News: SRAM Unveils New Roam and Rail Wheels

New light-yet-strong wheel line takes aim at the trail and all-mountain niches

Everything underneath us felt a little alien – the dust, the sand, the bikes, the components – so getting a solid hold on the SRAM wheels was hard, especially as they were barely noticeable. But mark my words, that’s a very good thing. Read on.


By Seb Kemp
Photos by Adrian Marcoux and Sebastian Schiek

It takes a while to line up all your ducks, especially when you are starting from scratch. This has been the case with the SRAM wheel department. Before wheels can be produced all manner of processes need to be aligned first. It’s not just a case of opening an office one day and spitting out a design the next. Design parameters need to be established, testing procedures need to be created, and a whole production and distribution line needs to set-up…and goodness knows what other clever science needs to be formulated.

The mountain bike wheel program came about four years ago and although it may have taken a while for the wheels to start rolling off the production line, things are really moving now. 2013 marks a radical expansion of SRAM’s wheel range.

SRAM engineer Jesse Jakomait is an animal on a bike as well as being a clever chap. The kind of guy who chooses to run 2.4-inch tires on a 140-millimeter travel bike for the Colorado Divide Race simply because he doesn’t want to lose out on any chance to go hard on the downhills.

Last month we saw (and test rode in Sedona) three new wheelsets that feature a lot of the technologies that SRAM wheel designers have been working on for some time now.

The Roam 50, Roam 60, and Rail 50 are versatile wheels that are designed with the needs of true mountain bikers – the kinds of riders who like to ride far, ride hard, and not have to worry about their equipment.

Before we move into the specifics of each wheel let’s cover some of the technologies and features that are shared by all three wheels and establish SRAM’s intention and design philosophies.

TAPER CORE AND CARBON-TUNED RIMS

The profiles of all three rims – left to right: Roam 50, Rail 50, Roam 60.

Designed to be strong in just the right places and with no extra heft, the rim’s sidewalls are reinforced along the wings to withstand major impacts. The sidewalls then taper in along the center—reducing overall mass. The result is a very light rim that we are told have exceptional dent resistance.

Designers used finite analysis to help figure out exactly where the rim needs material and where mass can be reduced in order to make the rim as light as possible, without sacrificing stiffness and impact resistance. The Taper Core profile of both the aluminum and carbon rims are different as both materials have distinct properties. Carbon is very good under tensile loads but not so good under compression loads unless layered is a very specific pattern. This is why (on the carbon rims) there appears to be more material under the clincher side wall.

By selectively layering woven carbon fiber at high-stress points and using unidirectional fiber throughout, SRAM creates rims that yield a remarkable level of strength and durability—while remaining lightweight and responsive. Carbon can be employed to make stiffer or stronger products. It can also be used to make lighter products. SRAM designers, however, chose to emphasize strength. To wit, the Roam 60 carbon rims weigh within 10 grams of the Roam 50 aluminum rims—the carbon rims are just, comparatively, much stronger.

Rim weights are as follows:
• 500g = Rail 50
• 410g = Roam 50
• 400g = Roam 60
(all based on 26” rim weights)

This cartoon might be a little overdramatized but you get the point, wider is better.


WIDE ANGLE
Before sitting down with SRAM wheel product manager, Bastien Donzé, I had never heard of ETRTO (European Tyre and Rim Technical Organization), an institution whose aim is to align the national standards of wheels, tires, and valves in order to achieve interchangeability, establish common engineering dimensions and load characteristics, and promote the free exchange of technical information of tires and rims.

SRAM wheels adhere to the basic ETRTO standards and guidelines for its mountain bike wheels. SRAM, however, decided to go make their rims wider than most because they believe a wider rims provides a better tire profile, which increases support, traction and comfort for the rider.

The wider base of support for a tire gives it a more stable profile, making it less inclined to pinch or roll. It also means tires stand less proud of the rim, increasing the footprint of the tire and decreasing the tendency of tires to wallow under braking and turning forces.

Here SRAM wheel product manager, Bastien Donzé, explains the difference between apples and oranges.

Bastien Donzé believes that for far too long mountain bikers have believed that a narrow rim is optimal, simply because of a hangover from our road biking cousin’s logic. Traditionally it was thought that a narrow rim was best because it would be lighter. Bastien says this thinking should have been left in the `90s. Bikes are vastly superior to those of twenty, ten or even five years ago, and tire patterns and sizes have changed to suit the more aggressive riding that even everyday riders are attempting. These days, what with changes in materials and construction methods, wider rims can be extremely light and provide more favorable ride characteristics over narrow rims.

TUBELESS FIX
The SRAM rims are designed to UST specifications. UST tubeless rims feature hooked edges designed to seal with UST-compatible tires. Unlike true UST rims, however, the SRAM rims are drilled and use tape to seal the bed. Bastien pointed out that they have tested all sorts of aftermarket tubeless tapes and most are completely satisfactory, meaning that replacing the tape isn’t necessarily a service center job that requires SRAM-brand tape. SRAM use the particular tape they do because it gave the lowest interference with the complex rim bed profile and therefore helped the rims sign off on their own stringent quality controls. Using Gorilla tape will work just fine.

One spoke to rule them all. Every wheelset shares the same spoke length and design, making replacement easy.


