Here's the current mirror arrangement we're using on barakta's ICE trike. The B&M mounting described above was sturdy enough, but the small mirror area was a problem that far forward, and it suffered from vibration blurring.
While in Decathlon back in December, I discovered
these:
Optically, it's similar to a Mirrcyle. It seems reasonably sturdy, with a good B&M-style ball-and-socket joint attaching the mirror to the arm. At a mere £4.99, it seemed silly not to give it a try.
Initially I tried attaching it directly to the B&M arm. In spite of the difference in ball/socket sizes, it sort of worked: while it suffered from droop, it was enough to determine that it gave a much improved view, so I set about fettling the bracket.
I came up with a way to securely mount it to the mudguard stay, and it's been in use there for the last few months. It's survived a couple of knocks as the trike squeezed through narrow gaps, and me tilting it on its side to fix a puncture without remembering to fold the mirror in first. There is no droop and the mirror is easily adjusted by hand, much like a B&M. There is some vibration blur, but not enough to be a problem.
Yesterday I bought a matching mirror for the left side, and documented the bracket mod:
First, dismantle the whole thing. You'll need the parts on the right:
You'll also need a couple of repair washers, an M4 pan-head bolt and nut, and some inner-tube cut to match the washers:
Using a junior hacksaw, cut the post mount down like so, tidying up with a file:
Assemble the parts like this, using the M4 nut and bolt to join the parts of the mount. Trim any excess bolt.
Attach to the mudguard stay, getting the bolt right up into the 'V', and tighten. A cable-tie prevents rotation. This is surprisingly secure.
Then simply fit the mirror. Stealth retro-reflective chevrons optional.
ETA: Not entirely surprisingly the middle joint turns out to be a weak point and is prone to droop. Copious numbers of cable-ties help, but in an attempt to improve things I've taken it apart and covered the whole area in epoxy:
Other than that, they're still performing fine.
Not bad for a fiver a go