The Big Iron v2

The ultimate modern fat bike.

The bike that won Outside Magazine Best Fat Bike of 2020 just got even better! Built around 27.5” fat bike wheels with clearance for up to 27.5×4.5” or 26×5” tires, this modern titanium steed will be your trusty companion on any snow or soft-surface endeavor. The crew at Why goes way back to the early days of fat biking in Alaska, and the Big Iron is the culmination of years of fat biking experience combined with modern design features, and an engineering oversight to optimize Why’s titanium tubing to the rigorous riding the Big Iron is made for. The V2 sees some updates to slightly more progressive geometry and a new UDH hanger to future-proof this bike even more.

Named after the the famous Marty Robbins song, the Big Iron is designed to be a tool to get the job done. Whether its a short weekend jaunt on the local groomed single track or an epic 1100 mile journey across Alaska, the modern geometry, stiff-yet-supple titanium frame, and lifetime warranty make this a bike you’ll be proud to take anywhere that requires big tires.  Would you like to see some custom built Big Irons?  Click Here.

Beauty at every angle

Interested in a Big Iron? See available stock now at!

Big Iron V2 Frame Specs

  • Headset Integrated standard 42mm upper cup, 52mm lower cup
  • Bottom Bracket Threaded 100mm BSA standard
  • Axle Spacing Boost 12mm x 226mm
  • Sram UDH 12mm Thru Axle, 1.00 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″
  • Universal Derailleur Hanger (UDH)

*Certain rim and tire combinations may prevent the ability to use full range of sliding dropouts.*

Big Iron V2 geometry

The Big Iron V2 brings an updated and further modernized mountain bike geometry adapted for use with super-huge 27.5 fat bike tires. Using feedback from the V1, the V2 offers a slightly longer reach paired with a taller stack, which allows for what we think is best balance of comfort and control that is unique to fat bikes. 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 post, but still keeps 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


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. 




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.