The rear shock absorbers on current Bajaj Pulsar series bikes are also popularly known as NITROX shock absorbers. These types of shock absorbers are actually called as ‘Gas Filled Shock Absorbers’. The visual differentiation between a conventional shock absorber and a gas filled shock absorber is a small canister (box) which is attached on one side of it. This canister holds a small amount of Nitrogen gas in it. Hence these hydraulic shock absorbers or dampers are called as gas filled shock absorbers. So what is the reason to use a gas filled hydraulic dampers instead of using a conventional one? we'll find out the answer here.
The 'Royal Enfield - Bullet Electra' was the first bike in India to have this feature. The Pulsar 150/180 UG II (2’nd upgrade) then became the second model (and the first in the 150 cc and above category) to make this feature available on Indian bikes. A few other Indian bike makers have followed it as well and put this kind of shock absorbers on their 150 cc or above bikes, and giving different marketing names.The XCD 135 DTS-Si becomes the second bike in the sub 150 cc category
(after the Bajaj Discover 135 DTS-i) to sport Gas Filled Shock absorbers
at its rear suspension. TVS Apache (MIG), HMC Karizma ZMR (GRS) are also the other bikes which uses a gas filled suspension at the rear.
A typical shock absorber or an hydraulic damper contains oil with two tubes sliding inside one another and also has a piston inside. It also has a valves inside. The oil inside the damper moves along the valves as the piston moves up and down to absorb the shocks. These dampers have a tendency for the oil to form foam (form bubbles) under heavy use and riding conditions. The foaming is usually caused by air bubbles inside oil during suspension action. This is similar to shaking a can of oil. After shaking the oil inside the can gets foamed. Similarly the same case happens to a hydraulic damper also. This foaming temporarily reduces the damping ability of the unit.
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| Nitrox suspension used in Bajaj Pulsar |
In order to solve this, a secondary cylinder is connected to the shock absorber which acts as a reservoir for the oil and pressurized gas (nitrogen). The pressurized nitrogen gas inside the canister prevents foaming of hydraulic oil inside the damper due to heavy usage or damping action. Due to this, the performance of the suspension remains constant.
This nitrogen gas also helps in absorbing the road undulations and provides a smooth ride for both the rider and the pillion. The new Bajaj Pulsar 200NS uses a Nitrox piggy-back type canister gas filled suspension.
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| Nitrox piggy back canister gas charged mono-suspension in the Bajaj Pulsar 200NS |
It is the first of kind monoshock and gas filled suspension to be used in Indian bikes. These type of dampers provide better stability and also provides comfortable long rides to riders as the performance remains unchanged since the foaming never occurs.