I'm looking to purchase a used 1991 Trek 520. According the the vintage trek site, it was manufactured with the following sizes: 17, 19, 21 and 23 inches. According to the seller, it's a 53 cm TT.

I currently ride a 54 cm road bike. Is this a proper fit? I've never toured before and looking to start with weekend tours (but I need a bike first).

I suggest you post a pic of your current ride showing the amount of seat post and bar height. That will give people a better idea.

Here ya go.

Looking at your pic my guess is the 53, or 21" frame size is going to be a bit on the small size. On a touring bike like the 520 it is better to err on the large size if you are between two sizes. The reason is that effectively raises the bar to seat relationship, putting you more upright.

I happen to have a 1995 21" 520 and it is slightly small for me because for 5'9" I have longer legs/shorter torso. As a result, the bars are at or below seat height which is a bummer on tour. Yes there are things I can do about it but I have another touring bike and I now keep it at my parents for general use and day rides which presents no problems.

The net of all this rambling is: consider the larger size or a different bike.

If your 53 cm measurement is accurate for the top tube, this bike is too small for you. According to the Trek Vintage site, the 19 inch seat tube bike has a 54cm top tube. The 21 inch has a 55 cm top tube.

You can find the geometry info under the 1989 brochure: "dealer info". I am assuming geometry did not change in 1991.

Is it close enough to you to test drive? This way you can check stand over & how this size bike "feels" under you.
I'm 5'11" & have a 21 inch* 1993 520, although the frame is way small by the numbers, I got it comfortable for me.

*do note that Trek measured their frames differently than most others back then, I still have the sticker from the bike in my owners manual that says "Trek Specs 21"/53.5cm Frame"

~Roger

PS. I bought this one new, & in those days we were buying smaller frames for touring & pulling trailers.

I guess I'm confused... so for touring bikes, you don't purchase as you would for a road bike? When I heard that the bike was 53 cm, I thought that it would fit. One thing about me is that I have the shorter legs/longer torso. From your picture, I see that you raised the handle bars quite high, is that normal for touring?

Sorry for all the questions, I'm just starting to look into touring and have been spending most of my time reading tour diaries.

No, you probably would get a "normal" sized frame these days. Back then we thought that a smaller frame could be stronger. Another reason for me to go with a smaller frame was that my kiddos were little back then & I pulled a trailer a lot. So I was on & off the saddle, starting & stopping a lot as my kiddos were learning how to ride their own bikes too. Think lower top tube, less chance for accidental contact with said top tube whilst jumping off the seat for a sudden stop (OUCH).
Handle bars for many touring folk end up even with the seat or a little higher.

Again, THE best thing to do would be to take that bike for a test ride.

Just for reference I'm also 5'9 and ride the 23" 520. Given the short head tube on this bike, I still needed a high rise stem to put the stem even with the seat. My road ride is a 55cm Litespeed.

Thanks for the insight and information. I just have to find out if I can still buy the bike. The ad expired on craigslist!

Do keep us posted, or send me a note.