wheel building with asymmetrical rims
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wheel building with asymmetrical rims
How do I find the spoke length? should the spokes be different lengths for drive side and non-drive side? Or should the be different, thanks.
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Originally Posted by you
How do I find the spoke length? should the spokes be different lengths for drive side and non-drive side? Or should the be different, thanks.
SpoCalc is available free. You just need an app that will run Excel spreadsheets (eg. MS Excel or Star Office). You can download Spocalc from Sheldon Brown's site:
https://www.sheldonbrown.com/rinard/spocalc.htm
It's great for several reasons. First, it has a very large database of rims and hubs. It does all the math for you. Once you plug in the numbers it automatically calculates the spoke lengths for radial, 1x, 2x, 3x, and 4x lacing patterns. If you can run spreadsheets it's a great way to go. Even if your specific rim or hub is not in the database you can do all the entries manually and the calculations are still automated. There is a specific variable entry for OC rims. It is "O.S.B." This is the "lateral spoke bed offset (from wheel center). Non-zero for asymmetric rims".
If you can't get Spocalc up and running, I can run the numbers for you, but you will have to supply them for me. For the rim you need the OSB and the ERD. For the hub you need five different measurements. The best bet is to supply the specific model numbers for the rim and hub and see if they are already in the SpoCalc database.
I looked at the other two spoke calculators I have used (DT Swiss and Promechanics.com) and neither of them accounts for offset rims.
Does anyone know of some calculator (other than SpoCalc) that takes an O.S.B. variable?
Last edited by cascade168; 01-28-06 at 07:23 AM.
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I used spokecalc and wasn't sure if the spokes should be the same length or not, I also noticed that the only rim dimension taken into account is the effective rim diameter not how the rim is dished or whatever. I am using the Aerohead OCs.
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Originally Posted by you
I used spokecalc and wasn't sure if the spokes should be the same length or not, I also noticed that the only rim dimension taken into account is the effective rim diameter not how the rim is dished or whatever. I am using the Aerohead OCs.
So, are they different lengths? I'd guess that they are 1mm different. Most rear wheels have spokes that are 2mm different from drive side to non-drive side.
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yeah they're a mm different, thanks.
should the spokes be of equal tension?
should the spokes be of equal tension?
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Originally Posted by you
yeah they're a mm different, thanks.
should the spokes be of equal tension?
should the spokes be of equal tension?
To specifically answer your question, no, I don't think they'll be the same.
So, what is that ratio?
A word of caution here... I have found that ratio number produced by Spocalc to be a nice guideline, but it's most important to tension up the drive side spokes to the rim manufactureres max specification to get the strongest wheels. Get them all tensioned up and then you can finish your truing and dishing with the non-drive side spokes. I just check them to make sure there is not a spoke that is much differnt from the rest - and, I have built wheels that this happenned to me. One spoke would be way loose and the wheel would seem to be done. In this case you tighten up that spoke and re-check everything else. Don't get hung up on the tension for the non-drive side spokes. Just make sure there are no noticeably loose ones. Concentrate on the drive side spokes. They are doing the "heavy lifting" for your rear wheel.
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Originally Posted by you
yeah they're a mm different, thanks.
should the spokes be of equal tension?
should the spokes be of equal tension?