Hello
As my title says, I have a question regarding the size of a road bike. I can get a decent deal on an Orbea H40 with Tiagra components, unfortunately I can't rest ride the bike. I have been riding for a while a MTB, but obviously the geometry is very different. I am 5'10" (178 cm) so my first thought is that a 51 is crazy small, but that's what the Orbea site recommends. I figured that this is happening because I have a very short inseam (31" or 79.5 cm). The geometry of the bike is more relaxed, better suited for endurance which I kinda like because I don't have a lot of flexibility. Here is the detailed geometry of the bike
Size 51 vs Size 53Seat tube | 470 | 490
Top tube | 537 | 549
Head tube | 150 | 165
Head tube angle | 71.8 | 72
Seat tube angle | 73 | 73
Standover height | 75.4 | 77.4
Reach | 370.9 | 378.4
Stack | 554.8 | 572.8
From what I can see, the 53 will have a slightly longer reach, but a way longer stack, so I think that a 53 would be better since the head tube is longer so the bike is taller, therefore a bit less race oriented. I know that the perfect solution is to get a bike fit, but as I've said, the only distributors of Orbea in my country just sell the bike online. The price is around 50% cheaper than getting a bike with the same components on a local bike shop.
Thank you for your help