OldTrek720

Hello,

I was wondering if someone could help me determine whether my bike fits me. I got an '82 or '83 Trek 720 that belonged to my Dad fixed up and am fearing it might be too big for me, just going by the sizing charts. (Feels fine to me, who knows nothing about bikes!) From some research on vintage-trek.com, I can determine by the serial number that it was an '82 or '83 and a size 22, which from the old geometry chart means 56cm seat post and 56cm top tube. I'm 5'7" with a 31" inseam. I've included a lot of detail below but the tl;dr version is: Can someone confirm whether this bike is too big for me and, if it unambiguously is, tell me if that's something that is just likely to affect performance (which I can live with), or is likely to cause me pain (which I'd like to avoid)?

When I ride the bike it feels great, but I'm also a complete novice and wouldn't know what to look out for anyway. I'm also not really used to the drop handlebars. I guess I would say it doesn't feel big, but I don't know what a big bike would feel like in any case. The only thing I notice is that I get some pain in the back of my neck right where it meets my shoulders after about 30, 40 minutes of riding. I don't know if that's from the fit, or because I'm not used to the posture one needs for drop handlebars and just need to beef up the muscles there, or even because I have a Bern (I think Watts model) helmet that's not really optimal for that head position.

As I said, I'd like to take this bike on what seem to me like long rides (although for seasoned cyclists they're probably fairly short): around 30-60 miles. I don't have money for a fancy (or even decent) road bike, so having a hand-me-down like this would be great if I can make it work. I've also read that the vintage Trek 720's are great and somewhat coveted, so I'd be loathe to give it up, especially as it's straight from my Dad, who was the original purchaser.

What I'm mostly looking for is someone to tell me which of three possibilities is likeliest: 1) The bike's not actually too big for you, hooray! 2) The bike is too big for you, but if you don't care about optimum performance, you should be fine. 3) The bike is too big for you and is likely to lead to some pain if you put a lot of mileage into it, a sign of which is already the soreness you get in your neck.

Thanks for reading and any help you can provide!