I remember, around 85/86, when i first got into the sport, my neighbor had a Cannondale, with the huge, downtube. It always kind of put me off as a buyer, & I never really cared for it much. My question is...when did Cannondale, decide to just make all the tubing on their bikes one size, and stopped using the oversized down tubes? I also remember they were aluminum, and my neighbor was constantly having problems with his frame(he wasnt a big guy, nor was he very rough on his bike), is that way they went smaller?

Perhaps your recollection isn't quite the reality?

you know, as someone new to cycling (less than 2 years) i know what the op means. When i was a kid I remember seeing one of those cannondales and I thought that the huge tube was where the name "Cannon"dale came from! lol. Now i realize that it was just that they were one of the first to mass market aluminum frames and the larger diameter tubing was required vs the steel bikes that I was accustomed to seeing. Now I've gotten so used to the large tubing that it doesn't look nearly as ridiculous as it did back then.

"Perhaps" it is(here's a few from back in the day, that have the larger tubing Im talking about):



https://www.ebay.com/itm/VTG-CANNONDA...item35b4add8dc

Just by looking @ the pics of the last link, you can CLEARLY see that there's a larger down tube, then the current frames.

I can't be sure, but I bet the downtube on my CAAD10 has a larger diameter than that.

You missed the point. He wasn't saying that they didn't have huge tubes back in the day, he was showing you a modern Cannondale aluminum frame (CAAD 10) and that it still has a huge tube. IT's not done for style points, all aluminum bikes need to have larger tubing like that. I forget all the differences between yield strength vs. tensile strength but basically it has to do with the fact that steel will bend while aluminum just cracks and breaks. aluminum going with wider tubing renders more strength as opposed to steel where you would add strength by going with thicker tubing. again, this is just my crude understanding of it.

Thanks Motobecane69, that's exactly what I meant. I recall those tubes being gigantic as well, and they were huge compared to the skinny steel ones, but they never really got smaller, everything else just got bigger.

The intention of the photos was to show an '84 Cannondale vs an '11 Cannondale.. pretty close to the same.

I still say the downtubes on the older ones are larger,then on the newer ones

No it doesn't. Carbon cracks and breaks (carbon does not bend, you load it until it snaps. The igher the modulus that faster that can happen and the less strong the frame, but the lighter it gets). All metals, to some extent will bend and stretch. Aluminum is the stiffest of the three metals from which bike frames are produced. And as time has gone on, the alloys have gotten better which allows thinner tube walls, but to get the frame to perform as needed the tubing does get larger to some extent.

Someone mentioned the CAAD10....take a look at the top tube. Biggest one since the System Six.

BTW...the thing to look at are the seat stays. As they got thinner, they improved the ride. But the CAAD3 was a pretty good bke. Cippolini worked with Cannondale on that design. He won a boatload of races on that frame.

I think you just won BF.

try that with a bike frame genuis.

I see the think tank's in session. You guys just get home from the bar?

Just in case you'd like to learn something so as to not look so foolish...

https://www.velocite-bikes.com/carbon-fiber.html

I can make a carbon bike frame stronger, which means it will have more flex. The higher the modulus, the stiffer and more apt it is to break.

I don't even know why I bother...this is too much like being in a bike shop.

I have a carbon shafts in my driver and three metal. But I can still load it until it breaks.

I love this place.

Hey now, everyone's wrong sometimes. Better to take it in stride, accept your failings with good humour.

I knew the rest of it was too complicated for this group.

Either it doesn't bend, or it has flex. Pick one.

Ummm...wut? Carbon doesn't bend? Haha...ok, if you say so.

There is a reason seat stays are thinner on many bikes (Cervelo is a great example of this idea), it is to provide "compliance"..that is another word for flex/bending. Yes, ever so slight, but it still flexes and bends enough, and depending on the type of carbon fiber, the layup etc...used, it could flex more/less.

Or you can carry on looking like an idiot

You all have it completely wrong on why Cannodale went to the larger tubing. It's simple. Bigger billboards for bigger decals!

I think that you will find that frames of the vintage of the red one had constant or near constant diameter down tubes. The appearance was quite bulky and resulted in a not very graceful joint at the head tube. In later years a tapered down tube was introduced that was clearly smaller at the head tube growing larger at the bottom bracket to at least the diameter of the constant diameter down tube. Recent Cannondale frames have some additional shaping added to the tapered down tube.

There are three generations of framesets before the CAAD ones.

Original (I called them 5.0s after their perceived weight and the newer 3.0 and 2.8s). "SR" framesets.



3.0s. These were 3 pound framesets. Originally came with one size downtube (huge), later divided into huge downtubes ('crit frame') and thinner downtubes ('road race frame'). The big feature was the dropout that extended past the stays, a feature named "cantilever dropouts" which really didn't match what "cantilever" means. This was their first foray into thin seatstays.



2.8s. 2.8 lbs or less for a frame. Tapered downtube, combining the best of the 3.0 crit and road frames.



After that I was out of the biz and I don't know what really happened. The SystemSix downtube is closer to the 'crit' size, that's the next Cannondale I owned. The Six13 was more like the 'road' version of this frame, softer overall. The SystemSix, when I bought it, was their most efficient frame ever, according to an engineer there. He recommended it to me based on my preference for 1-2 hour long rides, although it was fine for 6-7 hour rides too.

Ok thanks......But, to my recollection, the older frame that my buddy/neighbor had, had a LARGE downtube, it was the red bike, like someone posted here. I remember he mustve went through about 4 frames, as they kept cracking on him, and he didnt ride it hard & wasnt very big (he was an average rider, about 5'8 or 5'9 and about 165). For some reason, the frames @ nthe time, I dont think were as strong as they are now. Technology obviously plays a role/part in that now.

Good info...i always thought his bike looked clunky, and didnt understand the reasoning for the huge downtube. I rode it once, and didnt like the feel of it, I rode it for about 5 miles, and thought it was a rough ride. He loved my Bianchi.