Frame size
 

My height is 184cm. What is the appropriate bicycle size for this height?

58cm.

That's how tall I am but I have a long inseam (34.5") and short arms for my height. I'm very comfortable riding 61-62cm frames with short top tubes.

If you can't get professionally fit you are least need to provide your inseam to get a good estimate.

-Gregory

Measure your cycling inseam and decide what kind of fit you want.

I'm 1.84 with a cycling inseam of 89cm (35") and just built up a 66cm frame. I like a French fit. :)

https://cimg3.ibsrv.net/gimg/bikefor...2a76aa4c57.jpg

Height can give a range but not an absolute.

58cm might be center to center Or the prior way of center to top.

i was going to suggest a range, 58 to 61 cm BUT, I have no idea of arm length, leg length, your flexibility and intended use. Sport or touring.
with touring, a larger frame can get the bars up without appearing goofy. A larger frame can end up with a longer top tube, that might reduce the stem length. Personally, I like a 95mm to 110mm length stem for how it makes the steering feedback result.

My son is 4 cm taller than you and I am 7 cm shorter than you and we both fit well on a 58-59 ctc framesets.

Leonard Zinn used to have a large data base available so you could compare your measurements to the average. It helped me understand why for my height, a larger bike fit me better than a bike “better” for my height: long femurs, long forearms, short torso. I wish he would make it available again.

As you can see there is not one answer. Plus, it's not just leg/inseam that matter, it's also torso and arms. So you might like frames that are not as tall, but are longer on the horizontal. Or vice versa.

Also, crank length and saddle setback make a difference, since in addition to stand over height, there is saddle to pedal length. Frames are not sized vertically after all, so trig!

I am 189, I like a minimum 61 but 62 is better. But i also have a 57 with an upward sloping tt (from 1992, they did exist back then), that is comfy. And all this assumes you are taking about road bikes.

Best is just to try it.

This may be exactly the bad excuse i need to get that 64 i have been looking at, i mean totally in the name of science, really, to see if maybe 64 is better than 62.

I'm only 177 cm in height, with 32" (81.2 cm) pants inseam (don't know about cycling inseam) but prefer bike frames in the 61-63 cm range -- this is measuring from center of BB to top of top tube, a.k.a. "center to top" or "CTT", along the seat tube, which is standard nomenclature*. I am totally unbothered by the "private parts" concern that always seems to be expressed in discussions like this, have never had such a problem when stopping or crashing, and like the "road feel" of a larger steel-tubed frame, along with the way it makes it easier to get bars to the height I like (about even with top of saddle) with a stem having a normal shaft height. I do pedal "knees in, toes down" naturally, and seem to end up with saddle height 93 cm (EDIT: from top of pedal to top of saddle!). As you're seeing in the responses here, frame size is a very personal preference, with wide variation. I will admit being somewhat maladroit in the mount/dismount department, because I've never really mastered the "both legs on one side" on and off maneuver that seems so effortless to other people.
*("Center to center" or "CTC" only varies by being measured to the center of top tube, and the difference is only half the diameter of the top tube; though sometimes you will see "equivalent size" meaning, for frames without a horizontal top tube, how the bike would measure if it did have a horizontal top tube. I don't have any of those.)

Make it so, I already had several tall bikes that fit well, 61, 62-64 and plenty of 58-60 that seemed to be ok with tall stems, SP's, etc.

Then I got a 66 that changed all that, got a 26.5in to confirm and that was it, had a custom made that is 64.5 so it will fit as I shrink and become decrepit and it is amazing.

I am 6'.5" with 38in inseam (PBH).

You're welcome. :)

32" pants and a 93cm saddle height?! wow.

That's what I thought, guess it depends on the pants. :twitchy:

Inseam is a misnomer IMO, mine is 38in. but is actually PBH which is what really matters and should be used. ;)

I would love to see a photo of your extension, sounds like knee hyperextension waiting to happen (in fact I'd almost say it sounds impossible). As mentioned, I've got a 34.5" inseam and from center of BB to top of the saddle I am set at around 79cm with 175mm crank arms, and my size 12 feet and toes are already pointing downward on the downstroke. I literally don't have six more inches of extension even with evidently longer legs than you!

@KHD you might be interested in this site: Dave Moulton's Blog - Dave Moulton's Bike Blog

the difference in seat tube length comparing ctc to ctt is basically 14 mm
as rare would be the bike with a vertical seat tube.
more for how Masi measured who went to the tip top of the seat lug ( and that was before filing )

I have also found that way too many cannot locate the center of axis to axis.

