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Another boring bike fit question.(10 posts)

Another boring bike fit question.rightsaidfred
Dec 8, 2002 12:03 PM
I have a 56cm frame road bike that I ride all the time. It fits me well. I am 5'10" with a 33 or 34 inseam.

I also have an old hand-me-down 61cm Trek touring bike that I frequently ride. By all means, it should be too big. BUt I find that it is equally (if not more) comfortable than the 56.

I am now looking at buying a bike with a 60cm frame, but I'm put off by conventional sizing. In other words, is there a reason I should stay away from this bike for it's size, even though it's a good deal.

PS, I'm relatively new to cycling (1.5yrs)
I've found the same thingishmael
Dec 8, 2002 12:14 PM
I'm 5'8" and used to ride a 61cm...I could only stand over it on my toes and only could ride it with the post all the way down....worked fine and I can only remember it being a streach while riding on the hoods...Now I ride a 52
re: Another boring bike fit question.Rusty Coggs
Dec 8, 2002 12:42 PM
Frames are measured differently acording to manufacturer, and sometimes even by type. TT is most important.So be sure of what you are comparing.Does the Trek have a sloping TT and short stem? Go with what works best for you.I'm 6',with a 35.25" bike inseam and ride a 57 c-c and would not go near a 60.
re: Another boring bike fit question.rightsaidfred
Dec 8, 2002 12:54 PM
They were measured by me, c-c.

The trek's tt doesn't appear to slope and the stem is roughly the same size as my other bike.

The only bad thing, is when I stand off the pedals at a traffic light, parts of my body rest on the top tube.

I simply lean the bike a bit, and all is well.

I have shorter legs, than my height would suggest, so perhaps my torso/arms fit the larger (longer?) bike better.
re: Another boring bike fit question.motta
Dec 8, 2002 2:13 PM
Having the same dimensions as you, 5'10" and a 34" inseam, I have found that a frame measuring C/C 57, with a 56.5 toptube is perfect. We both have long legs and short torsos for our height and are better served riding frames built with traditional geometry. Go to wrenchscience.com and use their sizing system, it is the most accurate no cost system I have seen.
question for mottatarwheel
Dec 9, 2002 5:20 AM
Just curious -- what frame do you have that measures 57 x 56.5 c-c? That's the size I am looking for, and it's hard to find stock frames in that size.
question for mottamotta
Dec 9, 2002 6:06 AM
All 57cm Pinarello's, and Moser's. DeRosa Corum and Neo Primato in 57cm. Colnago's size 58 is measured C/T with a 56.3 top tube, really close when measured C/C.
check out Rivendellgtx
Dec 8, 2002 2:23 PM
http://www.rivendellbicycles.com/

http://www.rivendellbicycles.com/html/bikes_framesize.html
33 or 34, which is it?Kerry
Dec 8, 2002 4:37 PM
The difference between 33 and 34 inches would suggest 2-3 cm difference in frame sizes. The fact that you quote this number for your inseam suggests (duh!) that you've not measured yourself. Visit some of these web sites, get a proper measurement, and then you'll have something to talk about.

http://www.bsn.com/cycling/ergobike.html
http://www.coloradocyclist.com/BikeFit/index.cfm
http://www.sheldonbrown.com/harart-frames.html
http://www.rivendellbicycles.com/frameinfo/Frame_Sizing.htm
http://www.peterwhitecycles.com/fitting.htm

For adjusting the fit of the bike, there are roughly five starting points:

1. Seat height (top of saddle to center of pedal axle) at 108-110% of inseam.
2. Saddle parallel to ground.
3. Saddle fore/aft adjusted so that a plumb bob from the bony protrusion just below the kneecap passes through the pedal axle when the cranks are horizontal. This is known as KOPS (Knee Over Pedal Spindle)
4. Front hub axle obscured by the handlebars when riding in your "regular" position (drops, hoods, or tops).
5. Top of handlebars 1 to 4.5+ inches below the top of the saddle depending on your flexibility and size.

These are all starting points for "average" proportioned people, and many folks like to move away from these starting points as they learn what makes them more comfortable, powerful, or efficient. You want to get the fit of the frame as close as you can, then do minor adjustments with the stem, seat post, saddle position, etc.
33 or 34, which is it?mainframe
Dec 9, 2002 8:09 AM
Ditto on the inseam dimension. It should be precisely established before fit is considered. The rest of Kerry's advise is solid. Once seat height is set, drop and reach become the real comfort (fit) issues.