TM-1 텐션미터와 파크툴 텐션 분포도를 계산하는 프로그램을 이용해서 측정해 본 커스텀 휠 스포크 텐션값 분포도입니다.
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Tension...it's all relative
Winter above the 45-degrees North Latitude line can be a long and dark time. What better use of your time in sub-zero weather than to relax, indoors, with a TM-1 Spoke Tension Meter, a wheel, and a lap top computer? Many readers might appreciate the first two, but this article is intended to illustrate the advantages of using spreadsheets. This is a re-introduction of the Tension Conversion Calculator (TCC). To appreciate the TCC, you should first become familiar with the TM-1.
The true heart and soul of the TM-1 is the tension conversion table that lists conversions from the tool deflection reading into kilograms force, or the amount of pulling force on the spoke. Tensiometers work by pushing against the spoke and taking a reading of the amount of "push" or deflection. The TM-1 has a chart that converts the tool reading (a "deflection reading") into the amount of force pulling on that particular spoke. The TM-1 can measure the spoke tension (force) pulling on the rim. It can also be used to determine if the spokes are relatively even in tension between one another.
On a computer with Windows® Excel or an equivalent program installed, the TCC uses information drawn from the tension conversion table in a spreadsheet. The TCC greatly speeds converting a deflection reading from the TM-1 into a measure of tension force on the spoke. Additionally, the TCC creates a visual representation showing the tension balance between the spokes of the wheel. The TCC also allows the professional builder and mechanic to document on paper the quality of their work, and other wheels can be evaluated for tension problems.
NOTE: The TCC is provided as a support service for the TM-1. It will not work with other tension meters other than the Park Tool TM-1. Park Tool will appreciate any feedback, questions, or comments. Please email firstname.lastname@example.org directly any concerns. Use subject line "TCC".
There are two different version of the TCC spreadsheet. The TCC_15.xls works with Windows® operating systems. This version uses "VBA" and will not work with many MAC's. PC users should download and save the file below. Both versions will produce similar results and yield a chart similar to the one below:
TCC_Revision15FormBased.xls (PC USERS ONLY)
After downloading the file to your hard drive, open the file. The spreadsheet software will ask you to "enable macros". The macros must be enabled for the TCC to work. This version of the TCC uses one file, with one worksheet called "Instructions". As you create new charts, the finished worksheet will open as a tab. Data is entered on a series of forms. The first form begins with creating a name for the Sheet. This can be a short description of the wheel, or the customers name.
After filling in the Sheet Name, click the box below, "Set Up Sheet for this Wheel". After this, click the box, "Next". The next form begins with Select Spoke Type. View first spoke material, shape and size. Do not use the ordered number of spoke as the spoke size. A 2mm spoke is the fourth spoke down, "steel, round 2". Highlight the correct spoke, then enter the right and left side spoke counts. Typically these are the same. You must also list a target tension. If you are not sure, enter 100.
The form for data entry will open. Enter the reading from the TM-1 here. You will see the Kilogram force converted as you proceed. This page also averages the wheel kgf values. Any spokes that are outside of a plus or minus 20% range are highlighted in red. This can be useful when tension balancing the wheel. After entering the right side data, click NEXT and repeat for the left side. Click FINISH and the chart will appear. This page will not accept new data changes after hitting FINISH. All readings and kgf values are listed here, and a graphic representation of the wheel is shown. The left side and right sides are shown separately, and then a combined chart showing the two sides together.
This project and spreadsheet are a working version. You may experience errors, sometimes seen at a "Run Time Error". If this occurs, cancel and close the form and then delete that worksheet form the file. Begin a new worksheet.
MAC with 2008 Microsoft Office
The MAC using the 2008 Microsoft office is unsupported at this time. A separate TCC is to follow.
TCC_13MAC.xls for MAC users and PC users
After downloading the file to your hard drive, open the file. The spreadsheet software will ask you to "enable macros". The macros must be enabled for the TCC to work. Begin by selecting the page titled Spoke Tension Record. You may need to change view if you cannot see the entire spread sheet. Select "Zoom" from "VIEW" in the tools menu. Next, select the page titled Instructions.
