Even as overall car fleet maintenance costs dropped in 2013, GE Capital Fleet Services said the rising cost of replacement tires proved to be an issue.

The Eden Prairie, Minn.-based global fleet management company conducts an annual survey, and its 19th study showed that “overall fleet car maintenance costs decreased by 4% in 2013 as compared to 2012.”

Such costs include unscheduled repairs, preventative maintenance, tires and replacement rentals. The study analyzed actual maintenance expenses incurred by nearly 37,000 passenger cars from Jan. 1 to Dec. 31, 2013.

The research found monthly preventive maintenance expenses decreased 14% in 2013 and average vehicle maintenance costs decreased from $50.47 to $48.36 per vehicle per month.

Key to the decrease were increased oil change intervals, better vehicle cycling, and improved overall vehicle quality.

Although costs for replacement tires increased by 10% in 2013 versus 2012, fewer tires were purchased due to proper vehicle cycling – trading in vehicles on schedule and avoiding tire purchases. This resulted in a 3% decrease in overall tire cost per vehicle. Additionally, new tire technology helped to extend tire tread life, allowing for tighter trade-in scheduling.

While costs for oil services rose by $3 from the previous year ($39 to $42), the interval for oil changes increased from 3.6 months to 4.3 months and from 7,515 miles to 8,817 miles. GE Capital attributed that to improvements in engine design, onboard vehicle technology and oil quality.

“Vehicle quality improvements will continue to present opportunities for fleet maintenance savings in 2014 and beyond,” said Eric Strom, maintenance and safety product manager for GE Capital Fleet Services. “However, labor rates, rental costs and the price of replacement parts are expected to increase in the year ahead. As cost savings remains a top priority for fleet managers, our team of experts aims to provide customers with a thorough list of options for finding and achieving savings within their fleet.”