Frame fit: which is more important - Frame height vs. top tube length?

Wilbur Pan wrote:
I posted this on another bike forum, but I'm still casting for
opinions.

I'm looking to get my first road bike after many years of riding
mountain bikes. After much reading on these forums and on the web, I
think I have at least the basics of finding the proper frame size for
me.

Here's the issue I'm having. My inseam measured by the
book-jammed-into-my-crotch method is 76 cm. This gives me a frame size
of 50 cm. After trying out a number of road bikes in the 50-52 cm
range, I am finding that the most predictable measure as to whether I
felt comfortable on my test rides was actually top tube length. It
seems that I was most comfortable with frames with a 53.5 cm top tube
length (or effective top tube length, for compact/sloped top tube
bikes), almost irrespective of whether it was a 50 or 52 cm frame.

The reason I am bringing this up is that there don't appear to be many
50 cm frames with a top tube/effective top tube length of 53.5 cm. If
I go with a 52 cm frame, there are more options for me as far as top
tube length, but my standover clearance is down to about 1 cm. I
haven't noticed much difference in pedaling between the two sizes.

I know that I can get a longer stem, but an unsure as to how much
adding 1-1.5 cm to the stem will affect handling, or if that will
actually take care of the fit issue.

So should I:

1. Go with a 50 cm frame because that's the right frame for my inseam,
and get a longer stem, or

2. Go with a 52 cm frame so I don't have to worry about swapping out
the stem?

Definitely buy a bike that feels more comfortable to you; stand-over
clearance is way over-emphasized IMO -- especially for a road bike. (And
you /could/ go the 52 or 53 cm compact frame if really worried about it.)

Bill "and stop jamming that book up your crotch " S.

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In article ,
Wilbur Pan wrote:
I posted this on another bike forum, but I'm still casting for
opinions.

I'm looking to get my first road bike after many years of riding
mountain bikes. After much reading on these forums and on the web, I
think I have at least the basics of finding the proper frame size for
me.


So should I:

1. Go with a 50 cm frame because that's the right frame for my inseam,
and get a longer stem, or

2. Go with a 52 cm frame so I don't have to worry about swapping out
the stem?


_ I think top-tube length is probably more important on a road
bike. What really matters in the long run is that the bike
feels comfortable when riding, not at stop lights. The other
thing to keep in mind is that as you get accostumed to riding
your idea of what's comfortable will probably change. If you
start out at the extreme of a bike you don't have much room
to tweak things. As you get more used to the position, you are
likely to want a longer stem. Your stand over height will
never change so as long as you don't have to stand on
tip toe at stoplights, I wouldn't worry about it too much.

_ The rule of thumb seems to be a stem length of 90-140 is
good, much longer or shorter can lead to bike handling
strangeness.

_ Booker C. Bense

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In article ,
Wilbur Pan wrote:
I posted this on another bike forum, but I'm still casting for
opinions.

I'm looking to get my first road bike after many years of riding
mountain bikes. After much reading on these forums and on the web, I
think I have at least the basics of finding the proper frame size for
me.


So should I:

1. Go with a 50 cm frame because that's the right frame for my inseam,
and get a longer stem, or

2. Go with a 52 cm frame so I don't have to worry about swapping out
the stem?


_ I think top-tube length is probably more important on a road
bike. What really matters in the long run is that the bike
feels comfortable when riding, not at stop lights. The other
thing to keep in mind is that as you get accostumed to riding
your idea of what's comfortable will probably change. If you
start out at the extreme of a bike you don't have much room
to tweak things. As you get more used to the position, you are
likely to want a longer stem. Your stand over height will
never change so as long as you don't have to stand on
tip toe at stoplights, I wouldn't worry about it too much.

_ The rule of thumb seems to be a stem length of 90-140 is
good, much longer or shorter can lead to bike handling
strangeness.

