What is a Tubular?

In a Tubular, the tube is sewn directly into the tire. The tire is then glued onto a special rim.
The unquestioned advantage of tubulars lies with their puncture stability, as even in the case of a catastrophic puncture, the tire stays on the rim. The rider can safely stop without losing control of the bicycle, or even slowly ride on until the team car arrives.

The drawback of tubulars is in fitting. The fixing of the tire onto the rim with glue is much more awkward than fitting a clincher tire. Furthermore, in the case of a defect, the tubular cannot be repaired easily like a tube as the complete tire has to be replaced. The manufacturing process is also more labor intensive, which explains the high cost of top quality tubulars.

 

TUBULAR TIRES: Used by majority of competitive cyclists,from all tire types they have the lowest rolling resistance. Tubular tire is the lightest.Tubular rim is lighter than clincher rim. They can use a 
higher pressure inflation than clincher type tire. In case of flat the stability and safety of the rider is not affected as much as in the case with clincher tires and can be ridden flat in case of emergency
The necessity of gluing the tire to the rim means that the flat repairs are not easy, [this does not apply to TUFO tubular tires in combination with TUFO sealant, the repair is easy and in many cases instant and cheap].

The vulcanized tubular

The vulcanized tubular has the tread vulcanized to the casing before the casing is sewn around the tube. This is far less expensive than cold treating. You can expect that cheap tubulars will be vulcanized, have a low thread count and when inflated on the rim are rarely straight. Cheap tubulars usually have butyl inner tubes rather than the light, more efficient latex tubes found in better tubulars. Cheap sew-ups fail easily because their low-thread-count casings are very fragile. The ride quality is still pretty good, but I think this partly attributable to the flexible, supple design of a box tubular rim. There are good vulcanized tubulars. They make an intermediate step between cheap tubulars and often staggeringly expensive hand-made sew-ups. I know very good riders whose judgement I value who say that a cheap sew-up has a better ride quality than the best clincher. I'm not so sure. The easiest way to spot a vulcanized tubular is by looking at one without air, uninflated. It will be flat, looking almost like a thick strip of cloth.

A vulcanized tubular is more prone to flats. The tread was vulcanized to the flat fabric of the casing. With 100+ psi in the inflated tubular, the tread is stretched several centimeters longer around the outer circumference of the tire. Once the tread receives a road cut, the tread's tension will cause the cut to open up. The strain of this tension also causes the vulcanized tire to be less flexible and very slightly increases rolling resistance.

Hand-Made Tubulars.

Hand-made tubulars are works of art. The casing fabric of a hand-made tubular is not woven. Very fine threads, up to 320 per inch, are laid next to each other, compressed and then bonded with a latex coating. A good tubular will have over two kilometers of thread. These threads were traditionally cotton or silk. Now polyester is usually used. The threads are not interwoven as in a normal fabric. The first ply is laid on a round form. Then, another ply is laid at a 45 degree angle on top of the first one. They are bonded with heat (but not vulcanized) and the edges are folded over. The result is a casing of incredible strength and flexibility.

The edges of the fabric are sewn together as an inner tube, usually of natural latex rubber, is inserted. A base tape is glued to the inner circumference to protect the stitches.

The tire is then inflated and the tread is hand-glued to the tire casing.

This method of construction has several excellent consequences for the rider.

First of all, the tension between the casing and the tread that was found in the vulcanized tire is eliminated, making the tire more flexible. The tire doesn't flat as easily because cuts don't open up as quickly. The tire, with it superior suppleness and flexibility has a much nicer feel.

The unwoven casing also has benefits for the rider. The casing is so supple that when the tire rolls over irregularities in the road, a smaller area of the casing deforms compared to woven casings. This decreases rolling resistance. The tire is therefore faster. The high-thread-count casing resists the penetration of sharp objects. Flats occur less often. The tires is less prone to other road damage because the casing is so strong.

In professional racing, if the rider is not paid to ride clinchers, he will, if at all possible, ride tubular tires. The flexibility of the casing not only makes the tire faster, it handles better. The supple casing allows the tread to grip the road. The reduced harshness of the ride means more miles with less fatigue. Hand made tubulars are very expensive, but they remain the finest tires a rider can put on his bike.

Open Tubulars. An open tubular is a tubular tire whose edges have not been sewn together. Instead, a flexible bead of kevlar is sewn along the edges turning it into, if I may be allowed to mix up my definitions here for a second, a clincher that performs almost as well as a tubular. All the techniques of making the tubular; the high-thread-count unwoven casing and the cold-treated tread application are used in the manufacture of Open Tubulars. For this reason, a rider who is not willing to suffer the trouble of dealing with sew-up glue and the tricky job of repairing a flatted sew-up, the open tubular is a wonderful choice.

