Zipp Technical Page by Prowheelbuilder.com

ZIPP TECH TALK

SPOKE LEANGTHS | CARBON BRIDGE | AERODYNAMICS |COMPOSITE TECHNOLOGIES | ALUMINUM V.S. CARBON BRAKING

SPOKE LEANGTHS:

Year

Model

Note

Drive

Non Drive

Front

2008

New202 T

Internal Nipples

292

280

280

2007/2005

202 T

J Bend

280

286

290

2008/2005

303 T&C

Straight Pull

272

262

262

2008/2005

404 T

Straight Pull

260

250

250

2008/2005

404 C

Straight Pull

258

248

248

2008/2005

808 T&C

Straight Pull

236

226

226

2008/2005

1080 T

Straight Pull

222

206

206

2004/2000

303 T

Straight Pull

274

266

268

2004/2000

303 C

Straight Pull

278

266

268

2004/2000

404 T

Straight Pull

260

248

250

2004/2000

404 C

Straight Pull

258

246

248

ALUMINUM V.S. CARBON BRAKING:

By combining a lightweight, sub-200 gram welded aluminum hoop and the aerodynamic bulge of our structural carbon rim we’ve created something truly extraordinary – a nearly bomb-proof lightweight aero clincher wheel with no weight restriction, no worries about blown tires from overheating and no need for cork brake pads.
In fact, the M2CM process creates rims so strong our 303 clincher holds the all time record for impact drum testing in the U.S. and in Europe. While not the recommended use or covered by Zipp's warranty, the 404 clincher rim has developed a cult following in the 29er mountain bike world, with some riders putting up to 10,000 off-road miles on a single set of rims.
Where does this strength come from? M2CM permanently fuses the welded hoop into the carbon during the molding process of the rim. Once bonded the aerodynamic bulge of the carbon serves as a leaf spring to reinforce the aluminum rim during impacts. This suspension effect also keeps the tires in contact with the ground for better power transmission.
And, not only is M2CM strong, it’s also the first clincher rim with no aerodynamic compromise because we’ve engineered the shape to compensate for the “speed bump” between the brake track and the tire. M2CM: Added strength, more speed, better comfort. Just another in a long list of Zipp exclusives.
The Structural Rim Advantage:
There are 3 key advantages to a structural carbon rim over “faired” models which bond a fairing over a standard box rim:
1. Strength – with both Carbon Bridge and M2CM loads can be distributed over the whole rim for greater impact resistance. A fairing simply glues on to the outer rim and does not support any load.
2. Aerodynamics – the spokes of a faired rim terminate in the outer rim, which means the spokes actually go through holes at the side of the fairing instead of at the inner diameter of the rim. This disrupts the aerodynamics of the fairing so that, when the wheel spins the rim actually looks shallower to the wind. A 65mm faired rim performs about the same aerodynamically as a 44mm Zipp structural rim.
3. Comfort – The integrated construction of our structural rims allow us to use the aerodynamic bulge in our rim as a leaf spring to absorb and distribute shock – much like the suspension on a car. A non-structural fairing affords no damping effect.

CARBON BRIDGE:

Adding Kevlar®, stitched into a 6 bundle co-axial thread and placing this at the rim edge, allows Zipp to 'capstone" the top of each outside diameter bridge, providing an improved way to distribute impact forces. This gives from 28 to as much as 50 % improvements in impact depending on the rim type and allows us to increases the lateral stiffness with minimal weight penalty.

Kevlar® with 1/3 the stiffness of carbon, 7 times as strong as steel by weight, but is 3 and a half times more resistant to impact shear forces (there is a reason Kevlar® is used for body armor), helps distribute the compaction forces generated during an impact further down the rim sidewalls. This novel lamination process, which more evenly distributes heavy point loads across the entire rim structure has been achieved with none to very minimal weight gain.

Just as the key-stone caps the long standing Roman arch, distributing loads and allowing taller structures, so our Carbon + Kevlar® bridge serves to protect and strengthen the structural carbon laminates that make up the Zipp rims. Placing the right materials in areas where they are most needed while selecting materials that are the very best fit for the function, places Zipp ahead of the pack in advanced rim design.