GestapoTactics

looking at the people riding photo thread, i noticed that alot of people seem to be riding frames that are VERY small for them.

knees at the top of the pedal stroke coming WAY up above the top tube?
that ain't right.


right?

Ill Mitch

So I guess these guys are all riding too small frames?



You don't size a bike based on how high someone's knees come above the top tube.

elTwitcho

That doesn't really matter. What matters is how far forward your reach is, and how far down your saddle to bar drop is.

JacoKierkegaard

It seems the problem is so widespread not even Lance can pick a bike that fits. Hipster.

Aries

I think what matters more is that the leg is nearly fully extended at the bottom of pedal stroke. Therefore, there should be a moderate bend in the knee. (note lance's right leg above)

craigcraigcraig

the land of getting flamed.

dervish

welcome to oblivion.

but seriously, to the OP...i have seen more people riding frames with much lower seat tubes. this gives the fixed gear riders who are more geared toward to tricks and easier time flicking their bike around/ moving their weight around on the bike

StephenH

I remember reading a while back about Lance not being a fan of "compact geometery" but using it anyway on newer bikes. I assumed "compact geometry" meant shorter seat tube and then longer seat post. So the bike he's riding up there may actually be a lower frame than what he rode in the past.

Frame sizes have varied drastically, largely due to custom and expectation. You see some of the old pictures where people rode bikes with huge frames where they just had to dismount to stop; standover height exceeded their inseam, even on tiptoe. And of course, coming from the high-wheeler era, nobody thought that was odd. The flip side is department store mountain bikes or BMX-type bikes, where the smaller it is, the more people can fit on it, theoretically.

JacoKierkegaard

You're right on the shorter seat tube/longer seat post thing, but I think wrong on the method. Someone correct me if I'm wrong, but I believe "compact geometry" refers to bikes with a sloping top tube. The shorter seat tube is achieved by that, not by simply riding a smaller frame size. See the Cervelo in the first pic for comparison. In that case, the bike Lance is on doesn't appear to be compact from the picture. It's a little hard to tell from the angle, but it appears that if there's any top tube slope at all, it's definitely minimal.

MIN 

A compact geometry only implies that the top tube is sloping. Hence the notion of effective top tube length which is measured on the horizontal. Compact geometry makes it easier to fit a wider range of heights for a given bike size but it doesn't necessarily mean that the geometry is any different than a traditional non-sloping top tube geometry.

ADSR

I thought compact geo also meant that the seat stays are shorter/stiffer, and also lighter.

JohnDThompson 

Here's the C.O.N.I. Manual's take on rider position.

If you're not familiar with the C.O.N.I. Manual, it is a compilation of knowledge of Italy's top coachs and sports scientists to assist with development of professional caliber riders. It is somewhat old (early 70s), so feel free to blow it off it you choose.

MIN 

True, but that doesn't change the rider's contact points. It just changes the shape of the frame.

JohnDThompson 

Yeah, but you have to weigh that against the longer seatpost, which is basically an unbraced beam and therefore more flexible than a shorter post...

Johnny Nemo

Pfft... Italian cycling coaches, what would they know?!

craigcraigcraig

too much to read.