Compact vs Std Frame

[geoinmillbrook]

Hi all: I am in the process of building up my 5th bike since last November and am now looking at what #6 should be -- (replacing old stuff for me and family)... anyone know the technical genesis/advantages/disadvantages of a compact frame design vs standard ? Just looks like an old school girls bike to me no offense intended.

Also while I am here I just have to ask - does anybody really ride their bikes with the seat jacked up a foot higher than the handlebar stem or do they just do that to take a picture ?

Thanks ! George

Update/Edit: Well still curious about the the seat height thing , but was able to find quite a bit of info/opinions on compact geometries... and answer my own question sort of, although would still like to hear what others think... this one article sums most of it up... and also contained some good info on the downside of threadless headtube designs (mainly lack of adjustment) (not copied here)...

Compact Frames versus "Standard Geometry" Frames
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Compact frames (frames with a sloping top tube) were introduced by manufacturers seeking to reduce the number of different size frames that they had to manufacture. With three or four sizes of compact frames, the manufacturer can tailor the bicycle to fit most customers. They simply use a longer seat post to fit taller riders. They can also use a longer steerer tube and use spacers between the headset and the stem. The false rationalizations for compact frames are that the smaller frame is lighter, and "livelier." Of course the longer seat post negates the benefit of the lower weight of the compact frame.
​

There is a very good article about compact geometry frames on the Cannondale web site at: http://www.cannondale.com/bikes/innovation/sloping.html which states: "there's a disturbing trend among some bike companies to re-tool their road frames by shortening the seat tube and slanting the top tube down from the head tube. This new design "breakthrough," they argue, saves frame weight. And if you take their claim literally, they're right - a shorter seat tube does make a bare frame a little lighter. What they don't tell you is that their complete bicycle actually weighs more than a bike with a conventional geometry. Why? You have to use longer (and therefore heavier) seatposts and stems on smaller frames to fit the rider properly, and their added weight more than off-sets the few grams saved by their sloping top tube frames.
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While an aluminum frame and a threadless headset may not be the best choices, they are not all that terrible, and the cost savings over the alternatives are significant. But a compact frame is very undesirable, and the cost savings are NOT worth it. Whatever you do, avoid compact frames on road bikes. Get a properly sized, "traditional" geometry frame.
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[dhk2]

That's a biased opinion you've pasted if I ever saw one. No need to hate compact frames, or come up with bogus disadvantages for them. The fact is, they just ain't much different, period. If they fit properly, you'll never notice the TT angle.

I have a semi-sloping TT frame that came in off-the-shelve sizes of every 2 mm. Besides, if the frame fits, why worry about how many sizes they come in? I use a standard 250mm seatpost, with 5-6cm drop to the bars.

You might not like the look of sloping TT frames, but no need to bash them based on false arguements. If you don't like the style, just stick with horizontal TT frames.

 

[alienator]

That's a biased opinion you've pasted if I ever saw one. No need to hate compact frames, or come up with bogus disadvantages for them. The fact is, they just ain't much different, period. If they fit properly, you'll never notice the TT angle.

I have a semi-sloping TT frame that came in off-the-shelve sizes of every 2 mm. Besides, if the frame fits, why worry about how many sizes they come in? I use a standard 250mm seatpost, with 5-6cm drop to the bars.

You might not like the look of sloping TT frames, but no need to bash them based on false arguements. If you don't like the style, just stick with horizontal TT frames.

+1. Not sure what the OP's intent is with his cut and paste. It's sad, though, if he actually thought the clipped "info" was objective. It's far from it.

The difference between compact, semi-compact, and traditional is aesthetic. That's it.

 

[capwater]

I've been riding and racing traditional geometry frames for years, but this season I'm on a Giant TCR Comp. The shorter wheelbase makes it a great climber. Still love my straight top tube Klein and the semi-slopping C'dale. I don't believe this is a debate about "better", but really more about "different". Proper bike fit will always trump geometry or frame material.

As far as the seat height goes, I ride a pretty agressive set up with minimal steerer stack height so on a compact it might appear the seat is way up there, but in reality it ain't. How many people besides pros actually go around cutting their seat post anyway?

Don't be a "compact hater", to each his/her own.

 

[1id10t]

I have both a standard geometry and compact frame bike. I like both of them and find no real advantage/disadvantage of one over the other. They are both set up similarly (effective top tube length of the compact is the same as the top tube length of the traditional frame), same seat height, crank lengths etc.
I like the look of both and enjoy them in their own right. As others have said, to each their own.

