The goal is and has always been a true wheel, properly dished. That's the ONLY real objective, and while doing so with tension as close to even as possible is nice, true trumps even tension.

If the wheel isn't too far gone, put away the tension meter, and go back and true the wheel. But try to do so with smaller adjustments spread among many spokes rather than larger adjustments of fewer spokes which leads to uneven tension.

Agreed. Wheel truing is the most satisfying job there is in bicycle mechanics. You may find it's better to completely de-tension and start over. One day you'll get a chance to lace a new rim and you'll see just how pleasant a job it can be.

Thanks FB; you just talked me out of buying a tension meter. I've been building without one, but was somehow convinced I need one.

Thanks guys. I plan on keeping this wheel as a spare so if things don't come back I'll live. I think I will have to de-tension and bring it back up

I'm old school too. No tension meter or torque wrench. Haven't needed them for any of my bikes.

The thing many novices don't realize is that spokes primarily hold the rim in place in relation to the hub. They don't have the capability to change the rim itself. If the rim is physically bent no amount of "truing" will fix that problem. If you "true" by tensioning the spokes evenly the bend will remain exactly the same. If instead you try to make the rim run straight regardless of tension you will end up with very uneven spoke tension and an out of round wheel (because the spokes pull in more than they pull to the side).

Nothing wrong with using a tension meter, but it's a final step, not a wheel building tool, and in my opinion it detracts from one's ability to observe and think about the dynamics of a wheel. It's somewhat analogous to what happens when people slavishly follow their GPS off a pier or into a brick wall (yes, both have happened).

cny-bikeman, I conveyed essentially the same thing to an elderly friend who lent his mountain bike to a portly grandson who slammed into a 1 foot high curb and tacoed the rear wheel (the grandson pulled the front wheel up to avoid the curb, but his full body weight was on the rear wheel when it slammed the high curb and he was subsequently tossed off the bike). It wasn’t possible to ride the bike home and the rear of the bike had to be carried as it wouldn’t roll.

I told the elderly friend that I’d be glad to dismantle the wheel so I could straighten the rim, and then I’d true it to virtual perfection. He responded with, “It doesn’t need to be taken apart, just trued up again.” I replied, “those spokes didn’t suddenly loosen, and yet, the rim is wildly out of alignment therefore, the rim is most definitely bent and until you straighten the rim, you’re never going to regain the greater majority of wheel integrity that it once had and it’s going to need that integrity if your portly grandson is going to be riding it again. He knew I was correct, so he said, “You’re sure you can reassemble it and true it afterward?” I replied, “Look at that wheel; how could anyone not be able to do better than that?” We both chuckled. Then I said, “It’ll be a piece of cake for me, as I’ve done this many times and it’s something I enjoy doing. Wait until you see how bent the rim is once all the spokes have been removed and wait until you see how straight I make the rim prior to reassembly.”

When he saw how bent the rim was and that the rim wasn’t some flimsy component of the wheel (hence, not readily bent back into shape by hand), that’s when he realized how important it was that the rim be straightened. He was equally impressed by how well I had straightened the rim prior to re-lacing it to the hub. Just 30 minutes into tightening the spokes, the wheel was already near perfect true and only required a bit of tweaking to look brand new. It’s been working fine for the last 2 years now (and his portly grandson hasn’t gotten any lighter).

This ^. I'll add that it sounds like the rim is bent. I love the use of the word nonsense in that context.

IMO, the rim probably isn't bent, though it might be warped.

The distinction is the sharpness or whether the deflection is confined to a small area (bent) or spread out over large sections of the rim (warped).

Bent rims are difficult to correct, especially with modern, stiff rims, but warpage corrects relatively easily and will not need large tension imbalance to do so.

If the rim was relatively OK before the OP warped it, odds are it's still OK.

