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Big Iron
The Big Iron
The ultimate modern fat bike.
Beauty at every angle
Eagle GX Kit
- Frame – Why Cycles Big Iron
- Fork – ENVE Carbon Fat Fork
- Headset – CaneCreek 40-series IS42/IS52
- Wheels – Sun Ringle Mulefut Wheelset or upgrade to ENVE M685 Carbon 27.5 +$1899 (options available at checkout)
- Tubes – Tubeless set up included
- Tires – Terrene Cake Eater Lite 27.5 x 4.5″ 120tpi
- Bar – SRAM Descendant Alloy 35x800mm or upgrade to ENVE M6 Carbon bar +$100 or Why Cycles titanium handlebar +$170 (options available at checkout)
- Stem – SRAM Descendant 35mmx40mm
- Post – Crank Brothers Highline 7 dropper 31.6 x 125mm, 150mm or 170mm (options available at checkout)
- Saddle – Ergon SM10 Standard Black
- Shifters – SRAM GX Eagle
- Brakes – SRAM G2 R
- Rotors – Avid Centerline 160mm
- Rear Derailleur – SRAM GX Eagle
- Chain – SRAM GX Eagle
- Cassette – SRAM GX Eagle 10-52
- Crankset – Truvativ Crank Stylo 6K Alloy Dub FAT5 170 30t
- Bottom Bracket – SRAM Threaded DUB 100mm BSA Standard
- Grips – Ergon GE10
Eagle X01 Kit
- Frame – Why Cycles Big Iron
- Fork – ENVE Carbon Fat Fork
- Headset – CaneCreek 40-series IS42/IS52
- Wheels – Sun Ringle Mulefut Wheelset or upgrade to ENVE M685 Carbon 27.5 +$1899 (options available at checkout)
- Tubes – Tubeless set up included
- Tires – Terrene Cake Eater Lite 27.5 x 4.5″ 120tpi
- Bar – ENVE M6 Carbon 31.8x780mm or upgrade to Why Cycles titanium handlebar +$100 (options available at checkout)
- Stem – SRAM Descendant 31.8mmx40mm
- Post – Crank Brothers Highline 7 dropper 31.6 x 125mm, 150mm or 170mm (options available at checkout)
- Saddle – Ergon SM10 Standard Black
- Shifters – SRAM X01 Eagle
- Brakes – SRAM G2 RSC
- Rotors – Avid Centerline 160mm
- Rear Derailleur – SRAM X01 Eagle
- Chain – SRAM X01 Eagle
- Cassette – SRAM X01 Eagle 10-52
- Crankset – Truvativ Stylo Carbon DUB 5″ 30t fat bike
- Bottom Bracket – SRAM Threaded DUB 100mm BSA Standard
- Grips – Ergon GE10 Black
Eagle XX1 AXS ENVE Kit
- Frame – Why Cycles Big Iron
- Fork – ENVE Carbon Fat Fork
- Headset – CaneCreek 40-series IS42/IS52
- Wheels – ENVE M685 27.5″ Carbon wheel set-Industry Nine 28 hole 15×150 front hub and Industry Nine 28 hole torch 12×197 rear hub.
