'02 nrs

google will find it.

davidad

This chart looks similar to yours.

ThermionicScott 

A smart person uses the instructions for THEIR tool, not whatever else they can find on Google.

davidad

FINDING THE RIGHT TENSION The following method works well in determining proper spoke tension for conventional road rims of up to 43 0 grams with 3 6 spokes. Tighten all the spokes a quarter turn at a time, starting at the valve stem hole. Once a distinct tone can be made by plucking, and spokes are not easily squeezed together by grasping them in pairs, it is time to check tension. After each round of tightening, test the tension by stress relieving. If the wheel becomes untrue in two large waves during stress relieving, the maximum, safe tension has been exceeded. Approach this tension carefully to avoid major rim distortions. When the wheel loses alignment from stress relieving, loosen all spokes a half turn before retruing the wheel.

mpetry912 

I have the WheelFanatyk digital tensiometer that lets you generate a "radar plot" of spoke tension. It is a great tool. It gives merciless feedback !

Mark Petry
Bainbridge Island, WA

bikemig 

Yeah that's the passage I was thinking about too. It works well. I've used it in building my wheels and they have held up.

I also appreciate the quote from the book.

But this thread has me thinking that maybe it's time to buy the right tool as well.

Trevtassie

Calibrate it. I checked my Park gauge when I got it. Figure out a way you can hang a spoke with weight hanging off it. Then measure and compare to the chart. In my case I hung my 90kg or so off a spoke and checked the reading, was bang on... Could also use containers of water, one litre weighs one kilogram.

adipe

if you are not putting the data into a spreadsheet to correlate radial runout for each spoke with tension variance then you miss the main purpose/use of a precise tension meter. it's not as much as to provide circle graphs. but to be able to better adjust radial runout to tension variance and therefore being able to straighten the rim if you want to. or just let the wheel straighten itself over time. but i'd choose the first variant.

i'd only invest in a tension meter if it is at least as accurate as the acoustics method which has the disadvantage of being a slow one when using a tone generator (the computer doing the math after you feed in the value in Hz) with the advantage of being zero expense.

and then i'd not have too much use of a proper tension meter if not for figuring out the delta elongation from the average for each spoke. i'd have my estimation as to the final tension without needing anything else but acoustics and a quick calculation given the length between the cross and the nipple etc.

but that's just me who am a perfectionist and only build my own wheels.
if i were servicing/building more than 30 wheels per year i'd buy a precise tension meter to have productivity as well and not only accuracy.

then again... if you don't measure with dial gauges radial runout (supposing the lateral runout is low enough as to have insignificant errors) you also are unable to balance radial runout with tension variance unless you true down to zero which can be very tedious. many people don't get it. you can true the wheel but not have it fixed once and for good (best durability). it will be either luck once in a while or just sloppier work. and even more slow work.

need i mention that you can very well bring the lateral true to such a low value after you balance the other two figures which are more important for wheel durability?

if you don't believe me... just try it once.

and circle graphs are of use only to impress customers who don't have a clue regarding radial true needing to be balanced to tension variance. when it comes to working with imperfect from the factory or just bent rims (pulling the rim and twisting it etc.) you are better off with linear graphs from the spreadsheet software you'd have available.

just make the adjustments by calculating the angle for nipple turn - each spoke - and all will be easy as cake afterwards. and put some labels as to monitor spoke twist.
or you might as well just go on doing a bit less sloppy work than what machines do. machines don't monitor spoke twist as to calculate nipple turn angle by backing off from spoke twist. nor do they correlate spoke tension variance with runout for all the spokes as to calculate all 16 or 18 angles of adjustments afterwards. do they?...

if you aren't getting my my point... i give up. even if my english is not as from a native... you can give a careful reading if you want to.

then again... you might understand how easy it would be to achieve +/-0.05mm lateral and also radial runout (which is more important) with +/-5% spoke tension variance. that after you do the stress relieving and straightening the rim whenever it is not perfectly round. it is not hard to do when you adjust the DS nipples positions and from then on you work only with the NDS. it may take two operations if the first one has the bedding in of nipples/spokes/flanges not equal for all spokes.

~179GPa the elastic modulus of stainless steel - when not in very low tension that is; very low tension has 206GPa; the slight difference throughout the strain-stress curve is not to worry about (later edit).

davidad

I bought the book over 25 years ago. I also bought my Wheelsmith meter around that time so I did not use his method. I do stress relieve my wheels after tensioning and they hold up well.

mrrabbit 

What's really important here is that you have an assembly by which to keep the meter calibrated.

As general rule of thumb for modern day alloy rims:

Single wall = 90 to 95 kgf
Double wall = 95 to 110 kgf

...assuming they're the 32 to 36 hole variety and the inner wall thickness to the eye is around the 2mm to 2.5mm ballpark.

Helps though to have the manufacturer give you a number...DT, Stan's, Rolf Prima (Astral) and many others do.

Where you really really have to be careful are today's super light weight alloy rims . . .

