Originally Posted by Froze .
This is good info Alfeng. Do you take your inseam into the equation? I saw you mentioned your height at 5'9" but no word about your inseam which could vary from person to person even if their both the same height. I believe the Bikes Direct site starts you at the inseam measurement or also known as stand over height (letter J on the BD site). Usually once the inseam is known and you fit your bike to the inseam, the rest of the bike is adjusted by altering stem height and length, and saddle height and fore and aft positioning. I know you can vary that a bit, but too small of a bike may hunch your body too much, and too big may stretch you out to much, again I know you can change that to a certain degree with stem length and saddle position. That's why in my experience the inseam was the most crucial. Obvious [COLOR= #008000]in custom fitted bicycle the builder will take a lot of measurements to make the bike fit you "perfectly" in all areas[/COLOR], [COLOR= #008000]but you can't do that for a factory production bike.[/COLOR]
However, I don't own a sloping tube bicycle so not sure how the inseam measurement does compared with your method, but BD does offer the stand over measurement so I was assuming it was essentially the same thing. And if the top tube measurement is the most important factor in a sloping frame, [COLOR= #0000ff]how do you measure your body to get the right top tube length?[/COLOR]
[COLOR= #ff0000]Perhaps you can explain why I'm wrong[/COLOR].
[COLOR= #ff0000]What you say was probaby always valid for frames used by racers[/COLOR] ...
but, in the pre-MTB era, Road frames were generally sized larger than they currently are BECAUSE the apparent expectation was that the stem would be at about the same height as the saddle for most riders, so I don't know how you were sizing your non-racing frames way-back-when ...
- having said that, my brother, who is an inch taller than I am, did choose to ride 21" ([COLOR= #808080]53.4cm[/COLOR]) frames way-back-when even though he didn't race because it ([COLOR= #808080]competition sizing[/COLOR]) was apparently the norm amongst the people with whom he went to college ... so, I can believe that some people always preferred smaller frames than the accepted, recommended size way-back-when
- even about 10 years ago, and I presume now, one shop in town sizes the frames on the bikes he sells 1-or-2cms larger than I would suggest that most riders choose.
In the here-and-now, WE can-and-should take advantage of the
online sizing charts which can be used as a [COLOR= #0000ff]rough guide [/COLOR]... plus, [COLOR= #0000ff]
some subsequent trial-and-error for tweaking[/COLOR],
- FWIW. I reckon that there IS a way that anyone can approximate the size of the top tube + stem length [COLOR= #ff0000]from-the-comfort-of-their-living-room[/COLOR] while they are watching TV ... if if you sit on a forward edge of a kitchen chair-or-equivalent
- hold onto an unattached handlebar
- lean forward & look at the TV AND then hold that position for 10 minutes to 2+ hours ([COLOR= #808080]whatever works for you ... 10 minutes should do it[/COLOR]) to find the maximum forward position that you are comfortable holding ... I suppose you could rest the handlebars on something that is in front of where you are sitting
[*] gauge the distance ([COLOR= #808080]or, have someone measure it[/COLOR]) from where your sit bones are ([COLOR= #808080]hence "the forward edge" of the chair[/COLOR]) to the handlebars
- I reckon THAT will approximate the [COLOR= #0000ff]comfortable[/COLOR] saddle + top tube + stem length for the individual ... subtract the distance from the back edge of the saddle-of-your-choice to wherever on the rails that you want to mount the saddle to the seatpost ... subtract the stem length you want to use ... and, [COLOR= #ff0000]voila[/COLOR] -- the remaining measurement is roughly the top tube length you want (+/-).
FWIW. By my recollection, which anyone can correct, in the days of lugged bikes ([COLOR= #808080]
i.e., pre-TIG welding[/COLOR]), it seems that it was not uncommon for the TOP TUBE length to be closer to being
the same ([COLOR= #808080]
i.e., 57cm[/COLOR]) regardless of the frame size, than not! That is, it was undoubtedly expedient to mass produce frames if the top tube & down tube were the same & the head tube & seat + seat stays were the only variable in fabrication ...
- That may have been more true for British frames than French & Italian frames ... or, maybe it was just with ANY of the less expensive frames.
It seems that tThe Japanese frames which began to trickle in during the late 70s which also used the English threaded BB may have changed the trend on less expensive frames by being
proportional. So, [COLOR= #008000]by serendipity, my
60cm GITANE had a
57cm top tube & a
9cm stem[/COLOR] ...
[COLOR= #008000]Lucky me because that's still approximately the top tube + stem length that I still prefer![/COLOR]
- [COLOR= #008000]a perfect fit[/COLOR]
If I had been sold a GITANE with a smaller frame, it probably would have had the same 57cm top tube BUT a shorter stem. When I ordered my FUJI S12-S LTD frame ([COLOR= #808080]NOS overstock[/COLOR]) from Colorado Cyclist, I chose the frame whose top tube was 57cm; and, that meant a 57c frame. The notion of a longer stem ([COLOR= #808080]and, therefore a shorter top tube[/COLOR]) just didn't occur to me. Stand over? Inseam? I say "who cares?" IMO, stand over is still more of a cosmetic issue for most people ....
- Over 6'0" (?) and it probably becomes an issue, but the top tube length is probably more of an issue.
- Under 5'6" (?) and it could be a problem if the saddle can't be lowered enough to allow the rider's feet to reach the pedals.
- you can probably estimate my inseam by looking at the seatpost exposure & extrapolating
As I mentioned, currently, my "preferred" frame size has a 54.5cm top tube ... 55cm works for me ... 57cm works for me ... 53cm works for me ...
- with the larger frames, as in the past, 'I' simply lean the bike when I am stopped OR if I am in an urban area with curbs, I rest my curbside foot on the curb
FYI. I adjusted the fit on ALL of the following bikes so that they are the same
[COLOR= #008000]perfect fit[/COLOR] for me ([COLOR= #808080]the red Raleigh has 27" wheels & 170mm cranks, the rest have 700c wheels & 175mm cranks[/COLOR]):
For me,
after setting the saddle to the pedals, getting the reach to the hoods as close to the same as possible + the DROP in roughly the same place is my goal regardless of the frame's actual size ...
- the handlebar width affects how I measure the alluded to reach, BTW ...
- whether it seems arbitrary, or not, you may have noted that the height of the DROPS on my handlebars are all in the vicinity of the lower headset cup because that differential from the top of the saddle to the Drops did-and-still works [COLOR= #0000ff]for me[/COLOR] ... some people have a greater differential to the Drops and/or hoods from the top of their saddle, and others have less.
- the Track frame has a shorter top tube ([COLOR= #808080]53cm[/COLOR]) which I anticipated would need a 130mm stem, but using my gauge of the distance to the hood AFTER establishing the positon of the saddle relative to the pedals, I ended up with a 110mm stem because of the slightly greater differential between the saddle & the Drops due to the higher BB.