Bicycle Mechanics - Does the crossbar have a function in the 21st century?

I imagine that when bikes were made from wood, the crossbar had an important function in maintaining the rigidity of the frame, but nowadays, when materials are strong enough that the bar can be lowered to a position allowing the rider to step through the frame, does it honestly have a purpose other than pandering to the male's frequently fragile sense of masculinity?

I'm a guy, grew up in England and spent a few years in the Netherlands (where I think there are more "ladies'" than "gents'" bikes) before coming back and I prefer to ride a bike with no crossbar. I think it enables easier disengagement from the bike and is probably safer in the event of a fall, for similar reasons. The only advantage that I can conceive is that it may be possible to make a shorter path for a crossbar than if the bar was lower down, in which case it could save weight, but if that's the case, why aren't they restricted to bikes which are all about performance?

The average person likes to ride what the pros ride. So even though few of us are Lance Armstong we all like to ride a bike that LOOKS like Lance's. Second, not only is the basic triangle lighter it is also stiffer by design. So the tubes themselves can be made even lighter since they take the loads in pure tension and compression. The angled down or curved tube designs impose a greater bending load which requires a thicker wall. And even with that I think you'd find that even a bull headed amatuer would feel the reduced stiffness compared to a classic double triangle design.

So if you're just riding through downtown traffic and pedestrians to get to work or pick up a fresh baguette, some cheeze and a nice wine for dinner then a "ladies" style frame is perfect for the advantages you gave. But if you're keen on sucking up, passing and dropping your buddies in a training ride to be first to the pub back in town then the classic double triangle is king for a very good reason. It works.

Top tube, eh?

removing the top tube is like chopping away the roof of the car and making a cabriolet.
Sure, it can be done, but it's heavier and flimsier.

Right - the top tube........
http://i189.photobucket.com/albums/z284/JanMM/toptube.jpg

Yeah, the "cross bar" just fell there and they left it. Ooppss.

The top tube shows no sign of leaving. In fact considerable portions of bike manufacturers' R&D budgets goes into finding new ways of making this part of the bike even more effective through tapered head tubes and steerers, thicker tube diameters, hydroforming, and butting. So get your leg over it.

I'm female and I would never ride a step-through frame. Why? Because I dislike the look. It screams grocery getter, and I don't ride bikes to fetch my beer :)

^ That ought to be the last word in this discussion. Brava! Well said.

AND JUST WHAT THE HECK IS WRONG WITH RIDING A BIKE TO GET YOUR BEER, BREAD OR FINE SINGLE MALT! ! ! ! ! ! You one o' dem snobby bike sort? :D

Bike frames are a couple 3 triangles, a triangle makes a strong enough structure that you can make it out of lighter materials.

Take away a leg of the triangle and you have to add stronger heavier materials and joints to make up for the reduced strength.

I'm female and I would never ride a step-through frame. Why? Because I dislike the look. It screams grocery getter, and I don't ride bikes to fetch my beer :)

How do you fetch your beer then? Please tell me you don't drive?

If you remove the top tube on a double diamond frame it will have a thrilling ride downhill. The high speed shimmy will start sooner and last longer. Bikes have evolved over two hundred years and there are valid reasons for the current design. Most of the changes over the last century have more to do with the quality of the materials than the basic shape.

How do you fetch your beer then? Please tell me you don't drive?

I do indeed, since I collect large several 6 packs at once, and I'd rather transport such a delicate thing in the safety of my car. :)

The top tube shows no sign of leaving. In fact considerable portions of bike manufacturers' R&D budgets goes into finding new ways of making this part of the bike even more effective through tapered head tubes and steerers, thicker tube diameters, hydroforming, and butting. So get your leg over it.

The top tube did show signs of leaving back in the '90s, at least for time trial bikes where aero is more important than weight, before the UCI declared that all race frames shall be built around a main triangle. Time trial bikes are technically still allowed not to be a triangle but the 3:1 aspect ratio rule eliminates a lot of the things you can do with that.

I'm female and I would never ride a step-through frame. Why? Because I dislike the look. It screams grocery getter, and I don't ride bikes to fetch my beer :)
I certainly do. It's a fine excuse to get on my bike. I don't need Lycra or anything. It has a horizontal top tube.

I do indeed, since I collect large several 6 packs at once, and I'd rather transport such a delicate thing in the safety of my car. :)
disappointing. . . not because of the car. . . because you drink beer :P

hard liquor baby B-) all the way. No dear piss for me

The current design mens safety frame evolved in the 5 year period from 1885 to 1890 in England and has changed very little since then. at least when made of steel. The step through frame has historically been weaker and heavier and many older ones show damage where tubes have bent near the bottom bracket with heavy use and heavy riders. The step through frame has also historically handled poorly. The strongest low/no top tube frame has been the Mixte. If properly designed it is supposed to be very close to as strong and rigid as a mens safety frame.

Just the thing for all the Kilt wearing, bike riding Scotsmen!

disappointing. . . not because of the car. . . because you drink beer :P

hard liquor baby B-) all the way. No dear piss for me

Not my fault that you haven't discovered real beer yet :) Bud and it's ilk are watered down nastiness incarnate.
I do occasionally have some scotch or bourbon, but beer goes with dinner better in my estimation.

Oskar Blues! Dogfish Head Brewery! New Belgian Brewery!

:D

No top tube = FAIL

I do indeed, since I collect large several 6 packs at once, and I'd rather transport such a delicate thing in the safety of my car. :)

You're still buying beer by the six pack? I've transported several 5 gallon kegs on my bike. Let me tell you, that was a fun time.

Don't have proper storage for actual kegs. I live in an apartment, so no second fridge to store the beer products in :)

Eh, due to a pinched nerve I can't get my leg over the top tube right now. No bike at all or mixte frame? The mixte wins. If it never gets better, It's a Rivendell Betty Foy or Velo-Orange.