For some strange reason (probably because I have a 32/40-spoked bike), this question interested me.
It seems unlikely to me that any manufacturer would use 32/40 spoking simply to make the spokes equal in length. The cost of stocking two different rims probably exceeded the cost of dealing with different size spokes, which were bought in very large quantities and were almost certainly quite cheap, at OEM prices. It would also have constrained the hub selection somewhat, which would have had a cost impact and might have been unacceptable for other reasons. Finally, it doesn't explain why bikes (like mine) with nearly identical front and rear hub sizes still used 32/40 spoking.
To see if this idea is even plausible, I ran some numbers, based on typical front-hub dimensions and a Sturmey-Archer rear hub. Turns out that, yes, you can get the spokes nearly identical (say, within 2-3 mm) by using 3x front spoking and 4x rear. However, you can also get them nearly identical with both 36-spoke wheels by using 2x front and 3x rear spoking.
I suspect that the real reason was the obvious one: it looked good to customers, who recognized that the rear wheel carried more weight, and denser spoking in the rear made it appear stronger.
Steve Maas Long Beach, California
The Maaslands wrote:
> Wes wrote:
>
>> Or the British custom of 32 front/40 rear spoking. Was the reason for
>>this simply biasing strength toward the more heavily loaded wheel? I once
>>
> was
>
>>told that it enabled the same length spoke to be used with a small flange
>>front and hub gear rear wheels; I never investigated to see if this makes
>>
> any
>
>>sense.
>>
>
> There is absolutely no truth to this statement. Furthermore, Coppi almost
> always rode 32/40 hole wheels. His influence was so strong that Bianchi even
> started doing this for virtually all their top-end racing bikes too.
>
> Steven Maasland
> Moorestown, NJ
>
>
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