General Cycling Discussion - Yet another seat height question

An inquisitive, non cycling friend of mine had a question that I could not adequately answer. He noticed that many cyclists have their seat post extended as far as safely possible above the frame. (Mine is too) He asked me “doesn’t that mean that their frames are too small?”

I explained that my frame was fitted for the stand over height. And the seat was adjusted so that my leg is almost straight when on the bottom of the stroke. His contention is “That would mean that the seat post extension should be about the same distance as the pedal to the ground at the bottom of the stroke.”

That sounds logical, yet I think that my seat extension is more than that (although I didn’t measure it).

Is he right? And if so, why do so many cyclists appear to have their seats extended more than that? (I’m going to measure mine tonight.)

I actually have the opposite problem. My frame is a little too big for me. Is there anything that I can do to alleviate that?

My frame is a little too big for me

What are the symptoms of a big frame (besides no stand-over height)?

I hope your non-cycling friend does not spread this ugly rumor around or all the frame manufacturers are going to reaalize that they have screwed up.

Any other words...I think he may be right:(

It goes along with 53-12 gear sets.

There are 2 reasons for having a lot of exposed seatpost.

The most important one is fashion. Many modern frames are of the "compact" design, where the top tube is not horizontal, but tilted down to the rear. a few inches of bike frame are saved and a few extra inches of seatpost are required. This design gives a stiffer, lighter bike and the extra clearance is for off-road riding.

The second reason is to permit the handlebars to be down low; this needs a short headtube which is achieved by lowering the whole top-tube a few inches. Typically this type of frame is used by time-trialists who race against the clock and prefer very low aerodynamic riding positions.

There is no relationship between the amount of exposed seatpost and the height of the pedal off the ground. Pedal height should be related to the cornering requirements and clearing obstacles.
Modern seatposts are built long and are often of wider diameter to retain stiffness over a longer length. Dont try using a shorter traditional post in a long style role. If you can read the "Max Extension" warning, you have been warned.

you should have about 4-5 cm gap when you stand over the top tube right? Add that to the distance from the pedal to the ground and you have your seatpost extension.

:)

Originally posted by MikeR


What are the symptoms of a big frame (besides no stand-over height)?

I feel like I'm leaning over too far when riding and my shoulders get tired easily. Is this normal?

Originally posted by cowgirl


I feel like I'm leaning over too far when riding and my shoulders get tired easily. Is this normal?

It appears that you are another "long stemed american beauty" like my wife. We have worked for 10 years to get her a bike that fit, and honestly it still doesn't, but it is as close as we are going to get without the cost of a custom frame.

Lady you have been bite by the famous "It's a mans world" syndrome!! I hope a shorter stem will make you comfortable.

I assume you are talking about road bikes. Because Mountain bikers (non pure xc riders) have their frames small for them. Ease of maneuvering around tight corners, big drops etc... I would not want a frame that fits 'just' below my inseam. I could only imagine the pain.

Even for road bikes, the stand-over test can only be a very approximate measure of a proper fitting frame (i.e. not at all a reliably good measure).

You want a frame to fit you for when you are riding the bike, not when you are standing over it. Both longer and shorter torsoed folks will vigorously attest to this.

Better measures involve inseam measurements and so on. do a search for "bike fit" and you'll find lots of websites posted for helping with fit.

But taking a smaller frame (within reason) has small weight and handling advantages. Moreover, a too large frame can be more difficult to adapt to a cyclist (i.e. with handlebar stem, etc.) than a too small one.

I have a frame that passes the stand-over test like a charm. I am pretty normally proportioned, and the bike has a pretty standard geometry. Nevertheless, my bike is slightly too big for me (and I still have 3-4 inches of seatpost showing). The result is that the top tube is too long. If I want a stem that gives me a correct set up is hard to find, and would give me rather twitchy steering. My next bike will definited be a tad smaller.

Cheers,
Jamie

Originally posted by cowgirl
I actually have the opposite problem. My frame is a little too big for me. Is there anything that I can do to alleviate that?
You mean besides grow longer legs?
:)
Joe
:beer:

when getting fit it is crucial for the person doing the 'fit' to know what kind of riding you are doing. a lot of hills and climbing would have the frame 1-2cm larger (what everyone is complaining about) so the seat and its post doesn't bear the brunt of the stress... (an observation, not bike law/rule)

always ride flat and you can get away with a smaller frame and jack the seat way up. (an observation, not bike rule/law)

i noticed that during the tour de france, the time trial bikes were mini-frames with more of the seatposts showing and during the mountain stages the bikes were larger frames. does this have anything to do with the climbing position of sitting back on the seat so you get the stretch all the way up into the butt?!

of course you can brag of a lighter bike frame with the mini frame....but the longer seatpost it requires negates the weight savings.

Originally posted by 1oldRoadie


It appears that you are another "long stemed american beauty" like my wife. We have worked for 10 years to get her a bike that fit, and honestly it still doesn't, but it is as close as we are going to get without the cost of a custom frame.

Lady you have been bite by the famous "It's a mans world" syndrome!! I hope a shorter stem will make you comfortable.

You don't need to go a far as a custom frame, but you need a proper manufacturer, who has more than the standard 'Small', 'Medium' and 'Large' sizes.

Have a look at the SJSC web site, their standard frames come in 10 sizes, which should just about cover the giant legged dwarf, to the dwarf legged giant and everything inbetween

Click on 'Thorn Brochures' then select '26" wheel bikes', and then about 10 pages into the text (after all the bits about paint, tyres, racks etc) there is a section on frame sizing, which explains it all

http://www.sjscycles.com/

Originally posted by joeprim

You mean besides grow longer legs?
:)
Joe
:beer:

:D :D I already have too many britches that are highwaters.

Originally posted by RiPHRaPH
i noticed that during the tour de france, the time trial bikes were mini-frames with more of the seatposts showing and during the mountain stages the bikes were larger frames. does this have anything to do with the climbing position of sitting back on the seat so you get the stretch all the way up into the butt?!


This is interesting, as it contradicts the classification of compact geometry bikes as "climbing bikes" because they tend to expose more seatpost. I would agree with your theory though.


Dax

Originally posted by cowgirl

I feel like I'm leaning over too far when riding and my shoulders get tired easily. Is this normal?
Cowgirl,
Nope it ain't normal. Besides the entire stem length question
you might look at saddle adjustment. If your saddle is angled
down (nose down) it will pitch you forward and put undo
pressure on wrists, shoulders neck etc.
also you need to take into consideration handlebar height.
Most new bikes have bars way too low, face it we are all
not pro cyclists who need to be aerodynamic. If you have
a quill stem try raising your stem/bars a few cms at a time
until you find a comfortable position.
Are you rocking when you pedal? have to stretch to reach
pedal at bottom of pedal stroke? if so your saddle is too
high.
I'd strongly suggest going into your LBS and getting a
fitting done, its well worth the cost to be properly
fitted to the bike.
Hope this helps,
Marty

Mike, I have a 22" inch frame, and my seat post only extends out about 3 inches, maybe not even, and I find it perfect for me, I can ride with out discomfort.:beer:

Thanks lotek. I'll try making a few adjustments before I go out and see if that helps. I don't have any problems pedalling, but sometimes when I hop off my bike really quick to avoid trouble (I've become a big chicken after my last wreck :(), it seems a bit far. I think that's just due to where I stop on the trail though.