Need help understanding spoke tension on a new wheel set

[dlq001]

Edited values, thanks and TigWorld.

Hi all, this is my first post and I’m wanting to try building a wheel.
From everything I read, I decided to buy the Park Tool TM-1 tension
meter. I used it to measure the tension on the Swiss DT-370 Pure Trail
rims with 2.0mm spokes I just got from BWW.

Here’s some values I got for the wheels:
Rear Wheel (in Kfg)
Drive (right) Side Spokes
Avg 127
Low 120
High 153

Non-drive (left) Side Spokes
Avg 81
Low 53
High 120
Here’s the thing, that 153 is between the 53 and 120.
Going around the rim for 8 spokes it looks like this:
70 107 120 153 53 107 96

Front wheel (in Kfg)
Right Side Spokes
Avg 101
Low 70
High 153

Left Side Spokes
Avg 161
Low 135
High 173
About this wheel, the 153 is followed by the 135 and 70, and the
153 and 70 are are consecutive spokes on the right side.
Going around the rim for 9 spokes it looks like this:
153 96 173 153 135 70 173 113 163

My concern is that I may be worried about nothing, am I ?
To bring the values in, should I tweak the spokes a little?


What is an acceptable difference between the average tension and the
highest and lowest readings?

The web page called for double butted 2.0,1.8mm spokes,
but the wheels came with straight 2.0mm spokes.

Hope I was clear enough about this. If anyone wants to see an Excel
spreadsheet of my data I can email it to you.


Thanks for any input… Chris

Ok, think I got the values right, again thanks guys.

[beanbag]

I think u measured wrong because spoke tensions are rarely that high.

[TigWorld]

You are reading the chart wrong. The tension figures for 2.0mm spokes are to the LEFT of the 2.0mm spoke yellow vertical bar. You will find your spoke tension will be in the 120-130 range (eg 25-26 on the meter for 2.0mm straight gauge round spokes).

[dlq001]

Originally Posted by TigWorld

You are reading the chart wrong. The tension figures for 2.0mm spokes are to the LEFT of the 2.0mm spoke yellow vertical bar. You will find your spoke tension will be in the 120-130 range (eg 25-26 on the meter for 2.0mm straight gauge round spokes).

^^^^ Thanks, you are right.. How did I not see that !!!!

I'm editing my data, but would still like help with my questions.

[TigWorld]

There is a lot of variation in spoke tension. +/- 10% is normally OK but your figures are showing between 53 and 153 and 70 and 173 kgf.

How true are the wheels?

A reading of 53 (too low) and 153 (two high) on two successive spokes suggests that one spoke is doing all of the work here. You could try first reducing tension on the 153 spoke and then increasing the tension of the 53 spoke and to even things out.

Same could be done for the other adjacent spokes that have high variance in tension.

[jadedbee]

Hey dlq, welcome to mtbr.

Do i understand right: you bought a new, pre-built wheelset, want to learn how to build your own wheels, and are testing out your new spoke tension tool on the pre-built wheelset? I'm not trying to be facetious, 'just want to make sure i read you right.

Sounds like a good opportunity to get some truing experience, without the hurdle of calculating the spoke lengths and following a lace pattern. Carefully release the spoke tension around the wheel (maybe in a star pattern so it doesn't pull off to one side), then bring all the spokes up to an even, working tension (you can get close by feel or tone when plucked, then use your tension gauge to get them all the same). Then start adding layers of tension along with correcting the lateral and radial true, and allowing for dish when you get close to the recommended tension. Follow your chosen build guide and tweak the process as you go to make it your own so that it makes sense to you.

My guess is that unless your rim is bent, you'll get much more even tension than you have now. I know many wrenches that will do just this - buy a machine built wheelset to save money and simplify the build process, then de-tension and rebuild it by hand to a higher tension with more even distribution than the machines get.

[customfab]

That's a pretty poorly built wheel. It's something that should definitely be attended to. The one thing to keep in mind when using the park tool is that the release can change your reading. Are you getting repeatable results with the tool? If not figure out what is causing your inconsistent numbers and solve that first before you attempt to balance out the tension on this wheel. I would shoot for your tension to be within 5% with a couple of allowable omissions. Depending on the quality of the rim 5% may or may not be attainable though. If it's a disc brake wheel feel free to sacrifice true a little (up to 1 mm is fine)

[jadedbee]

What he said.

The Park tool recommends you always measure the middle of the spoke (most important on dbl butted), and that the spoke be horizontal when measured (I'm guessing that the weight of the wheel loads the vertical spokes more). Try not to "snap" it open either.

Also, if it's machine built and you haven't ridden it yet, some of the spokes could still be twisted - make sure to go around and squeeze spoke pairs to relieve any twist until they don't "ping" anymore.

[CupOfJava]

The spoke tension on a particular spoke can vary depending on where you place the tension meter. Too close the nipple the meter will read higher too close to the cross the tension will read higher. I usually take a couple readings on each spoke.

