Frame Sizes

\\¯`·.¸biz¸.·´¯/ said:

My question is: Are dual susp bikes measured differently?
ie are they deliberately shorter for off-road purposes, or
am I just looking in the wrong places?

There are very few "standards" in the bike business, and
"bike sizing" is one clear example.

The "size" measurements all start from the center of the
bottom bracket (or crank bolt, if you prefer), and run along
the centerline of the seat tube to:

a) center of the top tube (the most useful if you're
cutting tubes to build frames, but kinda meaningless to
the rider since he/she doesn't really care where the
center of the tube is)

b) top of the top tube (this one is IMHO the best since it
tells you where the part of the tube you need to worry
about is located)

c) top of the seat tube (this one makes no sense at
all, IMHO).

I suspect the thing that's confusing you is that the FS
bikes tend to be "smaller" from a frame measurement
perspective because the bottom bracket is higher (otherwise
you'd be dragging your cranks through the mud when the
suspension compresses). That means that a given size rider
will ride a "smaller" FS bike than he/she would a hard tail.

Mark Hickey Habanero Cycles habcycles.comhabcycles.comOpen ↗ Home of
the $695 ti frame

\\¯`·.¸biz¸.·´¯/ said:

Going by traditional sizing methods to check which size of
bike I'd need; having a long inner leg measurement I find
that a 21" or 22" would be about the correct size.

Not sure what you mean by traditional. If you mean using
some goofy math against your inseam to pop out a frame size,
well, don't do that.

The first measurement you should look at to compare frames
is effective top tube length. If a bike is close to the
right length for you, swapping stems and moving the saddle
around on the seatpost clamp can help you make the fit
perfect. If the bike is the wrong length by more than .75"
or so, there's only so much you can do. Seat tube height is
really a bad measurement to use to compare bikes (tradition
be damned) since you can "fix" the vertical fit just by
changing seat height, and lengths vary by mfger.

Full suspension bikes don't necessarily have a complete
"seat tube", so often the sizing is going to S, M, L, XL.
And that makes a TON more sense than talking about a 19"
bike (when one mfger's 19 has a 24.25" effective top tube
and another mfger's 19 has a 23.5" ett).

Since you admit that you are something of a newb, here's the
best advice for you. FIND A GOOD BIKE SHOP. Not just a
pretty shop that has the brands you like, but a shop that
has people who KNOW bike fitting. Especially if your body
proportions are atypical, you need the help of someone who
knows how to fit people to bikes. In person. And then you
need to test ride many bikes.
--
Tom Purvis - arkansasvalley.nettpurvisOpen ↗
"The whole problem with the world is that fools and fanatics are always so
certain of themselves, but wiser people so full of doubts."-Bertrand Russell

"Mark Hickey" <[email hidden]> wrote in message

Quoted message said:

Mark Hickey Habanero Cycles habcycles.comhabcycles.comOpen ↗ Home
of the $695 ti frame

"Tom Purvis" <[email hidden]> wrote in message

Quoted message said:

--
Tom Purvis - arkansasvalley.nettpurvisOpen ↗ "The
whole problem with the world is that fools and fanatics
are always so certain of themselves, but wiser people so
full of doubts."-Bertrand Russell

Thanks guys, advice taken on board. cheers biz