trekker pete

Apparently this was a common problem. Obviously using these bikes on any sort of off-road stuff would be unwise, but, how about light duty bike path duty?

There are a few of these for sale cheap. These were good old bikes with decent components and I would think would make nice rails to trails rides which the wife has finally agreed to try.

Is this risky?

jimc101

Why would you ride any bike with a known defect? Rockhoppers were only mid range bikes BITD, if it has the defect, it's only really a breaker for parts, not for riding.

dminor 

Can you weld? If not, shy away.

Number400

I just sold my 90's rockhopper single speed. It was fine on the gravel and for light use but the frame was like a wet noodle and flexed like crazy whenever I tried to sprint on it.

I would pass on this one especially if it is already compromised. An undamaged one would be fine for the Wife's gravel grinding.

trekker pete

Can Aluminum frame cracks be welded? I have been looking for a good reason to buy a welder and teach myself. Can Aluminum (tig, I think?) be welded with a cheapo arc welder?

dminor 

Yes and no. Yes they can be welded. No you won't get good results from a cheapy wire-flux MIG rig. The after-welding is more complex than you'll want to deal with - - it involves re-heat-treating the frame in a large enough device (I don't recommend the wife's good oven) for the proper amount of time at the proper temperature. And if it's 7000-series aluminum, everything is even more problematic. You don't want to go down that road.

If you want an excuse to learn welding, there are plenty of bike-related projects (stands, repair stands, bike racks, hitch racks, hitches, etc.) that lend themselves much better to your efforts.