funz

Hello,

I messed around with my spokes on a new bike/wheel because i was thinking it was not true enough (i was new to bikes and i was wrong, it was just a bit off true).

I did this without tension meter, I would true my rim but after ~200km of rides spoke started to unscrew themselves.
I would tighten them up and true the wheel but i kept doing this without tension meter.

I purchased a tension meter yesterday and i wanted to put it to use.

What i noticed:

- If i just true the rim tension is all over the place
- If i get pretty constant tension on both sides (did 70kgf NDS and 120kgf DS) rim is WAY off true, basically you could not even drive it.

Another thing i noticed, NDS is steel (reacts to magnet), DS does not seem to be steel, doesnt react to magnet AT ALL.
Is this normal? To have different material spokes on a rim?

29 wheel with 32 spokes (2mm round). Brand is Alexrim (ZX 20)

I am a heavy guy, 140kg.

funz

If i wasn't clear, my question is:

- Is my rim messed up beyond repair or do i just need to work on it?
- How do i handle tension on DS vs NDS seeing that materials are not the same?
- After reading bit more it seems that often you are not able to get exact same tension on all spokes, so what is % difference which is tolerable between spokes on same side?

Bill Kapaun

Make sure you have a consistent "release" on the TM. You can easily be +/- 1 division from sloppy technique.
If a "release" doesn't feel right, remeasure.

If it were me, I'd back off all the spokes so the first thread is flush with the end of the nipple.
Then tighten in consistent increments.

Many of us just get the NDS spokes slightly snug and then concentrate on bringing the DS up to about 90% desired tension.
1/2 turns, then 1/4 then 1/8 as tension increases. KEEP IT EVEN!
Then tighten NDS spokes to get proper dish.
Recheck DS tension and add a bit if needed.

36 spokes would be a better choice for your weight.
Mashing is tough on spokes. Remember, you are trying to "unwind" 1/2 of them whenever you pedal.

FBinNY 

let's clear the easy part first. It's very uncommon for a production wheel builder to use half stainless and half plated spokes in the same wheel. The only reason I can see for this is inventory issues and the need to keep production rolling along. But other than the potential issue with corrosion down the road, there's nothing wrong with it.

As for truing and even tension. It's possible to have both, but to do so, you have to understand how spokes work as part of a system rather than individually.

For example, if one area is u rue to the left, you want to tighten the right spokes and loosen the left. But there's a crossed pair on each side, and it's possible to align the wheel, but unbalance the tension in each pair.

So, the key is to step back and look at the whole situation, and align without creating uneven tension. Of course you may never get the tension perfectly even because the rim itself has some bends in it and you have to unbalance the tension to compensate.

So, it's all about your judgement and finesse, with goal being to have an aligned wheel first, and having the tension as even as that allows second.

One hint I can give you going forward is to not make big local corrections all at once, but to work in degrees, turning nipples about 1/4 turn then moving on, and coming back on the next pass. Work this way, making small corrections to the worst places, then moving on, as the wheel gets progressively better all the way around at the same time.

funz

Thank you for your replies!

Given the info i provided, what is my goal tension on DS and NDS?

NDS - steel
DS - non magnetic, so maybe titanium?

Also, what would be tolerable % difference in tension between spokes on the same side?

FBinNY 

The non-magnetic spokes are almost definitely stainless steel. Ti spokes were a bit trendy some years back, but are pricey and there's no way anyone would spring for them on anything but a wheel where they charged for them.

There's for answer for what's acceptable i tension variation. It's a question of balancing the need to end up with an aligned wheel with the minimum tension variation that makes that possible. This is especially true when realigning where a rim may be bent and fighting you.

Just take it slow, work by degrees and let the wheel find even tension by itself with only minimal help from you.

dedhed

My suspicion is the on NDS side is "work" magnetism. When SS is worked it has residual magnetism. Magnet will attract but not with the force of carbon steel.

Jon T

I rebuilt/trued the wheels on my '84 Peugeot over 25 years ago. Did it without any kind of a tension meter. Those wheels are still true and in use to this very day. Only occasional minor truing needed.
Jon

CliffordK

Since DS and NDS spokes are generally different lengths, it is possible they were different brands.

Magnets will stick to some varieties of stainless, and not others.

It is possible they would have different stretching/fatigue characteristics that some engineer thought would work well on a wheel, but I find that somewhat doubtful. A company, however, could have multiple sources for spokes. People have, however, experimented with using thinner spokes on the NDS than the DS. It is also possible that the company specifically chose to use higher quality DS spokes than NDS spokes to improve the wheel quality as well as make the wheel build cheaper.

For curiosity, you ,might look at the spoke heads (with a magnifying glass) and see if they have the same stamp (or any stamp at all).

Spoke Head Identification Chart

As far as spoke tensions, I haven't worried about spoke tensions in the past, and had reasonably round wheels. I'm trying to pay a little more attention to tension now. One thing someone suggested was to "ping" the spokes, and use tone to guide your truing. So, given a choice of tightening 3 spokes, tighten the one or two that have the least tension by tone.

However, being 140 kg (308 lbs), you put much greater stress on the spokes than the average rider, and may well benefit from more even tension.

