why clincher more pricey???

[CScriba]

just a quick Q...why are most carbon clinchers so much more expensive than the tubbies??? i want clinchers but the price differences between them and tubbies get me wondrin if it worth it gettin tubbies rather than clinch...anyone know why exactly??

[Guest colonel]

Cause they nail you solid for Tubbies!!

[spano]

the manufacturing process is more expensive for clinchers,

 

it very difficult to manufacture the "lip" out of carbon fibre...

[CScriba]

aha...thought so...but realy, does that lip realy cost R2000 rand more to make...that seems a bit much

[Jules]

kiwi posted something about this earlier. I reckon you should get aluminium braking surface. The weight difference is not much and if it means a lot to you then you should probably be riding tubbies anyway. And think of the hassles you'll save with brake pads.

[droo]

kiwi posted something about this earlier. I reckon you should get aluminium braking surface. The weight difference is not much and if it means a lot to you then you should probably be riding tubbies anyway. And think of the hassles you'll save with brake pads.

 

 

 

Not to mention wear on carbon braking surfaces...

[Kiwi]

Making the hook bead in full carbon is really tricky to do. There is a huge amount of side wall pressure from the tube that a tubular doesn't have to contend with because the tubular casing looks after that. Then there is heat build up which has to be dissipated to prevent a possible blow-out under heavy braking. <?: prefix = o ns = "urn:schemas-microsoft-com:office:office" /><?: PREFIX = O />

 

That's why a lot of manufacturers chicken out and bond on an alloy rim.

 

The pay-off of an all carbon clincher is that you are looking at 100grams per rim lighter than the equivalent alloy rim.

 

A point to remember is that weight on the edge of the wheel, eg the rim and tire, increases at the square of the speed. So a 100 grams saved at the rim will have a much bigger effect than a lighter frame for instance.

 

As long as you use carbon compatible brake pads the rim will last as long as any high performance alloy rim.

Kiwi2008-11-28 02:45:12

[Johan Bornman]

Making the hook bead in full carbon is really tricky to do. There is a huge amount of side wall pressure from the tube that a tubular doesn't have to contend with because the tubular casing looks after that. Then there is heat build up which has to be dissipated to prevent a possible blow-out under heavy braking.

 

 

Well' date=' this pressure is not so huge. It is equal to the pressure in the tyre. But you are right, the tubular's casing looks after that.

 

Ironically, heat build-up in a carbon rimmed tyre is lower than in an aluminium (aluminium can be alloyed, but so can steel, copper, zinc, scandium, magnesium, uranium, plutonium, lithium, etc etc ) wheel. Aluminium is a good conductor of heat and sucks the heat from the pad where it is generated and dissipates it into the rim, the tube and tyre and of course the spokes and air. All things being equal, a carbon rim insulates the tyre more from heat than an aluminium rim does.

 

 

 

A point to remember is that weight on the edge of the wheel, eg the rim and tire, increases at the square of the speed. So a 100 grams saved at the rim will have a much bigger effect than a lighter frame for instance.

 

 

This old old-wive's tale refuses to die. If you do the maths, and believe me, it is not difficult stuff, you'll see that this story is nonsense. The effect is negligible, so please stop perpetuating this myth.

 

Most metals in daily use are alloys. The exceptions being aluminium kitchen foil which is almost pure aluminium and copper in electrical wire.

 

Therefore, when we refer to an alloy of sorts, we call it by the name of its biggest component. Most aluminium alloys have less than 15% other metals in there and we then simply call it aluminium. Unless of course the fact that it is alloyed is of importance. The practice of calling aluminium alloy leaves all the other alloyed metals out in the cold. What do we call them?

 

The exception to the rule is steel and that is simply because iron alloy has a very specific name - steel.

 

The gold on your wedding finger is gold - not gold alloy. The platinum in your car's exhause is called....platinum and so on and so on.

 

Clarity of speech helps us all understand what you're trying to say.

