Out of balance wheels is definitely a probable cause. Tyres can get flat spotted eg, during a strong crosswind landing, throwing the wheel assembly out of balance. As the weight comes off the wheels on lift off the out of balance can shake the landing gear until the pilot selects gear up when the spinning wheels are brought to a halt by automatic brake application. If it is the nose tyres the pilots report it pretty quick as they feel it but the main gear tends to go unreported.