BMX - Gusset or no gusset?

[macky]

I am planning on building a few BMX frames to work on my fillet brazing skills among other things. Gussets appear in most older BMX frames, less so now. My research indicates better tubing quality and technique has led to the decline of the gusset, and several commenters have indicated a secondary heating of the joint to add a gusset weakens the joint.

Any advice?


Thanks,
Mike Cormack
Macky Bikes
Vancouver, BC

[jon_norstog]

A BMX bike really gets whacked. The reason most builders use gussets is so the bike will survive the usual whacking. I guess if you are using an ovalized, tapered downtube, you could probably skip the gusset.

If you're building for practice, why build BMX bikes? I mean, you are liable if somebody cases one and it has to be surgically removed.

Good luck!

jn

"Thursday"

[Amaro Bikes]

The wider the downtube, the less need for gussets, but as usually bmx frames goes with standard 36/37mm headtubes it usually means you're restricted on the downtube size (unless using ovalized tubes as Jon said).

If you're on 35-36mm downtube, either go with super thick stuff or reinforcements might be needed to avoid fatigue
If you can get some 46mm headtube to fit 42mm downtubes, you would be ok without reinforcements, as a thick 42mm downtube is already hell of a reinforcement itself

Anyway, if you're practicing, apart from the wise words form Jon, there's nothing better than try for yourself (without anyone else involved) and take your own conclusions. Most of the cases, common sense works, and if 90% of bmx brands do use certain type of design you might well consider there're good reasons for it

Cheers

[macky]

Thanks both. I am going with a 42mm downtube & 46mm headtube, but I don't want the frame to be too light (sic) so adding some cool Mongoose gussets. Will report back once the project is completed.

Mike Cormack
Macky Bikes