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by James Huang
December 22, 2016
Photography by James Huang
TECH NEWS BROUGHT TO YOU BY BIKEEXCHANGE
Of all the wide-profile road wheelsets on the market, none are pushing the envelope more than Enve Composites with its radically forward thinking, ultra-fat, SES 4.5 AR Disc. If you prefer higher-volume road tires and disc brakes, but still want to go as fast as possible, these are the wheels you want.
Enve’s SES 4.5 AR Disc is like no other aero road wheelset available.
That sort of hyperbole tends to get tossed around lightly in the marketing-heavy cycling industry, but in the case of the SES 4.5 AR Disc, it’s true.
Most modern, wide-format road clincher wheels have internal rim widths of around 19-21mm, but they’re still designed primarily for use on asphalt with tires measuring around 25mm across. The SES 4.5 AR Disc, on the other hand, inflates both of those figures by a substantial 5mm. From the outset, Enve designed the SES 4.5 AR Disc as a dedicated “all road” wheelset — hence the “AR” designation — equally adept at asphalt, dirt, and maybe even some gravel.
The SES 4.5 AR Disc rims are each 29-39g lighter than the SES 4.5 ones, despite being 4-5mm wider in both internal and external width. Photo: Enve Composites.
Enve has built its road reputation on aerodynamic performance, so plenty of attention has been paid in this area as well. As on other Enve aero wheels, the SES 4.5 AR Disc features unique front and rear rim profiles, with the front sporting a 49mm-deep, blunted shape for easier handling in crosswinds, and the rear using a deeper and slighter sharper 55mm deep section for extra straight-line speed. To help smooth airflow off of those 30mm wide tires, both rims also use an unusually broad external width — 31mm for the front, and a barely-narrower 30.5mm out back — along with a hookless design that makes for a more seamless transition between the tire and rim sidewalls.
Despite all that girth — not to mention the added mass of disc-compatible hubs and a more generous 24/24 front/rear spoke count — the SES 4.5 AR Disc wheels are much lighter than you’d expect. Actual weight for a thru-axle set with a Shimano/SRAM 11-speed freehub body is just 1,519g (818g rear, 701g front, without valve stems or rim tape). In fact, that makes the oversized SES 4.5 AR Disc wheels are lighter than Enve’s standard SES 4.5 carbon clinchers, which are designed solely for rim brakes and are also considerably narrower.
The Enve SES 4.5 AR Disc wheels are like none other on the market, but others are sure to follow its ultra-wide aero format before long.
According to Enve marketing director Jake Pantone, this is due to the AR’s disc-specific rim design, which eliminates some of the reinforcement layers that are normally needed around the sidewalls to contend with clamping forces and heat build-up. Whereas claimed weights for the standard front and rear SES 4.5 carbon clincher rims are 469g and 489g, the broader SES 4.5 AR Disc rims helps offset the extra weight of higher-volume tires with claimed weights of just 440g and 450g.
Granted, none of this takes into account the added heft of the associated rotors and calipers — a set of 160mm-diameter Shimano RT-99 Ice-Tech discs alone weighs about 250g, for example — but it’s quite the feat nonetheless.
Wet weather is normally the Achilles’ heel when it comes to braking on carbon rims, but with disc brakes, it isn’t an issue. Enve was also able to make the 4.5 AR Disc rims remarkably light since there was no need for a brake track.
Perhaps more impressive, though, is the fact that Enve also claims nearly identical aerodynamic performance between the SES 4.5 AR Disc and SES 4.5 (when paired with appropriately sized tires), as well as lower rolling resistance for the former, too.
I’m no stranger to the positive effects of wider rims and higher-volume road tires, which offer better handling, lower rolling resistance, and improved comfort than more traditionally sized rolling stock. That said, they’re also a little heavier, and those wide tire cross-sections usually don’t have correspondingly wide rims for proper aerodynamic performance.
With the Enve SES 4.5 AR Disc wheels, however, all of those positives are turned up to 11 and all the negatives go away entirely — although some aspects of why exactly that is the case aren’t entirely clear.
I tested the Enve SES 4.5 AR Disc wheels with both Schwalbe Pro One Tubeless and Specialized S-Works Tubeless tires. Both models are marked as 28mm-wide, but puff up to 31mm when mounted to these ultra-fat rims.
I tested the SES 4.5 AR Disc wheels over a two-month period using two different sets of tires: Schwalbe’s Pro One Tubeless and Specialized’s new S-Works Tubeless, both of which were marked as 28mm-wide but measured just a hair over 31mm when inflated to 60psi. All testing was done in and around Boulder, Colorado, on a custom-built Seven Evergreen Pro — a personal bike that I know very well — under a 70kg (153lb) rider. Keep in mind that I had this bike built specifically for these sorts of wheel and tire sizes; most road frames won’t be able to accommodate something this wide, although there is certainly a rapidly growing list of chassis that will.
