GT  Avalanche Comp Mountain Bike - 2021

$681.73Compared to $1,050.00* Save 35%
*Intermediate markdowns may have been taken.
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Color: Black
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Find what makes you happy, ride what sets you free. A well-rounded hardtail, the GT Avalanche Comp mountain bike is ideal for riders looking to fast-track their learning curve and love for pedaling.


  • Lightweight aluminum frame features the GT Triple Triangle design for precise handling
  • Completely redesigned alloy frame features floating seatstays for additional compliance and comfort
  • Internal cable routing allows for a clean look
  • 100 mm travel fork reduces trail vibration and increases traction control
  • 1 x 10-speed drivetrain for smooth, simplified shifting
  • Closeout
  • Specs and images are subject to change


This bike comes with Coast to Coast Support, which includes:
  • 1 year of free adjustments (see more below)
  • In-store bike assembly
  • Pickup in store or curbside
  • Bike experts available at 170+ bike shops
REI Co-op Members get more:
  • 20% off shop services
  • Free tubes with purchase of flat tire repair (Co-op Cycles brand tubes only; tube must be installed at time of purchase)
More about our free adjustments:
New bikes go through a normal break-in period, after which they should be readjusted. All bicycles sold at REI include free adjustments for one year after purchase date—as many times as you need. Included: derailleur and brake adjustments, lateral wheel truing, hub and headset bearing adjustments, tire inflation and chain lubrication. Not included: replacement or installation of new components or accessories, any other services. Call your local REI Co-op Bike Shop for more information.

View all GT Hardtail Mountain Bikes

Technical Specs

Item #215285
Best Use

Mountain Biking

Mountain Bike Style



GT 6061 T6 aluminum Triple Triangle with floating seatstays/Internal Cable Routing, Dropper Post Routing/Boost 141 Forged Drop-outs w/ Disc Brake Mounts/Zero Stack Tapered 1 1/8"- 1.5" Head Tube

Bike Suspension

Front Suspension


SR Suntour XCM-DS, 100mm, Hydraulic Lockout and Preload adjust, Coil

Fork Travel

100 millimeters


Prowheel Charm, 32T

Bottom Bracket

Cartridge, Square Taper


microSHIFT M850, 10-speed

Rear Derailleur

microSHIFT RD-M6205GM

Rear Cogs

11-42T, 10-speed

Number of Gears

10 gear(s)

Brake Type

Hydraulic Disc Brake


Tektro M275 Hydro Disc, 160/160 mm Rotors

Brake Levers

Tektro M275 Hydro Disc


WTB SX19, 32 h

Front Hub

Formula,100 mm quick-release

Rear Hub

Formula,141 mm quick-release

Wheel Size

29 inches


WTB Ranger Comp, 27.5/29 x 2.25 in., DNA Compound

Tire Width

2.25 inches

Handlebar Shape

Riser Bar


GT All Terra Alloy riser, 25 mm rise, 8 deg. sweep, 6 deg. rise, 720 mm width


GT All Terra, 6061 alloy, 31.8 mm, 8 deg.

Seat Post

GT All-Terra Micro Adjust alloy, 30.9 mm




GT Slim Line Flat Pedal


Semi-integrated, Sealed Cartridge, Tapered


KMC X10, 10-speed





Size Chart

Standover Height737679
Head Tube Length11.512.513.5
Head Tube Angle (degrees)67.567.567.5
Seat Tube Angle (degrees)74.574.574.5
Bottom Bracket Height31.431.431.4

Sizing Notes

Measurements are stated in millimeters unless otherwise indicated.

How we measure bikes

  1. Standover Height Standover Height is a measurement from the ground to the top of the top tube, measured at the midpoint of the top tube.
  2. Reach Reach is the horizontal distance from the center of the cranks to the center of the head tube, measured at head tube level.
  3. Stack Stack is the vertical distance from the center of the cranks to the center of the head tube, measured to the top of the head tube.
  4. Effective Top Tube Effective top tube is the distance from the center of the head tube to the center of the seat tube/seat post, measured parallel to the ground.
  5. Seat Tube Center to Top Seat Tube length is the measurement of the seat tube, from the center of the cranks to the top of the seat tube.
  6. Head Tube Length Head Tube Length is measured from the bottom to the top of the head tube.
  7. Head Tube Angle Head Tube Angle is the acute angle between the head tube and the ground (measured towards the rear of the bike)
  8. Seat Tube Angle Seat Tube Angle is the acute angle between the seat tube and the ground (measured towards the rear of the bike).
  9. Bottom Bracket Height Bottom Bracket Height is a measurement taken vertically from the ground up to the center of the cranks.
  10. Wheelbase Wheelbase is the measurement from the center of the front axle to the center of the rear axle.
  11. Chainstay Length Chainstay Length is the measurement from the center of the cranks to the center of the rear axle.
  12. Fork Offset Fork Offset, or rake, is the distance from the front axle to a line drawn parallel to the center of the head tube or steering axis.

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