Bike Mielec

I haven't ridden any pursuit frame ever and I can't find one to ride! I asked Robert from Mielec and he suggested a 53 (Low copy geo). Also from Low they suggest the same size. I always thought a 55 would be better for me (181cm or 5'11" with 86 inseam).I guess I am wrong. What should I choose?

I'm pretty much your dimensions and got a 53cm mash copy, you can always compensate with a setback seatpost and longer stem.