Get ready for a bold statement (from Zipp, not me): This is the fastest bicycle wheel… ever. That’s right – Zipp claims that the new Super-9 Carbon Clincher disc is the fastest wheel in the whole wide world. Faster, in fact, than their own negative-drag Sub-9 tubular that is now a few years old. I had the chance to test, fiddle with, and ride a new Super-9 carbon clincher, and the article that follows is my review.
To start off, let’s cover the basic specs. Weight of this disc is 1175 grams – very impressive for a clincher disc. Price? $2,375 US (start collecting your pennies). This wheel follows the trend of wider-is-better, with a brake track width of 26.4mm, which slowly grows to a maximum wheel width of 27.5mm. While I haven’t personally installed this wheel in every bike out there, my guess is that it will work with most, but not all frames. Super narrow frames such as the Cervelo P4 and original Ridley Dean will likely not accommodate the wheel. My custom titanium frame had plenty of clearance all around.
The internal width of the clincher bead hooks is 16mm. Unofficially, this would be called ETRTO 622-16c. “622” is the wheel diameter (or 700c as we all know it), and “16c” is the width. Keep in mind, the official ETRTO specifications only accommodate odd numbers (13c, 15c, 17c, etc), but more and more manufacturers are eschewing this to make their own widths. Mind you, I don’t think this really matters, but it’s worth noting. The reasoning behind the new 16c size is to accommodate more tire widths. A 15c width rim can accommodate a 21mm tire, but a 17c rim cannot. The 16c width splits the difference, and because there is no official rule about it – manufacturers of these rims suggest that they are safe to use with a 21mm tire. My armchair guess is that this combination is quite fine to use, similar to all of the technically-incompatible 17c rims matched to 23mm tires.
Here’s a look at that rim:
In any case, my test wheel included one of Zipp’s own Tangente 23mm clincher tires, along with their Tangente butyl inner tube and 18mm white rim tape.
Rim tape is intended to cover up spoke holes, to keep them from puncturing your inner tube. While this wheel obviously has no spoke holes, Zipp provided rim tape nonetheless. My guess is that this is to ensure that punctures can’t be caused from any rough edges at the valve hole. Whatever the reason, they supplied it, so I used it.
I like the non-adhesive Zipp rim tape. Keep in mind, however, that due to the way it fits (i.e. tightly), you want to make sure to center it after initial installation. I’ve installed a ton of these things, and have found the best way to center them requires a critical tool: a Bic ballpoint pen cap.
You need something small and sharp-edged to catch under the tape, but I’ve always been afraid that a screwdriver would damage a carbon rim. The pen cap works perfectly to sneak under the tape. Then I grab the edge of the tape with needle nose pliers to scoot it over to the center of the rim.
The other thing to keep in mind here applies to all handmade tires of this fashion. They fold up very flat for packaging and transport, but can struggle to take the shape of a tire (which is anything but flat). Vulcanized tires, by comparison, tend to hold that rounded tire shape when not on a wheel.
Once you put the first tire bead on, be sure to take extra care to tuck the inner tube down in to place as far as possible:
After this point, I installed the other tire bead. Zipp has done a fantastic job of shaping the rim with a deep channel between the bead hooks – this effectively reduces the diameter of the wheel slightly for easy tire installation. Once the tire is inflated, the beads get forced in to place in the “corners” of the bead hooks, which have a slightly larger diameter.
Once the second tire bead has been installed, I always check around the entire circumference of the wheel on both sides. What I’m looking for is any inner tube that got pinched by the tire bead, and is peeking out at me.
I’m glad I did check, because there were a couple sections that got pinched:
What to do? If it’s badly pinched, I’ll uninstall one of the tire beads and start over. If it’s only a small pinch, I inflate the tire with about 10 or 20 psi, and then visually check for pinches again. Sometimes this small amount of pressure is just enough to slip the tube out from under the tire bead.
Now that it was time to inflate, I grabbed the Zipp-supplied inflation adapter. This device is unofficially known as a disc wheel “crack pipe”. Wonder why?
The Zipp adapter is made to fit a Schrader valve pump – something to note if you have a Presta-only pump.
Every one of these “crack pipes” I’ve used requires that you hold it on to the valve with your hand while inflating. This means that you either pump with one hand, or find a friend to help.
The Zipp tubes feature a short 37mm length valve. This works very well with a disc wheel, as the valve cutout can only be so big. If you use a valve that is too long, there won’t be any space left to fit the inflation adapter.
Once I had the rim strip situated, the tube in, and the tire on, I was ready to roll.
Zipp representatives tell me that the reason this disc is so fast is because of the tire-to-rim transition. The brake track is slightly canted towards the tire.
What I wanted to know was how and why this disc could be so fast. Their claim that this is the “fastest wheel ever” is a big statement to make. My mind wonders: What tire does that assume? And what tire width? What bike frame? What wind angle(s)? Unfortunately, Zipp does not tell us this information in their promotional video about the Super-9 on YouTube.
