I have a Kabuki/Bridgestone that I have set up as a fixed gear around town errand bike. I really like it set up this way.

I converted this one on the cheap. I kept the original BB spindle, which was pretty long. So now, with one chain ring, there is quite a bit of spindle showing between the cranks and the BB shell. Maybe 5mm.

I have noticed that when I pedal hard (I am big and tall, and pretty strong, btw), there is a LOT of frame flex as I pedal. The BB shell seems to really torque around down there. At first I thought the cheapo plastic MTB pedals I had on it were flexing.

I have never noticed any bike I have ever ridden flex like this.

So, two questions,

-this must be largely a function of the overly long spindle right? (The frame is pretty heavy CroMo. Not all that lightweight at all. I am sure nothing is broken down there also.)

-Am I going to rip this thing apart?

jim