Buying the right MTB frame size
Justin C. Merritt
I own a '96 GT Timberline with a 22" frame. I am 6'1" with a 32"
inseam. When I was testing out potential purchases, I found that the 20"
GT frames seemed a little too small, but the 22" frame was a little large.
The 20" frame required a high seat height to accomodate my leg
length to get the proper knee angle with the pedal at the bottom of the
stroke. As a result, I felt too unbalanced, like I had to lean too far
toward the handlebars. My upper body angle was about 45 degrees with my
elbows straight, hands on the grips.
The 22" frame allowed a more comfortable, natural upright sitting
position. The upper body angle on it is more like 60-75 degrees. My only
problem with it is a low standover clearance (about 1/2"). The height of
the top bar makes me nervous. I settled on the 22" frame because I
figured I would be less likely to have a wreck on a bike that I felt more
balanced on, even though the standover clearance makes an "unfortunate"
collision with the main tube more likely.
So here's my problem. I want to buy a new '97 GT, and they still
don't make 21" frames. What do you recommend for a frame size? Is the
more leaning posture actually recommended for a MTB? Is it something I
should just get used to in order to have a bike with an adequate standover
clearance? Are there any tall GT owners out there with a similar problem?
Note: I am a stubborn consumer. Please don't answer with "buy a
(Cannondale/Specialized/Trek)" because I am set on the GT line of bikes.
I understand that another company's 20" or 22" frame will fit differently,
but I like the models that GT offers. I would like to know which GT frame
would best suit me. I ride everything from paved roads and campus
sidewalks to rough fire roads and singletrack.
Thanks for any advice you can offer. Please email replies as well
as posting to newsgroup.
Thanks,
Justin Merritt
jcm10 (at) ra (dot) msstate (dot) edu
Pete Banach
my 20" bike a 2.5-3" standover clearance. A 22" GT would be WAY TOO
big for me. But like you, I always felt a bit heavy on the hands with
the seat cranked up to the right height for my legs. Felt like I was
always sitting in a very aggressive position with lots of weight on my
hands. So when I added my Judy XC just two weeks ago, I had the shop
cut the steerer tube 3/8" longer than the original rigid fork. This has
solved my fit problem and makes the bike much more comfortable.
downhill riser type bars can have the same affect I would think and so
would getting a different stem with a higher degree rise.
The "fit" is the most important consideration when it comes to deciding
which bike to get. I personally think you can't possible fit a 22"
frame GT being only 6'1". Even at 6'2", I think I could either go
for a 18" or 20" GT depending on a few changes in the stock setup.
I dont know about GT full suspension bikes, they might fit completely
different from the hardtails. But try to find something that fits even
if you have to try another bike manufacturer. Get something with more
than 2" of standover clearance never mind 1/2".
Pete
Steven Cockerill
justin,
i suggest that if you're going to ride off road that you buy a frame
that gives you plenty of jock room- at least 2 to three inches of
clearance. That way if you take a big spill, you won't have to shop around
for new family jewels. You are probobly just used to riding a bmx that
seats you really upright. On a mountain bike while riding in teh woods at
high speeds, you want to be somewhat hunched over to keep your center of
gravity low. Get a 19-20 inch frame and keep the seat at a confortable
level. I am 2 inches shorter than you and I have a seventeen inch frame.
if you want to sit really upright get a shorter stem.
Justin C. Merritt <jc...@ra.msstate.edu> wrote in article
<Pine.SOL.3.96.970414...@Ra.MsState.Edu>...
L. Jack Reese
In article <Pine.SOL.3.96.970414...@Ra.MsState.Edu> "Justin C. Merritt" <jc...@ra.msstate.edu> writes:
>From: "Justin C. Merritt" <jc...@ra.msstate.edu>
>Newsgroups: rec.bicycles.off-road
>Date: Mon, 14 Apr 1997 15:15:02 -0500
>Organization: Mississippi State University
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>
>
> I own a '96 GT Timberline with a 22" frame. I am 6'1" with a 32"
>inseam. When I was testing out potential purchases, I found that the 20"
>GT frames seemed a little too small, but the 22" frame was a little large.
> The 20" frame required a high seat height to accomodate my leg
>length to get the proper knee angle with the pedal at the bottom of the
>stroke. As a result, I felt too unbalanced, like I had to lean too far
>toward the handlebars. My upper body angle was about 45 degrees with my
>elbows straight, hands on the grips.
> The 22" frame allowed a more comfortable, natural upright sitting
>position. The upper body angle on it is more like 60-75 degrees. My only
>problem with it is a low standover clearance (about 1/2"). The height of
>the top bar makes me nervous. I settled on the 22" frame because I
>figured I would be less likely to have a wreck on a bike that I felt more
>balanced on, even though the standover clearance makes an "unfortunate"
>collision with the main tube more likely.
Go with the 20" is my opinion. I'm 6'0" and my first MTB was 22".
