Tires & Tubes

The Tour de France tireTorelli tubes
Torelli Tour de France Tires Torelli Extra-Lite Tubes


Torelli Pneu Grande Vitesse
Dual Compound Tires

There are a couple of essays at the end of this page you might find interesting: how Torelli tubes are made, and some information about rolling resistance and speed.

 

Torelli Extra-Lite Inner tubes


Mountain Bike Action magazine 4-Star rated product.

Torelli Extra-Lite ATB tubes were also cited by Mountain Bike Action (June, 1994) as one of the ten hot things you should buy!

Torelli Extra-lite tubes are the most cost-effective way to improve the performance of a bicycle.

Torelli tubes enhance performance two ways. First, the rotating weight is substantially reduced. Given that the energy needed to accelerate the rotating mass of the wheels is greater than the energy needed to accelerate any other part of the bike, this weight saving is important.

The other energy savings is gained by flexing less inner tube mass. The tire and tube are deformed as they roll over the ground. This deformation takes energy. By reducing the thickness of the tube, the energy needed to roll the wheel over the ground is reduced. More of the rider's energy is used to propel the bike forward at a higher speed.

Torelli tubes are butyl rubber. Extensive investigation and tests convinced us that the reliability and repairability coupled with the low cost made butyl the only choice. We went to France for our tubes because the density of the butyl available there allowed us to make the tube only .4mm thick and have it still retain air.

Many riders live in areas where thorns and stickers are a problem. For them, using an ultralight tube is usually impractical. At the request of many riders in Arizona, the Torelli ATB tube is available with a schraeder valve, allowing the insertion of a small amount of tube sealant. The riders tell us that they still end up with a net lighter tube, and they also have a reasonable amount of flat protection.

To make our tubes perfect, we apply a thin coat of talc so that the tube will seat properly in the tire.

Torelli Extra-lite road tube, 75 grams, presta valve. 700C x 18-20-23-25, or 650C x 18-20-23. Suggested retail, $5.99
Torelli Extra-lite ATB tube, presta (135 grams) or schraeder (145 grams) valve. 26" x 1.85-2.125. Suggested retail, $5.99
Torelli Extra-lite BMX tube, 100 grams, schraeder valve. 20" x 1.75-2.125. Suggested retail, $5.99

Torelli Extra-lite tubes also come with a 51-mm long valve for use with deep-dish aero rims, like Torelli Wideguy, or Campy Shamal. 700C x 18-23 (90 grams), 650C x 18-23 (85 grams) or 26" x 1.8-2.125 (145 grams). Suggested retail, $9.95.

Torelli High Performance Tires

New. Torelli PGV Dual Compound tire. The PGV Dual Compound (DC) is identical to the PGV with our black tread compound except that the sides of the tread have a sticky silica impregnated red rubber compound. You get the same fine riding characteristincs that pleased the writers of Bicyclist magazine with the added bonus of the extra sticky sides. We think you will find them pleasing in another way. Most dual-compound tires have very thin treads that lead to two problems. The first is a very strong suspectability to flats. Some tires have a kevlar fabric in the casing to prevent this. This robs the rider of his valuable energy. The other problem is delamination. We've all seen dual-compound tires that suffer tread seperation. Our super-thick tread makes this a remote possibility. Even with our soft, sticky tread material, you'll find that you get 1,000's of miles out of a PGV or TDF, giving you great value for your hard-earned dollar.

At this time, we have not yet figured out how to give these qualities of reliability and performance to a 700 x 20 PGV Dual Compound, so it is available only in 700 x 23.

Bicyclist magazine (July 1998) rated the Torelli PGV as race-ready rubber superior to Michelin Axial Pro and the Specialized Turbo for a fraction of their cost We have always thought well of the Vittoria Open CX clincher tires, so when the tire shootout rated our PGV as nearly equivalent and to the CX and ahead of these other fine tires, we were thrilled. When one spends long hours working on a project, independant confirmation of our own feeling that we had made a world-class racing tire was very satisfying.

The tires of a bicycle are as crucial as any other part of the bike in determining its feel, handling, and comfort. The sidewall should be supple, the tread should stick to the ground. The tire's casing should be round. The tire bead should be precisely made so that the tire seats correctly on the rim without either blowing off under pressure or requiring extreme force to put the tire on the rim or remove it for repair.

Torelli Tour de France (TDF) and Pneu Grande Vitesse (PGV) tires meet all of these requirements.

If you can visit a store that carries Torelli tires, remove one from the box. You will notice how flexible and supple the casing is. This gives the bike a smooth, comfortable ride. A stiff casing contributes to a harsh feel that needlessly detracts from the rider's enjoyment, and contributes to fatigue.

The tread of the TDF and PGV is a blend of natural and synthetic rubber to get the amount of "stickiness" of the tread just right. If the tread is too hard, the tire slides in corners. If the tread is too soft, it cuts easily and attracts thorns that can stick to the tire. The right balance has been perfectly achieved in Torelli tires. The tread pattern is the well-proven herringbone, used by professional riders for generations.

