why is my car shaking when i drive fast

If your car starts doing the hokey pokey at 100 km/h and above, the usual culprits are tyres and wheels—think out-of-balance wheels, uneven tyre wear, or a bent rim. Wheel alignment that’s more guesswork than geometry will also have you shimmying down the motorway. If the shake appears mainly under braking, suspect warped brake rotors; if it’s under hard acceleration, look at CV joints or tired engine mounts. A persistent vibration that changes with speed can also point to dodgy wheel bearings or a driveshaft issue. Start with the cheap wins: check tyre pressures, get a proper balance and alignment, and inspect for tyre damage. If it still wobbles like a shopping trolley with a grudge, hand it to a mechanic before it hands you a bigger bill.