Grinding down welding on aluminum to make it look smooth, in fact removes material and makes the weld weaker. Those lumpy, layered welds are the correct way to weld aluminum for optimal strength. It creates a buttress at the joint, making it way stronger. It is a direct trade off. For me, the functional call made by R&M is the right one. Leaving all the weld in place, keeping it strong should be paramount, rather then weakening it to make it pretty. Go to any local welding shop and they will confirm this.
- All frames (during design and certification process) are ASTM tested. Smoothening or not smoothening is not really a factor if the certification criteria is met.
- The way Koga does it is that they double weld and smooth down the second weld. I just want to highlight that nuance. Koga bikes ride for over 100k miles with no issues, that too fully loaded up to 400 lbs. These frames are also ASTM and EN tested, and they pass those tests.
- This is definitely an aesthetic issue - one that should be functional and pleasing at that premium price point.
- Last point, if that is all functional, and good, then why does RM airbrush those welds off the pictures on their website???
See here (just taken off the US website).