Bicycle Mechanics - tob tube warp

Hello all,

I am new at riding bikes and i bought a Gary Fisher advance about 4 months ago. I recently noticed that the top tube has a slight downwards bent about an eighth of an inch. i stretched a thread along the bottom of the tube to see if it was straight because i noticed the bent, but thought i was seeing things, but the middle of the tube dips below the thread. I am 6'4" at 245 pounds so i know my weight has to do with that issue, but should i be concerned that the tube will continue to warp? Thanks much beforehand.

I would definately take it into your LBS where you bought it and have them inspect it.. Aluminum is a strong metal but it can fatigue should not be that fast even at your size & weight. Anyone here would just be making guesses since we can not actualy see the frame. Is it worth the risk of seriously hurting yourself by the tube breaking?

There are some weird frames out there but the pix of the Advance in the GF
catalog shows an apparently perfectly straight top tube. Is there also a visible departure for the cable on the top tube as well? Ditto Kev's advice. Bending Al is ferociously hard to do, they may have some ??... Steve

I've noticed this same phenomena with other brands of aluminum bikes. The best way to determine if it's liable to bend further is to check for cracks in the clear coat and paint. As the tubes are welded, some deformation can occur. It is structurally sound.

Thanks everyone. There are no visible signs of cracking on the paint job but there is some distance difference between the middle and the ends from the breaking cables on the top tube. I am going to take it to the shop to for them to check it out. Really appreciate the advice. I wish I knew of this site much earlier.