Your suspension and tyres take nearly all the abuse that a road can throw at a car, so it really is essential to check your tyre treads regularly. If your insurance company can prove that an illegal tyre tread is material to having caused an accident, it is likely your taxi insurance will be invalidated.
From a monetary-angle, the faster you can identify a part is wearing badly, the less damage and wear the breaking part can cause to other areas of your vehicle. This of course reduces down time, repair costs, and increases general efficiency.
When inspecting your tyres for tread-wear, make a note if the wear is uneven, the centre tread is thicker than the outer tread (this is called cupping), or if the centre of the tread is thinner than the outer tread -- this information will be handy if you visit a mechanic. Check for bumps in the sidewall, both inside and out, a weak spot in the sidewall of a tyre can cause a blowout. Cupping and excessive wear in the centre of the tyre indicate incorrect air pressure, while uneven wear on either the inside or outside of the wheel indicates an alignment issue that it’s best a mechanic checks.
Next we’ll have a look at your suspension: while the car is on the ground, using all your weight, push down on each corner of the car, and observe the way the car returns to its original position. The cab should return back to the original position smoothly without any bounce, or popping. If it returns slowly, or bounces you may need the shock absorbers or struts inspected by your mechanic. Popping is usually caused by the impending failure of a part, and should be checked immediately.
When driving pay special attention any kind shaking through the steering wheel, or a bouncing sensation when accelerating. Occasionally it’s worth ensuring that all four wheels are aligned correctly at a local garage.