Can I fit a frame one size smaller?

Kopzr

I am sorry for asking this question, since I believe it has been answered a bunch of times here.
I wanted to buy my first road bike. After searching around I am between getting a Triban 500 (which would allow me to invest in a proper kit) or a Triban 520. I would preffer the 520 but they don't have it in my size.

Here is my bikefit:
The Eddy Fit (cm)
Seat Tube Range c–c: 58.8 - 59.4 cm
Seat Tube Range c–t: 60.6 - 61.1 cm
Top Tube Length: 57.8 - 58.2 cm
Stem Length: 11.1 - 11.7 cm
BB–Saddle Position: 77.8 - 79.8 cm
Saddle Handlebar: 59 - 59.6 cm
Saddle Setback: 8.1 - 8.5 cm

The 520 is only available in size L (TT = 564 mm), while i can get a Triban 500 in XL (TT = 580 mm). At the store the Triban 500 felt amazingly good, very confortable, while the Triban 520 felt a little odd and snappy, It wasn't bad though.

So, can i compensate the shorter toptube with a longer stem or should i just get a 500? I plan on doing medio and granfondos in the future, but i don't wanna wreck my back due to picking the wrong size.

Here are the Measurements for both frames:

Triban 500:


Triban 520:


As you can see, the HT and ST are pretty simillar.

Cheers!

StillGoing

It depends more on your measurements, particularly reach, but remember, it is easy to make a small frame fit, but nigh on impossible to make a too big frame fit.

Kopzr

How can i measure reach? Would it be the saddle-handlebar relation?

StillGoing

Kopzr wrote:

How can i measure reach? Would it be the saddle-handlebar relation?

Your easiest and cheapest (free) option, is to sit on the bikes. Alternatively, go for a fitting to get your measurements, or download an app that will film you on your current bike and give you the ideal measurements for you.

https://youtu.be/kAhvWdTAVd4

This explains better the importance of stack and reach.

https://youtu.be/wfx3LqsCFSA