macteacher

Ok...the other day I tested out a bike. A Marin 19" Fairfax. A solid bike and I was impressed by it. My only hesitation with the bike was that it seemed big. Especially from what I was coming from. My current bike is a department store model, roughly 20 years old and at 20.5" frame.

SO...why does my 20.5" department store bike feel smaller than the new 19" marin? Should it not be the opposite?

I'm 5'10.

bikinpolitico

Because the size numbers don't mean much anymore. When all bikes had horizontal top tubes, it was easy to tell this number which was the center of the crank to the center of the top tube where it met the seat tube. Now days, most bikes have sloping top tubes, so the manufactures make up a number that they think would be the measurement if the bike still had a horizontal top tube.

Short answer: you have to try out a bike to see if it fits right. Ignore the size number.

alanbikehouston

The numbers on a bike don't mean much. Two identical bikes will be called a "19" by one company and a "21" by another.

When you stand flat-footed over the bike, with your belt buckle up against the back of the stem, the top tube of the bike should NOT be pressing painfully into your crotch...if it does, the frame is too tall.

Of the ten or twelve bikes I've owned over the past couple of years, the ones that fit me the best for long rides had tall frames...standing flat-footed over the frame, up against the back of the stem, the top tube was lightly brushing my jeans...no daylight between me and the frame.

A taller frame makes it easier to get the bars up level with the saddle, ideal for a four or five hour ride. On a road bike, having the high part of the bars level with the saddle puts the "drops" level with the top tube, making it comfortable to ride on the drops for extended periods of time.

At the other end of the spectrum, for a 30 minute crit or time trial, a pro cyclist gets a tiny "mini" frame, enabling him to drop the bars three or four inches lower than the saddle, getting an extreme "aero" position...the best position for a time trial, and the WORST position for commuting in heavy urban traffic.

macteacher

Hmm... thanks for the responses. It just seemed big when I tested it... HOWEVER.. I can easily stand over the top tube and lift it up a couple of inches before making 'crotch' contact. Salesguy said I could easily ride a 17 or a 19" due to my height...but of course he only had a 19 in stock. He said the 19 will allow for a more comfortable ride during longer trips. Other than just 'feeling' big I had no trouble riding the bicycle. Just not what im used to I guess. This is the bike in question:

macteacher

Im gonna re-test the bike soon (assuming its still there of course) Have a few more bikes I wanna try before I commit to anything though!!!

pinkrobe

The "crotch clearance" has little to do with the frame fit. If it feels too big, it's possible it is. Keep test riding...