LUBA 3: cutting discs spin the other way since the latest update

What one owner reports

A German-speaking LUBA 3 owner wrote on 18 October that since the last update the discs turn the wrong way. Grass is no longer thrown behind the mower but out to the side, and that clogs the deck¹. He filmed it in slow motion from behind. He says the discs run the wrong way, so the wrong edge of the blade does the cutting¹².

Two days later he posted again. He says the grass is pressed forward and sideways against the black mudguards, where it builds up and clogs, worst when it is wet. The mower gets very dirty⁶. He says the cut still looks good, but the clogging outweighs it¹⁰. He bought three LUBA 3 mowers, for himself, his father and an acquaintance¹³, and says he watched three and all had the error⁹. His father's mower sometimes spins only one disc, and that one the wrong way⁵.

This is one owner, writing about three mowers. No second owner has described it first-hand yet. One owner who has stayed on a July version says theirs mows well¹¹. Nobody says which version brought the change, and the original post does not either.

What Mammotion has said

A Mammotion staff account answered the first post on 19 October and asked for a log and a video. On 20 October it wrote that the discs do rotate in this direction in the current version². On 21 October it wrote that the team knows about the issue and will include an optimization for it in an upcoming firmware release³. A second staff reply, in the later thread, said the team is looking into it and will work on an improvement as soon as possible⁷. No version number or date was given. On 22 October the same owner wrote, under a video test of firmware 2.3.31.69, that the knives run wrong there too and that he seemed to be the only one who noticed. A staff account answered him that the relevant team had taken note of the issues reported by users and was working urgently on optimizations¹⁶. The reply does not name the discs, and it gives no version or date either.

The owner says support also told him, in his own case, that it is a firmware bug, a communication error between the mainboard and the cutting motors, to be fixed in the next update⁴. We can only see his account of that message, not the message.

Why the direction matters

Mammotion staff have said why the direction is set the way it is. In an earlier thread, where an owner suggested reversing the discs on alternate cuts so both edges wear evenly, a staff account answered that the clippings would then be thrown to the sides, the discs would jam easily, and the cutting result would not be very good⁸. That is the same clogging this owner describes.

Owners disagree on whether the two discs on a LUBA 3 can be swapped. This owner says he is swapping them so the sharp side of the blade is used¹⁴, and another owner, in an earlier thread, says the new discs cannot be switched between sides¹⁵. We have not checked either, and Mammotion has not said it is safe, so we do not suggest it.

What to do for now

Check which way yours turns, tell support, and keep the deck clean. The steps are at the top of this page. For how to handle the discs safely, see blade and deck maintenance and the mechanical checklist.