RAIL 40 Wheels

AGGRESSIVE BEHAVIOR

With WIDE ANGLE™ rim design providing superior stability, RAIL 40 can withstand the most aggressive All-Mountain / Enduro riding by setting a new benchmark for stiffness in its category. Featuring the perfect balance of strength, lightweight and width for enduro terrain, RAIL 40 delivers high performance ride quality all the way down.

  • Available in 27.5” and 29”
  • Lightweight but strong aluminum rim, asymmetrical profile with TAPER CORE™ technology. Welded joint
  • UST Tubeless
  • WIDE ANGLE™ profile—23mm
  • SOLO SPOKE™—double butted spokes
  • DOUBLE TIME™ ratchet mechanism for durable, quick engagement—SPEEDBALL™ bearings
  • Convertible axles: 
    Front Hub - QR 9x100, QR Torque Caps, 15x100, 15x100 Torque Caps, 20x110, 15x110, 15x110 Torque Caps.
    Rear Hub - QR 10x135, 12x135,12x135 XD, 12x142, 12x142 XD,12x148, 12x148 XD.
  • Available in XD™ or 10-speed driver body
  • BOOST™ 148 compatible
  • Weight: 1810g (27.5”), 1900g (29”). Wheel pair in lightest configuration. Wheel weights can vary 5%.

 

Alternate views

Some variations of this product featured on this page are not available for purchase and are installed on bicycles as original equipment only. See your dealer for details.

Wheels are priced and sold individually.

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Specs

Specifications for RAIL 40 Wheels

Wheel27.5", 29"
Weight1810g (27.5”), 1900g (29”), Wheel pair in lightest configuration, Wheel weights can vary 5%
Spoke Count24
Spoke Pattern2 cross
TypeDouble butted spokes
Rim ShapeUST - asymmetrical 2.5mm offset TAPER CORE™
Spoke LengthSOLO SPOKE™
External NipplesExternal
MaterialAluminum
OtherBlack Ano
Retail AvailabilityApril 2015

Technology

BOOST™

With revolutionary advancements in bicycle componentry, like SRAM’s XX1, X01 and X1 drivetrains, mountain bike designers have been given almost limitless freedom to focus solely on the performance of the bike. Each advancement demands that the entire package works flawlessly. Aggressive trail and enduro riders have been increasingly enjoying the benefits of larger wheels, but many still view 27.5" and 29" wheels as a possible weak link. Which is why SRAM has developed an open standard with Boost compatible components for SRAM drivetrain, hubs and RockShox forks.

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DOUBLE TIME™

Ratcheting up the smarts. This straight-aligned, 4-pawl design turns the 26-tooth ratchet ring into 52 points of contact. The result: smooth 6.9-degree engagement without reducing tooth size or offsetting internal geometry—which means serious long-term durability.

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SOLO SPOKE™

With SOLO SPOKE, you’re never wrong. SRAM 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/nondrive-side spoke handy. 
Front + Rear + Drive-Side + Nondrive-Side = 1 Spoke

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SPEEDBALL™

The only adjustment they’ll ever need was made back at the factory. Every part of the ball bearing comes from the exact same supplier—which means that each bearing bore can be precision machined to fit the bearing race exactly. With tolerances this tight, the days of adjusting play after every ride are over.

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TAPER CORE™

Strong in the right places. The sidewalls of SRAM rims are reinforced along the wings to withstand major impact. But the sidewalls then taper in along the center—reducing overall mass. The result is a very light rim with excellent dent resistance.

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WIDE ANGLE™

Take corners as fast as you want. SRAM wheels have a wider rim profile without significant added mass. This profile holds tire shape better, preventing tire roll and giving you superior comfort and traction around corners. 
19mm XC Racing
21mm Trail
23mm All-Mountain

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XD™ Driver Body

XD is a new cassette driver body design that allows the use of a 10 tooth small cog and provides an improved interface with the cassette.

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Service

Documents Available for RAIL 40 Wheels

See more documents available for SRAM MTB products.


SRAM Warranty (2.19 MB, PDF)

EN, DE, ES, FR, IT, NL, PT, JA, ZH, PL, DA, CS, EL, RO, FI, SV, GA, BG, MT, SK, SL, HU, ET, LV, LT, KO, RU
28 Pages Updated June 16, 2015

Video