How do I stop spokes from breaking?

By Richard Hallett
I recently broke three spokes on my Genesis Tour de Fer 20, during a tour of the Western Isles with two rear panniers. The first spoke broke on Harris, immediately buckling the rear wheel. I caught the ferry back to Portree on Skye, and local cycle shop Island Cycles replaced it. During the repair, they found a second broken spoke. Thirty miles later, another broke. During my trip, I had hit two hidden pot holes but I wasn’t riding off-road. I am looking for ways to avoid this happening in future. One option is to have the wheel rebuilt (as well as avoiding potholes). But is there any guidance on working out how much weight we should carry?

Alan Bowie

Hitting a pothole may dent a rim but is unlikely to break a spoke unless it is already weakened by fatigue, which is the factor responsible for almost all spoke failures. The best way to avoid spoke fatigue is to go to a skilled builder, who will advise on spoke count and rim weight (heavier rims are stronger…) and use correct spoke tension and proven stress-relieving techniques to minimise the cyclic loading responsible for fatigue failure.

As a rule of thumb, 36 spokes is the minimum count for any 700C wheel expected to carry a pair of loaded panniers; smaller wheels (e.g. 26in/ISO 559) are inherently stronger and you may find 32 spokes sufficient, depending on rider weight. Obviously, it is a good idea to avoid potholes where possible.

Richard Hallett

​​Cycle magazine's Technical Editor

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This Q&A was published in 'Cycle' the magazine for members of Cycling UK. To contact the experts, email your technical, health, legal or policy questions to [email protected] or write to Cycle Q&A, PO Box 313, Scarborough, YO12 6WZ

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