Almost everything that was written above about hand-made tubulars applies to open tubulars. Their high-thread-count casing makes them strong, while able to roll fast and resist punctures. The cold-treated tread application along with the fine casing give the tires a wonderful feel that must be experienced to understand.

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Clincher Tires

 

 

 

What is a Clincher Tires?

 

 A solid, monolithic bicycle tire made of urethane rubber with a cured hardness of from 50 to 95 Durometer.

 

The clincher tire has a separate inner tube, which is basically a rubber balloon. This fits inside the tire, and the tire is mounted on the rim by lifting the beads over the edge of the rim. The middle of the rim makes a sort of valley, and while the tire is being installed, most of the bead can fit into this valley. This gives enought slack to allow the bead to be pushed or pulled over the edge of the rim, even though outside diameter of the rim is larger than the inside diameter of the bead.

Under normal riding conditions, most of the light shock loads experienced when riding on a relatively smooth road surface are absorbed by the resiliency of the urethane rubber, with only a minor amount of deflection of the arched tunnel. A severe impact causes the tunnel to collapse to a greater extent, thereby absorbing the shock load and preventing damage to the wheel rim.
This is the normal type of tire, with a separate inner tube. The tire consists of two hoops called "beads", made of steel or Kevlar cable, which are held together by cloth, usually nylon. The whole assembly is dipped in rubber, with thicker rubber applied in the tread area.

Strictly speaking, the term "clincher" is slightly incorrect, as it applied to an obsolete style of tire which had ribs in the edges of the tire which fitted into grooves on the rim, where the tire was folded under the tube. The air pressure in the tube pressed the rib into the groove, and "clinched" the tire in place. People who are fussy about this prefer the term "wire-on."
 

From all choices, clincher tire is the heaviest. The necessity to use inner tube, adds more weight and lowers rolling resistance. The 
need to use rim liner, slime and a valve steem cap. Again more weight 

Generally, a tire factory will employ one or another of the two technologies, tubular or clincher, but not both. As I write this, the present limit for woven nylon casing is 120 threads per inch. This yields an entirely satisfactory tire with a very good road feel. The nylon rides harsher than polyester, silk or cotton, but it's not bad. The woven casing is stiffer and transmits more road shock. But even though the tubular technology remains the apex, a good, high-end clincher on a hand-built cross three spoke wheel gives a wonderful ride. The tread vulcanized onto clinchers is generally thicker. For this reason, a clincher tire will usually last longer.

 

Armadillo tires

While no pneumatic tire is 100 percent flatproof, the Armadillo flat-prevention technology has proven so effective that Specialized is now offering an unconditional guarantee. 

 

 

 

 

 

 

Airless Tires

 

 

 

What is a Airless Tires?

 

A solid, monolithic bicycle tire made of urethane rubber with a cured hardness of from 50 to 95 Durometer. 

The tire is formed with a pair of laterally spaced bead shoulders that seat on the bead seats of the wheel rim, and has a circumferential, arch-shaped tunnel formed in the inner side of the tire between the bead shoulders. The tunnel co-operates with the channel in the bottom of the wheel rim to form an annular void, or air space, that allows the tire to collapse locally under excessive impact loads, and at the same time provides a space into which the solid urethane elastomer can be displaced under compression. Under normal riding conditions, most of the light shock loads experienced when riding on a relatively smooth road surface are absorbed by the resiliency of the urethane rubber, with only a minor amount of deflection of the arched tunnel. A severe impact causes the tunnel to collapse to a greater extent, thereby absorbing the shock load and preventing damage to the wheel rim. The tire is cast in a mold, using liquid urethane resin catalyzed to cure in 3 to 5 minutes at room temperatures (i.e., 80.degree. to 100.degree. F).

 

Weight - equal to or less than pneumatic tire and tube.
High resistance to wear and tear. Laboratory tests have shown expected life span two to four times longer than a rubber tire.
A wide range of airless tire ‘pressures’ can be made available to provide the riding quality and firmness normally associated with rubber pneumatic tires.
Variable airless tire pressures can be simulated from 30 psi to 175 psi.
Guaranteed never to go flat!! Maintenance free - no need for inner tubes, air pumps and puncture (repair) kits.
All airless tires are made in a fully molded snap-on style to fit a wide range of rims.
Airless tires install easily in seconds with our tool and don’t roll off - even under the most rigorous conditions.
Airless tires performed as well or better than pneumatic tires in tests performed by an independent testing laboratory.

 

We think flats lead the list of things that keep people from riding. All those bikes that sit in garages, unridden, nine times out of 10 the only thing wrong with them is a flat tire.