The other interesting statement they made was perhaps equally as bold: “Clinchers are significantly faster than tubulars – aerodynamically speaking.” Period. End of statement. Again, I wonder what this statement assumes. ALL clincher tires are faster than ALL tubular tires? What does 'significantly' mean? Before the Super-9 Carbon Clincher debuted, they said that the Sub-9 tubular disc (with a 21mm tire) was their fastest wheel (including their clincher wheels). In the end, I’m not losing sleep over this stuff, but their statements just struck me as bold and lacking the sort of context that us data-hungry triathletes desire.
Zipp representatives did mention that with many newer aero bike frames, the exact tire width and model tend to not matter as much anymore. They say that the more shielding you have ahead of the rear wheel – the longer and taller that rear wheel cutout is – the less your tire matters for leading edge wheel aerodynamics. The highly shielded frames cause air to dump directly on to the rear wheel; the whole area is big a high-pressure zone. For this reason, Zipp says that the more shielded your frame, the more critical a disc wheel becomes.
You still have the trailing edge to worry about, but the back half of the rear wheel is the least of your worries in this regard, compared to front wheel trailing edge (there is no more bike behind the end of the rear wheel).
Aerodynamic claims aside, I think the most important feature of this wheel is a very simple one: You can easily change a flat on-course, and/or make a last-minute tire change before your race. I can’t tell you how many times I’ve seen both professionals and amateurs show up at a race with tubular tires… only to discover a small cut in one of them the day before their race. The questioning ensues: Should I change it? Is it safe and reliable? Should I use a different wheel? A clincher wheel eliminates this discussion entirely.
Of course, Zipp has had a clincher disc for many years, with their 900 clincher debuting in 2006. It was and continues to be a very nice wheel. The downside? It weighed about 50 or 75 grams more than the new Super-9 does. Not a big deal, if you ask me. I think the reason it struggled was simply that it had an aluminum braking surface. Let it be known, I love aluminum braking surfaces for their outstanding brake performance and feel. However, the fashion-conscious consumer couldn’t seem to get over the appearance. Who would want an all-black 808 Carbon Clincher front wheel and an aluminum-rimmed 900 Clincher disc on the rear? Blasphemy!
Speaking of braking performance, that was one area which I was very curious about on this wheel. Zipp supplies the wheel with a pair of their Tangente Platinum Pro brake pads. The braking surface itself is said to be made with updated materials, which are also used on the new 202 Carbon Clincher.
While test riding the wheel, I made a point to brake in several styles – feathering the brake on a long descent, normal stopping and starting, and the full-on panic stop. I consider the performance to be on-par with their other carbon clincher products (which is to say – good). It did not quite live up to my gold standard of carbon brake performance, the Lightweight Fernweg (which admittedly cost about six grand per pair). My personal opinion is that aluminum braking surfaces still win this war overall. Carbon is catching up, but due to the realities of physics, I doubt it will ever surpass aluminum.
Hubs and details
Zipp uses their 188 model hub in the Super-9 Carbon Clincher. I was told that all production versions will feature an updated design that is compatible with the 2013 11-speed Dura Ace, as well as all 9 and 10-speed cassettes. My disc is a pre-production model, however, and still has the 10-speed freehub.
Zipp also updated their discs to now feature the “Beyond Black” hub color; previously they were only available with silver hubs. As always, the non-drive side features threading for a track cog:
They offer a track axle conversion kit that changes the wheel from 130 to 120mm spacing for fixed-gear track use.
Overall, I was quite happy with the new high-end disc offering from Zipp. The finish quality looks to be outstanding, as would be expected. Ride quality was surprisingly smooth; aside from the usual “whoosh whoosh” disc sound while you pedal, it was hard to tell I was even riding a disc. Out-of-the-saddle climbing was good, crosswinds were no problem, and fast descents… well, they seemed really fast.
It’s good to see many more top-level professionals getting on the clincher bandwagon. This wheel really debuted in the Spring of 2012, under riders on the Omega-Pharma QuickStep pro cycling team. More recently, many of Zipp’s triathletes are switching to clinchers as well. Long-time Zipp clincher users include Jordan Rapp and TJ Tollakson. In Kona this year, however, big names such as Marino Vanhoenacker and Mirinda Carfrae made the switch. Both are former staunch tubular riders. It’s now commonly known that clinchers can be as-good-or-better than tubulars in the rolling resistance department, and if what Zipp tells us is true – they’re equal or better in aerodynamics. The weight delta continues to shrink, and the convenience factor cannot be ignored. The price is high, but you’ll get over that pretty quick… if you angle the light just right, you can see each individual “pie slice” of Zipp disc that will instantly make your wallet forgive you…
Zipp Super-9 Carbon Clincher Disc
Weight: 1,175 grams
Availability: January 2013
Brake Track Width (Center): 26.4mm
Maximum Wheel Width: 27.5mm
Maximum Tire Pressure: 125psi (8.62 bar)
Rider Weight Limit: 250lbs
All images © Greg Kopecky / slowtwitch.com