Bicycle Mechanics - Spoke Tension Meters

I’m in the process of obtaining a Spoke Tension Meter. Does any one have experience with any of the following tools?

DT Swiss Tension Meter
Hozan Spoke Tension Meter C737
Wheelsmith Spoke Tension Meter
Park Tension Meter TM-1

If you have hands on with any of these tools I would greatly appreciate your sharing feedback on the tool’s accuracy-precision, quality of finish/materials and workmanship, ease of use. Also suitability to the task, now that aero and bladed spokes are becoming commonplace. Most important: If you had to build/rebuild wheels professionally which would you own?

Note: I queried a Master Mechanic in my area (in person on a slow weekday afternoon), and received a very sincere reply. “After several thousand wheels, I now only tension by feel” He demonstrated by placing an index finger and thumb on two adjacent spokes, squeezing them together. While I have taken this to heart, does any one else have thoughts on obtaining this level of mastery of tension by touch?

Many thanks in advance for your thoughtful wisdom on the aforementioned.

Faith,
While I don't have any experience with tensionmeters
(I couldn't bring myself to buy one on top of all the
other wheelbuilding stuff) I did pick up one method
that works.
Find a well built wheel, pluck a spoke like a guitar string.
All your spokes should sound the same. Use the built
wheel like a tuning fork (pitch pipe?).
I also used the built wheel as a guide for feel of the spokes.
When I brought my completed wheel to LBS to double check
(veryify my work) the wrench said the spokes were pretty
close to ideal.
Give it a try, after all it won't cost you anything.

Good luck and let us know what you think about the
tensionmeter when you get it.

Marty

For a rear wheel all the spokes on one side should sound the same. The driving spokes will have a higher tension than the non-driving spokes due to dishing. Front wheel spokes should all sound about the same if properly tensioned.

faith,
I would suggest you pick up a tome entitled "The Art of Wheelbuilding" - by Gerd Schraner .

He is considered by many to be one of the true masters of wheelbuilding and he felt that initially plucking the spokes was very accurate - until he verified his results with a tensionmeter.

He also goes into the various tensionmeters and their respective strengths/weaknesses. Most accurate was the Hozan, followed by the DT. Unfortunately, the Hozan can not be recalibrated but, the DT can.

I have a DT on order as we speak. As an engineer I find a meter that can not be calibrated unacceptable.

I have a Wheelsmith tensiometer and also (don't laugh) a Cricket automotive-belt tensiometer. The Wheelsmith is easy to use, individually calibrated, and can be sent in for recalibration if desired. The Cricket is fast, foolproof and material-independent (rubber, titanium, stainless steel, whatever).

Neither one will make a bad wheelbuilder good. The idea of precisely balancing spoke tensions with a precision instrument sounds great until you enter the real world, where rims are not perfectly straight nor round by nature, forcing a "reality factor" into the equation if you want true and round wheels. Having built... heck, I have no idea how many wheels, probably at least one or two thousand pair at this point, I will venture the opinion that tensiometers may be good as a guide to overall average tension level on the wheel, but don't get carried away trying to make all the tensions the same.

Frankly, I use plucking to identify relative tension levels among spokes as I build, and use the tensiometer on an average-tone spoke (same one every time) to monitor actual tension level. I do NOT go from spoke to spoke squinting at the tension readings for each one.

So that is my 2c worth :) and may I suggest taking all the other aspects of the build very seriously, such as many stages of stress-relieving, settling the spoke elbows against the hub flanges, and making the rim labels face the same way and line up opposite the hub labels (if so equipped), so you can gaze fondly at your bike's harmonious appearance for hours :) Wheels are a form of art, as you know :)

This is not the last word, but just my experience:

I don't own a tensiometer. I have thought about buying one but they always seem expensive for the use I'd give it.

When I started building & rebuilding wheels for my bikes, the only book available was Jobst Brandt's book, The Bicycle Wheel. [My edition is (c) 1981.]

Jobst talks about making sure the tension of the spokes is as close to the same as you can achieve (with the difference noted above for the rear wheel drive and non-drive sides). In it, though he talks about using a tensiometer or plucking spokes and comparing to a known good wheel, he also has this to say about tension, following rounds of tensioning and stress relieving:

[quote] When the maximum tension is reached the wheel will not remain true after stress relieving. When the wheel begins to deform under stress, all spokes should be loosened half a turn and the wheel re-trued. A strong and safe wheel should be about a half turn below the maximum tension the rim can withstand. [unquote]

I have used this method to tension all the wheels I have built. So far at least, I have not broken a spoke. I can't recall the last time I've had to re-true a wheel, but it long ago and wasn't one I built.

I also always use double butted spokes for the resilience they give a wheel -- though they do make tensioning/stress-relieving/truing harder because there is more spoke interaction than with the more rigid straight gauge spokes.

Originally posted by faith
Hozan Spoke Tension Meter C737
Wheelsmith Spoke Tension Meter


No first hand experience, but here are a couple of data points from a table in Ch. 17 of Barnett's:
Hozan C737 Expensive, fragile, precise readings, cannot be re-calibrated
Wheelsmith N001 Less expensive, durable, less precise readings, but can be re-calibrated

A tension meter is simply a measuring tool, much like a torque wrench, a caliper, a tape measure, a stop watch, a heart rate monitor, or even measuring spoons. It is possible to work without one, but taking measurements will help a mechanic know what is going on. Using tension measurements allows the mechanic to build consistent wheels, to communicate better with rim manufacturers, and other wheel builders. Keep in mind that certainly some bakers can produce a great loaf of bread by using only "feel", but many prefer to use measurements in the process.

More details of the Park Tool TM-1 can be viewed at http://www.parktool.com/repair_help/tm_1.shtml

Calvin Jones
Park Tool

I have built many wheels for myself and others, I have built wheels without using a tensionometer and with, I have a wheelsmith, It allows you to make a well built wheel better. By tensioning the spokes so that they evenly carry the load, you build more strength into your wheels. They stay true longer and ride better. I also use dial indicators to do the final true. As far as new rims being out of round, I found that you get what you pay for, buy a good quality rim and it will be straight and round, buy a less expensive rim and you know what you get.