You will need to use and be familiar with the Windows® Excel program to open and run the TCC. The program will ask you to "Enable Macros". Macros must be enabled for the TCC to operate. It is recommended that you save the file when you download it with the original file name as given. As you work on new wheels, you can perform a "save as" procedure and rename the file for the wheel being worked on. The file name can include the date of service, customer, or model of wheel. Unlike the PC version of the TCC, the TCC_13MAC.xls uses one file per wheel.
There will be two worksheets in in the TCC, which are labeled on the bottom as Instruction and Spoke Tension Record. Begin by reading the Instruction page before continuing with the Spoke Tension Record.
The TCC has room to record consumer or user information such as name, address, etc. There is also room to record wheel information such as rim, or hub cross pattern. The key buttons are the MACRO CONTROLS. Begin by clicking "Step 1, Spreadsheet reset " to clear the sheet. For the next step, notice first the SPOKE CODE TABLE. You will see a code number next to descriptions of various spoke types. There are more choices on this TABLE than on the paper chart included with the TM-1. Find your spoke type, and click on "Step 2 Spoke Code". Enter the code here. Do not attempt to enter the spoke size or dimensions, only the SPOKE CODE.
The next step is Step 3. Click the MACRO CONTROL, "Step 3, Right Side Spoke Count". This is commonly one-half the number of spokes in the wheel. If there are 32 holes, enter here 16. Notice the diagram change to show the chart having your selected spoke configuration.
Step 4 is optional, but useful. Click the MACRO CONTROL "Step 4, Target Spoke Tension" and enter the desired kgf average. The TCC will give you the TM-1 reading equal to that kgf.
After these steps, make sure the cursor is in the RIGHT SIDE SPOKES table, in the "TM-1 Reading" box next to "Spoke Number 1". It is recommended to begin at the valve hole. On the right side of the wheel, number the spokes to the right from here. On the left side of the wheel, work from the valve hole again, but number the spokes to the left. This system will keep the numbers of the left and right side spokes adjacent to one another on the chart.
The TM-1 is measuring spoke #5, as seen at the rim
As you enter TM-1 reading, you will see the TCC convert these to Spoke Tension. The TCC will automatically determine the Average Spoke Tension ( in kgf), the standard deviation in tension, and the tension limits and reading limits in a range of plus and minus 20% of your average. Wheel builders may decide that they want a tighter range than this default 20%. For example, if you want a plus or minus 10% range, multiply your average by 1.10 and then by 0.9 for your kgf averages. The graphic chart to the right of the RIGHT SIDE SPOKE table shows visually the relationship between the spokes. Record readings from the left side of the wheel under the table LEFT SIDE SPOKES. The average tension in Kilograms Force (kgf) is again determined.
Notice the chart "Combined Spoke Tension". This is a graphic representation of forces between the left and right side spokes. This can be used to correct tension imbalances and for diagnosing potential problems with the wheel.
Tension Balance with the TCC
The TCC is a tool to help the wheel builder achieve a good average spoke tension. It can also speed the process of "tension balancing. This adjusts the spokes so they are relatively the same tension. Spokes that are too tight or too loose relative to other spokes create problems. However, it is unlikely all the spokes are exactly the same tension. When comparing spokes while tension balancing, compare only same side spokes. In other words, compare right side spokes to right side spokes, and left side spokes to left side spokes. This is especially true on rear wheels and front wheels with dish offset, such as front wheels with disc hubs. One side will be tighter than the other. This pulls the rim to center it over the middle of the axle locknuts.
In example #1 below, readings were taken from a 24 hole wheel, called here Wheel #1. The table shows the readings and kilogram force for each right side spoke. The TCC automatically configures the table from your deflection readings. The right side average spoke tension was 105.8 kgf. Deviation was 10.4 kgf. If a plus or minus 20% range was desired, the range was from 84.6 kgf to 126.9 kgf.