Oddball spoke needed

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offroader
Posts: 114
Joined: 18 Dec 2018, 4:47pm

Oddball spoke needed

Post by offroader »

After 20+ years my unusual Shimano WH-M575 rear wheel has suffered a broken spoke.
The original part, Y-4AF98010 as far as I can tell, is long since discontinued
It's a bladed J spoke fitted "upside down" with the J hooked to the rim and the nipple embedded in the hub. Spoke dimensions as follows:-

Length, tip to inside of j bend - 260mm
Diameter of spoke 2.25mm (13 gauge?)
Diameter of threads - 2.45mm
Thread length - 10mm
Blade - 2.5mm x 1.8mm at right angle to j bend
All measurements taken with an uncalibrated Machine Mart digital caliper so not accurate to the Nth degree.

What has me perplexed is the thread diameter being larger than the spoke diameter. I think that it's probably a side effect of rolling the threads but I don't have enough wheel building experience to know. The nipples are pretty proprietary looking things so I'm also unsure if they use a proprietary thread pitch

I don't care about the bladed profile so I'm hoping a bog standard 13 plain gauge spoke will fit. Otherwise it looks like 7 quid a pop at custom spokes UK!

Hoping someone well versed in the mystic world of bespoke spokes can offer insights

Muito obrigado
JohnMorgan
Posts: 111
Joined: 9 Jun 2022, 7:19pm

Re: Oddball spoke needed

Post by JohnMorgan »

Hi,
Sorry, too exotic, certainly for me. Good luck with the search, though I suspect you will be ‘biting the bullet’ and paying for the bespoke . . .spoke :-)
TheBomber
Posts: 525
Joined: 16 Feb 2020, 8:18pm

Re: Oddball spoke needed

Post by TheBomber »

Don’t stress about the threads - just buy the matching nipple and that element will be fine. As you say you’re not worried about the bladed profile that should make it quite straightforward. If you do want ‘aero’ then Sapim CX Sprint or CX Ray would do - but they might be difficult to buy individually.
ANTONISH
Posts: 2967
Joined: 26 Mar 2009, 9:49am

Re: Oddball spoke needed

Post by ANTONISH »

I bought one of these wheel sets in 2006 at the "Semaine Federale" (a distress purchase) .
Initially ok but then I broke a spoke - got a couple of spares - while waiting I managed to bodge a repair using a standard spoke.
The spoke nipple has a standard thread but the body is larger than a conventional nipple.
My wheels had a fairly heavy lump of metal inside the rim - nipple at hub as in your case.
Basically a stupid design - I continued to break spokes - those bladed spoke aren't any stronger at the ends where it counts.
You could probably rebuild the whole thing with standard db spokes with judicious use of washers.
offroader
Posts: 114
Joined: 18 Dec 2018, 4:47pm

Re: Oddball spoke needed

Post by offroader »

Brilliant info Astonish, thanks

I've ordered a couple of 13 gauge spokes, here's hoping...
If it goes well I might relace the whole lot as the wheels have become almost family members despite their unconventional design choices



iandusud
Posts: 1577
Joined: 26 Mar 2018, 1:35pm

Re: Oddball spoke needed

Post by iandusud »

offroader wrote: 7 Jun 2023, 1:04pm Brilliant info Astonish, thanks

I've ordered a couple of 13 gauge spokes, here's hoping...
If it goes well I might relace the whole lot as the wheels have become almost family members despite their unconventional design choices
I would expect the spokes and thread to be 14 guage. 13g is tandem territory, and even then usually single butted 13/14g
ANTONISH
Posts: 2967
Joined: 26 Mar 2009, 9:49am

Re: Oddball spoke needed

Post by ANTONISH »

offroader wrote: 7 Jun 2023, 1:04pm Brilliant info Astonish, thanks

I've ordered a couple of 13 gauge spokes, here's hoping...
If it goes well I might relace the whole lot as the wheels have become almost family members despite their unconventional design choices
Well I hope that works for you.
I took the cannibalized the freehub from the rear wheel and the wheelset sits in my garage as reminder not to buy another like it.
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