Racing geometry- why?
 

I was watching the Giro yesterday, and saw that all the bikes had a top tube that sloped down. Why is that? Is it to put the rider in a more powerful position?

What does the sloped top tube accomplish that tweaking your seat and handlebars couldn't?

Thats a compact frame... dunno quite what it means maybe better comfort... Sorry I dont have the patience to google and pose... :D

For shorter guys (and that includes most Italian racers), the sloped top tube gives them more standover clearance, even with the long top tube bikes that racers prefer. Any differences in stiffness or handling (vs. standard geometry bikes) can be easily tweaked by varying tubing thickness. The main advantage of compact geometry is that it gives shorter riders more fit options. Some manufacturers are abusing this by offering fewer frame sizes, however.

"Some manufacturers are abusing this"********************???? You've got to be kidding, right???

If not then just don't buy from them!

It is said to reduce the weight of the frame somewhat (reduces seat tube height and seat stay length).

Part of this weight savings is offset by the longer seat post needed.

What people seem to forget about the weight argument for compact geoms is that for UCI-sanctioned events like Giro, TdF, etc. you can't be under 15 lbs. total for the bike. Most traditional frames that the pro's have today can get there easily.

"Traditional" or "Italian" 73/73 geom with a fairly short chainstay is still alright with me. Probably the only geom I'll ever buy, except maybe in a CX frame.

The cross bike that I sold last fall had a compact geom, and it was fine for that. I didn't care for it as a straight road rig though, because I couldn't get stretched out enough at the bars without changing stems/bars, and then the handling was slower.

Compacts don't look like a road bike to me. They more resemble someone's attempt at mutating a MTB for road use.

Call me a retro-grouch, but it seems to me that traditional geom has been around for decades basically unchanged for a reason...it works.

Girl's bike.

Marketing tool.

Pro use + looks cool/different = punters depart with $$$$ for one.

hee hee:D

some people will claim various performance improvements, but compacts are mainly for "showbiz".

Giant sold a gazillion bazillion bikes with a sloping top tube, so heaps of companies copied.

The sloping top tubes do not REQUIRE any changes in the rider's position. Cut a photo of a rider from the 1960's out of a cycling magazine. Draw a line from the bottom of the stem to a point on the seat tube that is six inches below the seat bolt. You now have a bike with a sloping top tube, yet nothing else, including the rider's position has changed.

But, if the bike does NOT fit the rider...well...twenty years ago, some racing frames were offered in six to eight sizes. Today, some companies offer as few as three sizes. The sloping top tube allows them to claim that a "medium" fits half the adult males in the world, by adjusting the seatpost height, stem height, and stem length.

Twenty years ago, men's dress shoes were made in America, and could be purchased in six different widths. Today, most stores are selling Chinese-made dress shoes, that come in your choice of "medium" or in "medium", just like a communist-made bike frame. If buyers are dumb enough to think that "one size fits all", well, the vendors are happy to oblige.

You western running dog capitalist imperialists not know what you talk about. You think colonial-imperialist tell us what to do. My Chinese made medium dress shoe work fine on Long March. My one size fit all Mao boiler suit fine. 1,000,000,000 Chinese can't be wrong. You ever come China we ship you to re-education camp. Read 'Little Red Book', all will become clear. I hope your feet pinch.

Gold.

I dislike the sloping top tube for no other reason than it limits the size of the seat tube mounted water bottle (I use Zefal Magnums @ 32oz each).

ok ok, I think it looks kinda funny too. :p

http://www.sitcomsonline.com/fonzthumbsupbw.jpg
The Fonz approves.

Chinese people of great socialist people republic grateful for your kind words.

We continue to sell you unisex compact bike.

Oh no, the clone army has arrived....Obi Wan, get the other Jedi.....QUICKLY!

/lightsaber humm

Take a look at the bike the Giro winner was riding. Top tube does not slope, that's why he won.

http://www.cyclingnews.com/photos/20...id=giro0519/54

Al

Your right.. Nothing different about it.

It can be abused in the fitting process, by giving people a bike that would normally be too big for them (but stand over height is ok).

Correct.

Sloping top tube combined with steep climbs like the Finestre mean these dudes are amplifying the gradient.....effectively twice the hill to climb.


:D

That is the most asanine statement in this thread ... :rolleyes:

i think he was joking, or are you, too?:p

Sloping top tubes suck. Must be why alotta pros ride them. :rolleyes:

this way you feel like you are climbing all the time.

I heard they're making 'slopers' with smaller front wheels to overcome this problem.

Sloping top tubes are great for shorter riders as was previously mentioned. Think about smaller bike frames for a moment. Basically everything is shorter. The only problem is, the wheels are still 700. So the only way to compensate is to screw up the geometry if you don't use a sloping top tube.

There are also other advantages. On an alluminum frame, a sloping top tube with a carbon seat post gives you more carbon for vibration dampening (if you believe in carbon's vibration dampening qualities). More seat post also allows you to put the bike in a work stand without screwing up your seat height setting. More seat post also allows you to put a seat bag on and still have room for a light underneath.

There's really no disadvantage to a sloping top tube. Some manufacturers offer them in fewer frame sizes, which is a shame. Straight top tubes were necessary for many years because lugged frames required them. I suppose this is why some people who like the traditional look are opposed to them.