 

 

 

[Kiwi]

Cane Creek:

 

Physicists use the term Moment of Inertia (MOI) to describe the effects of mass during rotation. And MOI is one of the forces working against you every time you accelerate. More than 95% of the MOI associated with propelling a bicycle is attributable to the wheels. This means that gram for gram, your wheels are your bike?s most critical components. One of the ways our engineers minimize MOI is by locating Cane Creek spoke nipples at the hub. To understand how dramatically this affects acceleration, imagine if we moved the nipples to the traditional location at the rim: Given a nipple weight of 0.27 grams, the effect on the wheel?s MOI would be the same as if we?d replaced them with nipples weighing 48.55 grams.

 

Wikipedia:

http://en.wikipedia.org/wiki/Moment_of_inertia

 

 

The easiest way to see the difference is to ride an alloy rim carbon clincher back to back against a full carbon one and see for your self. You are welcome to take our demo Planet X Full Carbon Clinchers out to see for your self.<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

[Kiwi]

Rim Weight Specifically, Wikipedia. _lots of stuff here about what makes a bicycle go faster:

 

Kinetic energy

Consider the kinetic energy and "rotating mass" of a bicycle in order to examine the energy impacts of rotating versus non-rotating mass.

The translational kinetic energy of an object in motion is:^[8]

http://upload.wikimedia.org/math/b/0/0/b00285433cb3b36e23433488fff606d7.png,

Where E is energy in joules, m is mass in kg, and v is velocity in meters per second. For a rotating mass (such as a wheel), the rotational kinetic energy is given by

http://upload.wikimedia.org/math/c/a/f/caf45c982f47131b7a9ca1f4cd83a8f8.png,

where I is the moment of inertia, ω is the angular velocity in radians per second. For a wheel with all its mass at the outer edge (a fair approximation for a bicycle wheel), the moment of inertia is

I = mr².

Where r is the radius in meters

The angular velocity is related to the translational velocity and the radius of the tire. As long as there is no slipping,

http://upload.wikimedia.org/math/5/7/d/57dfe9909c4f90a93032f39a6155150d.png.

When a rotating mass is moving down the road, its total kinetic energy is the sum of its translational kinetic energy and its rotational kinetic energy:

http://upload.wikimedia.org/math/a/a/b/aab3ae9a2733fd83162f82c2f8054762.png

Substituting for I and ω, we get

http://upload.wikimedia.org/math/1/5/9/15909f0a24a703c95014ed6c27dc1d82.png

The r² terms cancel, and we finally get

http://upload.wikimedia.org/math/4/4/b/44b416d99429ab5dfe0ebb8715003d60.png.

In other words, a mass on the tire has twice the kinetic energy of a non-rotating mass on the bike. There is a kernel of truth in the old saying that "A pound off the wheels = 2 pounds off the frame."^[9]

This all depends, of course, on how well a thin hoop approximates the bicycle wheel. In reality, all the mass cannot be at the radius. For comparison, the opposite extreme might be a disk wheel where the mass is distributed evenly throughout the interior. In this case http://upload.wikimedia.org/math/a/d/4/ad4dc0c24a3759e70f5c385d981b9986.png and so the resulting total kinetic energy becomes http://upload.wikimedia.org/math/4/2/e/42eb5eba1f7282e44cf46b09907f6561.png. A pound off the disk wheels = only 1.5 pounds off the frame. Most real bicycle wheels will be somewhere between these two extremes.

One other interesting point from this equation is that for a bicycle wheel that is not slipping, the kinetic energy is independent of wheel radius. In other words, the advantage of 650C or other smaller wheels is due to their lower weight (less material in a smaller circumference) rather than their smaller diameter, as is often stated. The KE for other rotating masses on the bike is tiny compared to that of the wheels. For example, pedals turn at about http://upload.wikimedia.org/math/5/4/b/54bbd68cb89bf41f5bf194531c037bc0.png the speed of wheels, so their KE is about http://upload.wikimedia.org/math/8/1/9/81949794e9c5db48fcc9083f236eaf7b.png (per unit weight) that of a spinning wheel.