[dlq001]

You know, had I not planed on building my own wheels I wouldn't have the tension meter. Would have just thrown the wheels on the bike and rode it the way they are. Replaced some spokes, done some on bike truing, and replaced them in about a year. And that's what I want to avoid by learning to do it myself.

As I understand, Bicycle wheel Warehouse hand builds their wheels. Here's a statement off their home page....
Each of our wheels are meticulously hand built using the latest technology and thoroughly stressed and inspected for a top quality wheel that will survive through years of use.

From TigWorld:
"How true are the wheels?
A reading of 53 (too low) and 153 (two high) on two successive spokes suggests that one spoke is doing all of the work here. You could try first reducing tension on the 153 spoke and then increasing the tension of the 53 spoke and to even things out."

This is my thought too. Just tweak them a little bit at the questionable points (and keep my fingers crossed). Park Tools and other wheel building tutorials talk about one spoke's adjustment influencing the rim 2-3 spokes on either side. This is the part that worries me, I don't want to screw these wheels up by trying to make them better. I don't have a truing stand so whatever I do has got to be in moderation. The lateral true seems to be right on the money.


From jadedbee:
.........bought a new, pre-built wheelset, want to learn how to build your own wheels, and are testing out your new spoke tension tool on the pre-built wheelset?........

That about sums it up. I'm not even close to being a "wrench" as you say. There's no way at this stage that I'd feel comfortable enough to release the tension off all the spokes. I did save what you said for future reference thou, for when I get a truing stand.
I also followed Park Tools instructions for taking the readings. I just quickly checked on one spoke and the tension changed one point or so between the horizontal and vertical.

From CupOfJava:
I usually take a couple readings on each spoke. ...

Same here, and centered the tension meter between the nipple and cross point.

Thanks for the input everyone.....

Chris

[TigWorld]

Originally Posted by dlq001

... I don't have a truing stand so whatever I do has got to be in moderation...

Use your frame and some zip ties. Check the wheel dish first by setting the end of a zip tie up so it just touches the rim and then flip the wheel over in the frame.

If the dish is OK then just use your zip tie as your reference point and tweak away. Just ease back on the tension of the very high tension spokes and then try to bring the tension up on the low tension spokes to get things true. As customfab says, on a disk wheel a little laterial or radial runout is OK. Its better to go for consistent spoke tension than a perfectly true wheel with spoke tension all over the place.

[dlq001]

Want to thank you all again for helping me out with this wheel set.

I did the front wheel so far and I'm wondering if the spoke tension is alright or needs to be reduced a little. Here's what I got for tension (Kgf):
__________Disc Side__________Right Side
High.............173.........................113
Low..............163.........................101
Avg...............167.5......................107
Old Avg....160.1.....................104

Disc side: they are a 163 & 173 except two 153.
right side: they are all 107 except three 101, one each 113 & 120.

Do I tweak the 153, 113, and 120??

The average is 7.3 and 3.1 higher than the old values.
They're not within 5%, but closer to 5% than to 10%. I can get 5%
if I tweak the 113, 120, and 153.

Are the tension values or the 167 and 107 averages too high?

With all that being said, here's what I did:
First I tried to tension the questionable spokes and keep the rim true.
That turned out to be way too involved. Then I tried setting the tension on the
spokes so they were real close. Took me some time, but then I set the true.
For my first really involved wheel work, it came out real good, thou it did take 5-6 hours.

The most important question for me is Are the spoke tension values and/or 167 and 107 averages ok, or are they too high? I had a rim split on each side of a spoke hole from being too tight, and do not want that to happen with these rims.

Again thanks everybody for the lessons in wheels...

Chris

[One Pivot]

Are you sure you're reading the tensions right? Thats over 27 on the park gauge. Thats insane high.. the fronts should be around 120 max.

The numbers you're giving, those wheels are ready to bust! Far exceeds any normal rims acceptable tension. Getting a spoke to tensions that high usually strips out an alloy nipple as well.

[zarr]

tagged for future reference

[dlq001]

Originally Posted by One Pivot

Are you sure you're reading the tensions right? Thats over 27 on the park gauge. Thats insane high.. the fronts should be around 120 max.

The numbers you're giving, those wheels are ready to bust! Far exceeds any normal rims acceptable tension. Getting a spoke to tensions that high usually strips out an alloy nipple as well.

Ya, it's 27-28 on my TM-1 (160Kgf). The Bicycle Wheel Warehouse readings (before I did anything) were 26.5 -28. These are the readings on the disc rotor side. I know that this side has to be tighter. My average number is 7.3Kgf higher than what BWW had the tension set at. (The right side spokes are 23-24, ~107Kgf).
I'm unable to find tension spec's for the Pure Trail rims, but if the pros at BWW set them there, I can only assume that's an acceptable value for this rim. Am I Right about this????

Could my TM-1 tension meter be off? Maybe, but it is brand new. I've calibrated tension gauges used for small aircraft, so I'm gonna try and figure out a way to check my Park Tool gauge.

