Mac Gear Separation

[givitago]

My Mac hub recently started making a scraping noise. I opened it up and noticed that the gear inner housing had separated from the gear itself by a few mm and this metal housing had rubbed away some metal on the magnet housing. I replaced the gear with a spare.

I ride pretty rough, rocky terrain and do smallish drops (3-4 foot max). I know not ideal for a geared hub, but it has been quite reliable otherwise other than the usual clutch issues. If it keeps happening, I'm debating some small, countersunk screws to hold them together.

I was wondering if anyone else has had this problem?

 

[fechter]

That's a new one for me. There shouldn't be much force on the gear that would make it do that. Possibly if they got really hot the plastic might expand and loosen up on the hub. I'd suggest cleaning it with good solvent and use some epoxy to put it back together.

 

[givitago]

Thanks for the suggestion. Next time it happens, I'll give that a shot.

I think I have been overheating my motor as it has lost a lot of torque over the two years I've had it. It never feels too hot on the outside, but I guess with these motors, that is not an indicaton of the interior temp.

I was thinking it was the bashing because it started its scraping sounds at the bottom of a choppy run, but I can't quite figure out how that would cause horizontal force to separate the gears. Maybe some sort of axle flex.