I bought it because it was comfortable as you said, and it was on
a great sale (because the shop had lots of the BIG sizes left.)
I now ride an 18" bike and am VERY comfortable. If you ride
off-road - smaller is the way to go, if you use it mostly to commute
to school, like I did my first bike, big is OK - but then what do you
do when you want to ride?
You can always make a smaller bike more comfortable by adding bar ends
so you can stretch out and get different positions, but, there's
not much you can do about that top tube standover clearence....
$0.02
> So here's my problem. I want to buy a new '97 GT, and they still
>don't make 21" frames. What do you recommend for a frame size? Is the
>more leaning posture actually recommended for a MTB? Is it something I
>should just get used to in order to have a bike with an adequate standover
>clearance? Are there any tall GT owners out there with a similar problem?
> Note: I am a stubborn consumer. Please don't answer with "buy a
>(Cannondale/Specialized/Trek)" because I am set on the GT line of bikes.
>I understand that another company's 20" or 22" frame will fit differently,
>but I like the models that GT offers. I would like to know which GT frame
>would best suit me. I ride everything from paved roads and campus
>sidewalks to rough fire roads and singletrack.
>
> Thanks for any advice you can offer. Please email replies as well
>as posting to newsgroup.
>
>Thanks,
>Justin Merritt
>jcm10 (at) ra (dot) msstate (dot) edu
>
>
--
Jack Reese
__o re...@byu.edu
_'\<,_ http://students.cs.byu.edu/~reese
(*)/ (*) If I'm not here, I'm probably mountain biking!
Craig Gephart
Justin,
An 18" but no more than a 20" is probably best for you. I'm 5'11" with a
32" inseam and ride an 18" Giant ATX890. While a rider's height may be one
thing it's the inseam that really counts when talking frame size. a 6'1"
rider with a 32" inseam isn't going to have any more clearance than a 5'11"
rider with a 32" inseam (pretty basic, eh?).
While bike manufacturers have been known to size their bikes in slightly
different ways I can't imagine you'd want more than a 20". You really
should look for at least 2" inches clearance (the more the merrier). Plan
to make your adjustments elsewhere (stem, seat tube, bar ends, etc.) and
realize that positioning on a mountain bike WILL cause you to be less
upright than on other bikes.
Happy trails!
Craig Gephart
Grogoraggly
In article <01bc49fb$985bc020$104c...@cgephart.pipeline.com>,
>An 18" but no more than a 20" is probably best for you. I'm 5'11" with a
>32" inseam and ride an 18" Giant ATX890. While a rider's height may be one
>thing it's the inseam that really counts when talking frame size. a 6'1"
>rider with a 32" inseam isn't going to have any more clearance than a 5'11"
>rider with a 32" inseam (pretty basic, eh?).
Standover height is pretty important, but even more important is the length
of the top tube. There are manufacturers who make their frames with
radically sloping top tubes and slightly longer top tubes than most others
with the same seat tube length, with the benefit being a smaller frame which
is both lighter and stiffer. While you can tinker with the effect of the
top tube by replacing stems and moving your saddle back, it's a lot easier
to just raise or lower your seat post.
All this being said, you should just go and test ride some bikes to find out
what feels right.
Jason Morrill
I bought a used GT last fall with a 19" frame. I stand at 6'2" with a
34" inseam and I feel OK on the frame. However, there are times when I
feel like I am riding a bit too upright. I think if you have been riding
a 22" and haven't experienced any traumatic problems you should keep
going with the same frame size.
I used to ride a larger frame, 22" I believe, and I felt very unstable
on it. Maybe because I used to ride the tiny BMX bikes I like the
smaller frames. The 22" frame did allow me to extend my legs slightly
further, but not enough to counter-act the feeling of unease on the
large frame.
Just a little note. I believe the frame to be 19". I haven't measured
and the sticker that gives the frame size was missing when I bought the
bike.
-Jason
Justin C. Merritt wrote:
> I own a '96 GT Timberline with a 22" frame. I am 6'1" with a 32"
> inseam. When I was testing out potential purchases, I found that the 20"
> GT frames seemed a little too small, but the 22" frame was a little large.
> The 20" frame required a high seat height to accomodate my leg
> length to get the proper knee angle with the pedal at the bottom of the
> stroke. As a result, I felt too unbalanced, like I had to lean too far
> toward the handlebars. My upper body angle was about 45 degrees with my
> elbows straight, hands on the grips.
> The 22" frame allowed a more comfortable, natural upright sitting
> position. The upper body angle on it is more like 60-75 degrees. My only
> problem with it is a low standover clearance (about 1/2"). The height of
> the top bar makes me nervous. I settled on the 22" frame because I
> figured I would be less likely to have a wreck on a bike that I felt more
> balanced on, even though the standover clearance makes an "unfortunate"
> collision with the main tube more likely.