SRAM has just unveiled their first mountain bike wheels. Called RISE, they’re launching in two models with carbon or alloy rims.
Named with the idea that they help you climb above the rest, they’ve been working on them for two years. When they first started whiteboarding concepts, they knew they wanted wheels that rode well, felt good under the bike and provided a great ride quality. Sounds like a real DUH statement, but they say the key to accomplishing that is striking a delicate balance between six elements: Weight, Inertia, Engagement, Efficiency, Stiffness and Compliance. Mountain bike wheel product manager Bastian Donzé says finding the perfect balance between them isn’t easy.
Inertia is simply overcoming rotating weight, which is done through the rim and spokes. Make them too light, though, and you sacrifice lateral stiffness.
Make it too laterally stiff and the frontal compliance suffers. This is the ability for the wheel to be a bit forgiving when it hits a big bump or takes a hard landing, and it makes the ride more comfortable and reduces the likelihood of flatting or wrecking the rim.
Overall efficiency is a sum of all the parts, but it’s most felt in drag and weight. The engagement needs to be quick, but it can’t create drag.
So, how’d they do it? Click on through for a complete technical run down and photos…
FIRST, THE SIMILARITIES…
SRAM’s launching with the high end Rise 60 featuring a fully in-house designed and built hubset and carbon fiber rims, and the all-purpose Rise 40 with alloy rims and a more traditional hubs. Each model will be available in 26″ and 29er.
Lateral stiffness was addressed by using an asymmetric rim, widely spaced bearings and a strong axle. In their words, the design means you shouldn’t feel the need to automatically throw it in a truing stand and tighten all the spokes a couple turns.
Both wheels use asymmetrical rims with a 2.5mm offset, and both use the same rim front and rear. They flip them to balance the cassette spacing on the rear versus the disc rotor spacing on the front. They have a 19mm inside rim diameter. Out of the box, they’re intended for tubes, but SRAM is working on their own tubeless conversion kit. You can also use any third party conversion kit (Stan’s, etc).
When deciding on the rim width, they based the measurent on ETRTO recommendations for tire/rim interfaces based on CEN guidelines. Based on the intended use, CEN/ETRTO standards said a 19mm inside width works with 1.9 to 2.4 tire widths. There’s no doubt SRAM is looking for OEM placements, so meeting CEN standards was more important than having it 100% tubeless ready out of the box. It’s kind of a bummer, but our test bikes were equipped with Stan’s NoTubes original rubber strip conversion kit -necessary to raise the rim bed height so the tire would seat and seal easily- and they worked without problems on more than 14 bikes equipped for the test rides.
While the hubs are drastically different, both are about as simple as can be: an axle rolling on bearings housed in a hub shell. There are no tools required to pull them apart, including the pop-on axle adapters where available, and the freehub body pulls off with just your hands should you need to replace it or grease the pawls. SRAM says the simple design not only makes maintenance easier, but it keeps them lightweight. Speaking of weight, they’re only giving complete wheelset weights, not individual component (rim, hub) weights. Why? Because they’ve built the wheels as a system, much like Mavic does, and they don’t think it’s necessary to have people comparing pieces of the pie when it’s the whole wheel that makes it special.
Both also use stainless steel spokes in a 2-cross, 24-count pattern front and rear…and that’s about the end of the similarities.
SRAM RISE 60 XC WHEELS
Aimed at XC and enduro racers, the Rise 60 are the lightweight, carbon fiber-rimmed performers.
The Rise 60 hubs were designed completely in house to create the lightest, smoothest, fastest hub they could. They have a 54 tooth drive ring for a 6.7° engagement with three sawtoothed pawls that create nine points of engagement (below). Any more teeth would mean smaller teeth and possibly less reliability and strength. The design is a bit noisy at speed, but not obnoxious.
Weight is kept low with an oversized aluminum axle. Swapping end caps to change axles is tool free, and they slide pretty far onto the axle for better stability. There are four sealed cartridge bearings on the rear, two in the hub shell, two in the freehub body. Front has two large sealed bearings. Both have lips on the axle to support the bearings, keeping things very tight when you close down the skewers or thru axles.
The 60’s hubs use direct pull spokes that run through a chiseled, solid flange. Compare that to the open slot design on the 40’s, below.
If you look at the carbon rim profile photo further up, you’ll notice two distinct color tones and a UD outer finish with 3K weave on the rim bed. While they didn’t delve into the technical reasons for this, SRAM PR manager Morgan Meredith said there are also different resin mixes used in different parts of the rim to create the strength and compliance they wanted. SRAM is manufacturing these carbon rims in their Indianapolis plant (ie. Zipp’s facility), and these hubs are made in their own factory in Taiwan. From there, the 60 wheels will be assembled and shipped from Zipp’s U.S. facility.
