Ball Differentials Vs Gear Differentials

Ball Differentials

   Ball differentials were developed in the late 1980s to replace the high friction Gear differentials. Mainly used on Touring Cars, Pan Cars and Formula One Cars, Ball Differentials are designed to be totally frictionless and smooth in action to provide effortless drive to the wheels on cornering, where the inside wheels must rotate slower than the outside wheels for controlled stability.

Ball Differential Configuration

   Basically, the configuration of the Ball Differential is a number of small case hardened steel balls, spaced in a plastic cage that is in effect the drive gear for the axle. On each side of the gear are two hardened and tempered pressure plates that clamp over the steel balls, held in position by a screw through the centre of the assembly, incorporating a small thrust bearing and coil spring.

Adjusting your Ball Differential is Crucial

   To adjust your Ball Differential you use the central screw. Frequent adjustment is crucial to the effectiveness of the differential action. Too tight and the free movement of the diff is restricted. Too loose and the balls will slip on the plates when accelerating out of the corner, not only reducing drive, but damaging the balls and pressure plates - not good. The optimum setting is obviously somewhere in-between, and is where the small coil spring is important. It must be compressed, but not fully, to provide the desired exact pressure required. With a little practise setting up the diff becomes second nature. Patience is the word for this procedure.

Lubrication

   Lubrication of Ball Differentials is essential for that smooth operation, and special greases have been developed that allow the balls to roll freely in the cage, and push aside as they roll over the pressure plates.

Gear Differentials

   The Gear Differentials commonly used in Buggys, Trucks, Touring Cars, Monster Trucks and some of the early Tamiya Formula One and Le-Mans cars, are by design more robust than the high maintenance Ball Differentials.

Gear Differential Configuration

   The configuration uses a main drive gear, fixed on each side of the drive axles, and either three or four small metal orbital bevel gears, in a plastic gear housing, providing the drive to each side of the car when cornering, to allow the inside wheel to rotate slower than the outside wheel.

Maintaining your Gear Differentials

   Maintaining your Gear differentials is crucial if your car is to be competitive. Regular greasing is required, preferably molybdenum grease with graphite flakes, smeared over the gear teeth. If neglected, the gear teeth grind and wear at a rapid rate, and will quickly fail, leaving you with a potentially expensive rebuild.

Where Gear Differentials work best

   For slower moving models such as Monster Trucks, Rock Crawlers, and budget end Off road Buggys, Trucks and On Road Drift and Touring Cars, where low friction differential action is not essential, Gear Differentials are ideal, providing drive to each wheel as required. However, for top level competitive racing ,On and Off Road, Ball Differentials are preferable. Admittedly, they require a little more maintenance, but the benefits on the track far outweigh the negatives of the old Gear diffs.

Gear Differential Development

   More recently, sealed Gear Differentials, filled with oil and Hypoid Gear Differentials have been developed for the top of the range models, to provide more reliable smooth operation over Ball Differentials than previous versions. Although these advancements have proved themselves on the track, gear wear can still be an expensive problem.

   At present, the RC Model Manufacturers, Brands and Distributors covered by us are: ABC Hobby, Academy, Acme Racing, Agama Racing, Amewi, Ansmann Racing, ARRMA, Team Associated, Atomic RC, Axial, AYK, Bolink, BSD Racing, Capricorn, Carisma, Carson, Caster Racing, Cen, Corally, Custom Works, Durango, Duratrax, ECX - Electrix, Exceed RC, FG Modellsport, FS-Racing, FTX, Fujimi, Gmade, GS-Racing, Harm, HBX, Helion, Heng Long, Himoto Racing, Hirobo, Hitari, Hobao, Hong-Nor, Hot Bodies, HPI, HSP, Intech, Integy, Jamara, JQ Products, Kawada, Kyosho, Losi, LRP, Maisto, Mardave, Marui, Maverick, MCD Racing, Megatech, Mugen, New Bright, Nichimo, Nikko, Nkok, Ofna, Pro-Pulse, Protech, PTI, RC4WD, Redcat Racing, RJ-Speed, Robitronic, Schumacher, Seben, Serpent, Smartech, Sportwerks, Step-Up, Tamiya, Team-C Racing, Team Magic, Thunder Tiger, Tomy, Top Racing, Traxxas, Trinity, Tyco, Vaterra RC, Venom, VRX Racing, WLToys, X-Factory, Xmods, Xpress, Xray, XTM, Yankee RC, Yokomo, ZD Racing and Zipzaps.

   This is an ongoing project, with new and "lost in time" RC Models and Brands being added as they are found and although most of those listed above have been covered in relative detail, some are still being researched and will be completed in the near future.