Review on Aluminum Alloy Spoke Tension Meter Tool - Bicycle Wheel Accessory for Wire Tension Adjustment by Marlo Schlachter

I'm using a borrowed TM-1 from a well known blue bike tool maker. The design of the ZTTO TC-1 (as the tool was called) was very similar to the blue $82 tool. The movements are almost identical except that the ZTTO is made from slightly thinner aluminum but is still very strong. The end of the spring on the adjustment screw protruded too far from the body and could be felt when the tool was compressed. Must be cut. The most disappointing aspect of the instrument is that it is not calibrated. Out of the box I got readings of 34-35 on my 2.3mm needles which translates to a force of 143-164 kg (kgf). Incredibly high! My wheels come from the factory at 100-120 kgf, and on the pack, whoops, the blue tool shows the equivalent 28-29. Pretty big mistake! The ZTTO tool can easily be adjusted with a single adjustment screw, but a new tool needs to be calibrated. Once I adjusted it to match the blue tool, the readings tracked well over the range I ran. All bets would be deducted if a dissimilar spoke was measured: I just don't know if the tool stays accurate. Since the most important thing is that all spokes have the same tension, and I have calibrated the ZTTO to match the blue tool, I can adjust my two identical bikes. If you don't have a way of calibrating an instrument with a known correct one, I would recommend you ditch this worthy instrument.