One of my preferred road test loops includes a punchy, ten-minute-long out-and-back climb with a modest 150m (500ft) of elevation gain and a fun descent with six good corners, all covered in coarse pavement that serves as a good measure of tire traction. With a narrow, high-pressure setup (such as 23mm-wide tires, 15mm-wide rims, and 100psi), bikes tend to skitter and drift toward the outer edge of the curve, the tires audibly squealing a bit in protest. New-school setups (25mm-wide tires, 20mm-wide rims, and 80psi) are much better, but even those are no match for the 4.5 AR Disc setup, which sticks to the road in laughably confident fashion.
That a higher-volume tire at lower pressure is good through the corners should come as no surprise; after all, any increase in tire contact patch size will yield better traction. However, I was still able to corner harder and more predictably on the Enves, even when compared to the Stan’s NoTubes Avion Disc Pro wheels and identical tires I’d been using previously. Those wheels have a 3mm-narrower internal width, but with an actual inflated tire width difference of barely 1mm (and the same operating pressure), no credit could be given to having more rubber on the ground. Furthermore, both wheels sport the same spoke make and model (Sapim CX-Ray), lacing pattern, and nearly identical hub flange spacing.
So what gives?
A boost in rim stiffness is certainly possible — especially given the SES 4.5 AR Disc’s wider cross-section — as is improved tire casing support from the broader rim bed. Neither aspect was objectively measured in this test, though, so both of those hypotheses are unconfirmed. Regardless, the SES 4.5 AR Disc is one of the best-cornering and most planted-feeling road wheelsets I’ve ever used — and that advantage only grows with decreasing road quality.
Enve uses specific cross-sections for the front and rear wheels. The front is 31mm-wide (external width) and 49mm-deep with a more rounded shape, while the rear is 30.5mm-wide and 56mm-deep with a slightly more pointed profile. The idea here is to improve the crosswind stability where it matters most (up front) while focusing more on decreasing drag out back.
Buyers interested in the SES 4.5 AR Disc likely aren’t just looking for a wide footprint, though; it also entices with its promise of speed, and it seems to deliver there in that department as well.
The fact that that larger tire casing and lower air pressure combination rolls with less resistance than a traditional setup also shouldn’t come as any surprise; hard data settled that debate long ago, and it’s only on the most perfect of surfaces that the narrower and harder tires offer any sort of advantage. Indeed, the 4.5 AR Disc combination floats across the road like no other setup I’ve used, save perhaps for some Specialized/FMB cotton tubulars that I wouldn’t want to use everyday, anyway.
Up until now, though, aero proponents have still been able to argue (and perhaps rightfully so) that those small improvements in rolling resistance were offset by bigger increases in aerodynamic drag. But if you take Enve’s data at face value, even that argument now disappears with the SES 4.5 AR Disc’s unusually bulbous profile and hookless design. Add that with the expected reduction in rolling resistance, and what you should get is one of the fastest wide-section aero road wheelsets on the market.
That the SES 4.5 AR Disc feels fast on the road doesn’t mean much without the hard data to prove it, but how efficiently a wheel slices through the air is only half of the aerodynamic performance puzzle; for average riders, the small differences between multiple top-end models won’t mean much. What is more important on a day-to-day basis, however, is how well an aero wheelset performs in windy conditions, and the the SES 4.5 AR Disc shines here as well.
The blunted nose lessens the negative handling effects of crosswinds. The Enve SES 4.5 AR Disc is some of the easiest deep-section wheelsets to manage in blustery conditions that I’ve ever ridden.
Another favored test section of mine is a fast, sweeping dive out of the foothills back into town. The test loop mentioned earlier is mostly sheltered from the Chinook winds that plague the Colorado Front Range, but the descent is peppered with sudden gusts that can easily knock you offline as you shimmy through the corners. I regularly roll through there on gusty days with white knuckles, ready to counteract the next blindsiding swirl, but the SES 4.5 AR Disc’s ultra-fat and blunted profile makes for a relaxed run through the gauntlet. Likewise, steady winds require just the slightest lean with minimal input required at the bars. I’d previously found Enve wheels to be among the very best in this respect, and the SES 4.5 AR Disc only furthers that reputation in my view.
Otherwise, the rest of the wheelset’s salient features are about what you’d expect.
The SES 4.5 AR Disc can’t compete with dedicated climbing wheels in terms of weight, but they’re still amply light and stiff for attacking steep pitches — while also still retaining very good stability on the way down, which many ultralight wheels can’t provide. Both of the available hub choices — the DT Swiss 240s featured here, or Chris King’s R45 — are well proven, too, although with certain quirks that are worth mentioning.
