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Impending rim failure of a 650b WTB ASYM i23p

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Andrew Chaplin

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Jul 12, 2021, 7:24:36 PM7/12/21
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The rear wheel on my Kona Rove NRB DL has gone out of true. On closer examination, it is obvious that the rim is cracking around the spoke holes, apparently due to fatigue. Why is this happening? If it isn't a poorly engineered rim, how do I prevent it from happening again? Am I, at 85 Kg and carrying, typically, 10Kg (or less) too heavy for the bike? What rim would you recommend as a replacement? I notice that WTB has ended production of the rim, and I have read vague reports of failures from some 8 years ago.
--
Andrew Chaplin
SIT MIHI GLADIUS SICUT SANCTO MARTINO

jbeattie

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Jul 12, 2021, 7:40:32 PM7/12/21
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It is fatigue cracking and an unfortunate fact of life with highly tensioned and dished wheels built on relatively lightweight rims. It may be aggravated by braking loads produced by discs. The remedy is lower spoke tensions, perhaps lighter gauge spokes (if you wanted to buy new spokes), thread lock and/or more robust rims. If I were selecting a rim, I would replace the old one with the same model and just adjust spoke tension, or I'd find a more robust rim with the same ERD because I hate buying spokes. They're wickedly expensive these days. I've always liked DT rims for value/performance/availability.

-- Jay Beattie.


AMuzi

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Jul 12, 2021, 7:48:05 PM7/12/21
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Quality products exist:
https://www.velocityusa.com/tech/rims/

https://www.velocityusa.com/product/rims#sizes-tab

--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971


Frank Krygowski

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Jul 12, 2021, 8:08:56 PM7/12/21
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Just speculating, because I haven't needed to try this except in one
very unrelated case, but:

I wonder if washers under the nipple heads would distribute the spoke
force a bit and lessen the chance of cracking. I think a rim without
eyelets would have the best chance for this strategy being effective.


--
- Frank Krygowski

Andrew Chaplin

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Jul 12, 2021, 8:23:24 PM7/12/21
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Thanks, gents. Andrew, for whatever reason, velocityusa's site is not working or won't come up. ABC

AMuzi

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Jul 12, 2021, 8:33:28 PM7/12/21
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Probably yes (historically Fiamme Blue Label, Martano,
several Nisi models).
A better solution may be a better material with steel
inserts such as a Velocity Atlas.

AMuzi

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Jul 12, 2021, 8:36:38 PM7/12/21
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Velocity USA Atlas rim in 650B has steel inserts in a robust
cross section:

https://cdn.shopify.com/s/files/1/1403/7343/products/wsw7xtd_947e2137-3cbf-48b1-a83e-e571b9ab1ac1_1600x.jpg?v=1504642175

Tom Kunich

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Jul 13, 2021, 12:58:32 PM7/13/21
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They also make these rims out of high strength aluminum so they tend to crack after a time due to stress. As I have told many people - Mavic Kyseriums only last about a year if you are over 170 lbs.
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