6061 Trail+ v2 Fat Bike - Firehouse Red

A completely new frame, a much slacker front end, hydraulic brakes, and a dropper port. The fat bike grew up.

Version one was an honest entry-level fat bike. Version two is a different machine: new hydroformed 6061 frame drawn around modern progressive geometry, UDH dropouts, thru-axles front and rear, 180mm hydraulic discs, internal dropper routing, and a wide-range Shimano drivetrain with a genuinely low climbing gear.

Sand, snow, desert singletrack, and the kind of terrain where a 4.5" tire is the only thing that makes sense.

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What changed from V1

Almost everything that touches how the bike rides.

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The geometry is the headline

V1 handled like what it was — a budget fat bike built on conservative numbers. V2 was drawn from scratch, and the front end is where you feel it.

• 66° head tube angle. Slack. Most fat bikes in this class sit at 69°. Three degrees sounds small on paper and is enormous in practice: the front wheel leads the bike instead of darting, and it stops trying to tuck under you on a steep, loose descent.
• 455mm chainstays across every size. Long rear center keeps weight between the wheels, which is exactly what you want when the rear tire is searching for traction in sand or snow.
• 65mm bottom bracket drop. Low. Your weight sits below the axles — the thing that makes a bike feel planted in corners and on off-camber terrain.
• 45mm fork offset paired with that slack head angle puts a lot of trail under the front wheel. That's what makes the bike track straight through soft sand and chewed-up snow instead of wandering.
• 50mm stem on a 740mm bar. The short stem and wide bar are part of the geometry, not an afterthought. Steering gets precise and the weight distribution stays where the frame wants it.

Long front center, long rear center, slack head angle, short stem. It's the layout every good modern trail bike uses, applied to a fat bike.

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Hydraulic brakes, finally

V1 ran mechanical Tektro calipers. V2 runs Tektro HD-M275 hydraulic discs with 180mm rotors front and rear, on post mounts.

This matters more on a fat bike than on anything else. You're moving a lot of rotating mass — a 4.5" tire and rim assembly is heavy, and it carries real momentum. Mechanical brakes on a fat bike mean squeezing hard and hoping. Sealed hydraulics with big rotors mean one or two fingers and actual control over how fast you slow down, which is the difference between modulating a descent and surviving it.

180mm front and rear is deliberate. Plenty of bikes step down to a smaller rear rotor to save weight. On something this heavy, carrying gear, on loose ground, the rear brake does real work.

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Eight speeds, 409% of range

A Shimano ESSA 1x8 drivetrain: 11–45T cassette, RD-U2000 Shadow rear derailleur, and an SL-M315 Rapidfire Plus shifter with an optical gear display.

V1 was 9-speed with an 11–36T cassette. V2 has one fewer cog and a much wider spread:

• V1: 11–36T — 327% range
• V2: 11–45T — 409% range

That bottom gear is the point. Fat bikes get ridden up things — soft sand, deep snow, loaded climbs — where cadence collapses and you need somewhere lower to go. Trading a cog for nine more teeth at the back is the right trade every time on this kind of bike.

Eight speed also means a cheaper chain, a cheaper cassette, and a drivetrain that tolerates being a little out of tune. On a bike that spends its life in sand, salt, and snowmelt, that's not a compromise — it's the correct spec.

Cassette steps: 11-13-15-18-22-27-35-45T, paired with a 28T chainring on 170mm cranks.

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Choose Your Seatpost

A dropper is the single biggest upgrade you can make to a bike like this. V1 had no provision for one at all — V2 has the port and the internal routing already in the frame, on a 31.6mm seat tube.

On a fat bike it earns its place faster than you'd think: dune drops, technical descents, off-camber snow where you want your weight back and the saddle out of the way. Two ways to get one.

How much post will fit. Maximum insertion depth into the seat tube, by size:

• Small (42cm): ~206mm
• Medium (46cm): ~246mm
• Large (50cm): ~286mm

Check your dropper's minimum insertion requirement against the figure for your size before ordering. Longer-travel posts need more depth, and on the Small in particular a shorter-travel post may be the only thing that fits with the saddle at your pedaling height.

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Room for 4.8" rubber

Every build ships on Kenda Juggernaut 26 x 4.5" tires, and the frame has room past that:

If you plan to run the widest rubber the frame will take, the carbon fork is the only way to do it front and rear.

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Carbon fork upgrade — $299.99

Every build ships with the matched alloy rigid fork: thru-axle dropouts, cargo mounts, 485mm axle-to-crown.

The carbon fork is a $299.99 upgrade, and it does two things. Weight comes off the very front of the bike, which is the place you feel it most — in how the bike lifts over obstacles and in the first thirty feet of every ride. Carbon also damps high-frequency chatter, which on a rigid bike running low pressure is a real comfort gain on frozen ruts and washboard.

And it opens up the extra tire clearance: 4.8" versus 4.6" on the alloy fork.

• Axle-to-crown: 491mm
• Offset: 40.2mm
• Steerer: Tapered, 1-1/8" to 1.5"
• Axle: 150mm x 15mm thru-axle
• Mounts: Same cargo mount provisions as the alloy fork

The carbon fork is 6mm longer and 4.8mm less offset than the alloy fork, which slackens the front end very slightly and adds a little trail. In practice it makes an already-stable bike marginally more stable.

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UDH and modern axle standards

Universal Derailleur Hanger dropouts. A replacement is available at virtually any shop anywhere in the world — no proprietary part to source after you drop the bike on its drive side a thousand miles from home. It also opens a path to modern direct-mount drivetrains later without needing a different frame.

