I just bought a secondhand Raleigh C40 hybrid off Facebook. It generally seemed like a good bike but I'm definitely a bicycle noob. The lady who sold it to me was maybe an inch taller than me. I didn't necessarily think it was too big for me but I DO sit kind of upright while cycling and my roommate has made a LOT of comments saying it's too big for me. It's a 17" frame and I'm 5'2. Is there any other way to check if it's too big ?
The manufacturer of the bicycle should have a sizing chart and if they don't, you can use the sizing chart from any of the bicycle companies. The chart will tell you what size of bike you should be riding for your height.
You can make some size adjustments by adjusting the seat post height and handlebar position as well so keep that in mind. So check to see if you can lower your seat post by loosening the seat post clamp.
Generally speaking, while pedaling the bike, when your leg is at the 6 oclock position (the lowest point), your leg should be about 80-85% extended. Not fully extended but almost. If you have to lean off the seat for every pedal stroke, it's too big.
When stopped, you shouldn't be able to flat foot your bike with both feet. The bike should feel a little too tall for you. If the bike is too small, it would be like trying to run while crouched down which would be very tiring and not efficient so your legs need room to fully extend just like they do when we walk.
Raleigh has a sizing chart for their hybrid bikes on their UK website which suggests a 17" frame is suitable for rider heights from 5'5"-5'8"
From the photos I can find on the internet it looks like your bike has an adjustable quill stem:
This means you can easily lower the handlebars and also get them somewhat closer.
A rule of thumb for saddle height: With the pedal in the 6 o'clock position and your heel on the pedal your leg should be fully extended without tilting your hips. In a normal riding position (forefoot on the pedal) this means your legs will be almost fully extended on the bottom of the stroke.
It’s not necessary to be able to reach the ground with one or both feet while sitting in the saddle.
For handlebar height: For a hybrid I’d set the handlebars at roughly the same height as the saddle. Maybe slightly higher than the handlebars.
Handlebar distance: For a hybrid I’d aim for roughly a 90° angle between arms and torso (maybe a bit less). If you feel stretched the bike/frame is probably too long for you.
If it’s not possible to get the seating position set up this way on your bike it’s probably the wrong size. You could get a slightly shorter stem if the frame is too long but that’s about it.