_ Booker C. Bense

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Wilbur Pan wrote:
I posted this on another bike forum, but I'm still casting for
opinions.

Here's the issue I'm having. My inseam measured by the
book-jammed-into-my-crotch method is 76 cm. This gives me a frame size
of 50 cm.

Stop right there. For one thing, "frame size" or seat tube length can be
specified differently by different bike makers. Secondly, seat tube length
is not the best way to chose a frame.

After trying out a number of road bikes in the 50-52 cm
range, I am finding that the most predictable measure as to whether I
felt comfortable on my test rides was actually top tube length. It
seems that I was most comfortable with frames with a 53.5 cm top tube
length (or effective top tube length, for compact/sloped top tube
bikes), almost irrespective of whether it was a 50 or 52 cm frame.

Correct. Go for the right seat tube length.

The reason I am bringing this up is that there don't appear to be many
50 cm frames with a top tube/effective top tube length of 53.5 cm. If
I go with a 52 cm frame, there are more options for me as far as top
tube length, but my standover clearance is down to about 1 cm. I
haven't noticed much difference in pedaling between the two sizes.

That's passable, although I'd like to have 2 cm of clearance. Did you
check the standover in the cycling shoes you intend to wear?

I know that I can get a longer stem, but an unsure as to how much
adding 1-1.5 cm to the stem will affect handling, or if that will
actually take care of the fit issue.

In that size frame, I don't think you'd want to go longer than a 11cm
or 12 cm stem.


So should I:

1. Go with a 50 cm frame because that's the right frame for my inseam,
and get a longer stem, or

2. Go with a 52 cm frame so I don't have to worry about swapping out
the stem?

Go with the larger frame if it feels better. The larger frame will be less
prone to toe overlap, and will let you get the bars higher if you want.

Art Harris

Wilbur Pan wrote:
I posted this on another bike forum, but I'm still casting for
opinions.

Here's the issue I'm having. My inseam measured by the
book-jammed-into-my-crotch method is 76 cm. This gives me a frame size
of 50 cm.

Stop right there. For one thing, "frame size" or seat tube length can be
specified differently by different bike makers. Secondly, seat tube length
is not the best way to chose a frame.

After trying out a number of road bikes in the 50-52 cm
range, I am finding that the most predictable measure as to whether I
felt comfortable on my test rides was actually top tube length. It
seems that I was most comfortable with frames with a 53.5 cm top tube
length (or effective top tube length, for compact/sloped top tube
bikes), almost irrespective of whether it was a 50 or 52 cm frame.

Correct. Go for the right seat tube length.

The reason I am bringing this up is that there don't appear to be many
50 cm frames with a top tube/effective top tube length of 53.5 cm. If
I go with a 52 cm frame, there are more options for me as far as top
tube length, but my standover clearance is down to about 1 cm. I
haven't noticed much difference in pedaling between the two sizes.

That's passable, although I'd like to have 2 cm of clearance. Did you
check the standover in the cycling shoes you intend to wear?

I know that I can get a longer stem, but an unsure as to how much
adding 1-1.5 cm to the stem will affect handling, or if that will
actually take care of the fit issue.

In that size frame, I don't think you'd want to go longer than a 11cm
or 12 cm stem.


So should I:

1. Go with a 50 cm frame because that's the right frame for my inseam,
and get a longer stem, or

2. Go with a 52 cm frame so I don't have to worry about swapping out
the stem?

Go with the larger frame if it feels better. The larger frame will be less
prone to toe overlap, and will let you get the bars higher if you want.

Art Harris

Harris wrote:

Correct. Go for the right seat tube length.

Oops. I meant "Go for the right top tube length."

Art Harris

Harris wrote:

Correct. Go for the right seat tube length.

Oops. I meant "Go for the right top tube length."

Art Harris

Choose by top tube. The only real worry with seat tube is you won't be able
to straddle the bike. As long as you're not hitting the frame when
standing, all is well.

