Tuesday, August 1, 2017

Truing Bicycle Wheels Effectively

Are your bicycle wheels constantly going out of true? Or breaking spokes? The secret to fix this problem is the Park Tool spoke tensioner


Spoke Tensioner by Park Tool


For decades, I've carried weight on a bike rack over my rear wheel. And for years, my spokes broke. Or, if the spoke didn't break, the wheel went out of true. This occurred on either the front or rear wheels, but more often on the rear. 

The more bumps I rode over, and the greater the weight I carried, the more the wheels went out of true. Sometimes, this was after every ride! The maintenance was really time consuming. Sometimes I had to remove the tire to replace the nipple. And, sometimes, the rear wheel's cassette. 


Spoke Tensioner:

Why did my wheels keep going out of true? One day I visited a bike shop, and asked the mechanic about a certain tool hanging on his wall. 

He told me that it was for spoke tension measurement. They used it to tighten spokes evenly all around the wheels. He showed me a wheel where they had used the spoke tensioner on all the spokes. Each spoke was really taught, and made a distinctive sound when you pinged it. If you took the spoke, and tried to wiggle it, there was very little play. Cool!

So, I bought a spoke tensioner, and used it on my wheels. Here's now you use it. 


Oil:

Before using the spoke tensioner, I added a few drops of oil to every spoke nipple. When the tire and rim tape is off, you can add the oil both top and bottom. The oil allows the nipple to turn easier. As a result, you can tighten the spokes more. 

In general, I use motor oil (or black automotive axle grease) on threads everywhere. The oil helps prevent corrosion, so the spoke won't suddenly break when you try to turn the nipple. It happens. 

Once I went to remove a bike rack that had been mounted for decades. I worried that the threads would be corroded so bad, that the tool might break. But the nut turned easily.  I thought, "Of course, I greased the threads!" 



Start With A True Wheel:

Before tightening up the whole wheel, remove the tires, and replace any broken spokes. Then true the wheels. Remember that truing wheels, involves both tightening, and loosening. Tighten on one side, loosen on the other. 

The spokes should not vary a lot in tension. Even without the tool, you will be able to tell if there are some spokes that are much tighter than others, by pinging the spokes. 


Measuring Tension

Take a spoke tension measurement of all the spokes around the wheel. Get an idea of how tight or loose the spokes are. Then use the chart that comes with the tool to tell what the tension is. 

Measuring Spoke Tension, Read the indicator on the bottom


Slow and Steady

I had already started with wheels that were pretty true, within a millimeter or so. Then I went to each spoke and tightened each nipple 1/4 turn. Take the tension measurements again. 

As you do this, you will be able to feel the increasing tightness in the spokes. When you ping the spokes with your fingernail, they will make a higher strung sound than the looser spokes. 

Rinse and repeat until the spokes are nice and tight. Do not go to the extreme. You need to leave some room if you ever need to true the wheels in the future.


Why High Spoke Tension Works:

Often spokes will break either at the nipple, or at the hub. Spokes break because of movement. When the wheel is stressed, the rim compresses and decompresses slightly as you ride over bumps. The spokes also compress or decompress. 

By tightening all the spokes evenly around the wheel, it requires a lot more force to flex the rim. As the rim flexes less, there is less spoke movement, and less spoke breakage.

The same principle keeps wheels true. If the spoke doesn't break, force can still move the spoke within the nipple. Either the nipple turns. Or, the spoke pulls through the nipple's threads (as I understand).  Then the wheel becomes untrue. 


True The Wheels Again:

After you have tightened all the spokes, you'll need to true the wheels again. My experience was that after tightening the spokes, the wheel was already pretty true. 

Tire Pressure:
Mount the tires and pump them up hard. I usually pump my tires to within 10 PSI of the maximum recommended pressure.  

The benefits of hard tires are: 
the least rolling resistance
fewer punctures, 
very difficult to get a pinch flat,
wheels will stay truer, longer


Conclusion:

I'm glad that I was curious, and asked what that tool was. Getting this spoke tensioner has really made my cycling life a lot better. 

Try it. You'll like it. 




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