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introducing the 2014 wheelsets from crankbrothers


crankbrothers wheel history


original wheel design goals :: in 2005, carl and frank, the founders of crankbrothers, wanted to create a new wheelset that had a more logical design. in order to make something that is either stronger at the same weight or lighter at the same strength, you have to use materials in a better, more eďŹƒcient way. they wanted to completely pair up the spokes because this is an inherently stronger structure. paired spokes form a triangle, and triangles are the strongest shape in construction. with this in mind, they got to work designing what has become the iconic and unique crankbrothers ::twinpair spoke wheelset. in the beginning, it took some experimenting to optimize the design and get it right.


wheel timeline ::

2005 first wheel prototype with v-spoke design

2008 wheelsets introduced with ::twinpair spoke design

2010 redesigned hub and updated aesthetics

2013 the newest generation of crankbrothers wheels


the original v-spoke design concept (2005) :: the original wheel concept used 
 v-shaped spokes to connect to the rim at paired points through tabs protruding o of the rim.

carl and frank quickly realized that this meant no spoke holes would be drilled in the rim, making the rim stronger, tubeless ready, and removing the need for a rim liner. the first prototype was made in 12 pieces on a rapid prototype machine that fit together like legos. we later had master wheel builder, joe binatina, build and assess the rideable samples to determine how well the design would work. joe realized that the v-spoke design was not stable and would not stay true. we were advised to find a way to connect the spoke to the rim that was more fixed.


1st generation wheel launch (2008) :: the v-shaped spokes design evolved into the ::twinpair spoke lacing pattern that we use today, and the 1st generation of crankbrothers wheels were launched. ::twinpair spoke technology creates a strong and balanced structure by equalizing the load on each side of the wheel. the nipple and spoke were designed to come together at the midpoint for accurate and easy to access tensioning. this also creates a balance of stiness and compliance by using shortened steel spokes with elongated aluminum nipples. we originally decided not to create a new freehub system, and we instead adapted the hub flanges on an existing design to fit our wheels. however, we dealt with freehub durability issues, and we had to go through a series of hub improvements. our final hub was quite reliable, but we still wanted to make something even more robust.


2nd generation wheel launch (2010) :: the goal with the 2nd generation wheel development was to update the hub design and address the issues of the 1st generation wheels. we developed a freehub testing machine that could apply large repeated loads, allowing us to benchmark test our competition and our own freehubs. our 2nd gen wheels used a proven freehub design that has been very reliable. freehub warranty dropped from 17% to less than 1%. as bike technology developed, we realized that we faced some challenges being able to convert hubs between 135 and 142 spacing. testing also showed that our wheel stiness should be higher, our weights lower, and our rims wider. with the hub issue solved, we went back to the drawing board to improve the quality of our wheelsets by focusing on redesigning the rim.


3rd generation wheel launch (2013) :: the 3rd generation crankbrothers wheelsets feature an optimized rim profile that improves stiness and reduces weight. the collection is improved across all models and is better than ever. :: new price points for higher value :: optimized rim profile :: new bead hook design :: improved strength : weight ratio :: cobalt and iodine now available in 3 diameters :: wheelsets are now fully compatible with all end caps included :: SRAM XD 11-speed available (aftermarket kit)


product categories :: the crankbrothers wheel line includes three categories, each designed for a specific style of mountain biking. cobalt//xc/race

iodine//all mountain

opium//downhill


product levels :: all crankbrothers products have a numerical naming hierarchy, and it goes to 11. $$$$$$$$$$$ dreambike :: for bikes over $4,000

$$$ performance :: for bikes between $2,000 - $4,000

$$ step-up :: for bikes between $800 - $2,000

$ brand entry :: the gateway


development + redesign process


3rd gen wheel development + design goals :: with the 3rd generation of wheels, we wanted to make big improvements.

we had a lot of goals with this redesign: :: improve lateral stiness :: improve impact resistance :: improve rim strength : weight ratio :: reduce weight :: improve tubeless tire interface :: improve ride quality :: add 27.5 diameters :: simplify the collection

we went to work designing a new wheel collection that would exceed the demands of the athletes that ride our products.


optimized rim profile :: rim profile optimization was our #1 focus.

overview of new aluminum rim profile: :: design focused on improving strength : weight :: tapered wall design :: optimized for durability, lateral stiness, and vertical compliance :: internal widths all 2mm wider :: increased rim depth 
 (actual increase varies by model)


optimized rim profile :: all rims are now wider with lower sidewall heights. 2mm wider

2008-2013

2014 1.7mm lower

2mm wider lateral widths. :: improves lateral stiness because a larger cross section can better withstand bending forces.

1.7mm lower sidewalls.

:: improves impact resistance by allowing more clearance for tires to absorb more, as well as withstanding bending forces.


optimized rim profile :: the rim profile is deeper for increased strength. 2014 increased rim depth

2008-2013

improved bracing angle

increased rim depths.