The casing of our tires is round. This contributes to both the good feel of the bike and conserves the rider's energy by making a smoother rolling tire.

What's the difference between the TDF and the PGV? The casing. The PGV has 125 threads per inch in the casing. this stronger, more supple casing made of thinner, finer threads makes amore efficient tires that gives the wheel that "Pro" feel.

Putting a Torelli tire on a rim, compared to many other tires, is a joy. Most people will not need tools to either mount or dismount the tire. The bead is so precisely made that the need to undersize the bead's circumference is minimized. Different rim manufacturers build their rims to slightly different tolerances, so each rider's experience will differ.

Chairman Bill's note. Even though I sell clincher tires, I am the first to acknowledge the superior feel and ride of sew-ups. But their high cost and time consuming care is often a bother. I switched to clinchers, with no small amount of regret, a few years ago. When I got the first prototypes of our PGV tires, I was tickled. For the first time, that sexy resilience and road feel I love in a sew-up was there in a clincher. At this time, I believe that the difference between clinchers and sew-ups has become so narrow (it's still there) that I no longer miss getting sew-up glue on my clothes.

Before going on my 1998 Spring trip to Italy, I had a few PGV's sent to Mondonico to put on the bike Antonio and Mauro were building for me. When I got there, Mauro told me that he had taken a couple of the tires for himself to see what my fuss was about. He said he had been riding them for a few days. I asked what he thought of them, knowing that Mauro and Antonio know that I desire complete and brutal honesty from them in evaualting any of my ideas or projects. Mauro smiled and pronounced them excellent. That made my day.

Torelli Tour de France (TDF) folding tire. 700 x 20, 210 grams; 700 x 23, 240 grams. Suggested retail $29.95
Torelli Tour de France wire beaded tire (non-folding). Almost all of the perforamce of the folding tire for a bit less dough. 700 x 20, 230 grams; 700 x 23, 265 grams. Suggested retail $20.95.
Torelli Pneu Grande Vitesse (PGV) folding tire. 700 x 20, 195 grams; 700 x 23, 230 grams. Suggested retail $35.95
Torelli PGV Dual Compound folding tire. 700 x 23 only, 230 grams. Suggested retail $43.95

How Torelli Extra-Lite tubes are made

The factory receives the various raw materials, butyl rubber, natural rubber, the different chemicals added for vulcanization, as well as the valve stems, from other suppliers.

Each item the factory produces: tubes, tire treads, casing, etc., has its own recipe. The first step is to make the right mix of raw materials for the tubes. The workman puts big blocks of rubber on a giant scale until the quantities are just right. He has several large knives kept in a heater to slice off pieces of rubber to add to or subtract from the mix.

The batch is mixed by being forced between huge smooth rollers, round and round until the desired consistency is achieved. Then it is extruded in a wide, flat belt onto a pallet that is numbered and stored for 24 hours. During that time, a sample is sent to an on-site laboratory to make sure that the recipe has been precisely followed. If there has been an error, the batch is useless and must be thrown away.

The next day the rubber is transported to an extruding machine. The rubber, which is still malleable like a stiff clay, is fed into an extruder that squirts out a long continuous tube the diameter of the final inner tube. As it is being extruded, talc is sprayed in the interior of the tube so that the inside walls of the tube do not stick together. Passing out of the extruder, it enters a water bath, cooling it so that it isn't too soft to work with. A rolling stamp puts on the 'Torelli' and the tube size that you see in silver ink on the tube itself. Then, a drill precisely cuts a 5mm hole in the tube every yard or so. A little vacuum holds the top of the flattened tube away from the bottom so the drill does not go all the way through the other side of the tube.

A feeder from a large bin brings the valve stem to the hole in the tube where it is heat-bonded. The valve stem comes with the rubber reinforcing base already attached. The 53 mm long valve stems used on tubes for aero wheels must be placed by hand, as the automatic feeder will not accept the long valves. A cutter cuts the tube to the correct length and the outside of the tube is given a coating of talc. The ends are placed together by hand and heat sealed together to make an inner tube.

The tubes are stacked on racks of 1,000 for 'cooking' or more correctly, vulcanization. The tube so far, is made of a malleable, soft rubber that has no strength. Upon being 'cooked' the tube becomes a strong, reliable racing part. After cooling, the tubes are boxed and shipped to Torelli in California, ready to hot-rod a bike. Return to top of page.

Tires and rolling resistance

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 thery 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.

There is clearly an optimum size, and the fact that racing tubulars are around 22 should keep us from getting super wide tires looking for yet more speed. Other losses probably kick in as the tire gets still fatter. For me, the bike feels llike it doesn't have any snap or jump when we stray from the optimum which I believe to be in that 22-23 mm range.

Some have suggested that the skinnier tires make up for their losses because of their lower aerodynamic drag. This could be true for the solo time-trialist, I'm not sure. For the pack rider, it clearly is not an important consideration. Return to top of page.


 

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