Size advice

alfone

I'm 171 cm tall and my inside leg measures 80 cm. In attachment there's the geometry of the frame i am interested in. Which size would you reccommend? 50 or 53?

w00dster

I always look at top tube length as a primary indicator. But you then have to think about riding style and set up.
I prefer an aggressive set up with a large drop from seatpost to bars.
Difficult to say about sizing for other people but I would say that the size 50 would be the one I would say most suits me. I'm 172cm. My Trek Domane size 52 has an effective top tube of 53, With a seat tube length of 47.5.
I also have a Madone size 54. Effective top tube is 54.3. I'm comfortable on both, but my next bike will be a 52 as I prefer the smaller frame.

sloppyschleckonds

^whs

bontie

At 171cm, you should not even think of a bike with a 54cm top tube*


* Assuming you are in the 99% of people with near average proportions.

mamba80

Big difference in head tube length between the 50 and 53 - 30mm, but only 15mm in TT length, you also need to consider the saddle to bar drop and the number of spacers you may need, if you go for the smaller frame.

there are no hard and fast rules here but i know lots of people who are very happy on a 53 tt and they are less than 171 tall and equally the opposite.

You may need to reconsider your frame choice and go for a make that has smaller differences between sizes, you should go and ride some bikes that are in your size ranges and see what bar drop you are comfortable with.
sorry but internet fits are not a good way to go.