Are sizes different these days?
 

I noticed that on old bikes (from the 70's and 80's) I tend to fit on a 58-60cm frame. I had a 54cm Peugeot. Loved it. Too small. I got myself a 58cm Trek 1500 and it was too big. Now I'm riding a 56cm Tricross and it fits nice and I like it. Either I shrunk 2cm in the last couple of years or bikes are getting sized different. What gives?

Could be lots of things. When I go from SLR (olde skool) brake levers to modern brifter hoods I like a 2cm shorter stem cuzza the extra reach on the big plank of a hood.

Could be just part of getting old. I'm going up in size to deal with that, though. I find myself liking higher handlebars as I age.

Yeah, I found I had the same problem with my belts and pants. They were all shrinking. I found out out how to fix the problem and now they fit correctly.

Many older frames had top tubes that were short in relation to the seat tubes. It was common to see large frames with the same 57cm top tube as the smaller models -- people just used a longer stem to make everything work. I think this was so a builder didn't have to keep as many different lugs on hand.

Nowadays, bikes are more "square" -- a large frame will generally have a top tube that is effectively the same length as the seat tube.

Could it be the fact that some makers measure differently, some c-c and some c-top. ? :D

You must be living in 1990 ;)

Plenty of sloping top tube bikes aren't close to square.

For instance, Specialized Secteur : seat tube 485mm, TT 565mm. And the top of the head tube is about where a 60cm square, level TT frame's would be.

you also do tend to shrink with age.... and go bald :(

and your feet and ears keep growing. :roflmao2:

and the young people all turn in to smart mouth whipper snappers

Of course the seat tube is going to be physically shorter with a sloping top tube. ;) If you draw a dotted line where a horizontal top tube would cross through the actual top tube at the standover point*, then the geometry comes out a lot more square.

- Scott

(*I could probably be accused of moving the goalpost there, but with sloping top tubes, manufacturers are also taking the opportunity to make the head tubes taller than they otherwise would be so more average joes can ride with that "slammed stem" look...)

And yes, 1990 was a great time for bikes. ;)

Age really can have at least something to do with it. I myself rode a 58 cm Trek 1500 (ca. 1989) and was quite comfortable on it. Now it's clearly too big for me, and my latest road bike, a Cannondale Synapse, is an extremely comfy 56.

Bike geometry has changed some too. Back in my day :50: we rode with the saddle BEHIND the bottom bracket. Somewhere along the way they shoved the saddle forward so you were in more of a "running" position on the bike and spinning like a gerbil on crack. I am more of a masher than a spinner, but I could generate some serious power and climbed like a witch on a broom on Halloween night. :P

Find what fits you and ride the hell out of it. FWIW my favorite bikes are 64cm with short top tubes and slack angles.

Aaron :)

This seems like he best answer. The BIKES were from the 70's not ME. I mean, I was from the 70's but I really just started riding a few years ago and I still have a 60cm (maybe a 58) Raleigh Marathon that still fits me fine. The 1500 was an '05 (no sloping top-tube-of-deception on that bike) and it was just too long of a reach t the bars, so I like the square-bike theory just fine.

Two words: Stack and reach: http://www.slowtwitch.com/Bike_Fit/C...er_One_95.html

CM still =10mm..
Tape measure in your pocket, you can do your own measurement,
most companies call 'size' a seat tube length measurement.

they start at the center of the BB axle, for the Bottom,
where they vary is the top, and is the seat tube extending high above the top tube ,
or just a little bit.

then there is the whole top tube length issue, another measurement .
that is more typically center lines of seat and headtubes..
and the slope of the top tube, is another variable..

from the title i thought the subject was clothing! :lol:

since i mentioned the 'c' word, i have noticed that while i am the same size as in my late teens, clothing size designations have changed drastically. :innocent:

example: in 1971 i wore size 'medium' shirts. the clothing industry now calls them
'2XL'. :eek: :twitchy: :notamused:

somethin' wrong with this here picture...

as for bikes, if it fits i ride it. i don't worry about numbers.