For example, the R45s are 75g heavier for the pair, but offer a much faster 8-degree freehub engagement speed (and a slight buzziness to match). On the other hand, the DT Swiss 240s hubs are lighter and feature the more versatile Center Lock splined rotor interface, but come stock with glacially slow 20-degree ratchet rings (which can be upgraded at considerable additional cost).
The standard DT Swiss 240s rear hub comes stock with 18-tooth ratchet rings, which produce a languid 20-degree freehub engagement speed. Improving that figure requires either upgrading the ratchet rings yourself or choosing the Chris King R45 hub option, both of which cost more.
Thru-axle users will also want to note that the R45 front hub is only offered in a 100x12mm size, whereas the 240s is available to fit 100x15mm forks, too; either will fit the standard 142x12mm rear fitment, but at least for now, neither is available with both thru-axles and a Campagnolo freehub body together.
In either option, Enve builds the wheels with frustrating internal spoke nipples. Enve has always preferred this route since it allows for smaller and stronger molded-in spoke holes in the rim. Nevertheless, it turns a five-minute job into a much longer one, and in the case of tubeless setups, also a more expensive one since the requisite rim tape can’t be reused like regular rim strips. This won’t be a deal breaker for most users, but riders who regularly knock wheels out of line will perhaps want to give this fact a second thought.
My other complaint with the SES 4.5 AR Disc isn’t related to any performance aspect, but is arguably much more significant. Zipp’s recently announced 454 NSW may have raised the bar for carbon road wheelset prices from mainstream labels, but even so, the $2,700 SES 4.5 AR Disc can hardly be bought for pocket change.
Speaking of cost, the SES 4.5 AR Disc’s position on the pricing spectrum brings with it understandably high expectations in terms of finish work and general quality control. However, both of my test wheels had what appeared to be small voids and wrinkles in the carbon plies that could be both seen and felt.
“It is regrettable that a rim with these imperfections left our building; it should not have,” Pantone wrote to me in an email, when asked to address the blemishes. “This issue has generated a healthy conversation about the integrity of our QC process and I maintain that we have very tight QC inspection process that ensures that an unsafe product will not leave this building. What is clear is that some QC operators have been unclear on what level of cosmetic imperfection constitutes a first-quality rim. The nature of Enve’s manufacturing and finishing process means that each rim will have some unique cosmetic features and we don’t use paint, filler, or cosmetic layers to hide them. The rim you received should not have shipped to you and our customers should never receive a rim with this imperfection. If, by chance, they did, we would replace it immediately.”
Both wheels had disconcerting blemishes that could be seen and felt. Exactly how much such voids and wrinkles affect the structural performance of the wheel isn’t entirely clear, but either way, they’re unacceptable for a premium carbon-fiber wheelset.
It’s certainly possible to receive a blemished rim from time to time, but the fact that both of my test wheels were less-than-perfect gave me pause — so I contacted a few notable wheel builders for their experience, and what came back was a more negative feedback regarding Enve’s recent quality control than I had expected.
“In general, we see very high structural quality from Enve rims, but surface blems are pretty normal if you are referring to an occasional bubble in the carbon or a strand of carbon peeling away near a nipple hole,” said one builder, who preferred to go unnamed. “These are definitely cosmetic, but it can be frustrating when customers return them when they expect perfectly flawless product.”
“I’ve seen lots of QC issues over the last year,” said another. “Older rims are much better finished.”
“The blems we see are typically things we’ve seen since the beginning, but we do see them more frequently,” reported a third builder. “I don’t believe they are more common, just that they aren’t being QC’d as well when leaving Utah.”
In fairness, such irregularities are far from universal, but disappointing nonetheless, particularly given the reputation that Enve has forged over the years. Whether any of these constitute potentially functional issues is debatable, but it’s fair to say that for this kind of money, any paying customer shouldn’t tolerate anything short of perfection, especially when all the other aspects are so, so good.
Enve’s new SES 4.5 AR Disc has changed the game in terms of wide-profile aero road wheels.
The bulbous profile measures 31mm at its widest point, blending perfectly with higher-volume tires that normally create more of an lightbulb-like cross-section when mounted on rims of more conventional width.
The hidden nipples may help with rim strength and aerodynamics, but they’re a major pain if and when truing is required.
Enve still manufactures its carbon rims in the United States.
Enve offers the 4.5 AR Disc wheels with either DT Swiss 240s or Chris King R45 hubs, both with splined Center Lock rotor interfaces. Only the DT Swiss set can handle both 12mm and 15mm-diameter front thru-axles, though, plus they’re 75g lighter for the set. Custom builds are also available through WheelBuilder.com.
Enve builds the 4.5 AR Disc wheels with 24 Sapim CX-Ray bladed stainless steel spokes front and rear.
Thankfully, Enve includes a set of extra-long tubeless valve stems with the 4.5 AR Disc wheels. Their aluminum construction has less of an influence on wheel balance than steel ones, too.