The mid-size, 27.5in wheel is finally building steam as 2012 is quickly becoming the year of the 650b mountain bike. Not surprisingly, Enve is at the forefront of this movement with its Twenty7.5 AM Carbon Wheelset, as it shares the same rim, spoke, and hubs as its 26 and 29in stable mates.
Once, aluminum matrices and titanium ruled high-end mountain bike frames. However, the advancements of carbon fiber composites, manufacturing techniques, and polymers have boosted the wonder-weave's strength and durability to levels exceeding alloys. And in the case of Enve's carbon AM rims, proprietary molding techniques create full-carbon rims with strength and stiffness that bests alloy rims every step of the way.
One ride will quickly convince you that carbon fiber's heightened wheel tension and stiff platform provide the best steering precision. The AM Wheelset isn't the lightest of Enve's mountain wheelsets, but they're plenty strong for aggressive trail riding -- while rivaling the weight of some alloy XC wheelsets. That's because Enve uses a special bladder system to increase the heat and pressure while molding the rims. This packs the layers tighter, as well as improving both the internal and external rim surfaces. And a place where Enve stands nearly alone in weight reduction, is that the bladders are actually removed once the mold is set, thus shedding, literally, useless weight at the rim. The AM Rims are made with another proprietary Enve design, uninterrupted carbon filaments. How? Well, Enve's molding process is so precise that it requires no post-cure drilling, bonding, or machining processes.
In fact, the spoke and valve stem holes are created in-place during the molding process. This results in a final structure with long, intact, and continuous carbon filaments that distribute stress loads over their entire length. Basically, the principle at work here is that the longer the fiber, the greater the distribution of the stress. This is advantageous, as the wheels are accordingly able to exceed spoke tension capabilities of other carbon fiber wheels. In effect, higher spoke tension is better for the spokes, and when the rim can handle the loads, like the AM, the wheel is noticeably stiffer.
The Enve AM 27.5 (650b) is built with 32 hole DT Swiss 240 hubs. For a durable and low rolling resistance, the rear spins on four separate stainless steel sealed cartridge bearings. The ratcheting freehub offers tool-free access for routine cleaning and lubrication, and the freehub body is made of aluminum in order to keep the package lightweight.
The Enve Twenty7.5 AM Carbon 27.5in Wheelset comes with two UST-valve stems and a roll of tape to seal both rims. The rims measure 31mm deep, 24mm wide internally, and 30mm externally. These wheels are also compatible with UST tires. A 15mm thru-axle front hub and 12x142mm thru-axle rear hub come standard, however the hubs can be converted with the appropriate DT Swiss adapters.
Please note: The rims are covered under a five year manufacturer warranty. The hubs and spokes are not covered under the ENVE warranty. Also, we are only able to ship this product to addresses within the United States.