Shimano uses loctite on the spokes. I'm not sure I like the idea of using a high strength threadlock on the spokes, but a low strength one (purple) might be OK.

Another thing to try might be unwinding the spokes. It is pretty simple to visualize spoke windup with bladed spokes. With round spokes, it was suggested before starting to mark every spoke with a sharpie (spin spoke and mark). Then true the wheel, and at the end unwind the spokes. That should help with spoke popping, and perhaps the loosening of your nipples.

cny-bikeman

OK, folks - what about the obvious?? If even tension results in an out of true wheel the first thing to check is whether the rim is physically bent. even though the OP says the bike is new. Secondly, if new then why not take it back to the selling shop for assistance (yes, even though he worked on it)?

funz

Ok, after staying up until 6AM working on the wheel and 2 hours just now i think i have it in best possible shape i can get it to.

Tension is within 1 point on TM.

I had 24-25 on DS = (per parktool chart for steel 2mm 25 = 120kgf)
19-20 NSD = (per parktool chart for steel 2mm 20 = 70kgf)

Tension is down by 2-3 points on TM after i inflated the tire (so 23-24 vs ~18. (it is MTB with road tires on 4-4.5 bars)

It is just a little bit off true on 2 spots, but i do not want to mess with it, it is less than 1mm off by length of 2-4 spokes.

I got dish to perfect but i cannot (do not know how without messing the whole thing) make it perfect roundness.

Roundness is off on about 2 spots, for about 1-2mm for length of 2 spokes (bent inward).

Going for a short ride, i hope no unscrewed spokes will happen this time.

cny-bikeman

Congratulations on getting it back to fairly decent shape, but 1-2mm out of round is a bit much for a "new" wheel, and that short a flat spots says to me either a rim defect or damage.

funz

Condition is a lot better. But it seems combination of:

- Roundness being off
- Not perfect tension
- Not perfect true
- My weight

Causes wheel to go out of true after ~20km ride. Spokes do not unscrew themselves like before all the way, but some do lose some tension.

I guess i need a new rim which was not messed up with.
I will just look for one with 36 spokes.


I have another question, not to open another thread.

I have cracking sound when pedaling.
I was thinking it was pedals themselves, so i replaced them (i had original bike ones as reserve).
It is not that, still the same sound.

I can only hear it while pedaling, more pressure i put on the pedal the more i hear it (driving slower in higher gears). Cannot hear it when not pedaling or pedaling very lightly. Cannot hear it while going downhill.

I can hear it more when putting pressure on right side (drive side) pedal.
I tried to tighten crank arm (which is on the left) but bolts didnt really move, so it should be fine.

Any ideas?

davidad

If I were you I would detension the wheel and start again. When I build a rear wheel I primarily use the DS side spokes to get the wheel radially true occasionally bringing the rim back to near center with the NDS spokes. As the tension increases I began to true the wheel latterly with the NDS spokes and add tension to the DS. I use a Wheel Smith tensiometer to get the DS spokes even tensioned and then true and center th rim with the NDS spokes. I never check the tension on the NDS on a rear wheel and let it fall where it needs to be.

pdlamb

That cracking sound when riding is probably the spokes unwinding themselves. You've been twisting spokes instead of tightening them, and when they're de-stressed by your weight, they unwind and the wheel pops out of true.


The suggestion to back all spokes off and tighten them incrementally is a good one, although with this twisting you may want to go one step further. Loosen all the spokes, then unscrew the nipples so you can oil the threads. Screw the nipples in to where there's one thread showing and proceed as noted. Make sure you over-tighten the nipples and back them off a bit (maybe 1/8 turn on 1/4 turn tightening) so you don't wind them up again.


Don't forget to stress-relieve the wheel when you're (almost) done. I can't tell you how many times one or two spokes has unwound when I did that. Re-tighten while watching for wind-up, stress-relieve one more time for luck, and now you're (really) finished.

funz

Wouldn't this be happening when not pedaling also?

Bill Kapaun

The rear wheel is under different stress when pedal or not. You are basically trying to "unwind" 1/2 your spokes when pedaling. IF a disc brake bike, you reverse the process when braking.

One of your "flat spots" is probably the rim joint. Opposite side from the valve stem.

funz

Ok, i will try to test this with using brakes. I think i noticed there is less cracking after i go down the hill (use brakes a lot, and yes, it is disk brakes).

Is there some kind of guide (if possible video) for this "twisting spokes instead of tightening" thing?

Bill Kapaun

You pretty much "over tighten" a 1/4 turn or so and then reverse to relieve the wind up.

Used spokes/nipples make this job much more difficult then new parts.
I always use new nipples if the old ones are "balky" at all. If I replace nipples, I wire brush the spoke threads.

funz

Ok i see. I am not too keen on removing nipples etc, i would probably work on it for ~15h to get it back together and all even as i am new to all of this.

I will first try this method with over tightening and then reversing it a bit.

Bill Kapaun

You could change one nipple at a time...

Don't be a slave to your TM. Sometimes you simply have to compromise between even tension and good true.

It sounds like you are pretty close. I'd just do a little spot truing and let the tension vary a bit more if needed. You'll still probably have done a better job than the factory.

Building a wheel with new spokes & nips will spoil you. It's so much more pleasant than truing old, semi beat up wheels.