ENVE M60 Forty HV 29” Wheels
- Chris King ISO Disc Hubs
- Sapim CX-Ray Spokes (32, 2 cross)
Internal Rim Width (measured): 26 mm
External Rim Width (measured): 31.5 mm
Blister’s Measured Weight:
- Front: 776 g
- Rear: 959 g
- Total: 1735 g
Reviewer: 5’9” 155 lbs
Test Duration (Updated): 10 months of ride time / ~1000 miles
Test Locations: Whitefish, MT; Nelson, BC[Editor’s Note: We’ve put a whole lot more time on these rims since we initially wrote about them, so this is now our updated, long-term review.]
As I sit down to write this review, I realize that I’ve made a terrible mistake. And an expensive one. Because I now want these wheels on every bike I own.
ENVE was one of the first companies to enter the carbon rim market on the mountain bike side of things, everything they make is made in the U.S., and they continue to be one of the most influential players when it comes to high-end wheelsets. If you’re interested in a bit more of the backstory, check out our industry profile of ENVE from a few years back.
The most recent news from ENVE is the introduction of the “HV” (High Volume) option for a number of their rims. In other words, ENVEs are getting wider.
The M60 line is situated in the middle of ENVE’s lineup, and is designed around mid-travel trail bikes. Technically, the wheel’s name is the M60 Forty HV, which means that it’s intended for sixty percent downhill, forty percent uphill, and they’re the High Volume (wide) version.
Now, before I go any further, a quick note: these things are expensive, so I’m going to be hyper-critical—issues that might get a pass on a $500 wheelset don’t get a pass when the price tag is premium.
If you haven’t taken a look at our overview of ENVE’s HV rims, check that out. The long and short of it is, ENVE has spent a good amount of time researching widths and finding the optimal combination of tire support + low weight. The M60 HV’s have an internal width of 26 mm, which is designed with 2.3” – 2.4” tires in mind.
We’re also putting time on the next size up, the ENVE M70 HV’s, so stay tuned for a comparison between those and the M60’s. My preliminary impression is that the M70 HV is a pretty burly wheel. It seem like it’s overkill for a trail bike, and it’s probably even overkill for a lot of “enduro” bikes. In other words, for many bikes that are going to be pedaled to the top of a descent, I’d lean toward the M60 HV’s.
There are a few noteworthy aspects of ENVE’s products. First, many of their products, and all of their rims are made in the U.S., in Ogden, Utah. Particularly for carbon fiber products, that’s very much an exception in the bike industry.
Second, via a patented process, they mold the spoke holes in the rim rather than drill them. Less expensive carbon rims will mold the rim without holes, then drill them. The downside of drilling them is that the actual carbon fibers are being cut. Carbon derives a lot of its strength from those fibers remaining intact—this is why it’s bad if you crash and gouge your carbon bars; the gouge may have severed some of the fibers. So drilling holes through the fibers either means the rim isn’t as strong as it could be, or they have to make the carbon extra thick (and thus heavier) to make up for the lost strength.
Here’s a picture from ENVE’s patent for the hole molding process. Enve’s uninterrupted carbon fibers are shown on the left, while Figure 12 shows how drilled spoke holes affect the carbon’s fibers.
Another upside of molding the spoke holes into the rim is it allows for the shape of the material immediately surrounding the hole to be more accurately controlled. On a traditional aluminum rim, some rim manufacturers drill the holes at an angle to match the angle the spoke enters the rim (see, for example, WTB’s “4D” drilling). This helps the nipple sit flush against the rim, which makes for a more even-load distribution. Getting a properly angled surface for the nipple to sit flush against can be tougher with a carbon rim, but by molding the hole and the area immediately surrounding it, ENVE’s able to create a more uniform surface than if they were to drill the hole.
For largely the same reasons that they mold the spoke holes, ENVE’s rims don’t have a bead hook—the interior of the sidewall is flat. This makes the rim stronger (since there’s more material there), and as with the spoke holes, it means ENVE doesn’t have to sever any carbon fibers by machining in a hook. Hookless rims have been around for a little while, and the general consensus (which I fully agree with) is that it’s a non issue and the tire stays seated just fine.
ENVE also doesn’t leave any bladders in the rim. Most hollow carbon products are made by wrapping the carbon around something, then subjecting it to pressure and heat. In the case of rims, that internal form is usually a bladder; basically, a balloon.
The trick is: what to do with that bladder once you’ve got a rigid carbon structure wrapped around it? The easiest thing is to leave it in there, but that adds a bit of weight, and it’s messy. On some carbon frames, you can stick your fingers in the bottom bracket or headtube and feel the remnants of those bladders. But on ENVE rims, the bladder is entirely removed which makes for a lighter rim with a more even weight distribution.
From talking with various engineers, it’s clear that proper use of carbon has come a long way in the bike industry. There’s a delicate balance of weight, durability, and desirable ride characteristics that’s often elusive. This, in large part, is the reason that there are really expensive road bikes: achieving the perfect blend of compliance in one direction and stiffness in the other isn’t an easy task.
And this same conversation translates directly to carbon rims. Lateral stiffness is highly sought after, whereas some degree of vertical compliance sure is nice on long rides. And while this isn’t to say that ENVE has necessarily found the holy grail in this regard, it is worth noting that they’ve been refining their carbon rims for longer than most, and they’ve expended a lot of hours figuring out what the perfect blend of weight, durability, and compliance might be, and then even more hours figuring out how to construct little details like the aforementioned molded spoke holes.
NEXT: The Wheel Build, Mounting and Setup, Etc.