Narrator: MOUNTAIN BIKE TIRES
ARE TRUE TRAILBLAZERS,
SPECIFICALLY DESIGNED
FOR OFF-ROAD RIDING.
WIDER THAN
REGULAR ROAD TIRES,
MOUNTAIN BIKE TIRES
HAVE RAISED KNOBS OR LUGS
THAT ADD STABILITY
ON UNEVEN TERRAIN.
BUILT TO WITHSTAND THE TRAIL,
THESE TIRES CAN HANDLE IT ALL.
WHEN THE RUBBER HITS THE DIRT,
IT'S ALL ABOUT CONTROL.
MOUNTAIN BIKE TIRES ARE DESIGNED
TO GRIP THE GROUND
AND PROVIDE TRACTION
OFF-ROAD.
FIRST, DESIGNERS USE
A COMPUTER MODEL OF A TIRE
TO SIMULATE THE EFFECTS
OF DIFFERENT RUBBER COMPOUNDS.
CONSTRUCTION BEGINS
WITH RUBBER COMPOUNDS
BEING MIXED TOGETHER
TO CREATE PARTS OF THE TIRE.
INGREDIENTS INCLUDE SYNTHETIC
AND NATURAL RUBBERS,
SULFUR,
AND OTHER CHEMICALS.
ROTATING SPIRAL BLADES
BREAK DOWN THE MATERIALS.
FRICTION FROM THE MIXING
HEATS AND SOFTENS THEM.
THIS TRANSFORMS
THE INGREDIENTS
INTO A DOUGH-LIKE
RUBBER COMPOUND.
POWERFUL ROLLERS SQUEEZE THE
COMPOUND INTO THICK LONG SHEETS,
AND BLADES CUT THE ROLLED RUBBER
INTO NARROW STRIPS.
THEN, THE RUBBER TRAVELS
THROUGH MORE ROLLERS
THAT SQUEEZE IT DOWN
TO THE DESIRED THICKNESS.
THE RUBBER SHEETS LAND ON
A CART, READY FOR USE.
♪♪
TECHNICIANS INCASE
STEEL BEAD WIRE
WITH ONE OF
THESE COMPOUNDS.
THE BEAD WIRE IS
THE PART OF THE TIRE
THAT CONNECTS TO
THE WHEEL'S RIM.
AS STEEL WIRE TRAVELS
THROUGH AN APERTURE,
THE RUBBER IS EXTRUDED
TO FORM THE CASING.
THE MACHINE DELIVERS
THE BEAD WIRE
TO A SPINNING DISK.
THE DISK WINDS
THE BEAD WIRE,
SHAPING IT INTO RINGS,
WHICH FIT TO A WHEEL RIM.
♪♪
TO MAINTAIN THE DIAMETER
OF THE WIRE,
THE TECHNICIAN TAPES
THE ENDS TOGETHER,
HOLDING THE SHAPE UNTIL
THE NEXT STAGE OF PRODUCTION.
NEXT, RUBBER SHEETS WITH
VARYING CHARACTERISTICS
ENTER AN EXTRUDER.
USING HEAT AND PRESSURE,
THE EXTRUDER FORCES THE RUBBER
THROUGH DIES.
THIS PROCESS MERGES
THEIR CHARACTERISTICS
INTO A SINGLE SHEET.
THE SHEET WILL BE USED
TO MAKE THE BICYCLE'S TREAD.
THE TREAD RUBBER TRAVELS
THROUGH A CHANNEL OF COOL WATER.
MEANWHILE, ROLLERS COAT FABRIC
WITH RUBBER
TO MAKE PLIES
FOR THE TIRE CASING.
A MOVING BLADE
CUTS IT INTO STRIPS.
THIS RUBBER
IS NATURALLY TACKY,
SO THE PIECES
CAN BE EASILY SPLICED.
THE SYSTEM FEEDS THE STRIPS
TO TIRE-BUILDING MACHINE.
A SKILLED ASSEMBLER WRAPS
THE STRIPS TO THE MACHINE DRUM
TO FORM THE TIRE CASING,
AND SPLICES THE RUBBER
WHERE THE ENDS MEET.
NEXT, ROBOTS SLIDE TWO
WIRE BEADS AROUND THE CASING.
THE ENDS OF THE DRUM
FOLD THE SIDES OF THE CASING
OVER THE BEAD WIRES.
THE TECHNICIAN APPLIES
RUBBER-COATED FABRIC
TO THE BEAD WIRES,
STRENGTHENING THE AREA.
THE TREAD RUBBER
IS PLACED IN THE CENTER.
A ROLLER APPLIES PRESSURE
AS THE DRUM SPINS
TO WIND THE TREAD
AROUND THE CASING.
THEN, THE ENDS ARE
PRESSED TOGETHER MANUALLY.
AND ONE MORE TURN OF THE DRUM
SECURES THE TREAD RUBBER
TO THE CASING.
ONCE VENT HOLES HAVE BEEN
CUT IN THE RUBBER,
IT'S OVER TO AN EXPANDING MOLD,
WHERE THE TIRE TAKES SHAPE.
THE TECHNICIAN INSERTS
A RUBBER CURING BLADDER
TO MAINTAIN
THE SHAPE OF THE TIRE.
THEN, HE PLACES THE MOUNTAIN
BIKE TIRES IN CURING MOLDS.
THESE INDIVIDUAL MOLDS
WILL STEAM-COOK THE TIRES
UNDER PRESSURE
TO FURTHER SHAPE THEM.
THIS PROCESS FORMS KNOBS
AND OTHER PROTRUSIONS
ON THE TIRE SURFACE
THAT ARE DESIGNED TO GRIP
A RUGGED TERRAIN.
LIKE A BIG WAFFLE IRON,
THIS MOLD HAS COOKED,
AND FORMED
THE MOUNTAIN BIKE TIRE.
THE TIRE IS THEN PLACED
ON A RACK TO COOL.
NEXT, THE BIKE TIRE
UNDERGOES A DURABILITY TEST
WHILE A COMPUTER MEASURES
ROLLING RESISTANCE.
THAT'S THE ENERGY LOST
WHEN THE TIRE ROTATES,
AND AN INDICATION OF
HOW EASILY THE TIRE WILL ROLL.
THIS MOUNTAIN BIKE TIRE
IS NOW CLEARED
TO TRAVEL OFF THE BEATEN PATH.
♪♪
