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avantages of sloping frame??(30 posts)

avantages of sloping frame??dolmen cc
Feb 14, 2002 3:59 PM
"The three principal advantages of sloping geometry frames are as follows:

- Stability when descending: with a sloping geometry frame the combined centre of gravity of the rider and the machine is marginally lowered with respect to a conventional 'direct' frame, thus making the bicycle more stable when descending and more manoeuvrable when cornering, particularly at speed.

- Weight saving: a sloping frame will typically be 30-40 grams lighter than a 'direct' frame, a significant advantage, especially in a thoroughbred racing frame, in which a further weight saving through reduction of the tube wall diameters cannot realistically be contemplated.

- Increased rigidity: by reducing the size of both the main triangle and the rear triangle, the overall rigidity of the frame is significantly increased. This means that the bike will react in a more responsive manner to the forces of the rider, particularly in situations when this force is delivered in an 'explosive' manner, for example during fast climbing accelerations."

taken from bianchi's website.

anyone agree, disagree with their view on sloping frame
re: avantages of sloping frame??STEELYeyed
Feb 14, 2002 4:05 PM
The need for a longer seatpost offsets the wieght savings.
re: avantages of sloping frame??Keith Vorbet
Feb 14, 2002 4:13 PM
myth #1 - the difference between a sloping tube geometry center of gravity with a rider versus a conventional frame geometry is so minute that to even try to claim it make a perceptable difference to the rider is borderline ludicrous.

myth #2 - the frame is lighter, yes, the frame indeed is 30-40 grams lighter and the extra long elongated and in many cases thicker walled seatpost needed to ride a sloping tube bike essentially adds almost all of that 30-40 grams right back into the total frame weight. The total difference in frame weights between comparable sloping tube and conventional frames of the same materials and designs is also almost non existent.

myth #3 - well it's really not a myth at all, smaller triangles will tend to lead to a stiffer frame, but since most sloping top tube designs seem to be saturating the oversized tube aluminum frame bicycles, why in the world would anyone want to brag about making their harsh riding aluminum bike even stiffer?? Also, excess flex in that very long seatpost used in sloping tube bikes is a common complaint from riders who have tried them.

Advantages? Well, I guess you could say its a huge advantage to the manufacturer since now with a sloping top tube they have determined that they only have to build 4 different size bikes and fit them to then entire bike riding population, S, M, L, and XL.

Hard to imagine someone shelling out 2K or more for a bike so unprecisely fit to ones proper sizing. But new suckers and fools who buy into manufacturers marketing hype are born everyday.
Keith has it exactly right (nm)Kerry Irons
Feb 14, 2002 4:38 PM
Keith has it exactly right (nm)Kurt VF
Feb 14, 2002 5:12 PM
Everything he says makes sense. The center of gravity is as bogus as a claim as they come, even better than the claim they are lighter.(a light frame is somthing they can brag about in their ad) Specialized is one company that makes a full compliment of sizes of their compact frame road bike.
there is one great advantageishmael
Feb 14, 2002 5:23 PM
fit- most of the new compact frames have short top tubes and longer headtubes than the standard geometry which suits long legged people better..women would likely be better suitted to compact, and if they go really compact they could wear a skirt..other than that,weight- agreed, who really cares, but no one ever cuts there post anyway to benefit from the unneeded post...stiffness- my aluminum frame with a nice seat and carbon fork is just as comfortable as my old trek carbon if not nicer.
Feb 14, 2002 7:06 PM
Easier for the dopes in the LBS to sell bikes and cash checks without having to really worry about fit - plus they get to sell a bunch of stems when they return with aches and pains. "Gee I guess you're just not flexible enough - let's try this stem. That'll be $35 please."

You're going to have a hard time convincing a lot of guys that being able to wear a skirt and still ride the bike is somehow a plus. Hey, it's a girls bike - you'll love it when you cross dress.

