ENVE Twenty7.5 (650B) AM Review

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At Sea Otter this year, ENVE introduced a 650B rim, which they are calling the Twenty7.5 (650B), and they’ll come in an AM and XC version. The Twenty7.5 rims are 31mm wide (24mm internal) and weigh in at 410 grams for the AM, and 24mm wide (18mm Internal) and 360 grams for the XC, and will retail for an $875 each. They will also be available as built wheelsets, using the DT 240, DT 180 and Chris King ISO hubs. Like all their rims, the clinchers use 100% uni-direction carbon fiber construction, and use their molded spoke hole technology, and are hand built in their Utah plant.

I like the 650B size the longer I use it, and it's an interesting product, with attributes and characteristics of 26" and 29" wheels, and sometimes right in the middle of the pack. The actual bead seat diameters for the 26, 650B and 29 wheels, are 559, 584 and 622mm, respectively, so it's closer to the 26" size. I picked a few outstanding conditions and terrain that are encountered while riding and how I thought the 650B wheel size matched up against its brethren:

• Slow climbs - 29 like
• Fire roads - 29 like
• Fast singletrack - 29 like
• Downhill - middle
• Rough climbing - 29 like
• Up switchbacks - middle
• Down switchbacks - 29 like
• Technical - 26 like
• Maneuvering - middle

ENVE Twenty7.5 AM
This is going to be a different review, since although I am testing a wheelset; I am primarily focusing on the ENVE rims themselves. The wheelset I tested are comprised of the ENVE Twenty7.5 AM carbon rims (32 hole), laced to Chris King ISO hubs (15mm front and 12x142mm rear) using DT Swiss Aerolite spokes, and they retail for $2550. The basic dimensions of the rims are an outer width of 31mm and an inner of 25mm, and a height of 30mm, and they are available in 28 and 32 hole configurations. The prebuilt wheels weighed in at 1701 grams, and I'll have to use their specs of 410 grams for rim weight, since I was unable to measure them myself. For an All Mountain rim, weighing in at 410 grams is pretty amazing, and the big chunk of weight for the wheels was the moderately heavy Chris King hubs. For a lighter build, using DT Swiss 240 or 180 hubs can drop 110g and 180g respectively from their heft. You can purchase the rims separately for $875 for your own custom build. The rims have a 5-year defect warranty for materials and workmanship, and a Lifetime Crash Replacement policy, in which the replacement would be 50% off MSRP.

ENVE Technology
The ENVE rims are handmade at their facility in Utah, and the rims have gone through extensive and rigorous torture, including lateral stiffness and spoke testing, and meet the strenuous UCI test protocol. They have a molding process for the spoke and valve holes, so that the carbon fibers are continuous and unbroken around the holes, which creates maximum strength and allows increased spoke hole tensions. In addition, they mold in a conical nipple seat, which reduces spoke breakage and allows nipple articulation. In another innovative design, they use removable bladders, leaving no excess internal material, so they have a lighter end product and one that make for easier wheel builds. The unidirectional carbon rims are unpainted, without any coating or finish, and are raw and naked, other than a few decals.

Testing Rig and Terrain
Testing was performed on my medium Ibis Mojo HD with the Cane Creek Double Barrel Air rear shock, Magura TS8 27.5 fork, and Schwalbe Nobby Nic tires. I am 5'9", weigh in at 155 lbs and have been riding since the inception of the RockShox RS-1, and started out on a Bridgestone MB-2 for my first MTB steed. I have mostly ridden in the West, including vast portions of the Colorado Front Range, Sedona, Moab, Fruita/GJ and many parts of the Colorado mountains. The testing terrain is predominantly loose rocky conditions, with many long steep climbs and descents, rock gardens, slick rock, an occasional smooth singletrack and lots of ugly loose gravel.

Impressions
I got to test the ENVE wheelset for four weeks, so it was a pretty quick review period, but it didn't take long to love the attributes of their carbon rims. The rims have excellent damping characteristics, without feeling deadened or overly stiff. The rims are quite light at 410 grams for an All Mountain beast and they accelerated and rolled quickly, and their low rotational weight is very noticeable, especially when spinning, steering and cornering. When the wheels were rolled up to speed they felt like they had a little motor in them, and they spun like a buzz saw, greatly helped by the smooth Chris King hubs. They really came to life when I was sending the wheels through curvy terrain with lots of berms and rollers, and you could plow them in and out like crazy, making for a hooting and hollering session as you pounced on the terrain. Tossing them into a pump track was pure ecstasy, and brought an instant grin to the face. When pressed into corners and steered hard through difficult terrain, you could feel the exceptional lateral and torsional stiffness, which corresponds to excellent control and precision. The less tangible thing about these rims is that they feel nice and comfy, and offer a superlative ride quality. They have stiffness in all the required directions, yet they provide a touch of resiliency, damping and softness.

