Belt drive kits are designed for road use only. It is not suitable for any form of off-road use, including gravel tracks, green lanes, trails, or competition use.

Zero maintenance belt drives have been readily available on production motorcycles since 1981.

Quiet
Smooth
No chain snatch resulting in a smooth ride and effortless shifting
No more adjustment issues
No oily mess
No carrying chain lube on a trip
Lighter than the chain set
An industry standard belt that you can buy worldwide
Lower long-term cost due to extended belt and pulley life when compared to a chain drive.

THE BELT:

RSTech uses an industry standard, Gates 14mm pitch, high torque, Poly Chain Carbon GT belt, that is readily available from Gates Dealers worldwide. As the name suggests, this belt uses non-stretch, high strength, carbon fibre cords resulting in a belt with a greater tensile strength that the chain it replaces. Our design philosophy is to use standard components, and we do not use the 11mm pitch Gates MotoX9 belt, that you as a consumer cannot buy from a Gates Dealer.

EFFICENCY:

Described as a positive drive system, the belt teeth engage with the pulley similar to that of a chain, resulting in a very efficient method of transmitting torque. The old adage that a belt is less efficient than a chain is not the case with these modern positive drive belts running at 95-98% efficiency.

Properly lubricated chains running at the higher surface speeds seen on a motorcycle, tend to throw off the oil due to centrifugal forces, making it difficult to maintain proper lubrication at the load bearing. Consequently, chain drives are typically only 92-98% efficient. That performance degrades as the chain wears.

For all practical purposes, a properly maintained, oiled, quality, new chain running on new sprockets, and a properly tensioned positive drive belt, are the same efficiency. Chains do not stay new nor oiled in real life, and an old, or dry chain, and/or worn sprockets, is a different story, with the belt showing greater efficiency.

WEIGHT MATTERS – A lot:

“Simplify and add lightness” is often attributed to Colin Chapman of Lotus fame, and adding weight is the last thing you want in motorcycle design - more so when that weight is un-sprung, and a heavy rotating mass on the wheel; negatively affecting both performance and handling.

RSTech values the importance of a properly engineered rear pulley that “adds lightness” and results in a final drive system that is 11% lighter than the chain set it replaces, thereby improving the handling and performance of your bike.

Adding lightness with an aluminium rear pulley costs more than a steel pulley, and the lightweight rear pulley is a work of art that you will be proud to have on your bike. Fully CNC machined from a solid billet of 7075-T6 aluminium, (the same hard alloy used for sprockets) in a one-piece design that assures safety, and a perfect balance for long life and a vibration free ride.

Not a simple cosmetic coating, the rear pulley is Type III hard anodized in black. This results in a durable wear surface with a hardness in the mid-50s Rockwell C - the same range as high tensile steel.

The front pulley is engineered to be lightweight, and fully CNC machined from a billet of high tensile steel, and then post machining heat treated for durability. Rather than a cosmetic paint finish, we then take the additional step of nitriding the pulley for corrosion resistance, and increased hardness over that provided by the chrome moly steel substrate.

GEARING:

You have a choice of two gear ratios when buying a RSTech Bear belt drive kit – stock and a 3.76% higher ratio. To put that in perspective, the higher ratio would be like dropping 1.5 teeth on the rear of a chain drive Bear, or using a 16/41 sprocket combination.

As a 3.76% change is relatively conservative, you do not lose the soul of the bike. Belt drive is not for an off-road bike, and stock Bear gearing on the street behaves like an aggressive, short-geared urban hooligan bike. It maximizes off-the-line sprint times and provides fierce mid-range punch, but makes city riding feel frantic with constant gear changes and compromises long-distance comfort with pronounced high-RPM footpeg vibrations.

The higher gearing transforms the bike into a balanced, long-legged roadster. By making the gears 3.76% longer, it calms the engine down on the highway, smooths out the parallel twin’s natural vibration harmonics, and makes city commuting far more relaxed by smoothing out the first-to-second gear transition.

Click the sidebar for a more in-depth discussion on gearing

Royal Enfield Bear belt drive kit

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Gearing is a personal choice, so consider how you ride, and what you want from the bike:

Highway Cruising & Vibration Management:

If you use the Bear for highway commuting or long-distance sport touring, the stock gearing is a drawback. At 115–125 km/h (70–75 mph), the engine revs right into a prominent secondary harmonic buzz, sending a high-frequency tingle through the footpegs and handlebars.

The higher gearing drops the cruising speed, and shifts the engine just out of that buzzy harmonic pocket. The bike feels like it settles into a calm, relaxed groove on the motorway. The exhaust note changes from a frantic hum to a steady, deep drone, drastically reducing rider fatigue on long stretches of pavement.

Urban Rideability & Stop-and-Go Traffic:

The Bear is factory-tuned for 56.5 Nm of torque (4 Nm more than the Interceptor). Combining that extra torque with short stock gearing, and 1-2 kg lower weight, makes first gear rather brief. Pulling away from traffic lights requires shifting into second gear almost immediately to avoid surging, making the bike feel twitchy and a bit high-strung in heavy city traffic.

The higher gearing gives every gear "longer legs." First gear becomes more usable for filtering through slow traffic or pulling away from lights smoothly and elegantly. The throttle response feels less snatchy, providing a more deliberate street riding experience.

Sport Riding:

On twisty backroads, the short gearing means you are constantly shifting between 2nd, 3rd, and 4th gears to stay in the powerband. If you get back on the throttle mid-corner, the short ratio can make the initial throttle tip-in feel abrupt, which can upset the chassis when leaned over.

With the higher gearing, the power delivery becomes more linear and progressive. Because each gear covers a wider speed range, you can leave the bike in 3rd or 4th gear and smoothly ride a wave of mid-range torque all the way through a series of twisty S-curves without constantly clicking the shift lever.

Overtaking:

With the stock ratio, opening the throttle at 100 km/h (62 mph) results in an immediate mechanical lunge forward. The bike has plenty of passing power, but it runs out of breath quickly at the top end of the rev range.

At the higher ratio, the bike trades a fraction of that initial, aggressive snap for a much wider, more elastic spread of power. While a highway pass might feel slightly smoother rather than explosive, the bike pulls cleanly for longer, utilizing its horsepower curve more efficiently at high road speeds.

In summary:

Presumably you already have experienced the stock gearing and stick with it if you solely ride short, sharp trips—like a quick urban commute or carving up tight city streets, where you want maximum acceleration thrill from stoplight to stoplight and don't mind a busy left foot or highway buzz.

Use the higher gearing if you treat the Bear 650 as an upright sport-touring roadster. It capitalizes perfectly on the bike's comfortable riding position and Showa suspension, refining the parallel twin into a smooth, relaxed machine that handles highway miles effortlessly while remaining engaging on a winding road.

Gearing by the numbers:

Speed kph(mph)	Stock gearing	Higher gearing
80(50)	3420	3310
90(56)	3850	3700
100(62)	4240	4080
110(68)	4690	4500
120(74.5)	5090	4890
130(81)	5520	5310
140(87)	5950	5730
150(93)	6370	6120

5150 TQ peak	121 kph (75 mph)	126 kph (78 mph)

A belt tension tool is highly recommended, as proper belt tension is very important for belt performance and life.

Unless you have a belt drive tension tool you will need to buy one. are Harley part number 40006-85, but also made by Motion Pro, OTC, and a host of generic versions.

Buy one with a 10 lb. applied force indication.

A generic tool is listed under options should you not have one

Royal Enfield Bear belt drive kit

Gearing

Belt tension tool

Tyre clearance

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