I always cut off unnecessary seat post.
Feb 15, 2002 11:45 AM
the shorter toptube and longer headtube is a real plus for people with long legs and short torsos...on my traditional frame bike i need alot of spacers and a really short stem which is twitchy, not with the compact..also the low top tube is safer on the future kids...why not just except these benefits..sure, its easier for manufacturers to build 3 sizes, but if it works for customers too why ridicule.
Feb 15, 2002 12:11 PM
So, what do you do about the other half of the population that have short legs and long torsos? If we follow you logic then it seems that the mfr.s desperately need to come out with the anit-comapact frame to address this gross oversight. How can a plus for a select group be good for everyone?

Point is yes compact can work, but it offers no clear advantages over a normal frame for the average cycling customer. The real advantage is for the (lazy) shops and bike companies.
Who caresWannabe
Feb 15, 2002 12:05 PM
I love my compact frame. Couldn't give a rat's @ss what the rest of you think about it!

What you think about your bike is all that matters.

Andy - Wannabe
Feb 15, 2002 12:14 PM
It's OK for you to love your compact frame. Really.

Original poster asked about the hyped advantages from Bianchi. I just don't think you need to go sell your standard frame and replace it with a compact frame. I'm OK, you're OK....I think. ;-)
Two more: modern look and you can climb on the bike easier. (nm)Bruno S
Feb 14, 2002 6:22 PM
You mean guys ride those things too??! (nm)Chen2
Feb 14, 2002 6:36 PM
Key words: marginal and minimal.grzy
Feb 14, 2002 6:54 PM
What a bunch of horse pucky - I want what some of those marketing guys are smoking. Someone actually got paid to write that tripe, probably on a beach in Jamaica.

The theory is true but the effect is minute by several orders of magnitude. They acknowledge that the difference is slight, but go on to say that the effect is huge. Gawd just think about it - 30 to 40 whole grams lighter! You can save more weight and lower the CG further by swaping out the POS seatpost and stem they put on the bike. Or use something better than Tiagra components. As far as the stiffness rigidity goes - everyone bitches that aluminum frames are too stiff to begin with and that steel (is real) frames have an ideal amount of compliance. So why do they want to make it stiffer? If you really want stiff and light then you should be looking at carbon fiber - the modulus is much higher. Ask them to hang a number on any of the "huge" effects that they claim (hint: they've never measured them). Recognize that one of these midget frames requires a longer, heavier seatpost that applies a larger moment at the top of the seat tube and thus must be further reinforced to avoid a failure. If they don't have to reinforce it then the stock frame was over built to begin with. The guy with the better legs and lungs rules.

I can assure you that in about 5 years, or less, sloping frames will be so passe and that the manufacturers will be pushing the advantages of revolutionary new standard frames. It's a bunch of fashion hype designed to sell more stuff to people who already have it. They've realized that repeatedly selling to existing customers is easier than actually getting new ones. After all this segment has already self identified as being willing to spend some coin on bikes.

I guess I might kinda disagree.....maybe. ;-)
Rider prefference is all that matters just ask Oscar Sevillajunglejim
Feb 15, 2002 2:30 PM
Oscar Sevilla rode a compact Alu Look in last years Vuelta. Obviously he preffers the ride of these kind of frames as Look make some great Carbon "standard bikes". Mike Burrows came up with the TCR bike for Giant I am sure he found advantages in the design other than those for the company. Surely if these bikes are that bad people would not buy them and manufacturers would stop making them. I think it is important that manufacturer try out new ideas. I am not saying the compact design is any better just that some riders may preffer it which is the most important thing. Hey my road bike is not compact though my TT bike is. As the saying goes the is more than one way to skin a cat (and to make a good road bike).
this subject is sooooo old.CT1
Feb 14, 2002 8:58 PM
Sorry for the cynical subject line but this has been beat around sooooo much.

Total BS or nearly so..... that's my take. Get something you like be it "standard" or STT. The bottom line here.... your legs and lungs drive the bitch down the road not the angle of the TT.