- Tubes – Tubeless set up included
- Tires -Terrene Cake Eater Lite 27.5 x 4.5″ 120tpi
- Bar – ENVE M6 Carbon 31.8mm x 780mm or upgrade to Why Cycles titanium handlebar +$100 (options available at checkout)
- Stem – ENVE M6 Carbon stem 31.8mm x 35mm or 55mm (options available at checkout)
- Post – ENVE Carbon Seatpost 31.6mm x 400mm or Upgrade to Crank brothers Highline 7 Dropper-+$100 (options available at checkout)
- Saddle – Ergon SM10 Standard Black
- Shifters – SRAM Eagle XX1 AXS
- Brakes – SRAM G2 Ultimate Rainbow
- Rotors – Avid Centerline 160mm
- Rear Derailleur – SRAM Eagle XX1 AXS
- Chain – SRAM Eagle XX1
- Cassette – SRAM XX1 Eagle 10-52
- Crankset – SRAM XX1 Eagle DUB 5″ 30t fat bike
- Bottom Bracket – SRAM Threaded DUB 100mm BSA Standard
- Grips – Ergon GE10 Black
Frame and Fork Only
- Frame
- ENVE Carbon Fat Fork
- CaneCreek 40-series IS42/IS52
- Seat Collar
- Maxle
Frame Only
- Frame
- CaneCreek 40-series IS42/IS52
- Seat Collar
- Maxle
Big Iron Frame Specs
- Headset Integrated standard 42mm upper cup, 52mm lower cup
- Bottom Bracket Threaded 100mm BSA standard
- Axle Spacing Boost 12mm x 197mm
- Dropouts 12mm Thru Axle, 1.75 thread pitch, adjustable sliding and belt drive compatible
- Bottle Mounts – Bottle mounts on seat tube, top of down tube, bottom of downtube. Third bottle hole mount on downtube for accessory mounting
- Rack Mounts – All standard rack and fender mounts
- Seatpost – 31.6mm
- Seat clamp – 34.9mm
- Brake – Max 180mm rear w/adapter, direct mount standard
- Clearance – Max 27.5 x 4.5″ tires, 26 x 5.0″ tires or 29 x 3.0″
Big Iron geometry
The Big Iron uses truly modern mountain bike geometry adapted for use with super-huge 27.5 fat bike tires. The reach is longer than most other fat bikes, which allows for the same body position using a wider bar and short stem. The handling benefits of this setup are magnified in snow riding with a sometimes unstable front tire at low pressures. The chain stays are adjustable from 445mm to 460mm so you can really dial in the rear-end snappiness of this bike based on the tire size you choose. A lower seat tube and curved top tube allow for excellent standover height while allowing for the use of a longer than normal dropper seatpost, and still keep a nice big front triangle if you choose to use a frame bag for gear storage.
Because Titanium is Magic
We make our bikes form the best materials possible for the terrain we ride. For now, that means titanium, but we’re not stopping there stay posted. We use the highest quality Grade 9 3/2.5 titanium for our frames’ tubing, and 6/4 titanium for the head tube, bottom bracket shell, and machined bits all over the frame. The wonder material has so many excellent ride quality attributes: 43% lighter than steel, higher strength-weight ratio than aluminum, significantly more resistant to crash-damage than carbon, and the best vibration damping properties of all three listed here. We think you’ll agree that we achieved our goal of creating titanium frames with a modern twist by engineering guided internal cable routing, stealth dropper post routing, integrated headsets, and threaded bottom brackets. For riders who want a high-end, comfortable, fast bike built to last a lifetime, we believe a properly made titanium frame is the best option.
The Why Bikes
Guarantee
At Why, we believe in our products. If you are not fully satisfied with your purchase for any reason, you can return your Why for a full refund within 30 days of purchase. Of course, we ask that you respect this policy (no purposely buying a bike for a long term “rental” allowed!)
Further, we offer a lifetime warranty to the original buyer on all Why frames. This is a straightforward warranty policy- basically if you use your bike for what it was intended, and the frame ever fails due to a manufacturing defect, we will replace it for you for free.
And, to top all of that, we offer a lifetime crash replacement policy. If you crash your bike and damage it, or if you drive into your garage while forgetting there was a fresh new Why on the roof of your car, we will work with you to offer you a replacement frame at a very low cost.

WHY WHY CYCLES
There’s nothing better than pedaling up a mountain, cruising along backwoods dirt road, or flying through a flowy dirt jump line. We’re proud of our handmade, uniquely rad bikes that we know you’ll love. We sell bikes directly to you from our website here, promising to offer you the best experience possible when buying, receiving, and, most importantly, riding your new Why. You can rest (and pedal) assured that we designed, tested, manufactured, and built your bike to the highest possible standards throughout the bike industry. We only create bikes we want to ride, and we stand behind our products with a no-questions-asked return policy and a straightforward, legitimate lifetime warranty and crash replacement policy. Peruse our site or give us a call – we’re always here to help you find the bike of your dreams and explore the unknowns around the corner.