Date:23/03/2009 URL: http://www.thehindubusinessline.com/2009/03/23/stories/2009032350910700.htm

Revolutions in wheels and tyres

T. Murrali

Chennai, March 22

Wheels India, a TVS group company, worked closely with Tata Motors in developing the wheels for the Nano, challenging a number of assumptions along the way.

The Wheels India Managing Director, Mr Srivats Ram, said “the wheel that was developed is lighter than any other passenger car wheel in the country and the first wheel to my knowledge in passenger car wheels to have three bolt-holes instead of the conventional four.”

Production planning was a detailed exercise with the company asked to look at alternative processes every step. It resulted in an optimised product and process design meeting the specific requirements of Nano. “It has truly been a learning experience for us,” he adds.

TEMP tyre: MRF supplies three different types of tyres for the Nano. MRF’s Vice-President(Marketing), Mr Koshy Verghese, said this is the first time a car has been developed with engine at the rear and the challenge was to design and develop three different tyres with lower rolling and steering resistance to ensure better fuel economy.

The front tyre is 135/70 while the rear is 155/65 with tubeless radial tyres of 12-inch rim diameter.

The spare wheel — called temporary spare wheel akin to the popularly known Doughnut tyres in developed countries — is a biased (non-radial) tube tyre and smaller in size. The idea of the smaller spare wheel is not to use it permanently but only till the car is driven to a place where the puncture in the main tyre can be sealed. The tyre is branded as TEMP.

Usually vehicle manufacturers choose tyres from the existing sizes. But for Nano they were developed from scratch. Synergy between the vehicle and the tyre was paramount.

The tyre sizes evolved during discussions with Tata Motors for more than three years. “A number of iterations were gone through before arriving at these sizes,” he said.

The concept of a temporary spare wheel has been introduced in the Nano since it is smaller, lighter and cheaper. Also, space is at a premium. It also keeps the weight and cost in check.