Absolutely. Engine, not bike.Elefantino
Feb 14, 2002 9:27 PM
One year Mario Cipollini rides standard bikes. The next year he's riding sloping top tubes. Why? Because the bikes he's getting for free from the company sponsoring his team make sloping top tube bikes, not because they're better. (Angel Casero just the opposite.)

If you like it, buy it and ride it. Most of the stuff people say about bikes is hooey anyway. Particularly, at times, on this board.


PS: Whatever you do, don't collide with another sloping top tube bike. I hear that they explode on contact. Can't remember where I heard it. But it sounds feasible.
this subject is sooooo old.Cola
Feb 15, 2002 4:05 AM
Using that brilliant logic, there should be no posts at all in here concerning any bike frame or gear topics at all, including posts by yours truly.

That's my take...
re: avantages of sloping frame??SnowBlind
Feb 15, 2002 8:44 AM
The builder for my frame did it for one reason only: fit.

My bizarre body size resulted in a very long top tube, it is as long as the 62cm Gios A-90, while having the standover of about a 52cm bike , so he dropped it protect future children and maintain a short wheelbase with slack geometery. The drop is only about 2cm, so it is not real noticable.
Feb 15, 2002 10:57 AM
They do come out lighter.

1. Shorter chain stays. On a 55 it saves about 15cm of stay length.

2. Because of the smaller triangles, they can use lighter guage materials and keep the same stiffness while losing weight.

3. The seattube/post thing is a wash.

4. Theyre ugly.

5. Lower center of gravity??? LOL!
Feb 15, 2002 11:47 AM
no one mentions the shorter toptube and longer headtube which is a great benefit for some..and the lower toptube is safer..these are real benefits
Feb 15, 2002 12:16 PM
These same benefits suck for everyone else who is average or on the other side of average (i.e. 2/3rds of the population) depending on where you draw the line. You have to look at the whole picture, not just the stuff you _want_ to see. Do you work in a shop? ;-)
Feb 16, 2002 10:22 AM
compacts advantages may not be for everyone....but dont rule them out, they have great advantages for some..
re: avantages of sloping frame??jp2
Feb 15, 2002 11:56 AM
they do come in handy for us short legged long torso folks. as for myself in particular, to achieve "kops"(which i never strive for) i'd need about a 76 degree seat tube, this results in a much shorter(relative) tt on a conventional frame. i don't want a 14-15cm stem with only 4-5 cm of post sticking out of the frame. compact come in handy in these regards. doesn't apply to a lot of folks, but it does for me.
Advantage MFG!kyroadie
Feb 15, 2002 1:06 PM
The only real advantage goes to the MFG. They only have to make 3 sizes. This cuts their costs by having fewer jigs, lowers their inventory counts, and as an added benefit, they actually charge the consumer more because it's the latest fad. Just my opinion.
only onejs
Feb 15, 2002 1:08 PM
something to talk about
No real avantages to sloping framewoo hoo
Feb 15, 2002 2:40 PM
My opinion, if anyone cares, is that it's easier (cheaper)for manufacturers to produce only 3-4 sizes and easier for dealers to quickly size a customer, as well.

Problem, or benefit, is that they do fit some folks very well and some not so good. I found that I'm a "Tweener" i.e., between medium and large on the Giant series and would never buy one for that reason (and some others which have nothing to do with this topic).

I think smaller riders riding the medium benefit the most only if they truly like the look and the feel, both of which are very subjective criteria. Only by trying it can you decide. I did and they're not for me.
one advantagegtx
Feb 15, 2002 7:46 PM
you can clamp your bike into the repair stand by the seatpost. This is great on mtbs, where you tend to need to clean your bike up after every ride.
BINGO..... DIS IS DA ONE ADVANTAGE!!! congrats ..... nmCT1
Feb 15, 2002 8:53 PM
clean a mtn bike after every ride???nfm.
Feb 16, 2002 7:22 AM