Spoke tensioning
 

I have a question about ideal spoke tensioning.

I recently rebuilt my Wabi Cycles front wheel at a local volunteer shop. It's a 32H wheel with 14/15 double butted stainless spokes and a 100mm low flange hub. The mechanic said that the true of the wheel was more important than the tension reading, and he suggested that I get the wheel in true with the individual spoke tensions between 15 and 20 (using a Park Tool Tensiometer). I got the spokes all somewhere between 16 and 18 with the wheel as true as I could reasonably get it.

Later, I compared the spoke tension of the rebuilt front wheel to my rear wheel by squeezing them. It seems as if my rear wheel is noticeably tighter, but I would have to use a tensiometer to be sure. Using Park Tool's conversion table it looks like the tension in the front wheel spokes is something between 70 and 90 kgf for my 1.8mm spokes. How does this sound? Could my rear wheel be too tight?

Which side of rear wheel did you measure?
Tire mounted with air pressure or not?

Why not get some tensiometer readings on the rear wheel as well, on both sides?

Why not get some tensiometer readings on the rear wheel as well, on both sides?

It's a fixed gear rear wheel with a flip flip hub so it should be symmetric. I did measure the tension with an inflated tire on the wheel. Does this effect the tension?

Will do, as soon as I have access to the tensiometer.

An inflated tire can drop the tension as much as 20% in my experimentation.

I usually aim for ft spoke tension somewhat between the two sides of a typical rear wheel (that has rather off set flange to center of axle ends due to the many cogs on one side. A flip flop will have much less offset and thus less tension difference).

I will take some issue with the mechanic who placed trueness over tension. Both are nice to have proper but I would place a higher value of evenness of tension then absolute trueness. A consistently tensioned wheel will tend to be more stable and reliable over the miles then one that initially looks straighter but has some spokes fatiguing faster then others. Andy

Agree.

Question1:
In my experience, some wheels (rims) get "too untrue" when spoke tension is withing 1% of each other. In those cases, In those cases, I aim for spoke tension to be within +-7 % (even 10% on some rims that aren't in "nice condition") of a certain medium value - in order to get the wheel straight, without (what I think would be) too much difference in tension. I think of it as a compromise: even spoke tension makes a wheel last longer, but trueness (with at least decent amount of tension) makes it ride nicer.

Do you think that's a good policy, or should I aim for tension eveness, even if a rim is more noticeably out of true?


Question 2:
Could it be that what I said above, the OP's mechanic was also saying, only more awkward with words?
I've seen good mechanics who don't explain stuff all too well - combine that with an average novice (no offence meant to anyone) - you get all sorts of "but the mechanic said..." that you would never think a mechanic with a grain of experience would say.
Hell - I've heard people draw wrong conclusions from Sheldon Brown's and my website - then having asked them: "show me/tell me where that's said, it should be corrected ASAP" - they realize it's just bad reading/understanding on their part.

The numbers on your tensiometer are just numbers. They really don't mean anything other than 18 is higher, thus tighter, than 16. If your goal is 110 kgf, here's how to be sure:
1. The hard part is finding a standard. You need to find a spoke the same diameter and metallurgy as the ones that you are working with that is also known to have exactly 110 kgf of tension.
2. Measure that spoke with your tensiometer. Notice what the reading is. Match that reading as you are tensioning your wheel and you'll achieve your target tension.

So now you've got your wheel as true as you think reasonable with tension readings as close as you can achieve but the overall wheel tension is less than your proven reliable rear wheel. That's the balance between tension and trueness that you are looking for, but you're still not up to full tension yet.
If it was my wheel I'd tighten every spoke 1/2 turn and compare my spoke tensions with my rear wheel again. If they still seemed loose, I'd tighten every spoke another 1/2 turn until they feel about the same. It doesn't really matter if you compare your wheel with your known reliable wheel by feeling the tension with your fingers, plucking the spokes for tone, or using your tensiometer.

Tension meters like the Park has an app which allows you to translate the gauges tension numbers into actual spoke tension values in kgf. Targeting 110 for DS rear is about right. For the front you generally don't need to go quite that high.

The table itself isn't exactly hard to find, either. ;)

https://www.parktool.com/assets/doc/...conv-table.pdf

I like to use strips of painter's tape to cover up the neighboring spoke gauges of the wheel I'm working on. That helps avoid mistakes when going back and forth between the wheel and the chart.

I took my old rear wheel back to the shop and checked the spoke tension with the TM-1. All the spokes read something around 25. This wheel is 5-6 years old and I've never lost a spoke on it despite me riding it basically everyday, so I assume it's tension serves as a pretty good ideal tension (at least for durabilities sake).

As mentioned by a few people here, the mechanic at the shop (a different mechanic because its a volunteer shop) suggested that I tension the front wheel to be less than the rear, but close to being the same. He also agreed with the previous mechanic that having all the spoke tensions within 2-3 on the TM-1 scale was perfectly fine provided the wheel was in true. Perhaps if one had a truly accurate tensiometer and was skilled at getting accurate tension readings it would be worth getting the tensions of the spokes all very similar. However, given the roughness of the tool being used and my novice ability to use it, I reckon I'm can't get a very accurate spoke tension reading anyway.

Given this, I took the front wheel's tension up to 20-22 while maintaining good true.

Another digital vs. analogue discussion. The wisdom comes in understanding when it's better to use which.

No such thing -- the universe doesn't allow it so you'll somehow have to cope, sorry. Alternatively, you can contemplate how many angels can dance on the head of a pin (or just ride more). Good luck.