Cube Reaction GTC Pro review

Light, smooth carbon frame at a great price

Our rating 
4.5 out of 5 star rating 4.5
GBP £1,400.00 RRP | AUD $2,999.00

Our review

A great value bike with better than expected spec, but you might want to upgrade the tyres
Buy if, You're a racer or trail warrior looking for a responsive and smooth carbon ride at a great price
Pros: Efficiently driven, smooth riding, full feature full carbon frame at an alloy version price. Outstanding value Shimano XT transmission spec with decent wheels and fork
Cons: The cheap Active Line tyres are fast and hard-wearing, but lack grip and supple smoothness in wet conditions
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This carbon framed bike is light, smooth and effortlessly rapid, even on rough trails. Add a Shimano XT transmission, that would be remarkable value even on a basic alloy frame, and it’s a total bargain if racing or distance riding is what lights your fire.


The Gran Turismo Composite frame is a twin mould monocoque complete with well supported tapered head tube, bottom bracket and 142x12mm thru-axle at the end of the carefully sculpted stays.

Add the super stiff crank arms and carbon and steel chainrings of the XT chainset and that makes for a fitness flattering direct drive connection.

The tapered top, remote lockout, thru-axle Recon fork adds precision to the responsive geometry, while a 720mm bar means ruts can’t bully you

The super wide 2×11 gearset and 12.28kg weight reinforce the fact that climbs are a place to attack and drive home its advantage. Acceleration is amplified by the lightweight 28 spoke Atac wheelset, and while the hard compound ‘Active Line’ Schwalbe tyres aren’t great for grip, they certainly roll fast.

While it might look like an out and out racer, that would be underselling what a versatile and enjoyable ride the Reaction is. Despite transferring power keenly, the 29in wheels, slim rear stays, 27.2mm seatpost and flattened main tubes help the Reaction flow over rough ground rather than clattering and choking on stutter bumps.

The tapered top, remote lockout, thru-axle Recon fork adds precision to the responsive geometry, while a 720mm bar means ruts can’t bully you.


The Deore brakes even get a 180mm front rotor for more muscle, confirming its price conscious, podium topping position for racers or flat out trail warriors.

Product Specifications


Name Reaction GTC Pro
Brand Cube Bikes

Description Geometry based on size 21"
Rear Derailleur Shimano XT RD-M8000-DGS, ShadowPlus, 11-Speed, Direct Mount
Top Tube (in) 24.72
Seat Tube (in) 20.28
Chainstays (in) 17.13
Wheelset Answer Atac MA, 28/28 Spokes, 21C Tubeless-Ready Rim, 15QR/X12
Stem CUBE Performance Stem Pro, 31.8mm
Shifters Shimano XT SL-M8000-B-I, Direct Attach
Seatpost CUBE Performance Post, 27.2mm
Seat Angle 73
Saddle CUBE Active 1.1
Rear Tyre Schwalbe Rapid Rob, Active, 2.25"
Headset Type FSA Orbit I-t-R, Integrated
Available Sizes 16in 17in 18in 19in 21in 23in
Head Angle 70
Handlebar CUBE Flat Race Bar, 720mm
Grips/Tape CUBE Performance Grip
Front Tyre Schwalbe Tough Tom, Active, 2.25"
Front Derailleur Shimano XT FD-M8020-D, Direct Mount, Side Swing
Frame Material GTC Twin Mold Monocoque Technology, ARG2
Fork Rock Shox Recon Silver TK Air, QR15 Maxle, PopLoc, 100mm
Cranks Shimano XT FC-M8000, 36x26T, 175mm
Chain Shimano CN-HG600-11
Cassette Shimano XT CS-M8000, 11-40T
Brakes Shimano Deore BR-M615 Hydr. Disc Brake (180/160)
Wheelbase (in) 44.37