 

I can't help but be excited about the potential Nu-Teck tires have to increase street time for a motor-assisted bike, while greatly reducing the money and people-hours required to maintain them. I think that Nu-Teck tires would be a big factor in making a motor-assisted bike program in the U.S. sustainable. Not only is the initial flat tire a big problem with motor-assisted bikes, but problems stemming from ignored flats, ruined tubes, tires, and rims"

Deformation of the tire definitely affects its static coefficient of friction. A tire with less air has more traction and will be more effective when accelerating or changing directions. Tire deformation also affects your rolling coefficient of friction. Once up to speed, a tire with less air takes more effort to keep it rolling at the same speed.

On a car, underinflated tires give you better accelertion and cornering, but also decrease your gas mileage.

On a bicycle, the same principle would apply. For a road bike that will primarily travel the same speed in a straight direction for long distances, a rigid tire that resists deformation will make it easier to maintain your speed (even if it will be more uncomfortable as well). It will also require you to go slower around the corners, which also means you'll have to accelerate back up to cruising speed from a slower speed.

It's a trade-off and I don't know which would have the best overall efficiency. I would think that a bicyclist spends a lot more time going straight at a constant speed than cornering or going up hills.

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Don't dynamite your tires. In the last decade it has become an article of faith that the more pressure one puts in a tire, the better (that is, faster) the bike will ride. One brand of tires actually requires 140 psi. This kind of tire pressure makes the bike ride like a tank. [ With super high tire pressures the bike bounces, transmits road shock, fatigues the rider, causes the premature failure of bike frames and components and makes the tires more prone to flats ]. Running the tires at 105 - 115 psi will yield a bike that corners better and gives a far nicer ride. Try it. It will still go fast.

Tread hardness. How long the tread on a bicycle tire lasts is no accident. The tire designer has a certain total tire in his mind when he decides upon the casing, tire size and tread hardness. Does he want the tire to be primarily one that is durable? If so he will use a lot of the curing agent (see the definition of "Vulcanization" above). For instance, in general a hard rubber may have as much as 50% of the curing agent while a soft rubber may have as little as 5%. The durable, long-lasting tread comes at a price. The hard rubber does not grip the pavement as well as a softer rubber. This becomes especially apparant in the rain when long-lasting, durable tires break loose from the pavement with the slightest provocation. A softer tread will give better handling and performance at the cost of a shorter life. Torelli tires tend towards better gripping, softer tread compounds to give the bike superior handling. Riding a bike should be fun.

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Colored treads are vulcanized with silicon and are generally softer than black treads vulcanized with carbon. Manufacturers of dual-compound tires use soft silicon compounds for their side treads. However, carbon vulcanized rubber can and is made to be very "grippy" by controlling the amount used in the vulcanization.

Tire Width. There is a view that a 20 mm width tire is faster than a 23 by virtue of its smaller cross section and lighter weight. Interestingly enough, this is not true. The people making the Torelli tires had noticed that the pro teams that they sponsored asked for 23s because they felt they were faster. When they investigated and did the testing, they found that the riders were correct. Let me explain. Let's assume a 200 pound rider and bike unit. Let's also assume that the weight is distributed half over each wheel. That means that each wheel is supporting 100 pounds. Now, with a pressure of 100 pounds per square inch, the contact patch is one square inch. This is true no matter how fat the tire.

What changes when the tire gets fatter is the shape of the contact patch. With a 20, the contact patch is a long oval. With the fatter tire, the contact patch gets shorter and wider.

When a rider is using a skinnier tire, the long contact patch means he is flexing a wider arc of the tire casing, flexing more of the tire, causing more wasted energy from the internal friction of the tire and tube. The rider with the fatter tire is flexing fewer cords at a time.

 

With the development of polyurethane elastomer solid rubber tires for bicycles. [ this new age twists, makes the above old school statement invalid. Why? --- well!! ].

 

1...The fact that variable airless tire pressures can be simulated from 30 psi to 175 psi. Assures that you get the road resistance you need for your riding style.

2...While it can't be Guaranteed that an airless tire won't brake, it can be guaranteed never to go flat!! This is a big help, because a flat tire is the motor-assisted bike riders worst nightmare.

Not only is the initial flat tire a big problem with motor-assisted bikes, But the problems stemming from a flat, ruined tubes, tires, and rims. Is amplified by the question of where to put the bike while you take the tire to be fixed.

 

3...Maintenance free - no need for inner tubes, air pumps and puncture (repair) kits.

 
All airless tires are made in a fully molded snap-on style to fit a wide range of rims.

 
Airless tires install easily in seconds with [ a tool you rent ]. and if won’t roll off - even under the most rigorous conditions.

Airless tires performed as well or better than pneumatic tires in tests performed by an independent testing laboratory.