I'm working on building my second set of road bike wheels. Tonight I trued up the rear wheel (36-spoke cross-3 lacing) and got it stress-relieved and trued both radiallly and axially to within less than a half a millimeter, and dished to within about a half- millimeter.

In addition, the spoke tension (by sound) is remarkably consistent, with no spokes significantly tighter or loosed than the rest.

My concern is that I got it to this state relatively quickly, and the spoke tension might be a little low. The wheel is so darned true at this point that I'm afraid if I try to put some more tension on the spokes that I'll lose what I've gained.

The book I'm following (Professional Wheel Building by Roger Musson) and the wheel building class I took last year both were much more concerned about OVER tensioning spokes, so I'm not sure what I'm risking if the spoked are UNDER tensioned.

Depends on how loose they are and on your weight. As your wheel turns, the tension of the spokes near the contact patch is reduced. If those spokes are already low tension this might be enough to allow the nipples to turn and loosen them further. Gradually the wheel would then get progressively looser spokes and would come out of true since they're unlikely to all loosen by the same amount. In addition, spokes that are loose enough so they become essentially untensioned at the contact patch will tend to fatigue and eventually fail from the repeated cycle of tension changes as the wheel turns.

Why don't you just take the wheel to someone more experienced for an expert opinion? Livonia is not exactly in the sticks, so should not be much of a challenge to find someone. There appear to be two bike co-ops in Detroit.

If you tighten each spoke an equal amount it won't affect trueness.

No, but tightening the drive side and non-drive side the same amount will effect dish.

Hmmm. I'm not so sure. I've redished a lot of wheels by tightening one side 1/2 a turn or loosening the other 1/2 turn and not had to retrue the wheel afterward. I can't remember if I've ever added half a turn or a full turn of tension to every spoke and had to redish afterward.

Thanks, guys.

After I posted the question, I realized that I could just take the wheel to my LBS and have 'em put a tensionometer on it. If it is too loose, I'll put an additional turn on each spoke on the drive side, and maybe 3/4 turn on the non-drive side and see how it comes out.

My first set of wheels came out really good (according to the instructor) but these are coming out even better, and I hate to screw 'em up!!

Under-tensioned spokes will have more tension variation as the wheel rolls under load. Tension variation will result in metal fatigue, which is why under-tensioned spokes break more spokes than properly-tensioned wheels. IMO: the proper amount of tension is the maximum the rim will take without tacoing. (I think I stole that from Jobst Brandt.)

I've had several wheels last until the rims wore out with nothing more than an occasional touch-up truing. I've even reused the spokes used to build these wheels without incident.

On a rear wheel, the NDS spokes are at a greater angle than the DS spokes.
If you add a 1/2 turn(or whatever amount) to both sides, the rim moves toward the NDS.

That's different then intentionally changing the dish by tightening or loosening just one or both side.

The OP is talking about increasing tension without affecting dish. To do so, each side will be tightened a different amount.

Tighten just the drive side until you get the tension where you want it and keep the wheel radially true.
Then just adjust the dish and lateral by tweaking the NDS spokes.

Too much tension,cracks around the rim eyelets or spoke snaps in the middle if rim is bomb-proof....Not enough tension,spokes come loose if real loose or spokes snap at elbow if sorta loose.

Sweet spot somewhere in the middle...depending on who you ask.

1. Under-tensioned wheels can have problems staying true because the spokes loose enough tension passing the bottom of the wheel to allow the nipples to unscrew. This is especially a problem in dished rear wheels where geometry dictates a non-drive side tension that's a fraction of the drive-side. They may also have problems with breakage as the spokes flex back and forth then snap like paperclips.

2. Under-tensioned wheels can collapse on smaller bumps than wheels at proper tension. Once the rim deflects enough to completely slacken a spoke the rim becomes unsupported horizontally which allows it to move off center. Once the bump passes the rim springs back while still off center and tacos.

Both situations are exacerbated by thicker spokes since they stretch less at a given tension and loose more tension at a given rim deflection.

Getting to the round and true state quickly shouldn't be a concern, and is usually a sign that good quality components were used. The problem with low tension is that it leads to broken spokes, due to the repeated flexing at the spoke elbow. But the spokes have to be quite loose for this to happen. If you're still concerned, find a known, good wheel with similar design (spoke count, gauge, etc.) and give a few spokes some small adjustments with your spoke wrench. If the effort needed to turn the spokes is similar to the effort on the wheel you built, you should be ok.

