To Dismantle Reduction Gear

GP7145GB-2.4 and GP7255AGB-2.4 Repair Instructions

Remove screws (G4). Using screwing two screws into the both thread bores, press off the gear cover (G2). Remove screw (G11) and take off the spacer ring (G7) and tension disc (G10). Push the cogwheel

(G9) off the shaft by screwing two screws into both thread bores. Finally, take the crankshaft (22) out of the crankcase by tapping it towards the bearing cover side using a rubber hammer.

Check the surfaces of connecting rods (24), crankshaft (22) and crossheads (25). Check the surfaces of the crosshead guides in the crankcase for any unevenness.

Reassemble in reverse order. Regulate axial bearing clearance to a minimum of 0.1mm and a maximum 0.15mm by means of fitting discs (20A). Insert the crankshaft by passing it through on the bearing cover side. Press in the outer bearing ring (20). The crankshaft should turn easily and with little clearance.

Fit the bearing cover (14) and tighten screws (24) to 30 ft.-lbs. (40 NM).

Important! The connecting rod has to be able to slightly move sidewise at the crankshaft journal.

Heat the ball bearings (G13) before pressing them onto the pinion (G12). Slightly press the cogwheel (G9) onto the crankshaft, so that the pinion (G12) together with the bearing (G13) can still be inserted.

When mounting, place the pinion (G12) onto the cogwheel so that they correctly interlock. Carefully tap the cogwheel and the pinion simultaneously onto the crankshaft and into the bearing seat.

Fit tension disc (G10), and spacer ring (G7) and tighten screw (G11) with Loctite.

Fit seal (17) on to the cylindrical pins (G3).

Push the gear cover (G2) carefully on to the bearing (G13). make sure the radial shaft seal (G17) does not get damaged during fitting on to the pinion.

Important! Before putting into operation again, turn the reduction gear shaft by hand at least four full turns to make sure that the gear is correctly aligned.

GP7255AGB, GP7145GB specifications

The Giant GP7255AGB and GP7145GB are two notable models in the Giant range of bicycles, specifically designed for performance and versatility in varied riding conditions. These models reflect the brand's commitment to quality engineering and innovative technology, appealing to both casual riders and serious cyclists.

The GP7255AGB is characterized by its robust yet lightweight aluminum frame, which offers a perfect balance between durability and agility. This model features an advanced suspension system designed to absorb shocks and provide a smooth riding experience on uneven terrains. One of the standout features is its adjustable rear shock, allowing riders to customize the compression settings based on their preferences and the riding environment. With a wide range of gears, the GP7255AGB makes climbing steep hills effortless while ensuring quick gear transitions on flat stretches.

In addition to its performance-oriented design, the GP7255AGB is equipped with high-traction tires that enhance grip on various surfaces, ensuring stability and control during rides. The bike also incorporates reflective elements for improved visibility, making it a great choice for nighttime or low-light commutes.

On the other hand, the GP7145GB model signifies a fusion of style and functionality. With a sleek frame design and integrated components, this model prioritizes aerodynamics without sacrificing comfort. It features a lightweight carbon fork that reduces weight and increases response time during rides, making it ideal for road cycling enthusiasts.

The GP7145GB boasts a performance-enhanced gearing system, allowing for a wide gear range that caters to both intense climbs and fast descents. The bike is equipped with premium disc brakes for consistent stopping power, regardless of weather conditions. The ergonomic handlebar design also plays a critical role in rider comfort, allowing for longer rides without fatigue.

Both models utilize advanced technologies such as internal cable routing and a precise gearing system that offer a clean look and ensure low maintenance. The inclusion of a modern digital display on selected models provides riders with vital statistics such as speed, distance, and battery life for e-bikes, enhancing the overall riding experience.

In summary, the Giant GP7255AGB and GP7145GB represent the pinnacle of bicycle engineering, combining innovative features, advanced technology, and user-centric design to cater to diverse cycling needs. Whether navigating rugged trails or smooth urban streets, these models stand out as excellent choices for cyclists seeking performance and reliability.