Just an FYI for any AC 420 wheel users. We were on the fast group ride this morning, on point 31 mph and "PING", broken rear spoke.
Luckily, the wheel did not implode. There was a group of about forty riders behind us.
We are a 260 lb team. I bought the wheels used on e bay. So I don't know how many miles were already on them. They were perfectly true when I got them. We rode them for just over 2k miles on the tandem. These AC 420 wheels will now be relegated to a single bike use only.
Time for new wheels.