The 2015 GT Pro Series Pro XXL OS20 bike features a 6061-T6 aluminum frame with 1-1/8" integrated headtube and reverse dropouts, GT chromoly fork with tapered legs, GT frontload stem, 7.5" GT Interceptor chromoly bars, GT DOHC grips, Tektro V-brake and Promax lever, 180mm GT chromoly 2-pc cranks with sealed Euro BB, 42T alloy 4-bolt chainring, KMC Z610 chain, 3/8" sealed female flip/flop hubs with 16T freewheel, 36H Alienation OS20 rims, OS20x1.85" front and OS20x1.65" rear Tioga Powerblock tires, SDG Patriot I-Beam seat, GT plastic platform pedals and GT chain adjusters. 21.5" Toptube.
Note: The Pro Series Pro XXL OS20 uses an oversized 20" rim and tire (451mm bead diameter vs 406mm for standard 20x1.75" rims). OS20 is perfectly legal in the 20" race class.
The advantages of OS20 are:
- Rolls faster and smoother over bumps
- More stable at speed and in the air
- Larger contact patch for more traction off the gate and higher lean angles in the turns
The disadvantages are:
- Slightly higher rotating weight
- Small adjustment period getting used to the way the larger wheel responds to rider input
NOTE: To ensure that every component on your bicycle is working properly, Dans Comp recommends that all GT BMX Bikes be assembled by a qualified mechanic. Improper assembly of your bicycle may lead to premature wear or failure of individual components such as headsets, crank assembly and wheels. Failure to do so may void the manufacturer warranty.