spoke length calculator

[albion]

err Right. Now tell me, how did the spoke work loose ?


BTW Thread starter should be able work backwards from actual correct spokes in hand to find the hub or rim sizing. One of them was obviously wrong.

 

[Venod]

I can't relate to X Y ad Z without the book in front of me but a 140 OLD is not right. Mountain bikes are 135, road bikes 130, tandems 145 and some downhillers 150mm.
595 ERD is possible. That means it is a reasonably large profile 700C rim.

140 OLN Hubs are available.

http://philwood.com/store/page14.html

 

[Yellow Saddle]

140 OLN Hubs are available.

http://philwood.com/store/page14.html

Yes, but he said Giant PR-2, those were all 135mm MTB IIRC. There is also 142mm with 10mm through axles but not on those era Giants. I'll be very surprised if it is 140mm and being skeptical makes the difference between getting the right spokes first time and ending up with a batch of spokes that won't work. Where is the 140mm used? Can't say I've ever come across such a bike.

 

[confusedcyclist]

I haven't been able to find my steel ruler, and don't own a venire. I'll see what I can borrow from work.

Thanks for the tips guys, I'll just get like for like spokes, but really want to get to grips with wheel building so wanted to do properly. Guess I don't have the tools for the job at the moment!

 

[Venod]

Yes, but he said Giant PR-2, those were all 135mm MTB IIRC. There is also 142mm with 10mm through axles but not on those era Giants. I'll be very surprised if it is 140mm and being skeptical makes the difference between getting the right spokes first time and ending up with a batch of spokes that won't work. Where is the 140mm used? Can't say I've ever come across such a bike.

I was just pointing out that 140mm oln is a hub size it was the old tandem size.

 

[albion]

.. Guess I don't have the tools for the job at the moment!

Reading the whole thread, you now need a very large 'tangent'.
Though I'm now wondering, are there many proprietary spokes on top end wheels?
When I swapped an old Rim for a new old Rim, by luck they were identical. So the 295mm ones I did not clod like break, all got reused with good success. (no breaks so far)

 

[Smurfy]

I recently used Damon Rinard's Spocalc spoke length calculator, and the results came out spot on. The spokes should end at the bottom of the nipple slots, so make sure that you measure the ERD with that dimension in mind.

 

[FrankCrank]

Recently built my first wheel using this spoke calculator:

http://www.sapim.be/spoke-calculator

.....and this excellent video tutorial:

http://www.atomiczombie.com/Tutorial - 3 Cross Wheel Lacing - Page 1.aspx

I used a spoke size about 2.5mm shorter than the optimum, and worked out perfect. In the tutorial, just follow the nine video steps rather than the text, difficult thing to describe in words I guess

Sorry about the links - not sure how to do them as something you just click on.......
.....I see now - does it after you send - clever eh....

 

[voyager]

Thanks Frank

and a happy new year to you

regards emma

 

[Spoked Wheels]

I used a spoke size about 2.5mm shorter than the optimum,

Was there any particular reason to do that or you had some spare spokes?

 

[Ian H]

I recently used Damon Rinard's Spocalc spoke length calculator, and the results came out spot on. The spokes should end at the bottom of the nipple slots, so make sure that you measure the ERD with that dimension in mind.

That would be the minimum length for proper engagement. There's no problem with a mm or two above the spoke head on modern box-section rims. On old-style single section rims the final task would often be to file the spokes flush with the nipples. Remember the relatively short, threaded part extends all the way to the top of the slot.

 

[Yellow Saddle]

Was there any particular reason to do that or you had some spare spokes?

The calculator calculates the exact geometric length of the spoke from where it exits the hub to where it meets the nipple's slot (provided that's how you measured the ERD). When cutting spokes you always round down, never up. Reason is that spokes stretch during tensioning and the rim compresses. If you don't round down, the spokes tend to go past the nipple's slot which isn't really a problem other than you can't use a screwdriver to remove a nipple with its flats stripped off. I'm just fastidious, I don't like protruding spokes.
The calculator therefore comes up with a fractional length, say 297.4mm and spokes are supplied in mm increments only. You then round DOWN.
From experience my rounding down goes like this:
1) On a 700C/29er wheel with double-butted (1.8mm) spokes you round down by up to 2mm. The example above would then become 296mm.
2) On a 26" wheel with double butted (1.8mm) spokes you round down by up to 1.5mm. The example above would then become 296mm too, albeit a 26mm rim would have had an ERD of 560mm and the spoke length would have been more like 263.3mm. Rounding down would have made the length 262mm.
3) On a 700C/29" rim with double butted (1.5mm) spokes you round down by up to 3mm. The example above would then have become 295mm.
4) On a 26" wheel with double butted (1.5mm) spokes you round down by up to 2mm. The example above would then have become 261mm.

 

[Smurfy]

I always check how far the nipple will screw onto the spoke thread first. For my current Sapim-Sapim Spoke-Nipple combination, I've found the answer is not very far at all, and anything more than a tiny bit of spoke above the very top of the nipple will see the threads bottoming out on each other. Unfortunately that leaves very little room for error, as the nipple slot is only about 1mm deep, and some people suggest that the bottom of the nipple slot is an absolute minimum spoke length, so as to prevent the nipple acting in tension. The subject of rounding is a tricky one, seeing as some spokes only come in 2mm increments. If you have a required length of 263.8, rounding down would see you at 262mm. I rounded up my calculated lengths of 265.3, 263.8 and 265.4 to give me lengths of 266, 264 and 266, and all the lengths came out good.

 

[FrankCrank]

....I went along to my LBS in BKK and showed him the length of spoke I needed. He didn't have that exact size (no surprise), and gave me a bunch of them at 2.5 shorter. He knew from 60 years of building wheels that these would do the job. Any future builds I do will be the same - a tad shorter than optimum. If I went for the next size up I'd have to file or grind back the spoke protrusion from the nipples - no big deal, but why bother, just get shorter size instead. Once you've screwed the nipples onto the spokes 3 or 4 turns, you're not gaining any more strength, if you see what I mean.....

 

[Spoked Wheels]

....I went along to my LBS in BKK and showed him the length of spoke I needed. He didn't have that exact size (no surprise), and gave me a bunch of them at 2.5 shorter. He knew from 60 years of building wheels that these would do the job. Any future builds I do will be the same - a tad shorter than optimum. If I went for the next size up I'd have to file or grind back the spoke protrusion from the nipples - no big deal, but why bother, just get shorter size instead. Once you've screwed the nipples onto the spokes 3 or 4 turns, you're not gaining any more strength, if you see what I mean.....

I think I see what you mean.

Spokes don't come in half mm so your spokes were either 2 or 3mm shorter

My guess is that your measurements maybe weren't accurate enough, if you think you would have "to grind back the spoke protrusion from the nipples" with the next size up. Did the LBS ask what rims and hubs you were using?

The only advise I can offer is that if you entered the dimensions on three different spoke length calculators you more than likely get three different spoke lengths so I use only one. the wheelpro calculator and I follow his instructions..... anything up to 0.6 and round down, however, sometimes you are faced with the situation that only even spokes sizes are available and I have to brake the rule to maintain the other rule that I don't go over 1mm either way.and that seems to work for me.