:: improve radial strength and resistance to buckling :: improves spoke bracing angle, to better withstand lateral loading :: shortened spoke lengths by 4mm (keeping 1 spoke length per diameter)


optimized rim profile :: we reduced weight in the rim design. 2008-2013

2014 3.

1.

4.

2.

the new rim profile allowed us to reduce weight in 4 key areas.

1. removed I-beam :: re-distributed the material to increase width and depth. 2. tapered sidewall thickness :: keep material in high stress areas, and thin the material elsewhere. 3. reduced bead hook width :: by 0.2mm 4. reduced sidewall height :: by 1.7mm


optimized rim profile :: tubeless tire interface has improved. non-perforated tire bed :: no extra rim strip or tape needed. curved tire well :: allows for tire beads to easily slide into re-designed bead hooks. reduced bead hook width 0.2mm :: along with the 2mm increased internal widths allows tire profiles to open up, but still maintains a nice rounded shape. reduced sidewall height 1.7mm :: creates a tighter, more precise fit with the tire bead.


optimized rim profile :: aluminum rim profile comparison. 2008-2013

cobalt 2, 3 iodine 2, 3 opium 3

2014


rim analysis & testing


rim design + analysis :: we analyzed hundred of iterations of rim cross sections until we found the optimal design.

FEA stress analysis for: lateral bending vertical loading (buckling) radial stress & loading static tire pressure

with this thorough analysis, we are confident that our wheelsets will meet the demands of the most discerning and aggressive riders.


rim design + analysis :: FEA stress analysis for lateral bending:

150 N lateral load


rim design + analysis :: FEA stress analysis for vertical loading (buckling):


rim design + analysis :: FEA stress analysis for radial loading & inflation pressure:

radial stress

static tire pressure


testing procedures & results :: we put the redesigned wheels through extensive testing, and then we tested them some more.

we tested with machines: rim lateral stiffness wheel lateral stiffness frontal stiffness (radial) wheel fatigue testing vertical strength testing spoke tab strength testing hub fatigue testing wheel impact testing

and we tested with riders: crankbrothers race club xc team bianchi tx-active world cup xc team norco international dh team hans rey richie schley holger meyer karen eller crankbrothers product team

after all was said and done, these wheels passed the test.


rim lateral stiffness :: the lateral stiffness and stiffness : weight improved substantially in both the aluminum and carbon rims.

aluminum rim testing: cobalt 3 29”, 6061-T6 aluminum rim rim

weight stiffness

stiffness : weight

2nd gen

460g

12.70 N/mm

27.56

3rd gen

430g

15.15 N/mm

35.24

19% improvement in lateral stiffness 28% improvement in stiffness : weight


wheel lateral stiffness :: with the stiffer rim, the wheelset itself became much stiffer, with an improved strength:weight ratio.

aluminum wheel testing: cobalt 3 29”, rear wheel wheel weight stiffness

stiffness : weight

2nd gen

975g

31.58 N/mm

32.39

3rd gen

934g

34.52 N/mm

36.96

9% improvement in lateral stiffness 14% improvement in stiffness : weight


wheel frontal stiffness + fatigue test ::

frontal stiness (radial)

fatigue test


rim vertical strength testing :: vertical strength & compliance determines ride quality. this is how we test vertical strength: rim is fixed vertically, while a constant load is applied normal to the centerline. the rim is tested until failure, with the max force recorded for the first crack and ultimate failure. the resulting deflection (displacement) is also recorded.


spoke tab strength testing :: spoke tabs are tested to ensure they surpass 150% of the maximum paired spoke tensile strength.


hub fatigue testing :: our current generation hubs have a <1% warranty rate. these hubs are durable and reliable. the hub drive mechanism is fatigue tested using a proprietary test designed by crankbrothers to ensure durability:

a cycle test applies a given torque for 2 seconds, then reverse rotates 370째. this cycle repeats for the test duration. the rim is tested until failure, with the max force recorded for the first crack and ultimate failure. our current hubs have been in production since 2010 and have over 10 times the lifespan compared to the first gen hubs. all hubs are fully compatible, and end caps are included with all wheelsets. xd-driver adapter is available as an aftermarket kit.


wheel ride testing :: we had some of the best athletes put all of our wheel models to the test, incorporating their feedback into the final wheel design.

cobalt testing ::

bianchi tx-active uci team: gerhard herschbaumer (u23 elite xc world champ) crankbrothers race club: judy freeman chloe woodruďŹ&#x20AC;

iodine testing :: richie schley hans rey holger meyer karen eller

opium testing ::

norco international dh team: jill kintner bryn atkinson


aluminum rim finish treatments :: our 3rd generation aluminum rims feature a new finishing treatment to improve fatigue life. alloy rims receive a shot peened surface treatment that increases rim strength by 15% by hardening rim surface and reducing possibility of micro surface cracks. the rim seam is welded and polished for a strong and clean joint. all aluminum rims are anodized, and level 3 rims receive a 2-color treatment. graphics are laser etched.


wheel assembly :: all crankbrothers wheelsets are hand built, and we perform thorough inspection to ensure maximum quality control. 100% hand built crankbrothers wheelsets have always been hand built with no machine assembly. the ::twinpair spoke design have a unique and simple build process.

