sloping top tube question
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sloping top tube question
what is the advantage/disadvantage of a sloping top tube? I'm in the market for a new frame (spring time) something intermediate and i see a lot of newer bikes w/ sloping top tubes. It looks a little weird but i've never road a bike with a sloping top tube. any input would be helpful. thanks
if anyone has frame recomendations in the $300 range that would be cool.
if anyone has frame recomendations in the $300 range that would be cool.
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Originally Posted by coleadam
what is the advantage/disadvantage of a sloping top tube? I'm in the market for a new frame (spring time) something intermediate and i see a lot of newer bikes w/ sloping top tubes. It looks a little weird but i've never road a bike with a sloping top tube. any input would be helpful. thanks
if anyone has frame recomendations in the $300 range that would be cool.
if anyone has frame recomendations in the $300 range that would be cool.
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In most cases, sloping frames do nothing more than give you some additional standover room. They're nice in that they can make it easier to fit someone whose legs are a bit short for their overall body confirmation. They don't change riding position, they're not stiffer and they don't save (much) weight. Just another way of building a frame.
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The sloping top tube reduces weight, increases stiffness, reduces the quantity of sizes required thus reducing manufacturing and inventory costs resulting in greater corporate margins and a faster bike.
I am on record for dising them because they do not have room for the bottles and I prefer the look of a traditional frame.
I am on record for dising them because they do not have room for the bottles and I prefer the look of a traditional frame.
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ok so we have some coflicting info here i'm not that concerned about the weight issue a few grams isn't going to change much. My friend has a sloping top tube 59cm but his saddle is like 8 or more inches out of the seat tube it looks weird. i don't know i guess i'll just have to ride them but both of my bikes now have a non-sloping tube and i think it looks better and i ride comfortable. i was just curious...
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Aside from the argumentative advantages -vs- disadvantages...when shopping for sloping roadie, pay attention to the "effective/virtual length" of the T-T. This is perhaps the most important aspect of the geometry IMO.
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Originally Posted by FormerBMX'er
Aside from the argumentative advantages -vs- disadvantages...when shopping for sloping roadie, pay attention to the "effective/virtual length" of the T-T. This is perhaps the most important aspect of the geometry IMO.
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Originally Posted by plainsdrifter
The sloping tube compacts the frame, shortening your reach to the bars and positions you in a more upright/comfortable riding position.
A "compact" frame with a sloping top tube can be made with varying length top tubes, and can be made to favor an upright or an agressive position by changing a number of other dimensions, (not the least of which would be the length of the head tube.)
For example Giant TCR's and Giant OCR's both use sloping top tubes. Yet one is designed for a more relaxed set up, and the other is raced by Jan Uhllrich.
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Head tube length on sloping bikes is critical, while it pretty much goes without saying that you're going to want a bike that has the same effective TT length as the bike you're riding.
Make sure that the HTL is such that you can get your bars up or down where you want them. The most compact bike I own has a very long HT and that is somewhat compensated for by the fact that it has an integrated headset. But where I might use 5-10mm of spacers on a traditional frame, I use none on this in order to get my bars 10cm below the saddle. You need to watch out for this.
Aside from the minor differences in design, yes - they do look different. But I'll be very surprised to hear that there is a significant difference in ride that cannot be attributed to something else, like tires, saddle, wheels, etc.
Make sure that the HTL is such that you can get your bars up or down where you want them. The most compact bike I own has a very long HT and that is somewhat compensated for by the fact that it has an integrated headset. But where I might use 5-10mm of spacers on a traditional frame, I use none on this in order to get my bars 10cm below the saddle. You need to watch out for this.
Aside from the minor differences in design, yes - they do look different. But I'll be very surprised to hear that there is a significant difference in ride that cannot be attributed to something else, like tires, saddle, wheels, etc.
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Originally Posted by hiromian
...reduces the quantity of sizes required thus reducing manufacturing and inventory costs resulting in greater corporate margins...
With a mix of seat position, stem length and angle there is no real difference between a well fitted standard or compact geometry bike.
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Originally Posted by merlinextraligh
This is simply wrong. A shorter top tube shortens your reach to the bar, whether it slopes or not.
A "compact" frame with a sloping top tube can be made with varying length top tubes, and can be made to favor an upright or an agressive position by changing a number of other dimensions, (not the least of which would be the length of the head tube.)
For example Giant TCR's and Giant OCR's both use sloping top tubes. Yet one is designed for a more relaxed set up, and the other is raced by Jan Uhllrich.
A "compact" frame with a sloping top tube can be made with varying length top tubes, and can be made to favor an upright or an agressive position by changing a number of other dimensions, (not the least of which would be the length of the head tube.)
For example Giant TCR's and Giant OCR's both use sloping top tubes. Yet one is designed for a more relaxed set up, and the other is raced by Jan Uhllrich.
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Originally Posted by blue_nose
This is the real reason many more bikes are being made with compact geometry. If there were any competitive advantage (speed, weight…) then all pro riders would be using this type of frame. In fact, pro teams have relationships with manufacturers that have compact and traditional geometry bikes.
With a mix of seat position, stem length and angle there is no real difference between a well fitted standard or compact geometry bike.
With a mix of seat position, stem length and angle there is no real difference between a well fitted standard or compact geometry bike.
The Trek 5000 has traditional geometry comes in 7 sizes:
50, 52, 54, 56, 58, 60, 62cm
In contrast, the Giant OCR2 has compact geometry and comes in 5 sizes:
XS, S, M, L, XL
In realty, you can fit the same broad population with the range of bikes sizes from both manufacturers. Thus, Giant can save some production and inventory costs by manufacturing 5 frame sinstead of 7.
I personally like the look of traditional geometry, but that is just a personal preference.
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The sloping top-tube is a byproduct of a design to satisfy specific criteria. However, different manufacturers are trying to address different criteria. One may use a sloping top-tube simply to increase standover. Another may use it because in their specific design, the sloping top-tube provides for a more rigid rear triangle. Another may use it because they believe it saves some weight. Another may use it because they think it will make the bike look better. There is no one definitive positive or negative that can be said about all bikes with sloping top-tubes. You have to take into account thye rest of the frame design/geometry.
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Originally Posted by The Fixer
Compact frame stiffness is somewhat negated when you're riding on 3 feet of seatpost.
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I agree with Ernesto Colnago who says its all about marketing. I suppose the frame might be stiffer as it is smaller but then you have way more seat post hanging out. I personally I prefer the look of standard geometry. Plus it seems like you have more sizing options with standard geometry frames.
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Originally Posted by hiromian
The sloping top tube reduces weight, increases stiffness, reduces the quantity of sizes required thus reducing manufacturing and inventory costs resulting in greater corporate margins and a faster bike.
I am on record for dising them because they do not have room for the bottles and I prefer the look of a traditional frame.
I am on record for dising them because they do not have room for the bottles and I prefer the look of a traditional frame.
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Originally Posted by OCRider2000
I agree with Ernesto Colnago who says its all about marketing. I suppose the frame might be stiffer as it is smaller but then you have way more seat post hanging out. I personally I prefer the look of standard geometry. Plus it seems like you have more sizing options with standard geometry frames.
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ok i think i got it, just based on looks i don't like the design maybe b/c i already have 2 standard desined frames. I'll just take a few sloping bikes out for a spin and see how they feel. thanks for all the input
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I've always been a traditionalist, and thought that compact frames just didn't look right. But its growing on me. To my taste, the TCR Advanced Team I have on order looks pretty slick. Perhaps its the integrated seat post that pulls the look together
Last edited by merlinextraligh; 11-01-06 at 07:16 PM.