Author Topic: spoke length, round up or down?  (Read 9373 times)

Offline Andrew Tarrant

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spoke length, round up or down?
« on: March 13, 2011, 12:20:31 AM »
Guys I want to build a wheel and used a calculator which tells me the length is "184.5mm", only I can either buy spokes in 184mm or 186mm, which would you recommend?
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Offline RobWire

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Re: spoke length, round up or down?
« Reply #1 on: March 13, 2011, 12:36:05 AM »
186. You might have to put on an extra roll of rim tape but you'd want to round up

Offline metalbmxer

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Re: spoke length, round up or down?
« Reply #2 on: March 13, 2011, 03:22:41 PM »
forget that! round down--no one likes spoke heads poking thru!!!!!!

it sucks and not worth it when theyre too long.
Dax (now in LAS VEGAS as of July 2022)

Offline Andrew..

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Re: spoke length, round up or down?
« Reply #3 on: March 13, 2011, 03:42:14 PM »
Yeah I'd go with the 184s. an extra 2mm might mean spokes poking out of the nipples which could mean plenty of punctures in the future considering the high pressure we run our tyres at, whereas .5mm shorter than recommended is barely even noticeable and you'll be sacrificing perhaps one thread, which isn't worth batting an eyelid over.
Isn't that bike a bit small for you?

Offline dan4130

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Re: spoke length, round up or down?
« Reply #4 on: March 13, 2011, 04:23:41 PM »
iphone has a free bike spoke calculator     just pick your hub and rim
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Offline Tuftybmx

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Re: spoke length, round up or down?
« Reply #5 on: March 13, 2011, 04:46:25 PM »
What hub and rim? Most likely, use the 184.

Offline Andrew Tarrant

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Re: spoke length, round up or down?
« Reply #6 on: March 14, 2011, 08:54:53 AM »
brill thanks!

Here's the spec:

Rim: Alienation Deviant Rim
Hub: GSport Marmoset Hub
Spokes: Odyssey Stainless Steel 14g Spokes
Cross Pattern: 3x
Mechanic is easy, all you need is a hammer and a blowtorch....BURN MOTHERf*ck BURRN

Offline Jake4130

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Re: spoke length, round up or down?
« Reply #7 on: March 17, 2011, 03:32:39 PM »
Yeah round down. Bitd we used to order them for EVERY hub and rim and a 3 cross as 7 1/4" (which is pretty much 184mm). The magic number for 4 cross was 7 5/8" every time no matter the hub (low or high flange) or 20" rim.
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Offline wookie

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Re: spoke length, round up or down?
« Reply #8 on: March 18, 2011, 01:11:15 PM »
If your using regular alloy nipples round up!  Because you want the spoke to get entirely through the nipple.  If your using brass or G Sport nipples round down.  They are stronger and the G sports are longer so you wind up needing slightly shorter spokes than most calculations derive.


Offline Andrew Tarrant

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Re: spoke length, round up or down?
« Reply #9 on: March 18, 2011, 09:05:58 PM »
Cheers again!

Weird that both online spoke calulators give different numbers, the iphone app gives another different length, and recently they updated the app and it's changed again....
Contacted bike shop I was buying both spokes and rims from and they gave me a different measurement so I don't know what to think, I'll just go by what the guys told me at the shop.

Thanks
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Offline PSchoolen

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Re: spoke length, round up or down?
« Reply #10 on: March 19, 2011, 05:11:10 PM »
Use 184mm for that wheel. Its a little short but that is ok. If I was building that wheel with a spoke I could customize the length of, I would use 185mm. If you are choosing spokes like Primo spokes that are painted and come in specific sizes, use 184mm.
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Offline Andrew Tarrant

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Re: spoke length, round up or down?
« Reply #11 on: March 21, 2011, 11:09:24 AM »
Thanks Pat!  :beer:
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Offline Leone4130

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Re: spoke length, round up or down?
« Reply #12 on: March 22, 2011, 05:16:32 PM »
may be a dumb question..... but how do you calculate spoke length???
My front = Homer hub on a rollcage rim
My rear = geisha light on a rollcage rim.. you can tell me spoke length but I'd like to know how to calculate them please!!!

Offline Andrew Tarrant

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Re: spoke length, round up or down?
« Reply #13 on: March 22, 2011, 10:02:51 PM »
may be a dumb question..... but how do you calculate spoke length???
My front = Homer hub on a rollcage rim
My rear = geisha light on a rollcage rim.. you can tell me spoke length but I'd like to know how to calculate them please!!!

You would measure the hub flange diameter, the offset and spoke hole diameter, also you would need to measure the effective rim diameter.
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Offline Jake4130

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Re: spoke length, round up or down?
« Reply #14 on: March 22, 2011, 10:34:36 PM »
Built hundreds of wheels over the years and honestly 20" was always the easiest. You basically had three main lengths you memorized and that was it:

36 4 cross:7 5/8"
48 4 cross: 7 1/4"
radial: 6 1/2"

And that is how they were ordered too. All that flange height and width stuff was all for mountain bike and road bike wheels. Of course there were some sizes that were always the same that you forgot too like 20" 32 hole or 20" Mini wheels. I still have to look those up.
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