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Could somebody site out the advantages of each and to what type of ride do they excel? Thanks for the help I'm relatively new to road biking coming from an avid mtn. biker I'm clueless when it comes to this aspect..
 

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mikey_mike said:
Could somebody site out the advantages of each and to what type of ride do they excel? Thanks for the help I'm relatively new to road biking coming from an avid mtn. biker I'm clueless when it comes to this aspect..

one has more seat tube and less seat post and the
other has the inverse. it was borne out of giant bicycle's
early 90s desire to have fewer inventory sku's; "a 3-4 sizes
fits all" approach to dealer inventory and distribution. there
were less sizes, seat tube-wise, yet more selection in the
stem/seatpost assembly department. through all the ups/downs,
UCI machinations, and copycat-ers, "compact" won over a
generation. imo, it's mostly an aesthetic, yet so many assign
engineering attributes to it that i simply don't get. the weight
issue is one of them. recently, i took the offcuts of seat tubes,
seat stays, and seat posts that were the dregs of morphing
a trad frame into a compact design, and the net result was
that using less "tube" and more "post" was actually a weight
penalty rather than an asset. for the tech-minded, the test bed
was the thin end of a deda zero pipe as well as the tops of
corresponding seat stays, along with a campagnolo cf post.
e-RICHIE©™®
 

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e-RICHIE said:
one has more seat tube and less seat post and the
other has the inverse. it was borne out of giant bicycle's
early 90s desire to have fewer inventory sku's; "a 3-4 sizes
fits all" approach to dealer inventory and distribution. there
were less sizes, seat tube-wise, yet more selection in the
stem/seatpost assembly department. through all the ups/downs,
UCI machinations, and copycat-ers, "compact" won over a
generation. imo, it's mostly an aesthetic, yet so many assign
engineering attributes to it that i simply don't get. the weight
issue is one of them. recently, i took the offcuts of seat tubes,
seat stays, and seat posts that were the dregs of morphing
a trad frame into a compact design, and the net result was
that using less "tube" and more "post" was actually a weight
penalty rather than an asset. for the tech-minded, the test bed
was the thin end of a deda zero pipe as well as the tops of
corresponding seat stays, along with a campagnolo cf post.
e-RICHIE©™®
What he said.

Dave
 

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do a search...

This topic has been discussed to death. As already noted, it's more aesthetic than anything, but there are cases where long torsoed/short legged riders have managed to get a better fit on a stock frame, taking advantage of the longer TT on a frame size that would normally have little standover clearance.

Other than that, it's pretty hard to prove any real advantage or disadvantage, since few frames are available that are made exactly the same except for the sloping TT. You just can't legitimately compare a compact frame to a sloping when the tubes are also quite different.
 

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eminence grease
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mikey_mike said:
Could somebody site out the advantages of each and to what type of ride do they excel? Thanks for the help I'm relatively new to road biking coming from an avid mtn. biker I'm clueless when it comes to this aspect..
Depending on what size bike you need, and how high your saddle ends up, you have a better shot at clamping your seat tube in your bike stand if you have a sloping TT. Of course, all the suns and moons need to line up for this (they do in my case) and if they do, and if you like leaving your seat clamp alone, then yes, there is one real-live advantage to a sloping TT.
 

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Just one minor addition: Compact frames on the market today typically have 4-6cm of slope, which means you need about 4-6cm additional seatpost showing. Most people I know have roughly 11-13cm of seatpost exposed on their non-compact frames. That would require the seatposts to have 15-19cm of post exposed when they "go compact". Most seatposts on the market today are 25-27cm in length with around 7cm of minimum insertion, that gives you 18-20cm of post that can be shown. For a large number of riders, it means not having to switch the seatpost at all, hence no weight penalty at all.

With frames having drastic slopes and people with lots of seatpost showing, this does not apply.

I had an Easton EC90 which was 30cm at 160 grams, which is pretty much long enough for any compact frame and gives you no weight penalty whatsoever, unless your frame is way too small to begin with.
 

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If you're looking for a minimal seat-to-bar drop with a threadless fork setup, a sloping toptube and longer headtube are just about the only option (other than a horiz tt and long fugly headtube extension). The "comfort" geom. bikes offered by all the major mfr's use a sloping toptube.

Many purists still go with a horiz tt, threaded fork and longnecked quilled stem, and this is the classic comfort option.
 

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elviento said:
Just one minor addition: Compact frames on the market today typically have 4-6cm of slope, which means you need about 4-6cm additional seatpost showing. Most people I know have roughly 11-13cm of seatpost exposed on their non-compact frames. That would require the seatposts to have 15-19cm of post exposed when they "go compact". Most seatposts on the market today are 25-27cm in length with around 7cm of minimum insertion, that gives you 18-20cm of post that can be shown. For a large number of riders, it means not having to switch the seatpost at all, hence no weight penalty at all.<cut>
i may have missed a point here, but my point (above) included
the gem that the additional post needed for a trad to compact
design change always weigh more than the 3-6cm of thin walled
seat tube that is not present owing to the switch.
e-RICHIE©™®
 

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C-40 said:
This topic has been discussed to death. As already noted, it's more aesthetic than anything, but there are cases where long torsoed/short legged riders have managed to get a better fit on a stock frame, taking advantage of the longer TT on a frame size that would normally have little standover clearance.

