Hi all
I've searched this forum but couldnt find my specific question though I'm sure it's been asked before.
I bought a bottom bracket bash guard. It has a bracket that goes over your boom bracket thaking the place of a spacer. I'll include pics. My question is if I actually bashed into a rock or curb at speed would it hurt the bb? More importantly the threads in a aluminum bb shell? Bb are cheap, usually cheaper then a chainring. But destroying a bottom bracket shell wouldnt be. Has any one had any experience with this? Thanks!

This goes over the bottom bracket

doing big log jumping? it's the chainrings that are the lowest point, so the thing you add should be lower than the largest chainring..

Well, if you hit something with a chainring the force goes through the BB anyway....

your right lol now I feel pretty silly for asking the question. I had not thought of that. Thank yo

To say nothing of the likely medical bills/lost work and rehab that any mishap energetic enough to bend the
BB shell and ruin the frame could do to the rider.

Not sure that the question was silly. Some bikes have welded on flanges for bash guards. You're looking to add a guard to a bike without that flange. So you propose using an adapter flange that fastens to the BB via one of the BB nuts. I'd think that the force transmitted in each case might be different. The three cases:
1) No guard, force transmitted via chainring to spindle to bearings to BB in frame.
2) Built-in bash guard flange. Force transmitted through guard to flange.
3) Adapter flange for bash guard. Force transmitted through guard to adapter to BB assembly and nut to BB threads.
I think (2) is best, but if you don't have the flange, (3) probably works. (3) might avoid chainring or bearing damage if you "log" your chainring.

I definitely agree that option 2 is best. I guess the adaptor poses no more of a threat to the bb then the chainring does though.

Some frames added a loop of steel tube welded to them, under the BB for those kinds of off road log leaping tricks..