[Johan Bornman]

Cane Creek:

 

Physicists use the term Moment of Inertia (MOI) to describe the effects of mass during rotation. And MOI is one of the forces working against you every time you accelerate. More than 95% of the MOI associated with propelling a bicycle is attributable to the wheels. This means that gram for gram' date=' your wheels are your bike?s most critical components. One of the ways our engineers minimize MOI is by locating Cane Creek spoke nipples at the hub. To understand how dramatically this affects acceleration, imagine if we moved the nipples to the traditional location at the rim: Given a nipple weight of 0.27 grams, the effect on the wheel?s MOI would be the same as if we?d replaced them with nipples weighing 48.55 grams.

 

Wikipedia:

http://en.wikipedia.org/wiki/Moment_of_inertia

 

 

The easiest way to see the difference is to ride an alloy rim carbon clincher back to back against a full carbon one and see for your self. You are welcome to take our demo Planet X Full Carbon Clinchers out to see for your self.<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

[/quote']

 

One place where you should not take physics lessons is from bicycle company websites and from the back of bicycle product boxes.

 

What Crane Creek forgot to tell you is that MOI also helps you keep you going once you stop accellerating. It is like the wind chill factor thing. In winter they say, "hell it is going to be cold today, not to even mention the wind chill factor." In summer they say, "hell it is going to be hot today" and then they forget to mention the wind chill factor.

 

Further, Crane Creek didn't bother to quantify the effect of a little bit of weight saving at the rim. Do it, you'll see it is miniscule.

 

It seems as if my aluminium alloy explanation didn't touch sides??

 

Thanks for the offer of a wheel, but I'll be lying to you if I say I can feel a 0.0001% improvement in accelleration and likewise, a 0.0001% reduction in maintaining my momentum.

 

You mention the nipple's weight as if taking it to the hub saves the total weight. How does the spoke now fix to the rim? I bet there is a large blob of steel or aluminium in there to compensate for the lack of nipple. Crane Creek doesn't explain that either.

 

They also don't show the match in reaching that "Dramatic" increase in weight from 0,2 grams to 46 grams. We need to know the accelleration applicable in order to understand what they mean. They don't provide it because it won't make sense.

 

Physics is about common sense too. Seach this forum, I'm sure I've explained it before, complete with calculations.

 

 

 

 

 

 

[Spinnekop]

I'l get the Biltong and beer........

 

Popcorn is going to be too easy to digest on this one.......

[Kiwi]

 

Edmund R. Burke, Ph.D.

 

 

"Lastly, low weight in rotating components is even more important. To accelerate a wheel or pedal and shoe system, kinetic energy of rotation must be supplied, in addition to the kinetic energy of linear motion. For example, with a wheel, if the weight is mostly concentrated in the rim and tire it would take nearly double the energy needed to accelerate it than an equal nonrotating weight. In other words, one pound added to a wheel or shoe/pedal system is equivalent to nearly two pounds on the bicycle frame."

 

http://www.active.com/cycling/Articles/The_effect_of_weight_on_speed.htm

[Marius]

ooo my...here we go again.

[Jules]

I'm on the sidelines with my beer and biltong

 

 

 

This is an interesting debate and I'm not sure I know the answer. I'd think of it as spinning a merry-go-round with a large weight on the outside and then repeating the procedure with the weight on the inside. Surely it would take less force to accelerate the merry-go-round with the weight on the inside?

 

 

 

That said, I ride relatively heavy wheels with an aluminium braking surface and my nipples on the outside and I don't feel at all disadvantaged by them.

[Kiwi]

Once you accelerate a wheel up to speed the energy to maintain that speed on a light or heavy wheel should be the same if the are both aerodynamically similar. <?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

That's why wheel weight isn't such an issue when you are doing a TT or non drafting Tri.

 

The moment you need to speed up or slow down weight become the biggest factor.

 

When was the last time you did a road race and held the same speed through out?