Fuel EX 8 GX | Trek Bikes

You're cool with your wheels leaving the ground, but you also like to go the distance on marathon singletrack sessions. You want a bike that lets you crush any trail, and your priority is on the parts.

A lightweight aluminum frame, 140mm FOX Rhythm 34 fork, and 130mm of rear travel with an extra-efficient RE:aktiv damper. A SRAM GX Eagle 1x12 drivetrain with an extra-low 52-tooth climbing gear, plus a Bontrager Line dropper post.

Fuel EX 8 gives you added efficiency with SRAM's latest, widest-range drivetrain and Trek's unique RE:aktiv damper that provides firm pedaling support without giving up any plush compliance.

A wider gear range and more efficient suspension help you claw your way up tricky climbs you never thought you'd clean
If you measure quality in performance per dollar, you won't do better than Fuel EX 8
This bike will make you want to rail every corner, smash every rock garden, and charge every descent
The shifter-style, underbar remote dropper post lever is super intuitive and easy to use
We expanded our size range to ensure a better fit for all riders. And, you get the fastest wheel that fits your frame: XS frames get 27.5˝ wheels, S frames get to choose between 27.5˝ or 29˝, and sizes M to XL get 29˝ wheels

"Fuel EX is a beautifully balanced and capable trail bike. The rear suspension is beautiful; as close to ideal as any bike I've ridden. It's sensitive where you want it to be, firm and crisp where it should be. It feels deep and controls big hits very well, and there's a nice platform for pedaling, and to pump and pop off when you're playing."

"Fuel EX has a few tricks that help it keep a level head when outside of its comfort zone, and to be a cloud on rails when it's in the zone. Everything about the Fuel EX, which was already good at pleasing everybody, is now even better at it."

"Thanks to its burlier components, increased travel, and more aggressive geometry, it has become more of a shredder than ever! More performance, fun, and trail prowess."

"In a world where most new full-suspension mountain bikes are amazing, Fuel EX stands apart as even more than that."

Smaller frames (XS and S) have a top tube that dips down as it approaches the seat tube. This design makes for a lower standover height, which is good for shorter riders because it allows them to straddle their bike more easily. Larger frames (M and up) have a straight top tube because taller riders with longer legs typically don’t have the same issues with standover height.

Active Braking Pivot allows our engineers to tune how the suspension reacts to acceleration and braking forces independently. That means you get more confident control when you need it most.

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RE:aktiv technology gives you firm support for efficient pedaling that instantly gives way for smooth control when the trail turns rough.

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Trek's Straight Shot frame design optimizes the stiffness-to-weight ratio for a more responsive ride. You'll be able to push harder and stay more planted on your line when the going gets rough.

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This suspension calculator will help you optimize your suspension settings for your riding weight. Simply follow the steps to find your best set up.

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Tubeless Ready rims and tires make it easy to ditch the tubes so you get better traction, fewer flats, and less weight. The rim strips are already installed; just add TLR valves and sealant.

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Fine tune head tube angle by 1/2° and BB height by up to 10mm with the simple turn of a nut. Just flip the link to choose between slack or slacker geometry, without negatively affecting suspension performance. A Trek exclusive.

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Our premium lightweight aluminum is continuously cold extruded and butted at multiple points, and hydroformed into sophisticated tube shapes for maximum strength and minimum weight.

The lightest, quietest, most versatile cable management system allows any combination of shift, brake, lockout, and dropper post lines to be routed through the frame for clean looks and the ultimate custom setup.

Wider dropouts (110mm front, 148mm rear) give you the stiffness of a 27.5" wheel with all the benefits of a 29" wheel, and Boost148 in the rear lets you run wider tires and a larger chainring without affecting q-factor and pedaling efficiency.

*spec applies to all sizes unless otherwise noted

Frameset

Frame	Alpha Platinum Aluminum, tapered head tube, Knock Block, Control Freak internal routing, downtube guard, ISCG 05, magnesium rocker link, Mino Link, ABP, Boost148, 130mm travel
Fork	Fox Rhythm 34, Float EVOL air spring, GRIP damper, tapered steerer, 44mm offset, Boost110, 15mm Kabolt axle, 140mm travel
*Shock	Size: XS , S Fox Performance Float EVOL, 3-position RE:aktiv damper, tuned by Trek Suspension Lab, 210mm x 52.5mm
*Shock	Size: S , M , ML , L , XL , XXL Fox Performance Float EVOL, 3-position RE:aktiv damper, tuned by Trek Suspension Lab, 210mm x 55mm
Max compatible fork travel	150mm (561mm axle-to-crown)

