Broken frame

G

Gerald nason

Guest
Was working on tank in frame bike ,and noticed slight crack in down tube right above
The stub that my front mount attaches to.
My question is if it can be repaired being aluminum.
Really don't want to get new bike paid $600.00 for frame through bikeberry (bike scary).
Any help is appreciated just started new job don't have the money for replacement and don't want to deal with wal-marts beater bikes thanks gasbike jerry
 


GreasyChris

Active Member
Joined
Jan 3, 2019
Messages
174
The right guy with the right welder will be able to fix that no problem, maybe even make it better than new. Your challenge well be finding that guy. If you live in a metropolitan area it shouldn't be a problem.
 

FNTPuck

Well-Known Member
Joined
Jul 2, 2018
Messages
471
Pro tip: Cut the front mount off, grind it flush, and use an adjustable CNC mount for a more reliable setup.

They almost always break at that same spot, even the reinforced ones, because the mount and the seat post are never at exactly the right distance and angle.

One way to help make it last longer is to tighten the REAR engine mounts first, then use shims/washers/spacers to properly flush the front mount before tightening it down. It may need just a washer, or an actual tapered wedge, but if you do that it will last much longer. You also may need to angle the rear mount block since the seatpost is straight but the engine mounts angled.

I have one of the reinforced mount gas frames (I don't use it, just for mock ups) and when I installed the rear mount I noticed the front has almost a full 1/4" gap. Most people just TQ it down till its flush like that, and that is what causes it to eventually crack from stress and vibrations.
 
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