Fender failure

[trepaning]

Fenders on my acoustic bike now break away at the nut if something crushes it, so the fender won't stop the tire.

those break away nuts... is that a feature of the replacement fender, or something you worked out? seems like a nice failsafe.

It is a feature called a Release Tab which I just learned from the Planet Bike website, fenders section https://www.planetbike.com/bike-fenders/ , as mine are Planet Bike fenders. If something sticks into the spokes now, the wires will break at the release tab and the fender will not get crushed up and jam the wheel.

[Radding Along]

Sadly for you, the Mission was not designed for rough riding. It's mainly a paved trail/street bike.

The fender brace in the rear will bow out, which moves the fender closer to the tire. The bow effect can happen at installation time, or over time while riding. You need to be sure the brace is in a more straight position by pushing in on each side. That will move the fender away from the tire.

If you want to totally stop it from happening, make a couple of extenders out of plate steel, about one inch long and bolt them down at the back wheel where the brace it now bolted. That will raise the rear of the fender up and that should correct the issue.