Wheels

Wheel front	Bontrager Line Comp 30, Tubeless Ready, 6-bolt, Boost110, 15mm thru axle
*Wheel rear	Size: XS , S Bontrager Line Comp 30, Tubeless Ready, Rapid Drive 54, 6-bolt, 54T Rapid Drive, SRAM XD driver, Boost148, 12mm thru axle
*Wheel rear	Size: S , M , ML , L , XL , XXL Bontrager Line Comp 30, Tubeless Ready, 6-bolt, Rapid Drive 54, SRAM XD driver, Boost148, 12mm thru axle
Skewer rear	Bontrager Switch thru axle, removable lever
*Tire	Size: XS , S Bontrager XR4 Team Issue, Tubeless Ready, Inner Strength sidewalls, aramid bead, 120 tpi, 27.5x2.40''
	Size: XS , S Bontrager XR4 Team Issue, Tubeless Ready, Inner Strength sidewalls, aramid bead, 120 tpi, 27.5x2.60''
	Size: S , M , ML , L , XL , XXL Bontrager XR4 Team Issue, Tubeless Ready, Inner Strength sidewall, aramid bead, 120 tpi, 29x2.40''
	Size: S , M , ML , L , XL , XXL Bontrager XR4 Team Issue, Tubeless Ready, Inner Strength sidewalls, aramid bead, 120 tpi, 29x2.60''
*Tire part	Size: XS , S , M , ML , L , XL , XXL Bontrager TLR sealant, 6oz
*Tire part	Size: XS , S , M , ML , L , XL , XXL Bontrager TLR valve, 50mm
Max tire size	29x2.60"

Drivetrain

Shifter	SRAM GX Eagle, 12 speed
Rear derailleur	SRAM GX Eagle
*Crank	Size: XS , S SRAM X1 Eagle, DUB, 30T steel ring, Boost (52mm chainline), 170mm length
*Crank	Size: M , ML , L , XL , XXL SRAM X1 Eagle, DUB, 30T steel ring, Boost (52mm chainline), 175mm length
Bottom bracket	SRAM DUB, 92mm, PressFit
Cassette	SRAM Eagle XG-1275, 10-52, 12 speed
Chain	SRAM GX Eagle, 12 speed
Max chainring size	34T

Components

Saddle	Bontrager Arvada, hollow chromoly rails, 138mm width
*Seatpost	Size: XS , S Bontrager Line Dropper, 100mm travel, internal routing, 31.6mm, 345mm length
*Seatpost	Size: M , ML , L , XL , XXL Bontrager Line Dropper, 150mm travel, internal routing, 31.6mm, 440mm length
*Handlebar	Size: XS , S Bontrager Line, alloy, 35mm, 27.5mm rise, 750mm width
*Handlebar	Size: M , ML , L , XL , XXL Bontrager Line, alloy, 35mm, 27.5mm rise, 780mm width
Grips	Bontrager XR Trail Elite, nylon lock-on
*Stem	Size: XS , S Bontrager Line, 35mm, Knock Block, 0 degree, 40mm length
*Stem	Size: M , ML , L , XL , XXL Bontrager Line, 35mm, Knock Block, 0 degree, 50mm length
Headset	Knock Block Integrated, 58-degree radius, cartridge bearing, 1-1/8'' top, 1.5'' bottom
Brake	SRAM G2 R 4-piston hydraulic disc
*Brake rotor	Size: XS , S , M , ML , L , XL , XXL SRAM CenterLine, 6-bolt, round edge, 180mm
*Brake rotor	Size: M , ML , L , XL , XXL SRAM CenterLine, 6-bolt, round edge, 200mm

Weight

Weight	M - 13.78 kg / 30.39 lbs (with TLR sealant, no tubes)
Weight limit	This bike has a maximum total weight limit (combined weight of bicycle, rider, and cargo) of 300 pounds (136 kg).

We reserve the right to make changes to the product information contained on this site at any time without notice, including with respect to equipment, specifications, models, colors, and materials.

Bike and frame weights are based off pre-production painted frames at time of publication. Weights may vary in final production.

The charts below show our recommended sizes based on height, but there are some other factors, like arm and leg length, that determine a great fit. That’s why you’ll see some overlap in our recommendations. Not every rider who’s 5´8˝, for example, will fit on the same size bike. The best way to find your perfect fit is to consult the experts at your local retailer.