I ran them with a set of the sweet new Schwalbe Nobby Nic 650B tires, which are 2.34" wide, and together they came in at a whopping 27 13/16" tall. The wheels came with their tubeless tape installed, which looked a bit like fancy duct tape, so I just installed the extra tall valve stems, which are required due to the extremely tall 30mm rim height. I ran them with tubes for a week, but the Nobby Nic really came to life in a tubeless mode, so I left them that way for the rest of the test period. Their tubeless tape has a rough surface, so taking tires on and off, and using tubes seems to abrade them and wear things away, so I had to add a layer of tape to seal an errant air leak when trying to go tubeless on one rim? One annoying thing is that the rim bead hook likes to hold onto the tire's bead, and it can be an ugly wrestling match to get them to separate. I cursed more than a few times trying to get them to part ways, and it didn't seem to matter how long the tire had been on the rim, and it was like they were sucked up into the void and glued on?

The rims were stiff and strong, and offered incredible steering response and control, and concerning capabilities. In the rear, they added an extra bit of punch to the traction and control since you could really apply torque to the wheel with immediate power and got instant feedback, which was greatly helped by the high POE of the Chris King hubs. Due to the stiffness of the rim and the inherent ability to apply so much torque, I could feel the spokes and drivetrain ping a bit under power, which was exacerbated by my personal usage of low gearing. Although not all riders might have this issue, I might go up spoke gauge size in the rear for additional strength and less noise. The rims are brutally tough and bashing and smashing them through my typical heinous gravel fields, rocks gardens, slabs, ledges and other sundry rim destroyers did nothing to the sidewalls and rim edge, other than a peeled decal or two. I was pretty amazed at the strength and durability of the rims, and I would have assumed they would show some sign of wear and tear, especially with the unforgiving terrain that I tossed them into, but they were none the worse?

The rims are brutally expensive at $875 each, but their toughness, durability, stiffness and strength mean they will outlast most wheelsets, and that longevity should greatly increase the cost-benefit ratio? You can build a lighter wheelset with different hubs other than the Chris Kings, but their hubs are well-made and durable, and they needed no maintenance, other than an occasional tightening of the preload adjuster. The ISO hubs are easy to take apart, even in the rear, and their replacement axles and adapters are simple to install for any wheel configuration. They do make a pretty wild buzz and zinging noise, especially when they are wound up to speed.
Measured Specs:

• Rear Weight w/ Chris King ISO 12x142 & tubeless tape - 907.2 grams
• Front Weight w/ Chris King ISO 15mm & tubeless tape - 793.4 grams
• Wheelset Weight - 1700.6 grams
• Rim Dimensions - Inner 24.5mm, Outer 31.2mm, Height 30.2mm

Bottom Line
The ENVE Twenty7.5 (650B) AM rims are light, and have exceptional lateral and torsional stiffness, yet they offer superlative ride quality, with excellent damping and comfort qualities. Their low rotational weight makes them highly functional (and fun) while cornering and spinning, and their stiffness offers control, precision and power transition. The well-built and innovative design is extremely tough and durable, and should offer excellent long term usage, which is a good thing, since they're brutally expensive at $875 each.

Strengths

• Lightweight
• Exceptional lateral and torsional stiffness
• Superlative ride quality
• Extremely tough and durable

Weaknesses

• Brutally expensive
• Tough to separate installed tire from rim bead hook
• Tubeless kit is optional

Overall Rating: 5 Flamin’ Chili Peppers


Twenty7.5 (650b) AM Specs:

• MSRP : $875
• Visit the ENVE Twenty7.5 AM website
• Depth – 31mm
• Width – 30mm (24mm Internal)
• Rim weight – 410 grams
• Wheel weight – DT 240 1378 grams, DT 180 1406 grams. King ISO 1588 grams
• Hole count – 28 or 32
• ERD – 556
• Finish - UNI

Twenty7.5 (650b) XC Specs:

• MSRP : $875
• Visit the ENVE Twenty7.5 XC website
• Depth – 31mm
• Width – 24mm (18mm Internal)
• Rim weight – 360 grams
• Wheel weight – DT 240 1478 grams, DT 180 1306 grams, King ISO 1488 grams
• Hole count – 28 or 32
• ERD – 556
• Finish - UNI

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