MTB frame size question

Hi all,

At 6' + change, I currently ride a 21" hardtail. I am not sure of my
inseam; 34" jeans/pants tend to be a bit too short for my liking. I
weigh in around 190 (dropping to 180).

I am considering moving down to a 19" frame for my next bike. Reasons:
1) Smaller size = easier to store/transport
2) Less weight (negligible)
3) Relative strength of smaller triangles
4) Better handling??
5) More standover (not really an issue)
6) More aero position (higher saddle relative to bars)

Problems I see a
1) Saddle height...will probably need a longer seatpost
2) ??

Should I be considering anything else? What are some strong reasons
*not* to go with a smaller frame?

Dave, since I'm 6'7" myself I feel inclined to respond to your request.
Until a few months ago I was riding a stock XL frame. Since then I have
switched to a custom build bike and it makes a _lot_ of difference. My
advise is to use a bike that has an optimal fit for your body. It's not
just the saddle height but also the top-tube that's important. If the
top-tube is to short you lean to much over the front wheel which makes
steering very instable. It also puts more weight on your arms. The
position of your saddle in relation to your pedals will be incorrect.
Go to a good bike shop and have them advise you on a bike that fits
your dimensions. If you are concerned about weight then buy a lighter
weight bike (light-weight components, wheels, frame, etc). And from a
storage/transport perspective it will make a minor difference.


schreef:

Hi all,

At 6' + change, I currently ride a 21" hardtail. I am not sure of my
inseam; 34" jeans/pants tend to be a bit too short for my liking. I
weigh in around 190 (dropping to 180).

I am considering moving down to a 19" frame for my next bike. Reasons:
1) Smaller size = easier to store/transport
2) Less weight (negligible)
3) Relative strength of smaller triangles
4) Better handling??
5) More standover (not really an issue)
6) More aero position (higher saddle relative to bars)

Problems I see a
1) Saddle height...will probably need a longer seatpost
2) ??

Should I be considering anything else? What are some strong reasons
*not* to go with a smaller frame?

wrote: Reasons:
1) Smaller size = easier to store/transport
^^^^^^^^^^^^^^^^
A difference which will make the bike significantly easier to store and
handle will surely be larger than your body will like.

2) Less weight (negligible)
^^^^^^^^^^^^^
As you say, negligible.

3) Relative strength of smaller triangles
^^^^^^^^^^^^^^^
Triangles are inherently strong. Are you riding a bike that feels too
flexible? Or too weak? If not, the tiny gain in strength of a smaller
frame will not be noticed.


4) Better handling??
^^^^^^^^^^^^^^^^^
No reason to expect better handling from a smaller frame. Handling is the
result of a lot of variables, controlled mostly by the designer. You will
be able to test ride smaller bikes, some of which may handle better than
your present one, and some of which will handle WORSE. In any case, this
will not be so much good handling vs bad handling, as handling which suits
your riding needs, vs handling which does not suit your needs.

5) More standover (not really an issue)
6) More aero position (higher saddle relative to bars)
^^^^^^^^^^^^^^^^^^
This can be adjusted by seat height and stem geometry. More important is
the length of the top tube, which controls how you must lean to sit on the
bike and hold the bars. A smaller frame could put you in a bad position.

Problems I see a
1) Saddle height...will probably need a longer seatpost
^^^^^^^^^^^^^^^^^^^
A longer seatpost is weaker--the loss here is far greater than any gain due
to a smaller frame.

wrote:

Should I be considering anything else? What are some strong reasons
*not* to go with a smaller frame?

I'd stick with the larger frame.

I'm 6'5", and ride an XL Gary Fisher Hardtail. I think it's about 22.5"
or so. I recently had to raise the the saddle to allow my legs to
extend more, and the handlebars are now about 2" below the saddle, which
is a tad uncomfortable for me. I'm probably going to have to get a new
stem to raise them up to a comfortable position. On a smaller bike,
this would be even worse. I'd probably have to get an extra-long
seatpost and an extra long stem as well. Not very convenient.

I wouldn't be too concerned with aerodynamics - not for a mountain bike
anyhow. Hand positions can be fixed with bar ends or different
handlebars. In short, all of those "benefits" of a smaller frame are
negligible. Having a bike that fits you well is more important than all
of that.

If speed and weight are really what you're after, you may want a road
bike.

3Hank wrote:

Dave, since I'm 6'7" myself I feel inclined to respond to your request.
Until a few months ago I was riding a stock XL frame. Since then I have
switched to a custom build bike and it makes a _lot_ of difference.

So what did you get? How long is it in the top tube, and how long in
the chainstay?

Chalo Colina

A web search returns many frame calculators. Can anyone recommend a
reputable and accurate one?

3Hank wrote:

Dave, since I'm 6'7" myself I feel inclined to respond to your request.
Until a few months ago I was riding a stock XL frame. Since then I have
switched to a custom build bike and it makes a _lot_ of difference. My
advise is to use a bike that has an optimal fit for your body. It's not
just the saddle height but also the top-tube that's important. If the
top-tube is to short you lean to much over the front wheel which makes
steering very instable. It also puts more weight on your arms. The
position of your saddle in relation to your pedals will be incorrect.
Go to a good bike shop and have them advise you on a bike that fits
your dimensions. If you are concerned about weight then buy a lighter
weight bike (light-weight components, wheels, frame, etc). And from a
storage/transport perspective it will make a minor difference.


schreef:



Hi all,

At 6' + change, I currently ride a 21" hardtail. I am not sure of my
inseam; 34" jeans/pants tend to be a bit too short for my liking. I
weigh in around 190 (dropping to 180).

I am considering moving down to a 19" frame for my next bike. Reasons:
1) Smaller size = easier to store/transport
2) Less weight (negligible)
3) Relative strength of smaller triangles
4) Better handling??
5) More standover (not really an issue)
6) More aero position (higher saddle relative to bars)

Problems I see a
1) Saddle height...will probably need a longer seatpost
2) ??

Should I be considering anything else? What are some strong reasons
*not* to go with a smaller frame?

Per :
Problems I see a
1) Saddle height...will probably need a longer seatpost
2) ??

Should I be considering anything else?

Bar height.
--
PeteCresswell

Thanks for all the responses. Admittedly, none of the reasons I gave
are strong motivation FOR reducing frame size.

I recently bought a decent road bike, which could be fueling my thought
process here. I am satisfied with the trail capabilities of my MTB,
but I have been using it as transportation more and more frequently.
It is heavy and the seating position is so damn upright (ok, but
inefficient)! When on pavement, I raise my seat to the MIL, which puts
my bars below my saddle. On the trails, my saddle height is determined
by the terrain.

My next MTB will be significantly lighter than my current ride. I was
thinking frame size would be an easy way ($$-wise) to lose some (not
much) weight....obviously, a good fit is far more valuable than a few
grams.

I guess I was hoping that someone had tried this, and could provide
feedback (positive or negative) based on their experience.

Cheers,
Dave

wrote:
Thanks for all the responses. Admittedly, none of the reasons I gave
are strong motivation FOR reducing frame size.

I recently bought a decent road bike, which could be fueling my thought
process here. I am satisfied with the trail capabilities of my MTB,
but I have been using it as transportation more and more frequently.
It is heavy and the seating position is so damn upright (ok, but
inefficient)! When on pavement, I raise my seat to the MIL, which puts
my bars below my saddle. On the trails, my saddle height is determined
by the terrain.

My next MTB will be significantly lighter than my current ride.

There's your answer.