. . . AND the super lights such as Martano's from the 70s. Certain Martano's could only handle 50 kgf.

And yes, there are some alloy super lights out there today that are only rated for 95 kgf.

When in doubt, call 'em, email 'em.

=8-)

Winfried

I also got that el cheapo Deckas spoke tension meter, and here's a more legible scan of its "Convertible Table":

mpetry912 

I still think you are asking the wrong question here and following an unknown / uncalibrated "tension guage" will lead you further down the wrong path.

The right tension for a given wheel is determined by the expert builder (that would be YOU) based on your assessment of the rim, spokes, rider weight, and intended use. If the wheel "starts to taco" you have already deformed the rim and compromised the strength.

For most of the wheels we build and ride, you want to arrive at a true, round, properly dished wheel with an average spoke tension of about 70-80 KGF. Compare with other well built wheels and use your educated ear to listen for the right "ping".

The tension guage can help you find the outliers - spokes that are too tight or too loose - and then you can try to address those. But based on my own limited experience I suggest you not blindly follow the guage. I remember Spence Wolf showing me a Hozan guage (this would have been 1971 - 2) and saying "now Mark, this is the instrument of the devil".

Mark Petry
Bainbridge Island, WA USA

Retro Grouch 

Of course. Sometimes I feel like an analogue man whose been trapped in a digital world.

First of all, it's possible to have a wheel that is entirely acceptable in both lateral and radial true that has spoke tensions all over the place. If you take the digital approach and try to adjust all of the spokes to the same tension, the result will usually be a wonky trued wheel.

My system is to start with one thread showing on each spoke. Then I build tension into the wheel by counting turns as I tighten each spoke. When I think the wheel is close to the right tension, I check each spoke with my tension meter and make them all equal. I once built a 40 spoke tandem wheel that required no truing at all after this point in the process. Any required truing I do by tightening and loosening the same number of fractional turns from opposing pairs of spokes. I think that method results in the least deviation possible from the average spoke tension.

mpetry912 

this is not a bad way to go. If all spokes are equally tightened the rim "SHOULD" be perfectly round assuming all spokes are the same length (sometimes they are not but that's another discussion) and the rim holes / ferrules are perfectly even.

Then any deviation in tension should be attributed to making the wheel run laterally true.

Mark Petry
Bainbridge Island, WA USA

reburns

Just a warning: I bought a brand new Park TM-1 and tensioned spokes to the manufacturer’s specs based on it. Later I noticed cracks forming around the spoke holes in the rim. I finally got around to building a jig to calibrate the TM-1 and found out it was reading low...by 30 Kgf! I sent it back to Park and they replaced the spring for $5, but it still read low by 10-15 Kgf. However that was at least close enough to correct using the adjustment screw on the meter.

ThermionicScott 

Hopefully you also learned that the manufacturer spec is usually a maximum.

Drew Eckhardt 

No. You alternately tighten and stress relieve which creates a significant overload. When stress relieving causes problems you back off a half turn, true, and be happy until you bend the rim on obstacles.

Unfortunately, that only works for classic box section rims. With beam stiffness proportional to the cube of depth modern rims are too stiff for that to work and the limit comes from the tension which will cause eventual fatigue failures in the spoke bed. You need an app, tension meter, or similar wheel built with same gauge spokes to calibrate today's deeper profiles.

100kgf front, 110kgf drive side are rules of thumb.

Drew Eckhardt 

The purpose is to get correct _absolute_ tension. Tension determines how big of an off center hit a wheel will take before collapsing, but too much will cause stress cracks in the spoke bed.

True is adjusted purely based on clearance. Relative tension will be close enough based on tone.

mpetry912 

These tools measure spoke tension indirectly from the spokes deflection over a known distance when the spring force is applied.

The spoke guage can have a large impact on your readings. The same reading on the guage can vary by 5-10 KgF depending on the spoke guage (1.8-.2.0 for example).

So be sure you're looking at the right column on the conversion chart.

Mark Petry
Bainbridge Island, WA USA

avhed

Wonder what this one is like? More accurate than the Park?

70sSanO

Being the dunce in this group, I built wheels by feel, squeezing spokes, years ago. But I now have a Park tension meter that I use. I’ll follow the charts to be in the range. I don’t calibrate, but I do a comparison of readings from existing wheels that have survived many years. Seems to work well.

Because I’m running 32hole wheels, it is not critical.

John

pdlamb

Obviously the top one, and #2 & 4 on the bottom, are the most accurate. They're digital!

OK, getting my tongue out of my cheek, it would depend on the precision and accuracy of the readouts, and the calibration of the individual units. For most users, I'd think it's overkill. The point of using a tensiometer, in my book, is that it substitutes an independent measuring device's reading for user judgment. There is doubtless a number of skilled and experienced wheelbuilders who don't need one. There are also many more less experienced people who can build a wheel just as good as the experts by using the tensiometer. (And the latter is cheaper for a shop to hire.)