Wonky Wheel Building

[John Rinker]

Good afternoon,

I'm working with a rear wheel I built in 2019. M15 hub, 2.0/1.8 steel, round spokes, 9-speed cassette, and a 700c Dyad rim. After a little too much fun in the Arizona desert, the wheel was in need of a little truing. In the process, some of the drive-side (right) spokes were too tight. Velocity recommends 110-130Kgf for their rims and I was well above (131-168Kgf or 23-25 on my Park TM-1). I backed off 2 turns on all spokes and began truing from there.

The wheel is now laterally and radially true, and the dish is spot on. But the spoke tensions are all over the place. Below are Park Tension App values: with a variance of 20%.

When I built this wheel I worked with a variance of 15% and it came out beautifully. Here are those values from 2023:

I'm looking for advice on how I might proceed. Should I de-tension the wheel completely and start from scratch? Might there be an issue with the rim? 

I'll certainly allow for my intermediate (at best) wheel-building skills and I know I have much to learn, but I've built a fair number of wheels and most are still riding true.

Anyway, thanks for reading and any thoughts you might have.

Cheers, John

[Michael Connors]

The drive side looks ok. You could probably loosen the high one 1/4 turn.  The low tension spokes on the left are next to high tension spokes so try loosening spokes above 14 by 1/2 turn and then tightening the single digit ones to even things out. 

[Garth]

John, Seeing the values have changed so drastically I would be inclined to look at the rim itself also. 

Let's day, if you built an assumably perfectly manufactured rim with that variety of tension it wouldn't be straight laterally or radially. That it is now straight with that wildly varying tension, points to the rim. 

[John Rinker]

Thank you Michael and Garth.

Michael, I have followed your suggestions and the tension values on the wheel look much better (I'd prefer a little higher tension on the non-drive side- say, the upper 60s) but at least there's consistency. The problem now is that the wheel is no longer true. I'm going to play with this a bit more today.

New values with 15% variance:

Garth,  The rim was new in 2019 and has seen a lot of rough miles. This is, however, the first time I've had to play with it (re-true) since building it then. Seems a short life for such a rim if, in fact, the rim is the issue.

The following was taken from Aljaz Trenta's 'Spoke Calc' website: 

Advice: would you sacrifice an even spoke tension for a perfectly true wheel? In my opinion that is not a compromise to be taken. If not pleased with the wheel trueness, I would rather advise a client to dump the rim and replace it with a new one.

Thank you both for weighing in. I'll update you on my progress. 

Cheers, John

[Bill Lindsay]

I take it as a fundamental principle, without proof or derivation, that a perfectly straight rim can be held perfectly straight with even spoke tension.  The corollary to that is that a warped rim will absolutely require uneven spoke tension to hold it straight.  That's the way the world works, in my view.  

So, if you build a brand new wheel with a very good rim, you can likely end up with very even spoke tension.  If you take that wheel to the Arizona dessert and have a little too much fun and knock it way out of true, it very likely will require uneven spoke tension to hold it straight again.  If it's straight and the tightest spokes aren't much too tight, then you're done.  Ride it.  Nothing is likely to blow up on you.  Keep a spoke wrench in your seat bag and continue to have a little too much fun.  Someday you'll buy a new rim and build a new wheel.  That's it!

Bill Lindsay

El Cerrito, CA

[John Rinker]

Thanks Bill. Well said! I'm headed to my shop now to see what compromises I'll have to make with the wheel, but 'having a little too much fun' ain't one of them!

Cheers, John

[John Rinker]

An update from the 'Live and Learn' files... 

After spending some time this morning playing with the wheel, I finally got it to an acceptable place. True within 0.5mm and a spoke-tension balance I could live with. Here are the latest values within 20% variance:

With a spring in my step and a whistle on my lips, I removed the wheel from the truing stand only to discover (Garth: Winner, winner, chicken dinner!) that the rim was indeed at fault. A long, hairline crack in the sidewall! Ha!

Well, at least I got a lot of practice in and feel like a slightly more competent wheel builder as a result. And, I'm glad to be part of a universe that has a sense of humor!

Cheers, John

[Garth]

Ohhhhhh ...... that's a bummer John !  I'm not sure where the line is drawn between spirited riding and rim cracking as far as warranty goes but Velocity has always been stellar in replacing cracked rims for people. I mean, rims bending from "reasonable" spirited riding is one thing but cracking doesn't usually happen suddenly. The cracking could have already started before the ride, unnoticed,  and not until you rode harder was enough to effect the of alignment. Considering Velocity's history of cracked rims from many a different forum discussions, I bet they'll replace it without fuss.

[John Rinker]

Wow, that's great news Garth! I'll submit a warranty claim and see what they come back with. 

Please stop by for a ride and your chicken dinner next time you are in the Slocan Valley in British Columbia.

Cheers, John