Currently I have a FELT S32 with Seat tube length (ctr to top of seat tube) of 580mm and a Top Tube length of 580. My stem is about 10cm. I am looking at a road bike with a Seat tube length of 620 and a top tube length of 585. Now I have done tri’s for about 3 years and not really ever had a road bike. I will probably set up the bike at first as a tri bike for my brother-in-law who has about the same measurements as I do.
My question is: I have no idea if the road bike frame that I am thinking of getting is the correct fit. (As I will be getting it for $139 from the internet I will not be able to test the fit). Are there any rules of thumb going from tri measurements to a road bike? thanks