ONE SIZE FITS ALL
SRAM Solo Spoke wheel design eliminates the need for different spoke lengths—one size fits the entire wheel. This identical-length design means no longer wondering whether you have the right front/rear/drive-side/non drive-side spoke handy. It also means makes things easier and more cost effective for retailers, distributors, service centers and, of course, manufacturers.

Pull off, push on end caps, XX1 compatibility, and reliable DT Swiss internals.


FAMILIAR INTERNALS
Although SRAM designed the hub to their specifications, DT Swiss IS manufacturing them. Inside the hub the proven and much respected DT Swiss internals are used, making maintenance and replacement very easy.

The SRAM wheels use the Star Ratchet patented freewheel system. Precision ratchets with extremely high load capacity and reliability are used, and thanks to its no-tools-required design, routine maintenance is easy.

WHEELS FOR ALL
SRAM knows that all manner of hub standards are floating around and are likely to keep changing. To allow the wheels to be used and reused by customers, and to maximize OE sales, all hubs are fully convertible for all standards and the end caps can be replaced by hand.

AND NOW FOR THE WHEELS…

1,495 grams and willing to be roughhoused, the SRAM Roam 60 carbon wheelset.


ROAM 60
Price: $2,199

Weight
• 26” - 1,495 grams
• 27.5” - 1,550 grams
• 29” - 1,625 grams

The ROAM 60 wheels are the highest spec wheels SRAM offer and are the lightest and most aggressive package. Weighing just 1,495 grams (26”) and tailored to endure demented levels of abuse, they are very versatile wheels that are suitable for anything from XC to all-mountain daily use.

• Available in all three wheel sizes: 26”, 27.5” and 29”
• CARBON TUNED
• WIDE ANGLE profile: 21mm inside, 29mm outside rim width
• UST compatible
• Double butted, stiff stainless steel spokes

The Roam 50 is aluminum, but shares most of the features of the top Roam 60 wheel at almost half the price.


ROAM 50
Price: $1,072

Weight
• 26” 1,475 grams
• 27.5” - 1,530 grams
• 29” - 1,611 grams

The Roam 50 wheels are one of the lightest alloy trail wheels on the market.

• Available in all three wheel sizes: 26”, 27.5” and 29”
• Lightweight aluminum rim with asymmetrical profile
• 21mm inside, 25mm outside rim width
• UST compatible
• Aluminum nipples with nylon lock ring
• Durable hub internals with STAR RATCHET system

Available for all three wheel sizes, easy to maintain, reliable, robust and still under 1700 grams (26-inch version).


RAIL 50
Price: $1,072

Weight
• 26” - 1,690 grams
• 27.5” - 1,750 grams
• 29 – N/A

The Rail 50 wheels are designed to be the most aggressive and durable of all SRAM alloy offerings, but still don’t tip the scales in the wrong direction. Aimed more at the all-mountain segment, although they have the widest rim (23mm) and are the portliest of all three SRAM wheels, the weight is still very impressive (1690g compared to a Mavic Crossmax ST – 1755g).

Interestingly, SRAM weren’t going to offer the 29-inch version of the Rail 50 until Specialized presented the world with the Enduro 29er, a wrecking ball of a bike that demands stout, stiff, strong wheels.

• Available in three wheel sizes: 26”, 27.5” and 29”
• Lightweight aluminum rim with asymmetrical profile
• WIDE ANGLE profile: 23c, 28mm outside rim width
• UST compatible
• Available with 11-speed XD driver body for SRAM XX1 or 9/10-speed driver body
• Aluminum nipples with nylon lock ring
• SOLO SPOKE design with double butted, stiff steel spokes
• Durable hub internals with Star Ratchet system
• SIDE SWAP easy conversion to all axle types

INITIAL IMPRESSIONS
How do you really test a good wheel? Often a good wheel will feel invisible whereas a bad wheel will stand out like a sore thumb. It was hard to pick out the merits of SRAM wheels (we rode the top of the line ROAM 60) while riding largely unfamiliar terrain and on foreign bikes that were dripping in other new products.

What I couldn’t feel was a considerable amount of lateral flex, slow engagement or inertial heft. All very good things to not feel.

Bastien Donzé explained that he and the designers had spent a great deal of time creating a matrix that covered all the different design parameters and variants that exist within a wheel to find the optimum balance of weight, stiffness, and compliance to find the most suitable ride characteristic.

They stayed straight, they felt light and not once did they feel like they bound up or flexed. The SRAM wheels seem like contenders, but more testing is required before we can come to a well-rounded conclusion.

A wheel can be changed in so many ways to alter the ultimate ride characteristics – rim profile, rim height, rim material, spoke material, spoke numbers, spoke pattern, hub flange width etc etc. – but what SRAM wanted to create were wheels that were very stiff laterally (meaning they track true and hold a line), had a subtle amount of vertical compliance (offering a more comfortable ride) and were light enough to position them to be incredibly versatile.

Ultimately, what became clear was that this isn’t a case of SRAM throwing some stickers or fancy graphics on rims and hubs from other manufacturers. Rather, SRAM has designed these wheels from the ground up. We expect to be able to spend more time on these wheels and when that happens, we’ll have a clearer indication of their longevity, strength and resistance to wear and tear.

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