TM-1 - Spoke Tension Meter Tool

For 20+ years, I have built wheels that needed to be re-tensioned/trued occasionally. I didn't realize that a spoke tensioning tool can make a huge difference in wheel builds until I got this Park spoke tension tool.Now, I am building some of the best wheels ever, and properly tensioned wheels need less maintenance and truing.

Let's hit the first question off the bat; Do you need this doo-dad to properly build a wheel or keep your wheels in good working order?The answer is it depends upon how close you wish to be to the bleeding edge.Mechanics have been building bike wheels for about 200 hundred years now (dating back to before the early velocipede designs), usually without the benefit of a spoke tension gauge. And for decades, racing wheels used in everything from the Tour de France to serious downhill competitions have been built without spoke tension meters as well. That is because mechanics overbuilt their wheels for the riding style and course, and their fatigue limit was sufficiently far from their elastic limit. (spokes that are tensioned too high are too close to their elastic limit, or that of the rim) Likewise, if you wish to build your own wheels and follow some basic safety factor limits when building a wheel, then a tension gauge is not important. That said, in today's world, there is always that rider out there who is 200 lbs (90.7 kg) and who wants a 24 spoke radially laced front wheel on a 330 gram rim. If bleeding edge riding is your style or you are trying to save 150 grams on your carbon fiber road or mountain bike or you want to push it right to the physical limits, then a spoke tension gauge becomes essential.This Park Tools TM-1 gauge works by using a spoke diameter gauge to measure the middle (or butted part, if your spokes are such) part of a spoke (or you could use precision calipers) and then applying the the tool so that the spoke runs between the two fixed posts and the moveable post. The arrow at the top will point to a number on the graduated scale and you then refer to the separate conversion table to see what kilograms of force (kgf) measurement this corresponds to. For most wheels, you want somewhere between 80 and 130 kgf. Although, this value can vary depending upon the exact riding application.I am not a professional or shop mechanic, but I do build wheels for myself and others that join our off road riding group. I have used this gauge for about twenty wheel builds over the last five years or so. I find it to work fairly well. My older mountain biking wheels (rim brake) are often set up with Mavic 32 hole X517 rims and are typically radially laced in the front and three cross drive/radial lace non-drive in the back. While my newer rims are often 32 hole DT Swiss, Mavic X317 disc or Stans racing rims. I can usually tune by hand and by sound my wheels so that no spoke is 20% above or below the spoke average of the entire wheel (this is a standard reference limit for bike wheels), but the TM-1 really helps me to keep my older wheels at right around 100 kgf and my newer disc rims at about 110 kgf. And these values are right in the happy middle between allowing for a long fatigue life while maintaining ample tension so that if one spoke breaks, the wheel does not taco and I can ride back to the trail head. Those tension levels also prevent fatigue at the rim eyelets and ensure long rim life.Are than any negatives about the TM-1? Not really, but I do find the spoke diameter gauge to be cheaply made. I much prefer to use my Neiko digital caliper when measuring spokes. I also wish that Park Tool would include a standard guide for major manufacturers in their conversion table. The values for a 1.5 mm butted generic spoke from China and one from DT or Sapim are not the same. (Although, you can find these exact values online) And because the gauge is a calibrated spring, I suggest any owner send it back to Park Tool every 25 wheel builds or so, so that exact calibration is maintained. However, those are relatively small quibbles.Thanks to the TM-1, I have never had a wheel taco so far or a spoke break. While this gauge is not essential to wheel building for most riders who are not bleeding edge weight weenies, it does allow the home builder to have some quantitative idea of how their wheels are doing. And for me, that means longer wheel life and no problems on the trail. Five stars in my book.

I've built a few wheels with and without this gauge. I know that I feel a LOT better knowing that my spokes are not too tight or too loose -and that the relative tension is even all the way around the wheel.There seems to be two schools of thought reading the other reviews. One says that this gauge is not necessary and a good wheelbuilder only needs to tell by "feel" if the wheel has correct and/or even tension. The other is that this is just more information that gives you more exact knowledge of where you are with spoke tension.The question is how does one get this "feel" if one has nothing to compare it to? The old canard about striking the spoke and listening for the correct musical note is a bit funny IMHO. Seriously? There are so many variables with regard to thickness and length of spokes that this seems to me to be just more mumbo-jumbo voodoo.A lot of wheel builders seem to be quite proud of their "mad skillz" and look down on this gauge it seems. Some say "take a wheelbuilding class for $100+ each session and "learn" this feel." I tend to go with the "get the right tool for the job" school of thought. With this gauge you will know exactly where the wheel tension is and it is one less variable that one has to guess about.Many of the reasons why some reviewers put down this tool or say that it is doing "more harm than good" in some circumstances seems to read to me as rationalizations why they or other people shouldn't spend the money on a tool such as this. Most bikes shops I visit have this very tool and wouldn't work on wheels without them. And they KNOW what they are doing. Sure, I think that a person may mislead themselves about how important this tool is with relation to other knowledge about building a wheel but if one is careful and does a lot of reading those other things can be figured out as well. Doing everything else right won't help if you have way too much tension on your wheel and start to damage the rim -or have too little and the spokes fatigue and wear quickly.Perhaps some of the VooDoo practitioners don't like the idea that just about anyone has access to the magic of spoke tension with this simple and inexpensive tool. I can't help but feel that they might be a little jealous/upset that just about anyone from the "outside" can jump ahead miles in their abilities without doing their time under the tutelage of a wheel-witch doctor such as themselves and learning the "black arts" like a proper acolyte.Raleighphile doesn't role that way! Knowledge and skills should be free to learn and all should have access if they only know where to look.One more thing:* the first meter I purchased was defective and was showing a much higher reading than what was actually present. This caused my first wheel build to tensioned WAY too loose. I thought at first that all the wheels I've ever built have been WAY too tight but I checked the gauge against one at the LBS and saw that my gauge was in fact defective. Amazon took it back and gave me another one free of charge with free shipping.It's something to be aware of. I don't know how common this is.I keep the gauge safe in the original box whenever I'm not using it an am very careful not to drop or bang it to get the calibration messed up. Having another gauge around or available to check against periodically might be a good idea. If you are friendly with your LBS I'm sure they will let you use one of their gauges to make sure they are reading the same.

Great tool.