On the other hand, if you have a really long top tube for the size, you
might find that it is difficult to get the stem as high as you might want.
However, a really odd size (54 x 50, etc.) is starting to demand a custom
bike.

-Dion

"Wilbur Pan" wrote in message
om...
I posted this on another bike forum, but I'm still casting for
opinions.

I'm looking to get my first road bike after many years of riding
mountain bikes. After much reading on these forums and on the web, I
think I have at least the basics of finding the proper frame size for
me.

Here's the issue I'm having. My inseam measured by the
book-jammed-into-my-crotch method is 76 cm. This gives me a frame size
of 50 cm. After trying out a number of road bikes in the 50-52 cm
range, I am finding that the most predictable measure as to whether I
felt comfortable on my test rides was actually top tube length. It
seems that I was most comfortable with frames with a 53.5 cm top tube
length (or effective top tube length, for compact/sloped top tube
bikes), almost irrespective of whether it was a 50 or 52 cm frame.

The reason I am bringing this up is that there don't appear to be many
50 cm frames with a top tube/effective top tube length of 53.5 cm. If
I go with a 52 cm frame, there are more options for me as far as top
tube length, but my standover clearance is down to about 1 cm. I
haven't noticed much difference in pedaling between the two sizes.

I know that I can get a longer stem, but an unsure as to how much
adding 1-1.5 cm to the stem will affect handling, or if that will
actually take care of the fit issue.

So should I:

1. Go with a 50 cm frame because that's the right frame for my inseam,
and get a longer stem, or

2. Go with a 52 cm frame so I don't have to worry about swapping out
the stem?

By the way, getting a custom frame is way out of my budget at this
point in time.

Choose by top tube. The only real worry with seat tube is you won't be able
to straddle the bike. As long as you're not hitting the frame when
standing, all is well.

On the other hand, if you have a really long top tube for the size, you
might find that it is difficult to get the stem as high as you might want.
However, a really odd size (54 x 50, etc.) is starting to demand a custom
bike.

-Dion

"Wilbur Pan" wrote in message
om...
I posted this on another bike forum, but I'm still casting for
opinions.

I'm looking to get my first road bike after many years of riding
mountain bikes. After much reading on these forums and on the web, I
think I have at least the basics of finding the proper frame size for
me.

Here's the issue I'm having. My inseam measured by the
book-jammed-into-my-crotch method is 76 cm. This gives me a frame size
of 50 cm. After trying out a number of road bikes in the 50-52 cm
range, I am finding that the most predictable measure as to whether I
felt comfortable on my test rides was actually top tube length. It
seems that I was most comfortable with frames with a 53.5 cm top tube
length (or effective top tube length, for compact/sloped top tube
bikes), almost irrespective of whether it was a 50 or 52 cm frame.

The reason I am bringing this up is that there don't appear to be many
50 cm frames with a top tube/effective top tube length of 53.5 cm. If
I go with a 52 cm frame, there are more options for me as far as top
tube length, but my standover clearance is down to about 1 cm. I
haven't noticed much difference in pedaling between the two sizes.

I know that I can get a longer stem, but an unsure as to how much
adding 1-1.5 cm to the stem will affect handling, or if that will
actually take care of the fit issue.

So should I:

1. Go with a 50 cm frame because that's the right frame for my inseam,
and get a longer stem, or

2. Go with a 52 cm frame so I don't have to worry about swapping out
the stem?

By the way, getting a custom frame is way out of my budget at this
point in time.

In article ,
Wilbur Pan wrote:
Here's the issue I'm having. My inseam measured by the
book-jammed-into-my-crotch method is 76 cm. This gives me a frame size
of 50 cm.

Note that LeMond's book specifies a center-to-center measurement,
with big tubes center-to-top can be 2cm more, and some companies
measure to the top of the seat collar.

--
a href="http://www.poohsticks.org/drew/"Home Page/a
Life is a terminal sexually transmitted disease.