Other than that, it's pretty hard to prove any real advantage or disadvantage, since few frames are available that are made exactly the same except for the sloping TT. You just can't legitimately compare a compact frame to a sloping when the tubes are also quite different.
you don't need standover clearance on a road bike. what "better fit" you are talking about? looks? no one should feel depressed or hang up cause his bike shows less seatpost.. it doesn't mean anything when you are riding on the road.
 

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cost cutting move by industry

turns into design fad with all kinds of 'science' to support it. my fave is 'it makes a stiffer frame' by having a tighter triangle. Well maybe so for those moments when you are standing (climbing, sprinting) but the other 85% of the time when you are seated you are now placing all that body mass on top of a single unsupported pipe held in by a clamp. With a traditional frame you have the seat tube supported by the TT and Seatstays and a far more minimal exposed seat mast (post) which will make the area stiffer. It really kills me when I see larger riders on this type of frame. a big long seat post and a whole lot of weight just floating on top of it. it gets both fore aft wag and side to side
 

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e-RICHIE said:
i may have missed a point here, but my point (above) included
the gem that the additional post needed for a trad to compact
design change always weigh more than the 3-6cm of thin walled
seat tube that is not present owing to the switch.
e-RICHIE©™®
compact geometry and the new headset designs, incl. the venerable ahead, screwed up the very rational, traditional way of sizing a road bike: by the size of the headtube. if you could live w/ a lot of drop, meaning you were highly flexible, you rode smaller frames. if you felt like a shallower seattube and less drop, you moved bigger.
compact may look cool, aheadsets mean lighter bikes but i see a LOT of people complaining about bad fit nowadays.
 

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classiquesklassieker
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terry b said:
Depending on what size bike you need, and how high your saddle ends up, you have a better shot at clamping your seat tube in your bike stand if you have a sloping TT. Of course, all the suns and moons need to line up for this (they do in my case) and if they do, and if you like leaving your seat clamp alone, then yes, there is one real-live advantage to a sloping TT.
My bike is not compact geometry. It just has longer headtube so that I use fewer spacers to get the correct stem height and look ;-).
 

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I have a compact frame and have long arms. The frame seems to fit me fine as I have also tried a standard frame but found the top tube to be a bit shorter than my compact.

Whereas in a compact I ride ~a 58cm, I would have to ride a 62cm standard frame with a gigantic headtube
 

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whatever makes you happy...

colker1 said:
you don't need standover clearance on a road bike. what "better fit" you are talking about? looks? no one should feel depressed or hang up cause his bike shows less seatpost.. it doesn't mean anything when you are riding on the road.
Personally, I don't want my balls resting on the TT when I stop at a light. The long torsoed/short legged guys can gain some TT length for a better fit, without suffering from this problem, with a sloped TT. I'm just repeating thIs "advantage" noted by some riders who found even a 130mm stem too short on a frame fit fine vertically.

I don't have this problem. Even my horizontal TT frame provides 6cm of standover clearance.
 

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e-RICHIE said:
i may have missed a point here, but my point (above) included
the gem that the additional post needed for a trad to compact
design change always weigh more than the 3-6cm of thin walled
seat tube that is not present owing to the switch.
e-RICHIE©™®
I wonder if that's still the case when you use a 350mm 134g seat post?
 

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I had to switch to a stiffer seatpost on my Schwinn Fastback compact because of noticeable lateral sway.The inexpensive Kalloy alu seatpost was replaced with a Easton alu MTB post with good results.I am 6' 2" 200 lbs. with normal proportions.If you are a heavy rider you should beware of lightweight carbon or flexy alu posts on a compact.
 

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or if you qare 6'2" tall and 200

you should buy traditional geometry. 6'4" 225ish in love with my regular bike frames.
another great turn a lemon into lemonade marketing piece of genius
"Compact Alu frames are more comfortable as the longer seatpost creates shock abosrbtion"
(Read as Flex)
 

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divve said:
I wonder if that's still the case when you use a 350mm 134g seat post?
For my custom carbon frame all the calculations showed it would be a little lighter with an ultralight post and a compact frame for otherwise identical geometry. Of course you have to be under the weight limit for the post too and be willing to cough up the $$$$.
 

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I think this is probably right.

A compact frame also saves on the weight of the toptube and seatstays because they are also shorter. So for a 6cm slope, for example, you could end up saving 10cm worth of tubing on the frame. That could be more weight savings compared to the added length of the seatpost. In addition, as mentioned in my earlier post, if you could manage to go compact without getting a different seatpost, all the weight savings is net.
 
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