 

[mongooseboy]

I have both a standard geometry and compact frame bike. I like both of them and find no real advantage/disadvantage of one over the other. They are both set up similarly (effective top tube length of the compact is the same as the top tube length of the traditional frame), same seat height, crank lengths etc.
I like the look of both and enjoy them in their own right. As others have said, to each their own.

I ride a compact, have ridden standard. they both are fast and agile. but how many of you have ridden a knobby tired MTB down a paved hill at 45 MPH with less than 45 psi in the tires? I have and let me tell ya, even a poorly fitted road bike would handle nicer

all joking aside, i like the sloping top tube of the compact better. traditional road bikes have boring angles (although classic...) and being an mtb person, the compact frame on my Allez triple looks more pleasing to my eye

 

[pistole]

- have one classic roadie , in carbon (fuji team).

- and 3 compact roadies , in carbon.

- have ridden them back to back , on long century rides.

- the compact frames ride/perform/climb much better than my classic frame.

- between the compacts , the smaller they are , the better they perform.

.

- me thinks that how the frame 'mates' to you has alot to do with your
personal body shape/weight.

cheers.

.


nb : oh yeah , the "cut & paste" on the top by the OP is way biased. To say
that the objective of compact frames was to reduce the number of frame
sizes which had to be made is not on.
.

 

[bobbyOCR]

Cause traditional is this hot.
Sorry, but I love it. I don't think its boring at all.

 

[alienator]

nb : oh yeah , the "cut & paste" on the top by the OP is way biased. To say
that the objective of compact frames was to reduce the number of frame
sizes which had to be made is not on.

Well, that part is mostly true. Giant went down that road. It was also a savvy move at the time because roadie sales were in the doldrums, and going to compact frames was thought to attract some of the MTB crowd, who were figured to be less keen on trad roadie frames.

 

[hd reynolds]

A given compact frame can fit 2-3 riders of different inseam whereas a horizontal TT frame can fit only 1. Therefore it is less costly for the manufacturer than tooling to accomodate many sizes. Less costly = savings passed on to consumer (why do you like to pay more?). Also the smaller rear triangle (front and rear) makes for a stiffer and lighter frame than a traditional frame.

But essentially the dimentions like chainstay length, wheelbase, rake can be made the same as per the diagram.

 

[footsie]

Cause traditional is this hot.
Sorry, but I love it. I don't think its boring at all.

how did you get the bike to stand up for the **** shot

 

[Bro Deal]

- the compact frames ride/perform/climb much better than my classic frame.
.

Uh-huh. And you measured this how??

And to think, Armstrong wouldn't have needed Dr. Ferrari if he had just switched to a compact frame.

 

[bobbyOCR]

how did you get the bike to stand up for the **** shot

Its a BMC, they tend to have special abilities.

 

[pistole]

Uh-huh. And you measured this how??

And to think, Armstrong wouldn't have needed Dr. Ferrari if he had just switched to a compact frame.

- by feel.

- if you want empirical figures , go test it yourself.

- I am way past being , in any way , a competitive cyclist , so as long as it
"feels" better , for me , thats a good thing.

- I am sharing my personal experience with my bikes ( since I have them all
at once , I can really compare them ). And the compact frames ride much
better.

- and that Armstrong argument is neither here nor there.
.

 

[alfeng]

Hi all: I am in the process of building up my 5th bike since last November and am now looking at what #6 should be -- (replacing old stuff for me and family)... anyone know the technical genesis/advantages/disadvantages of a compact frame design vs standard ? Just looks like an old school girls bike to me no offense intended.

FWIW/IMO. There is a real world consideration which MAY exist with smaller/(some) COMPACT ROAD frames -- the location of the water bottle bosses AND/OR the subsequent in-/ability to easily use larger water bottles (vs. the smaller/traditional size) ... while the larger bottle MAY fit, it will probably be more difficult to readily insert/extract from ONE of the TWO water bottle cages, if not both. Secondarily, fitting a frame pump MAY be a concern to some.

You can STOP reading if that is sheds enough light on whether or not a COMPACT frame will be annoying to you when you are on the road.

While there ARE aesthetic considerations, an advantage of a COMPACT frame is that shorter seat stays theoretically stiffens the rear triangle ...

Here's my multi-decade, armchair observation with which others may choose to disagree -- I would suggest that the COMPACT ROAD FRAME design is almost a logical design progression of the notion used in the triple-triangle design from the 80s (as seen on GT bike frames until recently, in particular, and even, somewhat cosmetically echoed on the BMC, now) which one MAY suggest as having been inspired by the MIXTE frame. The GIANT Cadex is certainly an earlier adopter of attaching the seat stays as if the frame had a phantom triple-triangle, but with the seat stays terminated in the single extension on the large aluminum seat lug.