Thanks guys. I completely detensioned all the spokes and brought them back up using truing stand and my eyeballs. Currently it is rideable and I'll spend a little time today trying to get it better. Chalk it up to another good learning experience. I will probably get some new wheels at some point but I think I should be able to ride these for a while. These wheels are about 30 years old and probably should be updated

OK,

NOW, you're ready to consider tension. Spin the wheel and run your thumb nail or a pencil against the spokes listening to the pitch. Don't worry about having them all match, just listen for ones far from the rest, wither high, or more commonly clunkers. Adjust these closer to average compensating with their crossed pairs, and keeping the wheel aligned. Do this in small repetitive sequences feeling and listening for even tension, but always keep the wheel true. (don't forget about dish as you do this)

When you've finished and are pretty happy, it FINALLY time for the tension meter. Measure 2 or 3 spokes on both sides and use the conversion chart to check that the wheel is within the tension target. If you need to add tension overall, always add to the right side first, and expect that the right will need more turns than the left, so use the right to reach 90-95% of your tension goal, then use the left spokes to move the rim back to correct dish as you add the last bit of tension.

Lastly, DO NOT OVERWORK THE WHEEL. Get it good and within acceptable limits and quit when you find yourself tweaking but not seeing improvement.

I have the greatest respect for both your knowledge about bicycles and also the orderly and understandable way that you impart it to novices. Time and again I am amazed that something I thought was obvious and absolutely correct is debunked by your deeper knowledge set. Nevertheless I am shocked at the advice you provided above. Wheel true may be the number one characteristic in importance, but you cannot reasonably call a wheel well built with widely divergent spoke tensions. True only relates to how well the wheel rides, while evenness of tension relates to the equally important characteristic of both short and long term durability, i.e. short term maintenance of true and long term spoke life, respectively.

I understand advising a novice that a tension meter isn't required to get even spoke tensions. Some people, but not all, can accomplish this by an alternate method. I for one can't do it to my own personal standards without the meter. But putting that aside, I simply cannot understand telling someone that even tension is nice, but not necessary. Of course the wheel has to be true in the short run to be rideable, but it also has to be evenly tensioned for the true to last more than a ride or two and for the wheel to last for the long haul. You cannot focus on just one and not the other. If you cock up a wheel on a ride and just need to get back home, sure true is all you have to worry about while wrenching it on the road. But that doesn't mean that wheel is fixed for continued use. Even tension is required for that to be the case.

Maybe why FB told me now I'm at the point to consider tension. He's not telling me to ignore it totally just not get caught up in it until I have a fairly true wheel (at least that's what I'm getting)

I also have the utmost respect for FB. It's rare in life and especially on the forums for someone with so much experience to also have so much patience with the newbs like me.

every single spoke does not need to be exactly 100kg. a range is fine within reason. if you learn to build with lightweight rims the tension will be even when you are done anyways. use proper technique and the end result is the same.

Sorry to shock you, but I stand by what I said. The objective is a true wheel. Even tension is a secondary objective to that, and IMO a distant 2nd. You do not use a tension meter to build wheels, and should not need one to get even tension. A tension meter is used to confirm that average tension is within target range. It's a QC tool, not a building too.

Even tension is a matter of good basic technique, and with that you don't introduce uneven tension in the first place, except maybe near the joint or other anomaly in the rim, and tension meter or no, it wil require uneven tension to compensate for where the rim wants to be.

At max tension, spokes are elongated only a bit over 1mm, so what positions the rim is even spoke length which is key to the process. What so many people fail to mention is that the spokes work as a system, so in the early stages of tensioning and truing it's important to keep all the lengths close, and correct any rim misalignment (radial or wobble) with small adjustments over a number of spokes rather than a large adjustment of one or two which is how you introduce uneven tension.

When a skilled builder builds a wheel, he's turn out a tight, true, evenly tensioned wheel without at any time checking the relative tension of any spokes, except maybe catching a clunker by eye here or there.

Even tension is the norm when building a wheel, uneven tension doesn't happen until/unless the builder produces it.


BTW- I might point out that after repeatedly building a potato chip, the OP followed my advice and ended up with a wheel. Now he has something close enough to refine into a better wheel.

