Frame Size Help

anotheroneontheway

Wonder if someone can help?
My work's signed up to a cycle to work scheme, but through Halfords and capped at £600!!
I fancy a single speed and have narrowed it down to a Kona Paddywagon or a Genesis Flyer.
I can only get the Flyer in a 52cm, the Paddywagon is available in a 52cm or 54cm.
My current road bike is a 54cm (5'8", 30" inside leg). I'm struggling to find a 52cm Flyer to try and as they have to order the bike I won't get to try it before I buy it.
Any thoughts about sizing or either bike would be appreciated.
Thanks!

ilm_zero7

you need to try it - for me sit on and clip in, and still be able to push your heals down comfortably below the pedal when the cranks are vertical with a 6 inch seat post

not very scientific I know, but it works for me.... That said I found this picture from the Giro and if (in my dreams) that had been a picture of me I would have thought my bike was too small and legs not extending properly

anotheroneontheway

Ideally I would try it - but nowhere local to me has any stock of the Flyer and I have to order through Halfords - so can't try it.
I was just wondering if the higher BB and shorter cranks make a huge difference to sizing.
Thanks, though.