Originally Posted by
Kommisar89
Can someone explain to me why comapct frames are supposed to be stiffer? I'm not asking why manufacturers use compact frames today (current style, mountain bikes, less sizes to stock) and I understand the advantage of more standover clearance without a giraffe neck stem and I am not saying compact is better or worse than traditional . But why would a compact frame be stiffer than a traditional frame? That's one of the biggest advantages claimed about compact frames. Supposedly Abraham Lincoln was once asked how long a man's legs should be and he replied, "Long enough to reach from his body to the ground". It's pretty similar with bicycles: the seat tube/seat post/saddle has to be long enough to reach from your buttocks to where your feet touch the pedals right? So if you take a compact frame in isolation, I suppose it is stiffer but if you include the longer seat post, why would it be any stiffer than the traditional frame? We had sloping top tubes back in the day too - we called them "girls' bikes" but we always said that one of the main disadvantages of that frame design was that it flexed too much. So what gives? Can anyone enlighten me? Why would a compact frame plus seat post be stiffer?
Smaller triangles.
Even Zinn, which specializes in bikes for very large cyclists (over 6'5" which can't be served by an off the shelf bike) uses compact geometry bikes.
Even Rivendell, which specializes in bikes that aren't trendy or fashionable, but appeal to the classic style uses sloping top tube geometry.
However, there are plenty of classic horizontal tube geometry bikes that are both stiffer and lighter than modern compact geometry bikes. Most modern bikes are made in Taiwan/China. The margins on bicycles are razor thin. The quality and materials aren't there compared to what they have been historically (obviously not true at the high end).
Believe it or not you can get a better bike by looking backwards rather than to the current product line.
I have a couple of 'road' bikes. You can't even begin to compare my '89 Cannondale 3.0 to my '04 Giant OCR1 frame. The Cannondale is a 63cm classic horizontal top tube bike. It came spec'd with Suntour Blaze back in the day. A horrible group. However, Cannondale didn't make different frames back then. Their top of the line road bike got the same frame as their bottom of the line road bike.
And its an epic frame. The Cannondale 3.0 was the lightest frame on the planet when it made its debut. It also set the benchmark for being the stiffest frame ever measured on the Bicycling Magazine 'tarantula' jig (back when Bicycling wasn't just a big advertisement or when editorial wasn't dominated by advertising dollars).
My '04 Giant Aluxx OCR1 frame is aluminum. It came on an Ultegra spec'd bike. You'd think the Giant, which was made fifteen years later than the Cannondale would be a 'better' frame. More optimized, stiffer, lighter, etc. Dream on. The Giant has a mass produced Taiwanese compact geometry aluminum frame and is a price point bike based on the components. The frame is nothing special. Its completely forgettable in every way. The only reason I bought the Giant is because they were marketing the XL as fitting up to being a virtual 67cm. Giant no longer makes that claim, and rightly so, the bike fits no bigger than as a virtual 63~64cm. No bigger than the Cannondale (which is 63cm c-c and 66cm c-t, and yes I need that extra 1cm I was hoping to get, more even).
Is the compact geometry Giant stiffer? Lighter? Better?
Nope.
The truth is that the Taiwanese and Chinese bikes being sold for between $1200 and $2500 today take a back seat to frames that were made fifteen years ago, and that's with compact geometry.
Now if you could find me a compact Geometry XXL Cannondale 3.0 frame, well, sign me up...but the Giant OCR1 ain't it, and the carbon bikes aren't nearly as stiff either.
So that's my rant. I've got a modern aluminum compact geometry bike, and a classic high quality American aluminum traditional horizontal geometry bike. The truth is that smaller triangles only make for a stiffer and lighter frame everything else being equal. However, it isn't. You just can't compare a Taiwanese compact geometry aluminum frame with the quality of the classic Cannondale. Its like comparing Wal-Mart Schwinn with bike store Schwinn, only dressing the Wal-Mart Schwinn up with high end components (okay, its not that bad, but its not that far removed as you might think either).
There are epically good bikes that are worth only hundreds of the thousands they used to cost that will embarrass modern production bikes (Klein, Cannondale, etc.).