fhloston

I have a new set of Weapon Ambush hubs on my Trek Marlin 29er. The rear hub uses 24T magnetic ratchet technology instead of pawls.

When the cassette is off of the hub the ratchet engages and works normally.

When the cassette is on the hub, the ratchet becomes disengaged and the cogs spin freely. If I give the cassette a whack, the ratchet engages temporarily but then it will disengage again after a short period.

Any ideas about what might be going on here?

Andrew R Stewart 

Sounds like some dimensional interference inside the unit, something isn't sliding/or is sticking. Never dealt with one of these so no advice but to contact the manufacturer, assuming the place you bought the hub/wheel/bike from can't help and won't make the call. Andy

mpetry912 

Weapon ambush, huh ? and you have to give it a whack to make it work. Reminds me of a story. But Andrew is right, there's something binding in there that is preventing the pawls from engaging.

make sure the cassette body is FULLY engaged in the hub. Look for a space at the place where the hub body meets the cassette. There should be only a very small gap.

Mark Petry
Bainbridge Island, WA USA

tomtomtom123

It's a magnetic ratchet. So it probably looks similar to these, except the moving magnetic part is either in the hub body or the freehub (on the inner side or outer side):
https://vimeo.com/105035051
https://vimeo.com/118022755

The hub below has the magnetic moving part on the outside.

The magnetic moving part in the hub below is on the inside.



Perhaps the design of your Weapon Ambush's direction of magnetic force is flawed and the steel cassette is attracting the ratchet components, causing them to separate.

If the magnetic moving part is on the inside (like in the 2nd and 3rd photos, and the videos), then the magnetic attraction to the steel cassette would simply increase the force that presses the teeth together. However, if the magnetic moving part is on the outside (like in the first photo), then the magnetic attraction to the steel cassette would pull the teeth apart, causing the possibility of unintended disengagement.

tomtomtom123

If it's this silent ratchet system, some kind of magnet pushes away the ratchet when freewheeling.

https://bikerumor.com/2018/11/12/fos...noise-no-drag/





The Rotor hubs are similar to the magnetic ratchet in the previous post, but there is some other mechanism keeping the ratchet ring from engaging until the freehub spins forward, in order to reduce the friction (so it doesn't keep moving back and forth while freewheeling).
https://road.cc/content/tech-news/22...nd-save-weight

fhloston

Thanks (to Andrew). The wheel is at the bike shop and I'm assuming they know how to contact the manufacturer. This is the Philippines though so I'm checking to see if anyone else has experienced a problem like this and if they have, what their solution was.

AnkleWork

Maybe check your spokes for excess magnetism.