100% inspection all wheelsets are inspected for:
 :: lateral, radial, dish within ±0.4mm
 :: spoke tension
 :: cosmetic finish

we are serious about consistency and quality control in our wheelsets.


the final product


cobalt 3 wheelset :: weight 27.5 / 29

1650g / 1735g

rim material

6061-t6, smooth weld joint

finish

shot peen, black + red anodizing

width (int / ext)

21mm / 24.9mm

depth

19.5mm

spokes material

sapim

butting

2.0 / 1.6 / 2.0

length (27.5 / 29)

147mm / 166mm

spoke pins

hollow 7075-t6 aluminum

nipples material

7075-t6 aluminum

size

3.2 x 139

hubs front hub

6061-t6, cobalt

bearings

sealed cartridge 6804 (x2)

front hub end caps

15mm (installed), 9mm (included)

rear hub

6061-t6, cobalt

bearings

sealed cartridge 6903 (x2), 6902 (x2)

rear end caps

12x142 (installed), 10x135 (included)

freehub

3-pawl, 21T, alloy

msrp / warranty warranty

2 years

msrp

$900


cobalt 2 wheelset :: weight 26 / 27.5 / 29

1660g / 1710g / 1790g

rim material

6061-t6, smooth weld joint

finish

shot peen, black anodizing

width (int / ext)

21mm / 24.9mm

depth

19.5mm

spokes material

stainless steel

butting (26 & 27.5)

2.0 / 1.8 / 2.0 (29â&#x20AC;? is 2.0 straight gauge)

length (26 / 27.5 / 29)

134mm / 147mm / 166mm

spoke pins

solid 7075-t6 aluminum

nipples material

7075-t6 aluminum

size

3.2 x 139

hubs front hub

6061-t6, cobalt

bearings

sealed cartridge 6804 (x2)

front hub end caps

15mm (installed), 9mm (included)

rear hub

6061-t6, cobalt

bearings

sealed cartridge 6903 (x2), 6902 (x2)

rear end caps

12x142 (installed), 10x135 (included)

freehub

3-pawl, 21T, steel

msrp / warranty warranty

2 years

msrp

$600


iodine 3 wheelset :: weight 27.5 / 29

1780g / 1850g

rim material

6061-t6, smooth weld joint

finish

shot peen, black + silver anodizing

width (int / ext)

23mm / 27.2mm

depth

19.5mm

spokes material

sapim

butting

2.0 / 1.8 / 2.0

length (27.5 / 29)

147mm / 166mm

spoke pins

hollow 7075-t6 aluminum

nipples material

7075-t6 aluminum

size

3.2 x 139

hubs front hub

6061-t6, iodine

bearings

sealed cartridge 6805 (x2)

front hub end caps

15mm (installed), 20mm (included)

rear hub

6061-t6, iodine

bearings

sealed cartridge 6903 (x2), 6902 (x2)

rear end caps

12x142 (installed), 10x135 (included)

freehub

3-pawl, 21T, alloy

msrp / warranty warranty

2 years

msrp

$900


iodine 2 wheelset :: weight 26 / 27.5 / 29

1810g / 1845g / 1910g

rim material

6061-t6, smooth weld joint

finish

shot peen, flat black anodizing

width (int / ext)

23mm / 27.2mm

depth

19.5mm

spokes material

stainless steel

butting

2.0 straight gauge

length (26 / 27.5 / 29)

134mm / 147mm / 166mm

spoke pins

solid 7075-t6 aluminum

nipples material

7075-t6 aluminum

size

3.2 x 139

hubs front hub

6061-t6, iodine

bearings

sealed cartridge 6805 (x2)

front hub end caps

15mm (installed), 20mm (included)

rear hub

6061-t6, iodine

bearings

sealed cartridge 6903 (x2), 6902 (x2)

rear end caps

12x142 (installed), 10x135 (included)

freehub

3-pawl, 21T, steel

msrp / warranty warranty

2 years

msrp

$600


opium 3 wheelset :: weight 26

2100g

rim material

6061-t6, smooth weld joint

finish

shot peen, black + red anodizing

width (int / ext)

26mm / 31.1mm

depth

23.4mm

spokes material

sapim

butting

2.0 straight gauge

length

132mm

spoke pins

hollow 7075-t6 aluminum

nipples material

7075-t6 aluminum

size

3.2 x 139

hubs front hub

6061-t6, opium

bearings

sealed cartridge 6805 (x2)

front hub end caps

20mm (installed)

rear hub

6061-t6, opium

bearings

sealed cartridge 6903 (x2), 6902 (x2)

rear end caps

12x150 (installed), 12x157 (included)

freehub

3-pawl, 21T, alloy

msrp / warranty warranty

2 years

msrp

$900


the new wheelsets from crankbrothers lighter :: stronger :: stiďŹ&#x20AC;er :: better

2014 crankbrothers wheels  
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