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Sloping top tubes and climbing bikes...(9 posts)

Sloping top tubes and climbing bikes...Al Nipples
Jul 20, 2001 12:33 PM
Is there anything extraordinary about sloping top tube road bikes? In just a few years, we've seen a big emergence of them in the pro ranks. (Strangely, sloping top tubes were popular on low end road/touring/hybrid bikes for some time. I kinda think it's goofy to make an expensive ride look like a basic low-end road bike.)

I understand that a more compact frame will be stiffer and such, but is this move to sloping top tubes just a bunch of marketing hype? I mean, it's getting tougher every year to make a frame approach 2lbs and frames are probably stiff enough as it is... so bike-makers have to resort to other hype like frame materials and geometry, and tube orientation to entice consumers to upgrade to "better" products.

I ride a Klein Quantum and think it climbs well, but now I'm wondering if there's something to having a sloping top tube. Does it make it easier to swing side to side as one climbs (I like my mountain bike because the tube is lower and out of the way... could this be so for a road bike too?

What do you guys riding sloping top tube bikes think? Any difference between the sloper and regular bikes?
re: Sloping top tubes and climbing bikes...DaveG
Jul 20, 2001 1:26 PM
The angle of the top tube offsets the slope of the hill, making the climbing almost effortless! The sloping design does take weight off the frame. Since the weight of the monstrous seatpost does not count against the framemaker that's fine by him. Overall, there is some weight savings though. It can make the rear triangle stiffer which has some benfits. For some manufacturers it allows them to make fewer frame sizes (such as Giant). For retro-grouches like myself it represents an abomination of nature. Whether I like it or not they are here to stay. Other than esthetics, I doubt there are any major downsides to the sloping design.
Giant sizingJohnG
Jul 21, 2001 9:41 AM
Giant's simplified sizing system doesn't work for everyone. Too bad .... they would sell more frames if their sizing wasn't so limited.

JohnG
It's like an engine...Jofa
Jul 20, 2001 2:21 PM
Not. Doesn't make any difference, except that it make a little more sense design-wise. No rear triangle in my experience has ever exhibited detectable flex, it not being a triangle but a tetrahedron anyway. The question really should be- "why must top-tubes always be horizontal?" To which there's no reasonable answer other than convention. Whichever design you already have will surely be fine; so will your next one, whatever it is. The sloping top-tube at least removes 'standover clearance' from the 'fit' equation, largely. But don't buy a new bike just because of this... 'climbing ability' (I always thought this was a cardiovascular concern) or anything else, remains totally unaffected.
had both and can't tell the differenceDog
Jul 20, 2001 2:29 PM
There are far more significant factors in bike design and ride. Doubt anyone could detect the difference blindfolded.

Doug
don't try this at homeDaveG
Jul 21, 2001 5:04 AM
.. "Doubt anyone could detect the difference blindfolded"
Other than the pain of crashing blindly into a pole! It would be great if a "blindfold" bike test were possible. That could put to bed a lot of marketing hype and presumed superiority of certain bikes.
The hotest new trend since disco.Doll Face
Jul 20, 2001 3:07 PM
Just a gimick to sell a new frameset to those poor souls feeling left out because they have no sloping top tube. It is the bike industries way of generating profits, much like the fashion industry.

Improve your climbing! How? Ride lots!
re: NoSteveS
Jul 20, 2001 5:01 PM
No, there ain't nothin' magic about a sloping top tubed bike. I have both a sloping top tube frame (Zeppelin) and a horizontal top tubed bike (Spectrum)and there ain't no great difference other than looks. The advantage, in my opinion, to the sloping top tube is not that standover clearance is eliminated as a concern, but rather that it allowed me to ride a much larger frame and get my handlebars much higher and more comfortable than before. (The 56cm Zeppelin is almost the same dimensions and angles as a 59cm Lspeed)

Besides, the guy kicking everybody's buns on the climbs in the TDF is riding a traditional horizontal top tubed OCLV. And man can he spin up mountains.
I wonder if they are a scam...Skeptical
Jul 20, 2001 7:44 PM
You can make the frame lighter, as was pointed out above. But what is heavier...a few inches of the middle (and lightest) part of the seat tube, or the equivalent amount of seat post needed in replacement? You are making the frame lighter, but adding heavier parts back onto the bike to make it fit the rider!