Rider Height

Inseam

137.0 - 155.0 cm

4'5.9" - 5'1.0"

64.0 - 73.0 cm

25.2" - 28.7"

153.0 - 166.5 cm

5'0.2" - 5'5.6"

72.0 - 79.0 cm

28.3" - 31.1"

161.0 - 172.0 cm

5'3.4" - 5'7.7"

76.0 - 81.0 cm

29.9" - 31.9"

M/L

165.5 - 179.0 cm

5'5.2" - 5'10.5"

77.0 - 84.0 cm

30.3" - 33.1"

177.0 - 188.0 cm

5'9.7" - 6'2.0"

83.0 - 88.0 cm

32.7" - 34.6"

186.0 - 196.0 cm

6'1.2" - 6'5.2"

87.0 - 92.0 cm

34.3" - 36.2"

2XL

195.0 - 203.0 cm

6'4.8" - 6'7.9"

92.0 - 95.0 cm

36.2" - 37.4"

All measurements provided in cm unless otherwise noted.

Frame size number	Frame size letter	Geometry position	Wheel size	A — Seat tube	B — Seat tube angle	Effective seat tube angle	C — Head tube length	D — Head angle	E — Effective top tube	F — Bottom bracket height	G — Bottom bracket drop	H — Chainstay length	I — Offset	J — Trail	K — Wheelbase	L — Standover	M — Frame reach	N — Frame stack
14.0	XS	Low	27.5"	35.6	69.0°	75.0°	9.0	66.0°	54.6	33.5	2.1	43.7	4.3	11.1	112.0	69.5	39.5	56.3
14.0	XS	High	27.5"	35.5	69.5°	75.5°	9.0	66.5°	54.5	34.1	1.4	43.6	4.3	10.6	111.9	70.0	40.0	55.9
15.5	S	High	27.5"	39.5	69.5°	75.5°	10.0	66.5°	56.7	34.1	1.4	43.6	4.3	10.6	114.3	70.7	42.0	56.8
15.5	S	Low	27.5"	39.5	69.0°	75.0°	10.0	66.0°	56.8	33.5	2.1	43.7	4.3	11.1	114.4	70.0	41.5	57.2
15.5	S	High	29"	39.5	68.0°	75.5°	10.0	66.5°	57.7	34.6	2.8	43.6	4.3	11.5	115.3	70.7	42.0	60.5
15.5	S	Low	29"	39.5	67.5°	75.0°	10.0	66.0°	57.8	34.0	3.4	43.7	4.3	11.9	115.4	70.1	41.5	60.9
17.5	M	Low	29"	42.0	67.5°	75.0°	10.0	66.0°	60.3	34.0	3.4	43.7	4.3	11.9	117.9	74.2	44.0	60.9
17.5	M	High	29"	42.0	68.0°	75.5°	10.0	66.5°	60.2	34.6	2.8	43.6	4.3	11.6	117.8	74.8	44.5	60.5
18.5	ML	Low	29"	43.5	67.5°	75.0°	10.5	66.0°	61.9	34.0	3.4	43.7	4.3	11.9	119.6	74.5	45.5	61.3
18.5	ML	High	29"	43.5	68.0°	75.5°	10.5	66.5°	61.8	34.6	2.8	43.6	4.3	11.6	119.5	75.1	46.0	60.9
19.5	L	Low	29"	45.0	67.5°	75.0°	10.5	66.0°	63.4	34.0	3.4	43.7	4.3	11.9	121.1	75.0	47.0	61.3
19.5	L	High	29"	45.0	68.0°	75.5°	10.5	66.5°	63.3	34.6	2.7	43.6	4.3	11.6	121.0	75.6	47.5	60.9
21.5	XL	Low	29"	50.0	67.5°	75.0°	12.0	66.0°	66.3	34.0	3.4	43.7	4.3	11.9	124.2	76.2	49.5	62.7
21.5	XL	High	29"	50.0	68.0°	75.5°	12.0	66.5°	66.2	34.6	2.7	43.6	4.3	11.6	124.1	76.8	50.0	62.3
23.0	XXL	Low	29"	54.0	67.5°	75.0°	14.0	66.0°	68.8	34.0	3.4	43.7	4.3	11.9	127.0	80.0	51.5	64.5
23.0	XXL	High	29"	54.0	68.0°	75.5°	14.0	66.5°	68.7	34.6	2.7	43.6	4.3	11.6	126.9	80.6	52.0	64.1

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favorite_borderWhy you'll love it

"A world-class trail bike"

"Good at pleasing everybody"

"An absolute trail rocket"

"Perfect all-arounder"

Features

Suspension Calculator

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Tubeless Ready

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Mino Link adjustable geometry

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Alpha Platinum Aluminum

Control Freak Cable Management

Boost148/110

Specifications

Sizing & fit