[First wheel build] 20" ultra-durable cargo front wheel + repair questions

Tech
1

Hej hej,

I want to do my first wheel build and would love a bit of help from the experienced builders here.

The Context: I commute year-round in Gothenburg, Sweden on a Lovens Explorer 1 cargo bike. Total system weight is around 180kg (me + two kids in the box). Because changing the front brake pads is much easier on this bike, I rely almost entirely on the front brake, which I guess subjects the spoke to unusual torque. At the 3000km, the front wheel (Ryde Andra 40 / Shimano Deore 36h) had one spoke snapped at the J-bend, repaired at around 3500k, and at 4000 another one broke.

The Plan: Instead of just replacing the spoke on the original wheel, I want to use this as an excuse to build an ultra-durable summer wheel from scratch, and repair the stock wheel to keep as a dedicated winter setup for my studded tires. My fork only accepts a 15x100mm thru-axle.

So far my research led me to this build:

  • Rim: DT Swiss U 663 (20" / ETRTO 406, 36-hole) Going with 30mm internal width to better support my 55mm Schwalbe Pick-Up tires.

  • Hub: Shimano Deore XT HB-M8110 (15x100mm, Center Lock, 36-hole) or if I can’t get it delivered in Sweden, the Hope Pro 5 Limited by the fork here

  • Spokes: Sapim Strong (2.3/2.0 single-butted J-bend) just want the absolute strongest possible

  • Nipples: Sapim Polyax Brass (14mm) same here

Standing questions:

  1. Lacing Pattern: I’m planning on 2-cross. I know 3-cross is the disc brake standard, but on a 36-hole 20" rim paired with the XT’s flange, I assume 3-cross will create terrible nipple entry angles and spoke overlap at the hub. Is 2-cross the right call here?

  2. The Hub Choice, 32 vs 36 holes: I originally wanted to build a 36-hole wheel using a DT Swiss 350 hub (for the sealed bearings in winter weather). However, the 350 in 15x100mm maxes out at 32 holes. If I want 36 holes, I have to use a Shimano XT (HB-M8010). Given how short 20" spokes are, is a properly tensioned 32-hole wheel with Sapim Strongs genuinely enough for a 180kg system weight, or should I absolutely stick to 36 holes and just deal with repacking the XT cup-and-cone bearings?

  3. Winter Wheel Repair: To fix my stock wheel, I plan to replace the two broken spokes and then properly bring the entire wheel up to a high, even tension. Will fixing the factory tension solve the fatigue issue, or do you strongly recommend relacing the entire wheel with new spokes because the others are already stressed?

Thanks in advance for the help!