(Just mentioning that I now just checked the rear wheel drive side and got mostly 26-27 with a 25 & 28 at the ends. On the disc brake side I got 21-24, with a 18 & 26 at the ends.)

I've got a quote from the book The Art of Wheel Building here. I mention it because I didn't see anything like this while working with the wheel.
The quote goes like this: "The amount of spoke tension that a rim can take can be quickly judged when, while at the end of the truing and tensioning work, the wheel demonstrates odd behavior. The more you correct the truing, the more it distorts. The tension is too high and the rim is trying to collapse."

Hope I'm not being to word'y, but I want to get as much info on here as I can. I really want to learn about this, and want to thank One Pivot and everyone else who's helped out here....... Thanks All

Chris

[jadedbee]

Originally Posted by dlq001

"The amount of spoke tension that a rim can take can be quickly judged when, while at the end of the truing and tensioning work, the wheel demonstrates odd behavior. The more you correct the truing, the more it distorts. The tension is too high and the rim is trying to collapse."
Chris

That's a good quote from The Art... I just de-tensioned a rim for a buddy last week and it was doing this. For reference, it was an DT Swiss rim that had been branded for Specialized (520 SL, 29er). The tension was up there in the 27-28 range on my Park and the alloy nips were rounding off (he bought a bike used that had a re-built wheelset).

It might be a good idea to check the calibration of your meter; if the wheel came that highly tensioned from a reputable builder and you are not getting any wacky/collapsing behavior or rounding off nipples with that amount of tension on it, the meter may be wrong.

But if you do find that it is right, just go around the rim and lower each spoke by a quarter turn (try to be consistent). Make sure to lube the nipple threads and eyelets first, and feel the spoke with one hand when you turn the nipple to see if it's winding up. You may have to go around twice in quarter turn increments to get it in the 120s. Then re-balance the tension again with your meter to within 10% and correct for rough true, if needed.

I find that getting the right spoke tension can be like tuning a guitar string - if you tune up to the pitch it will usually hold better than releasing down to it. So when you are sharp (too high of tension), you have to come down past your target tension, then "tune" back up to it.

[dlq001]

Originally Posted by jadedbee

That's a good quote from The Art... I just de-tensioned a rim for a buddy last week and it was doing this. For reference, it was an DT Swiss rim that had been branded for Specialized (520 SL, 29er). The tension was up there in the 27-28 range on my Park and the alloy nips were rounding off (he bought a bike used that had a re-built wheelset).

It might be a good idea to check the calibration of your meter; if the wheel came that highly tensioned from a reputable builder and you are not getting any wacky/collapsing behavior or rounding off nipples with that amount of tension on it, the meter may be wrong.

I've read posts on MTBR where people say Bicycle Wheel Warehouse (BWW) makes good wheels, so I'm guessing they're a reputable builder.

Right now I'm leaning towards my tension meter being inaccurate. There's no wacky/collapsing behavior of the rim. There's no rounded off 'alloy' nipples. And the wheel did read 26-27-28 (disc side) as I received it.

Want to check my tension meter but don't know anyone that has one, and oddly enough none of the LBS's around here use one. In order to get a reading of 23-24 I would need 211-222 pounds of dead weight. I don't have that much mass laying around, well except for me, and I don't think I can be stable enough to get any type of reading. But I am going to give it a try and see what happens.

I'm going to request some information from BWW and Park Tools, see what more I can learn from them.

Again thanks, and thanks to everyone.

Chris

[DavesBikeRepair]

Chris

Industry standards.....Front Drive Side: 100KGf = 22 Park Tension Tool (drive side is on the left side
Rear Drive Side: 110KGf = 24 Park Tension Tool (derailleur side)

Typically don't worry about non-drive side if drive-side is up to spec.

Bassplayer
Certified Wrench

[One Pivot]

Ultimate NDS tension is what it is, but it should still be fairly even.

My park gauge gave much more repeatable and consistent readings after i lubed up the whole thing. The anodizing on the tool is pretty rough and scratchy, not the best thing for consistency. Also the pointer on mine gets loose a lot, and drags sideways.

I know its been a few weeks.. but im curious if you've done the spoke pluck test (plucking spokes like a guitar)? The tensions on that wheel should produce significant tone variation, proving the meter is reading right, and your tensions are all over the place.

[meltingfeather]

OP- Take your meter to a bike shop and ask them if you can compare it against theirs or just read a few wheels.

Originally Posted by DavesBikeRepair

Chris

Industry standards.....Front Drive Side: 100KGf = 22 Park Tension Tool (drive side is on the left side
Rear Drive Side: 110KGf = 24 Park Tension Tool (derailleur side)

Typically don't worry about non-drive side if drive-side is up to spec.

Bassplayer
Certified Wrench

drive side is the side the drivetrain is on.
that'd be the rider's right side of the bike, whether you are talking about front or rear. industry standard...