Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 11-10-04, 08:57 PM   #1
kappa_italia13
Senior Member
Thread Starter
 
Join Date: Oct 2004
Bikes:
Posts: 71
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Spoke tension?

I have a pair of Gipiemme wheels with Platinum rims. The front wheel has 8 pairs of two spokes. The rear has 16 on the one side, and 8 on teh other, and they are paired in groups of threes. Does anyone know the proper spoke tension for these wheels. I have checked the manufacturers site and can't find any information. Any help would be great. Thanks.
kappa_italia13 is offline   Reply With Quote
Old 11-10-04, 09:30 PM   #2
cascade168
Klaatu barada nikto
 
cascade168's Avatar
 
Join Date: Sep 2004
Location: Southern NH
Bikes:
Posts: 1,453
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
It's pretty straight forward. If you can supply the gauge of the spokes, material, and bladed/or not. If you don't know the gauge, you can mike the diameter and give it in mm (to 0.1 mm accuracy). For bladed spokes you need the flat dimension and the thickness in 0.1mm accuracy. If the spokes are round and butted, just give the smallest diameter. This is all in a table at:

http://www.parktool.com/pdf/instructions/TM_1table.pdf

If you are not using a Park Tensiometer, the numbers are still good, but you cannot use the scale readings in the left hand column. You would need to convert to whatever tensiometer you are using. Hope this helps.
cascade168 is offline   Reply With Quote
Old 11-10-04, 10:32 PM   #3
AndrewP
Senior Member
 
Join Date: Sep 2001
Location: Montreal
Bikes: Peugeot Hybrid, Minelli Hybrid
Posts: 6,521
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
If you are not using a Park Tensiometer that table is useless, because all it tells you is how to convert the reading on the tool to kg tension. It does not tell you the correct tension for any particular rim. Usually the tension is in the range 80 - 130 kg. It depends on the strength of the rim, so go directly to the rim manufacturer and ask. Note that the spoke tension drops when the tire is inflated, and the recommended tension will be for a rim without the tire inflated.
AndrewP is offline   Reply With Quote
Old 11-11-04, 01:12 AM   #4
cascade168
Klaatu barada nikto
 
cascade168's Avatar
 
Join Date: Sep 2004
Location: Southern NH
Bikes:
Posts: 1,453
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by AndrewP
If you are not using a Park Tensiometer that table is useless, because all it tells you is how to convert the reading on the tool to kg tension. It does not tell you the correct tension for any particular rim. Usually the tension is in the range 80 - 130 kg. It depends on the strength of the rim, so go directly to the rim manufacturer and ask. Note that the spoke tension drops when the tire is inflated, and the recommended tension will be for a rim without the tire inflated.
I do not agree that the table is useless for other tensiometers. It lists a safe range of tensions for spokes of given diameters, shapes, and materials. These figures have nothing to do with the instrument itself. All tensiometers are doing essentially the same thing by measuring the amount of spoke deflection under a given load. The scales they use are relative to the specific instrument. No matter what tensiometer you are using, you are looking for a measurement that will convert to Kgf (or Newtons, or pound force). So, assuming you can convert whatever reading you get from your tensiometer to Kgf (or Newtons, or pounds force), then you are in business.

If you can't get a manufacturers spec for max spoke tension you can find it during truing. When you get the wheel trued increase the tension for all spokes equally in small increments (try 1/2 turn or less) and re-true. Eventually you will get to a point where the rim does not respond normally to truing corrections - this is because it's overtensioned and trying to collapse. For example, if you are truing to <0.5mm for lateral and radial and all of the sudden you have a 2-3mm error(or more) after increasing the tension all the way around, it's time to back off. So, then you back off until it does true normally and this should be very close to the maximum tension for the rim - and that is what you want for a strong wheel. This method is tedious but it works. You can find this method described in more detail in Gerd Schraner's book.


I will agree that 80-130 Kgf will work as a safe maximum (assuming the wheel is behaving normally), but you can often go higher and will get a better finished product.
cascade168 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:29 PM.