SPECS:
- Sapim CX Ray stainless steel spokes
- 1330g 26″ (without tape or skewer)
- 1420g 29er ( ” ” )
- 26mm tall rim, 19mm inside width
- Front Axle: convertible 9mm QR/15 thru axle
- Rear Axle: convertible 10mm QR/12×142
- Aluminum hubshell
- Aluminum axle
- Aluminum drive body
- MSRP: $2,000 (€1,800)
In addition to standard side caps for the hubs, they’ve made a 31mm diameter Rockshox-specific end cap that fits into the oversized slot on the inside of their fork’s dropouts. By using the caps with a quick release skewer, SRAM says it increases front end stiffness 15% over a standard 9mm QR. Clockwise from top: 9mm QR, 142×12 rear, 31mm Rockshox specific and 15mm thru axle front. At right, the end caps slide off easily enough, but sit firmly on quite a bit of axle to keep things plenty stiff.
The wheels will be sold with one type of axle end cap, the others will be available separately. So, order what you need now knowing you can convert the Rise 60 down the road.
Production starts in late Oct for the 26″ for late year availability. The 29er gets into production in January, for sale in February.
SRAM RISE 40 – THE ALL PURPOSE MOUNTAIN BIKE WHEELS
Rise 40 is a mid level alloy-rimmed wheelset aimed at most users. Rather than segment it into trail, all mountain or freeride, SRAM says they’re good for what we used to simply call “mountain biking.” This means they’re good for all of the above, light enough for the occasional race and strong enough for occasional bike park thrashing.
The 40’s also get more conventional hubs. They have a straight pull design using an open slotted flange, steel axle on the rear QR, aluminum for the others. They have a normal three-pawl ratchet. In the right photo, the rubber ball between the spokes is an “anti-ejection” feature. When you hit something really hard, wheels can deform enough to slacken the spokes, and this keeps them from popping out.
The rim is made of 6000-series alloy. Along with the asymmetric design, they pushed the non-brake side flange on the front hub out a bit further, giving them better spoke triangulation and get closer to having equal spoke tension on both sides.
SPECS:
- Front Axle: non-convertible 9mm or 15 thru axle
- Rear Axle: non-convertible10mm QR or 12×142
- 1710g 26″ (without rim tape or skewers)
- 1840g 29er ( ” ” )
- Aluminum Hub Shell
- Chromoly Axle and Driver Body
- 21mm tall rim, 19mm inside width
- MSRP: $550 (€465)
Rise 40 hubs are made in a third party Taiwanese factory and use the same internals as their X9 hubs. The 40 rims will eventually be made in one of their own factories, but for now are made by a contractor. They use Alpina stainless steel spokes. All of the 40’s parts are then shipped to one of SRAM’s Taiwanese factories for assembly, giving them final control over the build.
One other small detail. The Rise 60 QR wheels get the refined (and lighter) skewers on the bottom. The Rise 40 get more traditional looking ones.
TEST RIDES
Our test bikes were new Rocky Mountain Element carbon fiber 120mm suspension bikes equipped with the Rise 60 carbon wheels, Maxxis Ikon LUST tires running tubeless, SID forks and X0 drivetrains. Our test rides were in some very rocky, loose trails with plenty of drops and technical sections. What you see above was fairly typical along the almost 60 miles of riding we’ve done on these over two days.
They felt very stiff, holding a line very well and letting me focus on where I was going, not picking around every little obstacle. My particular bike was equipped with a standard 9mm quick release/end caps, too, so there was no fat axle there to sway the results. On the gravel-laden fire roads, everything held together predictably, even when an inside foot placement led to some intentional drifting. All in all, the handling seems really good.
While I didn’t pay particular attention to engagement speed, it never had a glaring delay between beginning to pedal and propelling the bike forward. To me, that means it’s quick enough not to be an issue.
We had plenty of climbing, some small ledges and rocks to hop up and various other obstacles. The light weight of the wheels made bunny hops and front end lifts super easy (the SID fork didn’t hurt this either).
I ran my tire pressure pretty low, probably around 30psi (I’m 6’2″, about 190-195lbs with gear and a Camelbak). While I did manage to tear a sidewall a bit on day two and had to put a tube in for the last ~12 miles, I checked the rims of mine and several other bikes after the rides were done to see how the carbon held up. I never noticeably hit the rim on mine, but rocks were flying and caused a few scratches on some rims. The only consistent wear I found is shown above, where the superficial glossy layer is worn off near the edge. This was evident on about half of the rims I checked. Time will tell if this is a long-term durability issue, and we should have a test set in around January for long term thrashing.
FUTURE PROGRESS
As mentioned, SRAM is definitely looking at the OEM market with the Rise wheels. Because of their late-in-the-year release, you won’t see them until 2013 models, though.
These first generation Rise wheels used steel spokes because it’s easy to find top quality spokes, the ride quality is good and they’re fairly light. They’re also readily available and easy to service. Moving forward, SRAM’s not ruling out developing a proprietary alloy spoke (again, much like Mavic). They say that could shave another 70g to 80g off the Rise 60, but price would go up and long term durability would be slightly diminished over steel spokes.
While they didn’t mention it, there’s no reason why they couldn’t make a Rise 50 hybrid with the alloy rims and higher end hubs. Oh, and if we were bettin’ folk, we’d say DH wheels are near the top of their R&D queue.