In the old days, around the time Jobst was learning what he wrote in his book, what we did was to keep increasing tension until the wheel started to taco. Then back off slightly so it was straight. This gave the "strongest" wheel with most durability and resistance to going out of true. And longest spoke longevity as well. Of course this was back in the days of eyelet rims that were bomb-proof. Heck, I still have a set of Dura-ace wheels with Mavic MA-40 rims. Over 65,000 miles on them including two cross-country trips.

My $0.02 is that if you got the wheel in true to good tolerances once, it will be easy to do it again after you adjust tension equally. If tension is low, bump everything by the same amount, then check true and dish again. My bet is that they'll be fine. In any event, if you've tweaked things off a bit, it will be easy to tweak it back. Wheels just don't go from true to way out when you add a little tension.

I REALLY like my tensionmeter and wouldn't want to build a wheel without it.

- Mark

Interesting read here... low spoke tension.
Nobody has mentioned what the low spoke tension actually is in 15 posts.
How about measuring it?

This issue is exactly why I decided to pop for a tensiometer. Some of my early wheels were very true and spoke tension felt consistent. But some started to unscrew the nips and go all soft. Since using a tensiometer I've had no problems with wheels.

OK. But I am asking you, what do you consider as "low spoke tension?"

I'm the last person who should be answering this, but I was curious and found one reference (amazingly, not on Mavic's site) that the recommended spoke tension range for Mavic rims (I'm lacing up A119's) is 70-90kgf.

I did take the wheel that prompted me to start this thread to the LBS. The mechanic I talked to said that he doesn't use a tensiometer, but can now pretty much go by feel which isn't surprising as even I can feel the difference between the tighter and looser spokes (and they're all pretty close to the same, but could be improved), and his judgement was that they might be a little on the loose side, but that if it were his he'd go ahead and take it for a couple of rides then re-check the trueness.

Something that I ran across that in the 5 minutes I played with it seems to work pretty well. If you have an iOS device, this app accepts the spoke length (nipple to cross) and diameter, and uses the tone of the plucked spoke to estimate the tension. If you do this in a quiet room and follow the instructions to dampen the crossing spoke when plucking the spoke to be examined, it shows a tension reading that is certainly reasonable. It was showing drive-side readings of between 70 and 80 kgf, and non-drive-side tensions around 60kgf, which is consistent with the mechanics' judgement of the tension being on the low side.

I'm going to play with it some more and might post a review somewhere around here. I figured it was worth the risk of a sawbuck...

https://itunes.apple.com/us/app/spok...518870820?mt=8

I do use that app for my iphone.
Also seen other posts....Mavic saying max tension about 110kgf
At some point I need to put the tensioner away and just true the frickin' wheel!

It surprised me that I had so much trouble finding a chart showing recommended tension ranges for anything, let alone a specific brand. You'd think this would be readily available.

I'm only working on my second wheel build, but from my very limited experience and the study I've done it seems that unless you're trying to get the spoke tension up close to the maximum specified for each rim, the value of a tensiometer is primarily as a learning tool. It's going to help me to get my ears and fingers attuned to how big a tension difference (as determined by sound or by feel) between spokes is sufficient to require adjustment, and when the spoke tension is within an acceptable range.

One reason that it's hard to get authoritive data on ideal tension is that there's no single answer. Correct tension depends on the rim's strength and rigidity, and the spoke count and gauge. As John T mentioned the real issue is rim deflection and spoke elongation. So all the tools in the world can't replace judgement and experience. Measuring is helpful, but you have to know what you're measuring for.

BTW- with 32 spoke wheels there's generally a decent amount of latitude in "ideal" tension. As long as you're in the band between too tight and too loose you're OK.

If you plan to build wheels, why not have the correct tools? It's a one time purchase: Park-Tool-Spoke-Tension-Meter

I don't remember it being that expensive. Did it go way up in the last 5 years? Love mine.

Everything went way up in the last 5 years. I suspect that Park might have kept the initial price low because there were Wheelsmith ones out there, and now feels that with less competition, the market will bear the higher price.