Wheel true/spoke tension conundrum
 

I've read some opinions that I shouldn't get too caught up with tension meters, but my husband's Mavic Open Pro rear wheel continuously falls out of true and I'm scratching my head as to why. It's a 32-hole 2X laced to Shimano Ultegra hub. My husband bought them already laced not too long ago, and estimates that it's got less than 500 miles on it (but we do live in California where the roads are in bad shape). I'm just assuming these are steel rounds, looks to be 2mm wide spokes but I'm using Park's spoke ruler, and not calipers.

Anyway, I've got this rear wheel as laterally and radially true as I can get it, plugged it away into Park Tool's wheel app and get these results, attached. This always happens where I get a few straggler spokes that are super out of whack, but I feel like if I go back to those areas, that the wheel will become untrue again. I already feel like the DS is at or beyond Mavic's max of 110kfg and the NDS is slightly lower as expected for a rear wheel, but I'm unsure if it's too low?
https://cimg8.ibsrv.net/gimg/bikefor...c224db59b9.png
Any expert insight from you wheel masters would be greatly appreciated. Trying to get better at understanding wheel truing, but mostly this is to silence the complaints from hubby over his finicky rear wheel ;-)

I can see I am going to have to play with some of that kit, it looks fascinating :)

Do you have to measure the tension at an exact distance from the rim or hub? I have always wondered, as I usually just tap the spokes about midway between where the spokes cross and the nipple.

Can I ask what you mean by 'falling out of true'? Do you mean you can see or feel that the wheel is out of true physically, or the test results?

I would imagine that 500 miles would be a good distance for things to settle in, it was when we would give a car its first service back when I was a mechanic in the 1970s. The other thing is, does your husband carry much extra weight?

From your tension graph it looks like you can probably even tension out more. It would be preferable to do this at less than final tension, but have you tried going through the wheel and evening the tension between paired spokes before recorrecting for true? Most of your outliers are clustered together, like the section 15,16,1 on the DS at tensions 106, 152, and 106. The high tension is between two low tensions. In general, each spoke, particularly on a conventional spoke count wheel, acts in a region overlapping with a few other spokes. Whenever there's a deviation from tolerance, it's best to adjust it with the spoke farthest away from the mean on its side within region of 4 or so spokes, even if it's not precisely the closest to the deviation. Spokes 8 on the NDS and 16 on the DS I would consider unacceptable for an undamaged rim. NDS tensions look pretty normal to me for a modern 11 speed road wheel.

Also, are you correcting for spoke twist, and are you correctly stress relieving and retruing as your final step? https://www.wheelfanatyk.com/blog/wh...ss-your-wheel/ is the best guide on stress relieving. Also, despite naysayers, there's no harm in some GENTLE thread lock on the nipples. It shouldn't be necessary in normal conditions, but if a spoke looses tension it can spin, which can happen in extreme, infrequently seen loads, and there's no harm in a tiny drop of DT Spoke Freeze or Loctite 222 dripped in at the spoke/nipple interface on top of lubricating oil. This should prevent loosening in extreme loads while allowing truing in the future.

I measured roughly in the same area of the spokes all the way around, probably midway between the nipple and the cross.

When I say 'falling out of true,' I mean I can visibly see it laterally out of true against the brake pads.

My husband is about 160 lbs.

As the gauge measures deflection from the spoke's long axis, which is inversely proportional to tension, it doesn't matter where on the spoke the reading is taken as long as there's no change in the diameter of the spoke at that location. You usually wind up being somewhere in the middle, though. The Park spoke tension app is quite fun to work with, though you can probably drive yourself a little crazy!

I'm not as experienced as most but you do need to go back and tighten up some of those outlier spokes. If all you do is tighten one outlier it will affect the true, but like cpach say you can then go back and adjust the spokes around it to even them out. I probably won't explain this well, but if you properly tension one spoke, you can then tighten the spokes near it on the other side to maintain true. Sometimes even loosening the adjacent spokes on the same side will allow you to tension the loose spoke.

Hard to explain but I have pretty good luck with it. Remember to do small changes. I use pieces of tape to mark spokes that are too tight or too loose. Sometimes you can see a pattern.

Would also like to add that the tension meter is an excellent tool, but for the final check I pluck the spokes and put each side to the same note. Much more repeatable than the meter.

I'll echo @cpach's advice, try to even out the adjacent spokes. For instance, on the drive side, tighten up #10 a quarter turn (or a half turn, if that doesn't balance it), and loosen #9 and #11 an eighth (quarter) turn.

When you stress relieve, do you hear spokes pinging? If so, they're probably wound up, and you need to do one more pass. It should be quick this time.

I'll admit to using some "thread locker" (linseed oil, in my case) on the non-drive side spokes. I'll usually put Phil's Tenacious oil on the drive side, to prevent both spoke wind-up and the nipple freezing to the spoke down the road.

I would lower the tension on the high ones to 110kG and use the NDS spokes to bring it to lateral true. If this doesn't work detension the wheel and start from scratch, first truing radially and as tension rises begin bringing the NDS over.

Looking at the NDS, spoke 8 is way low while the adjacent NDS spokes are somewhat high.
Back off the adjacent spokes some and tighten 8 to average things out.
Ditto to 6 & 12 to a lesser degree.
DS, 10 & 12.
Go slow.

Do you “feel” the wheel will become untrue, or does it?

If you can’t true it with fairly even tension, I would loosen up all the spokes and see if the rim is damaged/warped. If it isn’t, worst case is you re-tension it from scratch.

John

This is a 9/10/11-speed wheel, no? (Guessing from the big left-right tension differences. If so, lots of dish.) I have several thoughts.

First - using the same spokes left and right, while it can be and often is done, is far from ideal. If you replaced the left side spokes with either butted or 15 gauge, you task would be much easier and the final wheel better.

Second - back off the tension 2 or 3 full turns on every spoke and work on relative tensions and true before re-tensioning. Oil or grease the threads. Now true and even the tension. I find pinging the spokes and listening far faster than using the Park tool. I do the tensioning by pairs. Each pair being the spokes that cross. I even up each pair, then true by manipulating right and left pairs. As the true comes closer, this no longer works. At some point I have to make a decision between true and even tensions. When you like that true and tension, crank in one turn per spoke and repeat the pinging, tensions and true. And again until you are back up to full tension. (The last several times, do just a half a turn at a time and do your truing with just the left if possible. Moving the right and keeping the spoke untwisted is hard (and hard on the nipple flats).

And on the balance between true and even tensions - long lasting wheels have even tensions. Show wheels are true. Not all rim/spoke/hub combinations will allow you to do both. There are thousands of rims out there with slight irregularities at the junction. To pull that into true can take wildly different spoke tensions.

Edit: Yes, 76sSanO above has a good point - a warped rim cannot be trued with even tensions. In the old days (before higher strength aluminums) we used to slam warped rims back to straight, then do our re-true. (We'd tell the customer it took 2 hours so he would leave and come back and NOT see the slam!. Operation took less than 20 minutes beginning to end with our best mechanic. New rims we had doubts about were laid on the glass counter to check that they laid flat (or see just how much we had to deal with at the joint).