Skyhawk GT2-A Frame Fail

Here's the picture of the frame crack:

crack1.jpg

It's in one of the worst places possible.

I talked to a TIG welder. he told me he could probably rig a temporary repair but, being that the aluminum is seriously compromised, he figured new cracks would start appearing.
 
Aluminum framed Felts never crack.

There is no comparison between these Chinese frames and a Felt.
The aluminum feels thin and they probably don't heat treat the welds
properly.

There are other quality made aluminum frames too.
There are also knock-off GT2A frames, gasbike has been selling them for over 2 years.

The real Grubee Skyhawk frame can't be found there, Don won't sell to them and took them off the official China Gas registered Skyhawk distributer list for stealing his designs and getting cheap knock-off's made but still using his known brand name on them.

I don't know if the real deal is any better than a knock-off or not, but they had to save money somewhere to undercut the price.

Just on a side note, there is a new fat tire disc brake equipped GT2A frame coming this year that will take 26" x 3" wheels ;-}
 
You guys never asked what I did. I have effected a repair that is holding.

I tried to braze alumalloy into the damaged area / crack. Complete fail.

I am not gonna waste a penny to have a TIG welder TRY to fix this.

I went to Lowe's and bought some Fiber Fix. This is a resin soaked material that clings intensely to metals costing about $7. I followed the directions and wrapped the hell out of the downtube on and around the damaged area. The frame is rigid again, and I've successfully ridden my moto about 30 miles. This stuff is tough!

Of course, I am extremely conscious of the damage and I am inspecting this area before, during and after every ride.

I think I have saved myself plenty of time to find a new frame for my next, best build yet. It has to be perfect. I am going to be picky!
 
that's pretty good, I never thought of just fiberglassing the crack. that might be a good cheap solution for the pedestal mount too
 
My first build was on a Schwinn Alloy Seven, which was a 6061 T6 aluminum version of the classic 1955 cantilever Schwinn design.

My frame cracked in the very same place, and I found it the same way OP did. Bike felt loose all of a sudden, so I stopped and had a look.

Sadness. I ended up moving everything, wheels included, to a new frame. A steel frame.

It is my belief that aluminum frames are generally unsuitable for MaBing in the long term, especially with a chinagirl. Aluminum frames fatigue much quicker than steel.

One thing's for sure: I never liked any of Grubee's bike frames. They remind me of older Hyundais and Kias: they look okay, but upon further study are rather shoddy.
 
I went to Lowe's and bought some Fiber Fix.
This is a resin soaked material that clings intensely to metals costing about $7.
I followed the directions and wrapped the hell out of the downtube on and around the damaged area.
The frame is rigid again, and I've successfully ridden my moto about 30 miles. This stuff is tough!
Cool!
Nice solution.

I'd bet that Caswell epoxy sealant would do the same thing maybe even without a fiberglass mesh for strength, that Caswell just flat amazed me with it's tenacity to permanently bond to anything and after a couple of days of curing be incredibly strong all on it's own.
 
I know that Trek, among other bicycle manufacturers, had sold numerous models using composite frames of aluminum and carbon. Probably still making them.

This got me to thinking: TIG welding requires real skill and expensive equipment. Mig welding on steel tubes is super tricky.

With resin joints, you could really build anything in terms of a frame very inexpensively. I am accumulating a lot of parts and materials. Just picked up a pristine old Schwinn frame off a curb. Time for experiments!
 
Back
Top