Thru-axles front and rear. V1 used a 135mm quick-release front and a 190mm quick-release rear. V2 moves to 150mm x 15mm front and 197mm x 12mm rear thru-axles on upgraded sealed-bearing hubs. Stiffer, more precise, and the wheel goes back in the same place every time.

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Mounts for actual bikepacking

New on V2: cargo mounts on the top tube and the down tube, plus bottle mounts. The fork gained cargo mounts too — on both the alloy and the carbon version.

Fat bikes and bikepacking belong together — the whole premise is going where roads aren't, and that usually means carrying what you need. V1 gave you a frame and a hope. V2 gives you threaded bosses where you want to bolt things: a top tube bag, cargo cages on the fork, a bottle inside the frame instead of strapped to the bars.

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Tire pressure — read this part

Tire pressure is the single most important adjustment on a fat bike, and it's the one most new owners get wrong. These tires run far softer than anything else you've owned — a floor pump gauge often won't even read accurately that low. A low-pressure gauge is worth the ten dollars.

The Kenda Juggernaut is rated 5 to 30 PSI. Where you sit in that range changes the bike completely:

• Deep snow or soft sand: 5–8 psi. Low enough that the tire visibly flattens and floats instead of digging in.
• Packed snow, dirt, hardpack trail: 8–12 psi.
• Pavement and gravel road miles: 12–15 psi. Rolls faster, still comfortable.

Start in the middle and let air out until it feels right. Most people's first instinct is to run far too much pressure, which gives up the entire reason to ride a fat bike. You will almost never want to be near 30.

Ships with tubes installed. These rims and tires are not rated for tubeless setup.

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Geometry

Shared across all three sizes:

• Head tube angle: 66°
• Seat tube angle: 74°
• Chainstay / rear center: 455mm
• Bottom bracket drop: 65mm
• Fork offset: 45mm (alloy fork)
• Fork axle-to-crown: 485mm (alloy fork)

By size:

• Small (42cm) — reach 450.5mm · stack 591.1mm · top tube 620mm · seat tube 420mm · head tube 110mm · front center 736.9mm · wheelbase 1184.3mm
• Medium (46cm) — reach 467.9mm · stack 600.2mm · top tube 640mm · seat tube 460mm · head tube 120mm · front center 758.2mm · wheelbase 1205.8mm
• Large (50cm) — reach 480.3mm · stack 609.4mm · top tube 655mm · seat tube 500mm · head tube 130mm · front center 774.6mm · wheelbase 1222.2mm

Handling is consistent across the range — every size shares the same head angle, chainstay length, bottom bracket drop, and fork offset. Only the front end grows.

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Size Recommendations

• Small (42cm): riders 5'6" – 5'10"
• Medium (46cm): riders 5'9" – 6'1"
• Large (50cm): riders 6'0" – 6'5"

Sizes overlap on purpose. If you fall between two, the smaller size gives a more nimble, upright fit and the larger one stretches you out. With a 50mm stem and a 740mm bar, reach is the number worth comparing against a bike you already ride. Full numbers are on our geometry chart.

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Complete Component Spec

Frame & Fork

• Frame: Hydroformed 6061 alloy, UDH thru-axle dropouts, internal dropper routing, cargo mounts on top tube and down tube, bottle mounts
• Rear spacing: 197mm x 12mm thru-axle
• Fork: Alloy rigid, 150mm x 15mm thru-axle, cargo mounts, 485mm axle-to-crown, 45mm offset
• Fork upgrade: Carbon, 491mm axle-to-crown, 40.2mm offset, tapered steerer, +$299.99
• Brake mount: 180mm post mount
• Headset: A-head, 23.5mm stack, State Bicycle Co. laser-etched top cap

Drivetrain

• Shifter: Shimano SL-M315-8R Rapidfire Plus, 8-speed, optical gear display
• Rear derailleur: Shimano ESSA RD-U2000 GS, 8-speed, Shadow design
• Cassette: Shimano CS-HG400-8, 11–45T, 8-speed
• Crankset: 28T steel chainring, alloy 170mm arms
• Bottom bracket: Sealed cartridge
• Chain: KMC Z8.3
• Pedals: 9/16" platform with reflectors, included

Brakes

• Tektro HD-M275 hydraulic disc, front and rear
• 180mm rotors front and rear, 6-bolt

Wheels & Tires

• Rims: 26" double-wall alloy, 32h
• Spokes: 14g steel
• Front hub: 150mm x 15mm thru-axle, sealed bearings
• Rear hub: 197mm x 12mm thru-axle, cassette, sealed bearings
• Tires: Kenda Juggernaut 26 x 4.5", 30 TPI, 5–30 PSI
• Tubes: 26 x 4.5" Schrader, installed

Cockpit

• Handlebar: 740mm alloy, 15mm rise, 7° backsweep, 5° upsweep, 31.8mm clamp, State Bicycle Co. laser-etched
• Stem: 50mm, 7°, 31.8mm clamp
• Grips: 135mm with alloy lock rings
• Seatpost: 31.6 x 350mm alloy, State Bicycle Co. laser-etched
• Saddle: Black cover, steel rails

Max tire clearance

• Frame: 26 x 4.8"
• Alloy fork: 26 x 4.6"
• Carbon fork: 26 x 4.8"

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Want to get technical? Full Geo / Specs here.