Undoubtedly, the dominance of MTBs which adopted the sloping top tube, first (not counting the "girl"/Mixte frames), made the eventuality of the design showing up on ROAD frames inevitable (was GIANT the first?). If people (undoubtedly, initially MTBers vs. "traditional" ROAD riders) hadn't bought them (AND/OR, if GIANT hadn't co-sponsored Telekom thereby giving the COMPACT ROAD frame street-cred to "roadies"), the design would have probably "vanished" into production obscurity the way Mixte frames are no longer produced for ROAD bikes OR the COMPACT design would possibly have been relegated to "comfort" & hybrid bikes + MTBs.

Now, whether-or-not a stiffer rear triangle is significant for plain-folk is for someone else to decide ... but, most people seem to agree that a stiffer BB & rear triangle ensures a more efficient transfer of the rider's input than a comparatively "soft" BB & rear triangle. Pegoretti, followed by Colnago (to name two frame builders), increased the chainstay dimension as ONE WAY to stiffen the rear triangle.

Of course, I suppose it is debatable as to how stiff a rear triangle should actually be OR whether it isn't already stiff enough on most frames ... and so, for most people, whether one chooses a COMPACT or TRADITIONAL frame can be based on aesthetic preferences OR a matter of availability of one frame style or the other at one's LBS & what THEY are pushing.

 

[capwater]

Ride what feels right/good. I love compact frames for crits. Maybe it is just a feeling I have being on a slightly tighter frame, maybe it is just my imagination. Either way, I enjoy either frame style.

While there is merit to the argument that compact frames offer the ability of a manufacturer to have fewer sizes, I do not believe that is the motivation of the trend. Instead it is a byproduct.

 

[waxbytes]

Co9mpact frames have better standover clearance for short legged long torso types like me. I can finally get a bike that fits and that I don't have to lean over sideways at stops to prevent bar balls.

Other than that I think the traditional frame looks nicer, but form has to bow to function.

 

[geoinmillbrook]

+1. Not sure what the OP's intent is with his cut and paste. It's sad, though, if he actually thought the clipped "info" was objective. It's far from it.

The difference between compact, semi-compact, and traditional is aesthetic. That's it.

Although the OA does make a few statements and a conclusion that some may not agree with, the cut and pasted info was just about what I said it was - a pretty good representation/summation of everything else I was able to find and read on compact vs std geometry - including archived threads from this forum. There was of course also no assessment by me of the information's objectivity, implied or otherwise. Hopefully no one assumed that there was . Besides - spiking a post with some controversial thoughts often generates more posts and activity than something everyone agrees with

Some good thoughts and personal experiences here in the thread by other posters. If I had to sum up what I think I have learned so far ?:

1.) No one here, that I can tell, has really succeeded in presenting the technical thoughts or epiphany of engineering that lead to the compact frame, other than a theoretical assertion that it may produce a stiffer rear end ? Maybe because there was none ? The genesis appears to be, for at least one company, for manufacturing and sales efficiency, and maybe for others an aesthetic change or marketing manuver .. Not sure what the finite elemental analysis, frame member or component deflection, power transfer studies say that Alienator has run on his mainframe , that supports his assertion that the deltas are only aesthetic , or about the possible effects of resultant "other" geometrically induced stress/force vector/balance changes on the overall efficiency of the rider/bike combination (or if any good scientific studies have ever even been done by anyone) -- or in the end, if any differences are even notable/noticable by the average rider.
One might think that other differences like tubing butt dimensions, wall thicknesses, etc etc can be changed to make up for any changes in tube length and geometries to produce equivalent "stiffness" of a triangle, and I certainly don't know what the designers and manufacturers have done, and whether it varies by brand so who knows how much is true and how much is mythology ?
2.) Some folks are saying they like the way they ride, or they can climb faster, etc, and comfort of course is a subjective merit. Not sure how much of these comments can be supported by anything other than anecdotal evidence and are repeatable by others.
3.) Whether you choose a compact frame or a std geometry frame, like other aspects of life, if it feels good and fits, ride it. Differences appear to be maybe a nit other than room to place accessories ...
4.) Hmm -- what should bike #6 be ?-- maybe I'll try one (a CF) and "experiment" with it !

Geo

 

[formernoreasta]

I think compact frames look as if you're always going uphill. Bleah!

 

[artemidorus]

Compact frames are best for tall people, in terms of looks. A trad geometry frame for me would look too freaky - just about taller than it's long. The irony of the whole debate for me is that my compact seat tube is longer than the average trad seat tube.