My experience is different. Time and again I have found that spoke lengths and rim spoke seats were variable enough that good technique alone did not produce even tensions. I have had to make in-process tension adjustments with the meter to get back to a desired "starting" point. C'est la vie.

Yes, rims aren't exactly perfect, but they're damm close. Closer than the starting point of attaching the nipples to a set depth, either by thumbnail on 1st thread, by ejector pin on screwdriver, or by eye to bottom of the slot, which will have an error of ± 1/2 turn or so. So along the line, there'll be some need to correct this. But if you keep in mind that you're starting out within a 1/2 turn of matched lengths and do not work individual spokes more than that (except for the rare outlier) you'll come to a true, even tensioned wheel pretty quickly.

Train yourself to think length, not tension and you'll build better faster.

On the rear the tension meter is used on the drive side. The NDS spokes are used to laterally true the wheel and center it between the hub nuts. I have rarely used the tension meter on the non-drive side.

OP, if a rim is not perfectly true unlaced, it cannot, IME, show even tension (front wheel only) when laced. in addition, AFAIK, tightening a (one) spoke on a fully laced wheel, will influence the tension on all others.

FB did say that "Even tension is desirable, but is not the key objective. The goal is and has always been a true wheel, properly dished. That's the ONLY real objective, and while doing so with tension as close to even as possible is nice, true trumps even tension."

I'm not an expert wheelbuilder but it seems obvious to me that if the spokes are evenly tensioned but the wheel isn't true, the end result is no good. If the wheel is true and the tension is as close to even as possible, you've got a good wheel. I read FB's post as saying that you want tension to be as close to even as possible, while stressing that a true wheel with slightly uneven tensions beats an out of true wheel with even tensions.

If the only way to get the wheel true is for the spoke tensions to be wildly away from anything resembling even, my first thought would be that there's something badly wrong with the rim. The first (and so far only) time I ever built a wheel for actual use (I practised on a few trashed wheels to get the hang of lacing and truing first), trueness and roughly even tension pretty much came together as I tightened the nipples. My wife is a musician and she couldn't tell the difference in pitch between most of the spokes on any given side, and the lateral and radial runouts were both within about 0.5mm

ETA: The wheel I built has carried my fat ass (240lb plus the weight of the bike) for north of 3000 miles so far and hasn't caused me any issues.

Suppose the wheel is true, all spokes have tension above some minimum, but some spokes have higher tension than others.

Why is the uneven tension bad? Other than offending our OCD perhaps.

Spokes work as a system, is essence a team. Imagine trying to build a football team with a line having a couple of good players, and some not pulling their weight.

Also, modern rear wheels have quite a bit of dish, so half the spokes are near the maximum acceptable tension, and the other half near the minimum allowable. So the working band of tension is fairly narrow, yet uneven tension means that the band will be wider, meaning some spokes will not be within an acceptable tension range.

So IMO, it's not about even tension per se, but the benefits of even tension, and the drawbacks of uneven tension.

i suppose, theoretically at least, it would be possible to lace a wheel with a single strong 14ga metal cable (i claim no precedence here) and a one turnbuckle. it may even work on a really true rim on the front wheel. but it would be hell trying the dish the rear!

For the record I've got the wheel as true as I think I can get it. I measured tension and on the meter one side almost every spoke was around 25 and on the other almost every was around 20. 1 or 2 that were 15. So without using the the tension meter as I guide I was able to get pretty even tension and a pretty true wheel. This is a 30 year old 36h wheel. I have no idea what the history of this wheel is.

That's not the way I read his remarks. I read that tension is distant second in importance i.e. don't worry about it. I just don't build wheels that way. They are always true and I work them very hard to get the spokes as close in tension as possible. Different strokes for different folks, BUT I sure would be pissed if I bought a wheel and it wasn't as good as what I build. To me tension and true are neck and neck in importance. And why not? It is easy to get the wheel true and the tension nearly perfectly even. When I can't, I return the rim for a replacement. And BTW, by using the tension meter, I hit the desired tension right on the button. No by guess, by golly. That's my story, and I am sticking to it.