Diamondback Mission 2 Mountain Bike Frame Crack Repair
Updated: Sep 24, 2019
NOTE: Before I get into this repair I just want to point out that it is not advisable to re-weld a aluminium frame. In almost every situation is it advised to replace the frame due to the weakening of the frame during the welding process. This is a backup bike for me and will be replaced shortly.
After 10 years of riding my Diamondback Mission 2 it finally got a small hairline crack on the weld where the rear suspension triangle mounts to the frame. I found it when washing out the frame and noticed water seeping out.
The decision to repair was hard and not always one I would recommend. Keep in mind this frame is 10 years old and at the end of its life, replacing it is by far the better option as repairing an aluminum frame can potentially lead to further failure. However due to a time constraint I needed a bike to be my backup so I set out to repair it.
I ended up taking the frame to a local shop that specializes in welding and fabrication. You could go to any muffler shop if you needed a basic steel weld, but because I was dealing with aluminum I wanted a pro who knew how to properly weld aluminum. I found an amazing shop in Chicago called C&B Welders which I cannot recommend enough. They were awesome and really knowledgeable on aluminum welding. I would definitely go back. They said they had welded a few bike frames before and informed me of the concern with new cracks forming. They charged me for 1 hour of labor and had it done in a few days.
Here are some pictures of the welding:
Once I got it back and everything looked good, just had to paint it up to match the rest. Started with taping up:
Then painted it with some gloss black spray paint:
Once the tape was removed I finished up with a few coats of clear coat enamel and it looked decent:
Repair was done in July 2018, Ill update with how long the frame holds up.
UPDATE: (Jan 2019) Frame is still holding up great. No sighs that the crack is returning, worsening, or additional cracks forming. Rode the bike hard at Whistler over the summer and it is was going to crack it would have there. Held up through that and still going strong.
UPDATE (Jul 2019): After a trip to the east coast and some pretty rough riding the crack has developed again at the outside of the weld in a new location, weaken by the welding (as suspected and advised by the welder). I suspected it would come back and am happy enough with the additional year of use I got out of it. Just keep that in mind if you are debating welding an aluminum frame.