Rolling carriage wheels and bearings on a slide gate
On a gate that runs every day through a Georgetown, TX summer, the wheels and bearings wear several times faster than the frame, and the work logged at sliding gates georgetown apollo pony (the carriage is always the first part to need attention) bears that out. Every slide gate and every cantilever gate hangs its full weight on a few small wheels, so those wheels set how the leaf feels.
What does a carriage do?
A carriage is a steel bracket holding a wheel, or a pair of wheels, on a bearing and an axle. On a track gate the wheels sit on the track in the ground. On a cantilever gate the carriages are bolted to the posts, and the leaf rolls through them along its bottom rail. Either way the carriage carries the vertical weight and keeps the leaf from drifting sideways.
What are guide rollers for?
Guide rollers are small wheels that bear against the side of the frame or the top rail and hold it upright. They carry almost no weight, but they keep the leaf from twisting as it travels. A set that is too tight makes the gate hard to push, and a set that is too loose lets the frame rattle and wander. They are set so a sheet of paper just slides between roller and tubing.
How do bearings wear?
Sealed ball bearings last longer than plain bushings, but both wear from grit and dried grease. Dust blown across the drive near Interstate 35 works into a worn seal, mixes with grease and forms a paste that grinds the balls. The first sign is a rumble as the leaf rolls, followed by a gate that needs a harder push and an operator that strains at the start of each cycle.
What does Texas heat do?
Heat thins grease and drives it out of a cheap bearing, and a steel carriage left in direct sun gets too hot to touch by afternoon. Nylon and polyurethane wheels soften and flatten, while hardened steel wheels stay round but wear the track faster. Galvanized axles resist the rust that locks a wheel in the humid months, and a powder coat finish keeps the carriage bracket from flaking.
When should wheels be replaced?
A wheel with a flat spot, a visible groove, a wobble on the axle or a bearing that grinds when spun by hand is due for replacement. Replacing wheels in pairs keeps the leaf level. An annual check with the gate unplugged and the operator in manual release lets the owner roll the leaf by hand and feel every rough spot long before a wheel fails.