KEPT BUSY: Scott Paterson, of Paterson Brothers Tyre Services, says punctures, wheel fractures and rim damage are up 30 to 40 per cent.
Screwdrivers, nails, screws and sharp stones are some of the items being found in Christchurch motorists' tyres.
Tyre repair services say they have been inundated with puncture repair and wheel alignment jobs since the February 2011 earthquake.
It was not only quake-hit roads taking their toll, but demolition rubble as well.
Staff member Phil Seath said they now had someone assigned specifically to repairing punctures fulltime, whereas they used to share the job around throughout the day.
Paterson Bros Tyre Service owner Lyndsay Paterson said punctures, wheel fracture and rim damage work was up 30 to 40 per cent.
"There's a lot of screws dropping off the back of trucks," he said.
A customer had two tyres blow out after hitting a pothole on the new Christchurch southern motorway at Halswell at 80kmh.
"There were 18-inch-long (45cm) splits in the rims," he said. "The insurance guy said six cars hit that one pothole in one night," he said.
Automobile Association national road service manager John Healy said roadside rescuers had seen a "significant" lift in punctures and suspension failures because of road conditions.
"The cars are getting more thumped around on the road," he said.
St John regional operations manager Chris Haines said the cost of the "significant increase" in the number of tyre and wheel alignment repairs was proving a challenge.
City council road corridor operations manager Paul Burden said it was inevitable rough surfaces and loose metal would damage cars.
"Motorists are reminded to keep to within the posted speed limit to minimise this risk," he said.