ขอบคุณครับพี่ Griz, พี่ Wat3355 ที่กรุณาชมรถอลูฯ โหลๆ ของผม
ล้อคู่นี้มีจุดเด่นที่น้ำหนักเบา, จำนวนซี่ลวดน้อย(หน้า 12, หลัง 16 ส่วน Zipp 808, 1080 ซี่หน้า 16 หลัง 20), ราคาไม่แพง ดุมเป็นลูกปืน ceramic และเป็น internal nipple ทำให้ stiff ใช้ได้เลย
Narrow is faster
Easton’s proprietary narrow-flange R4TT front hub reduces frontal spoke area by 50% for improved aerodynamics. Combined with a new wind tunnel-tuned 90mm rim, and
the new EC90TT displays lower drag than the Zipp 808 at 0, 5, 10, 15 and 20 degree yaw angles. It even rivals the much deeper (and heavier) Zipp 1080 at 5 and 15 degrees.
Faster and lighter
At 1424 a set, the EC90 TT is a full 30 grams lighter than the Zipp 808, and still 9mm deeper in rim profile, thanks to Easton’s Variable Nipple Bed (VNB™) Technology. This process of internally tapering the rim bed eliminates excess carbon between spoke holes and allows for a sharper inner edge. Less weight, improved aerodynamics with no loss in strength.
Aerodynamics 101: leading edge vs. Trailing edge
There are two ways to make a wheel fast in the wind. One is to design the leading (forward) edge to help smooth the path of the air around the tire. Zipp’s bulged rim profile attempts to do this. The other way to design a fast wheel is to focus on sharpening the rim profile on the trailing edge to manage the air as it exits the rear edge of the wheel. You can’t have it both ways. At Easton we feel you can design a faster wheel with a sharper, narrower profile like the EC90. And our wind tunnel data confirms this.
Dimples are for golf
Dimples work on blunt objects like golf balls, but they’re irrelevant on bicycle wheels. On a golf ball, they reduce drag because they create turbulent flow. They diminish what's called pressure drag, caused by a relative "void" behind the ball.
However on sharper, wing-shaped objects like deep section wheels (or F1 cars) dimples don’t work because the air is already flowing over a narrow, optimized shape that by design reduces pressure drag.
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