All I can tell you is that I have a pubic bone height of about 83 mm (32-3/4'), and I've come to 93 cm saddle height by a method Sheldon Brown recommended: keep raising the saddle in 1/4" increments until it feels like your hips are rocking, and then lower it 1/4". It seemed like a pretty definite place where this happened, and from experience I've determined that if I lower the saddle any more, it feels like it needs to be raised. I don't have particularly large feet (9-1/2 or 43) either. Using 170 mm crank arms since forever, and don't feel like I need longer. I've ridden this way since the mid-'80s, when I started with a 57 cm frame; used a DirtDrop stem or Technomic, and lots of seatpost exposed in order to get comfortable. Enjoyed that frame (pretty upright ST/HT angles), but didn't like the way it looked, and have felt better on larger ones. I've never been "coached" on how to ride, just have done what feels most comfortable. Do have some trouble with iliotibial band inflammation now, and arthritis in knees, but I think that's an "old people" thing rather than a cycling thing. Have been told by a physical therapist that I exhibit excessive pronation.

I guess I just want to confirm that you're talking about saddle height from the bottom bracket center rather than from the pedal. If you ride a 63cm frame and have a 93cm saddle height using the traditional bb-saddle measurement, you're telling me that you're comfortable with your saddle and stem set 1 foot higher than the top tube (as you said you like them horizontal). It just sounds super strange and like an almost impossible physical feat for someone with your height and inseam, hence my inquiry!

My bad: I set my saddle height from top of pedal! (w/crank aligned with seatpost) Never thought to do it otherwise. I've edited my post above, to clarify.

Well, is the top tube height measured from BB center to saddle top, or from pedal center to saddle top? With a typical 170 mm crank arm, that changes “saddle height” from 93 cm to 76 cm.

Now, is the saddle position with the saddle center in line with the seat tube axis? Or is it measured (as a few of us do ) to the sit bone contact point, that actually supports your weight on the saddle? In this case the sit bone contact points are several cm behind the axis of the seat tube. If you figure the effect on actual leg extension while pedalling (this should IMHO be nearly equal to the actual PBH), there can be a few more centimeters of “mismatch.” In my experience it can be a challenge or at least easy to become confused when trying to keep track of the numbers. You have to do trigonometry to total everything up correctly. Even though I’m a retired degreed engineer with 44 years since getting degreed, I have trouble keeping this stuff straight without checking my work diligently.

Is the saddle top level? After you set everything up perfectly assuming a level saddle, did you have to reset the saddle angle (nose up or nose down) to make the saddle bottom suit you r butt? After that you could have lost or gained a cm, maybe two, Thi might help or hurt the fitting model.

At the same time, maybe this just reflects how the human body is not strictly a set of ideal rigid links joined by ideal pivots. But I believe making fitting models (I.e. calculations) match up with the math of a sharp pencil and a ruler, is a challenge. Neither the knees nor the hips are such simple points. Plus, where exactly are the sit bone faces which support our weight as they make contact with the saddle, which is also compressible? What am I resting on, anyway?,

Definitely NOT 58 with a level TT.
I'm 173 cm. I have had 4 bikes 58 cm, with NO or an inch of seat tube showing. LOL

Agreed, absolutely and always in flux, moving target, etc. ;)

And our physiology changes depending on work outs, age, injuries and so many other factors that may or may not be apparent, relative, obvious, etc, etc, ad nauseum.

I have just always made adjustments based on my own experience for me, lots of hunt and peck, counterintuitive, finally getting the hang of it after a lot of bikes and miles.

And I have also willed many bikes to fit based on KoolAid, the bike is too cool to not fit. I've ridden many too small bikes by making them fit the best I can as big ones my size are very few and far between so I got good at making too small bikes work early on by necessity. :twitchy:

Yes same here! I’m getting too old to “wish “ a perfect fit where it just isn’t there. But it’s easier to “stretch” a smaller biker than it is to “squeeze down” a bigger bike

That sounds reasonable, but the reality is that moving up or down a size is only 1 to 1.5cm of reach change, so it is rarely important. You would really need to have some unusual fit needs to end up with an extreme stem going up or down one.

OTOH, the only bikes I've had that felt weird were undersized. My fit was fine, but something about the handling was odd. Size up doesn't seem to matter as much.

When I say I’m having trouble fitting, I’m not saying I’m having trouble with new frames - I don’t have any new frames. My frames range in age from 1952 to 2013, are all steel and all have flat top tubes. There are a range of TT lengths, ST angles, and consequently, of saddle positioning ranges. While I now know to ask about such dimensioning, for a long time on these forums nobody was prepared to talk about those dimensions even though I knew they could be critical for me. Fitting was treated mostly as a one-number solution, complete with scoffing at the opinion that more information was needed. I did not know and do not now know enough that I can easily select a good fit. For myself I can’t just pick it out of a bike house’s catalog. I still need to measure, calculate, then build it up and experiment with parts. I’ve learned a few little things but not enough to understand fitting. And yes, I have had the “professional fit,” a few times. My solution is to try to cleverly and logically tinker. Sometimes it works out. But I can’t claim there is any single number which is the magic formula for my good fit.