sorry about posting it in here, but I believe i don't need a new topic, and the question is about a steel frame. But if the moderators think it should be a topic, feel free to move.
I got a cr-mo Colossi frame, brand new. Cheap, but damn nice. Straight and really well buit. Made with Columbus Zona, 54 top tube (wich by the way, is a bit small to me - I should use a 55,5 TT). Built with DA7800, wheels are DA hubs with a Mach1 rim (32 holes), Velo orange alu seatpost (with huge setback) and a Velo seat with titanium rails. 700X23 clinchers, butyl tubes and maxxis tires.
Anyway, the bike rides damn nice almost all the time, but it just jumps A LOT in the rear. If I run over some bad tarmac (wich we have lots here in Brazil) the thing acts like a freaking Kanguru. It's annoying me too damn much
any ideas on what cause this, and what I can try to do to fix it? The Zona tubing was suposed to be strong. By the way, since the frame is a bit small, I got a lot of seatpost showing. I run with 120 psi on the clinchers, as I weight 81kg. With my AL and carbon bikes, never felt this weird problem...
Thanks in advance and again, if I should make a topic for it, just tell me.