Front Wheel Rebuild

I’m in the middle of rebuilding the front wheels of the black Sprint. They served me very well for close to 6,000km and it was actually nothing wrong with them.

Ok, the spokes where too short. Despite meticulously measuring the rim size (ERD) several times and consulting several online spoke calculators multiple times, the calculated spoke length I used, was 3mm too short. I got an other of these rims in 24″ size for the rear and there the spokes are 3mm too short, as well.
The only explanation I came up with, spoke calculators estimate some ‘rim shrinkage’ due to spoke tension, but these very sturdy rims simply don’t budge. I never had the same problem with any other rim.

Sadly these beautiful, 47mm wide, polished, 20″ rims are not available anymore. Hence, they get ‘updated’ with black anodised, 90mm Sturmey Archer drum brake hubs from Gingko. Thought about the new heat-sinked SA+ drum hubs for a moment, but I’m not living in a mountainous area and haven’t actually experienced brake fading from overheated drums.

The first wheel went quite well, the rim is about 0.25mm radial out of true and 0.11mm latheral out of true. The new spokes are 0.5mm too long, but that’s well within the tolerance (+/- 1mm) you have for spoke length.

old vs. new:
_ms22485_web

to get an idea how massive these 47mm wide rims are
_ms22490_web

not exactly the right rim size for 28mm wide Duranos 🙂
_ms22489_web

skinny tyres on way too wide rims sure look nice
_ms22487_web

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