If there is a standout among ENVE’s newly redesigned M Series wheel line, that distinction must go to the M7 family: the M730 and M735. While the entire M Series has undergone a ground-up redesign, the M7 employs a genuinely unorthodox design featuring what ENVE has dubbed Protective Rim Strip technology. It is claimed to nearly eliminate the possibility of pinch flats and rim damage, which makes it not only unique, but an audacious attempt to address one of the most infuriatingly persistent problems that mountain bikers face. Of course, such a bold claim is likely to be met with skepticism, so we were left with only one option—to put them to the test and find out if they live up to their stated promise.
Like the rest of the M Series, the M7 family sees rim profiles that are shallower than the M70 Thirty that it replaces. The goal here is simple: by decreasing rim depth, the degree of vertical compliance is increased. The upshot is greater rider comfort, and an overall reduction in stiffness, which addresses the complaints of some riders that carbon wheels can feel harsh.
Where the enduro optimized M7 Series departs from the XC focused M5 and trail tailored M6 Series is ENVE’s Protective Rim Strip Technology. This replaceable strip sits between the rim and the tire, acting both as a tape-free seal for a tubeless setup and a bottom out bumper, protecting the tire from pinch flats and the rim from impact damage. Despite the incredulity of some vocal forum posters, the Protective Rim Strip is not compatible with other rims. Indeed, it’s an integrated component of the M7 system, meaning that a tire cannot be mounted to the rim without it. This two-piece construction is, so far as we are aware, completely unprecedented in mountain bike rim construction, and its effectiveness has been proven both on the trail and in extensive laboratory testing.
The M7 Series is available in two rim widths– 30mm and 35mm, both measured internally, while its predecessor, the M70 Thirty, was available with internal rim widths of 25mm or 30mm. As follows from ENVE’s new naming convention, the designations are M730 and M735, respectively. Each version is available in 27.5 and 29 inch configurations.
In the interest of avoiding hyperbole and blanket statements, it was considered worthwhile to test our set of M735s back to back against their predecessor, ENVE’s M70 Thirty HV. Well-loved for their stiffness and lightweight, the M70 Thirty HV has widely been considered a standard bearer amongst enduro-rated carbon fiber wheels. That said, they did not escape criticism from some riders for what was seen as undue stiffness. Having put dozens of hours on M70 Thirty HVs, as well as owning and racing a full season aboard a set of M60 Forty HVs, the stiffness never seemed to be a nuisance, but the lack of radial compliance has become more apparent as shallower rim profiles have come into vogue with genuinely excellent rim offerings such as the alloy Stan’s Flow MKIII, or Santa Cruz’s carbon fiber Reserve 30. When judged against such competitors, the increased degree of trail chatter experienced when riding the M70 Thirty HV’s becomes readily apparent.
In comparison, the M735 is orders of magnitude less jarring. The degree of chatter transmitted to the rider, although subjective, is in line with a shallow profile alloy rim. The difference, of course, is the superior resistance to lateral deflection under cornering loads, which seems to be on par with the M70 Thirty HV. Of course, there is still deflection, arguably a bit more than many popular carbon fiber wheelsets, but as most master wheel builders will tell you, the goal is not to eliminate flex entirely, it’s to provide sufficient flex to allow the tires maximum grip without inviting a sense of disconnection from the trail. To that end, the M735s strike this balance beautifully. Of course, this is to be expected– these are, after all, a wheelset with a roughly $3,000 asking price, which positions them squarely at the top of the market, at more than twice the cost of some truly worthy options. Regardless, the M735s offer ride quality that is simply unsurpassed.
Beyond ride quality, the promise behind the M7 Series is the elimination of pinch flats and rim damage, and to that end, ENVE compares the M7 series against a technology that’s rapidly being adopted by enduro racers worldwide– tire inserts. For the uninitiated, the best examples of tire inserts are engineered foam units designed to work in a similar fashion to the Protective Rim Strip. Under full compression, the inserts act as a buffer between the rim and the tire, dissipating energy and mitigating the risk of pinch flatting the tire’s casing.
ENVE claims that the Protective Rim Strip is the lightest rim protection system available, which is debatable should one choose to interpret this claim in its most literal sense. For instance, a 29″ M730 rim weighs a claimed 571g. A 29 inch Santa Cruz Reserve 30 rim, weighing a claimed 490g, paired with the lightest widely used rim insert, Huck Norris at a claimed 80g, comes in at 570g. Of course, manufacturing variations will sway the difference in either direction by much more than the gram in question, but for the sake of argument, there are certainly lighter weight 30mm rims that could be used for comparison, and as such, combative keyboard jockeys might rightly claim that there are lighter systems available. But to take that stance is to entirely overlook effectiveness.
It has been the author’s experience that the Huck Norris inserts are a minimalist solution providing minimal benefit. On the other hand, even the lightest rim paired with the best tire insert available as measured by effectiveness, Cush Core, at over 200g per insert, ends up much heavier than an M7 Series rim of comparable width. Although Cush Core lends a noticeable degree of vibration damping for the tire not afforded by ENVE’s Protective Rim Strip, the past three months of testing have not suggested that Cush Core provides a meaningful improvement in rim and tire protection over the Protective Rim Strip, this coming from an individual who spent most of the 2017 race season aboard a Cush Core setup. When viewed through this lens, ENVE’s claims regarding the Protective Rim Strip’s pound for pound benefit ring true. As someone who is all too familiar with tire damage, and who has extensively tested, and broken, nearly every carbon fiber rim on the market, the resistance of the M735 wheelset to both rim damage and flat tires is genuinely impressive.
Despite the boldness of ENVE’s marketing claims, the M735 wheelset has, at this point, backed up those claims to a remarkable degree. Having settled on 30mm as an ideal rim width for tires in the 2.3-2.4 inch range, this rider would opt for the M730 all things being equal. But the fact remains that, as someone who has found the structural limits of nearly every carbon fiber rim currently available, and has a history of occasionally pinch flatting even the most rugged reinforced casing tires, the M735s have been entirely problem free for the duration of this test. And when considering the exemplary ride quality, it would seem that enduro racers and those prone to rim damage would be well justified in putting an M7 Series wheelset at the top of their wish list.