Your new ICAN wheels are held true by tension spokes, how many of you knew the correct term for your spokes was tension spokes? Probably not a lot of you. That is why you need to know about wheel tension.
Once you have understood wheel tension, you will find it easier to true your own wheels. You will no longer have to believe that wheel builders are mystic that uses magic to build you a perfect set of wheels. Everyone can learn and understand the intricacies of wheel building.
Don’t worry we will explain any jargon used. We’ll keep the guide as simple as possible so as to help you understand the importance of keeping your ICAN wheels under tension.
First thing’s first we are going to recommend you buy yourself a tool. The old myth of pinging spokes and listening to the noise will not tell you the tension of your spokes. For measuring spoke tension, we recommend Park Tool’s TM-1.
So you are probably looking at that image and thinking “How does that even work?”
Which is an understandable question.
Firstly we need to understand exactly what the TM-1 (and other spoke deflection tools) does, that will then feed into our knowledge of how it works.
The TM-1 can measure the tension of each of the spokes in your wheel, it is designed to work on any and all spoke varieties. It can also though measure the average tension of the spokes in your wheel and the relative tension of all the spokes in your wheel.
- Average tension. The average tension is as you would imagine the sum of all the right hand or left hand spokes individual tension measurements added together and then divided by the number of spokes on that side of your wheelset.
- Relative tension. Relative tension is the tension measurement of one spoke when compared to at least one other spoke in the wheel build. In order for your wheel to be an acceptable build all of your spokes will need to be plus or minus 20% of the average spoke tension.
For your new wheels to last a long time, it is essential to check the tension on your spokes. Your spokes have to be tensioned as to keep your new ICAN wheel’s true and also be able to support your weight. A wheel that can not support your weight is not a great wheel. All wheels lose tension over time so keep an eye on your tension.
You will want to check the tension on new wheels over the first couple of weeks. There will be a bedding in process, and it is better to catch any issues now than just to let them become a bigger problem. All wheels need to bed in. After the first couple of weeks you will not need to check your wheels as often but get into the idea of doing quarterly or so.
The reason why spokes lose tension over time is that every time that a spoke hits the ground on the bottom of a wheel revolution the spoke loses tension, we call this a stress cycle. So if your spokes are already loose, then this exacerbates this part of the cycle. It will significantly reduce the lifespan of your spokes.
Many people think that the obvious solution to this is to ramp up the tension on your spokes. You don’t want to do this if anyone tells you to do this then feel free never to take their advice ever again. Too much tension will lead to your rim cracking or deforming. Both of these options will have you buying new rims and spokes or a whole new wheel.
It is not only your rim you could destroy, but you can also pull the flange off your hub or crack your hub shell with too high a tension. Your rim and hubs are designed to withstand a certain degree of tension, but you do not want to go over that limit.
You also need to pay attention to your relative spoke tension as well as your average spoke tension. You would ideally want all of your spokes to be around the same tension. The closer they all are to each other the better.
If your wheel suffers from big differences in relative tension, you will find that your wheel is not laterally stable. You will also see that it comes out of true a lot. You want neither of these issues, so by checking your wheels over you can save yourself a lot of problems in the future.
Wheels are designed to withstand forces, that is one of their primary jobs and why they feature a lot of triangles in their design. Look at a wheel it is more triangle than a circle, remember a triangle is the strongest geometric shape.
You will find a lot of variation in what spokes can withstand tension wise. That is why we look at the weakest part of the wheel and build around it. Your rim is a circle and not yet supported by triangles. For that reason, you build your wheels tension around what your rim can withstand.
Tensioning Your Spokes
I have talked a lot about the dangers of not having correctly tensioned spokes, you may now be suffering from an overload of information. So rather than spelling out what you need to do to tension your spokes. I am going to pass you over to a Park Tool demonstration on YouTube.
So now you have all the information, we can carry on.
Average Spoke Tension
So you now know each of your spokes deflection measurement. You can also work out the average by adding all the totals together of each side and dividing by the number of spokes on that side of your wheel. The left side and the right side will nearly always have a different average deflection measurement.
You will the want to take that deflection number and convert it into spoke tension by using the conversion chart below. It is not as scary as it looks. Just take your time. The blanks spaces mean your ICAN wheels are either over tensioned or under tensioned if they are above or below the numbers listed.
The below conversion table allows you take the deflection number that you see on the TM-1 and turn it into kilograms force (kgf). At ICAN we use kilograms force as it is the easiest tension measurement to understand, other companies may use Newtons and pounds force.
You will find that 1 kgf is equal to 10 Newtons or 2.2 pounds force. So a 100 kgf is 1000 Newtons or 220 pounds force.
Tension Balancing and Relative Spoke Tension
Relative tensioning is when you compare one spoke to one or more other spokes on the same side of the wheel. You do not want to be testing a rear drive side spoke against a rear non-drive side spoke. A drive-side spoke will always have more tension. You will find with disc brakes that the front left is always higher than the front ride spoke’s tension.
You need your spokes to be within plus or minus 20% for the wheel to be considered acceptable. Working out relative tension is a bit more difficult than working out the average tension.
- Once you have your average tension measurement multiple that number by .8 and by 1.2. The new numbers will the range within which your spoke’s measurement should be.
- Take a deflection reading and convert it with the chart above.
- If the spoke is acceptable, move on. If not make adjustments.
Your ICAN Wheels
So you have taken the deflection measurements and turned them into tension measurements. You are now wondering exactly how much tension you should have on your ICAN wheels, that is why we have created you the simple to use chart above.
You want your tension to be about or just below the kilograms force (kfg) listed above, if you can do that your wheels will have a long and happy life.