Auto Service World
Feature   April 1, 2001   by CARS Magazine

Equal Tire Performance Automotive Formula

Vibration has long been a major source of tire-related comebacks in the service industry. Modern computer balancers helped by removing much of the "feel" required for a good static/dynamic balance, bu...


Vibration has long been a major source of tire-related comebacks in the service industry. Modern computer balancers helped by removing much of the “feel” required for a good static/dynamic balance, but occasionally a customer will still complain of a vibration on a “zero” balanced wheel assembly. The cause is “road force variation” and is one of the most elusive phenomena from a service standpoint. “Drop in” tire balancing powders have been in use in the trucking industry for some time, but formulations for passenger car tires and a way of getting the product into the tire without a dismount have been barriers. IMI Inc. of Akron, Ohio has addressed the problem with a device that blows the balancing product into the tire through the valve stem.

SSGM tested Equal on a Ford Mustang wearing P225 60R15 Goodyear Eagles on stock alloy wheels. Road force variation is different from traditional balance issues, and a good dual-plane balance is necessary before installation of the product. The balancing bead “powder” comes in pre-measured pouches, and is added to the chamber of an airline-powered installation machine that the company calls the “Equalizer”. Tires are deflated, then attached to the machine, which blows the balancing product through the valve stem during tire re-inflation. The process is done by the time it takes to describe it. The machine operates through the opening and closing of two valves, and the process ends with the installation of a special filtered valve core (supplied with the product) to keep stray particulates from clogging or jamming the valve. Small coloured O-rings are supplied to tag the valve stems so those technicians in the future are aware of the presence of the powder.

On the road, Equal smoothed a vibration noticeable between 100 and 105 km/h that the dual plane balance hadn’t cured, and had no ill effects on cornering or braking. Equal shouldn’t be used in tires containing sealants or with advanced run-flats that use internal lubricants. As a “fine-tuning” tool following a good dual-plane balance, or as an upsell to a high-performance driver, Equal can be an alternate profit centre for shops with customer demographics that demand an especially smooth ride, operate at high speeds, or when troubleshooting elusive vibration problems.