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**sunilg** · 02-21-2011, 12:40 PM

Query approved.

**khush** · 02-21-2011, 12:55 PM

Originally posted by abhiwar View Post

Hey guys i want an little help on this(as i am confused and very few people around me has any interest discussing about Gear Box.) topic as am completely non technical guy . My question is as follows :-

1> What is Gearing ...?
A gear is a rotatingmachine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, magnitude, and direction of a power source. The most common situation is for a gear to mesh with another gear, however a gear can also mesh a non-rotating toothed part, called a rack, thereby producing translation instead of rotation.
The gears in a transmission are analogous to the wheels in a pulley. An advantage of gears is that the teeth of a gear prevent slipping.
When two gears of unequal number of teeth are combined a mechanical advantage is produced, with both the rotational speeds and the torques of the two gears differing in a simple relationship.
2> How it is Designed to Synchronize with various Speeds in Different Gear at same RPM ( for expml my RTR Dose max 40kmph @ 9k RPM in 1st gear where as in Top(5th Gear) RTR touches 120kmph aprox @ 9k(same RPM)

3> What is an Overdrive Gear ..? Why it is needed ...? ( i often heard 6th Gear of R15 is an Overdrive Gear..? what is it about)

4>Why P220 being 21bhp has 5 Speed gear box where R15 being 17.5 Bhp uses 6 Speed gear box..?

5> and Final query What is Gear Ratio (3.05:1 ..? )
-->For example, a normal bicycle has wheels that are 26 inches in diameter. The "lowest" gear ratio on the bike might be a front chain wheel with 22 teeth and a rear gear having 30 teeth. That means that the gear ratio is 0.73-to-1. For each pedal stroke, the rear wheel turns 0.73 times. In other words, for each pedal stroke, the bike moves forward about 60 inches (about 3.4 mph / 5.4 kph at a 60-rpm pedaling rate). The "highest" gear ratio on the bike might be a front chain wheel with 44 teeth and a rear gear having 11 teeth. That creates a 4-to-1 gear ratio. With 26-inch wheels, the bike moves forward 326 inches with each pedal stroke. At a 60-rpm pedaling rate, the speed of the bike is 18.5 mph (30 kph). By doubling the pedaling rate to 120 rpm, the bike has a maximum speed of 37 mph (60 kph). A range of 3.4 mph to 37 mph is fantastic, and it lets the rider climb the steepest hill very slowly or race almost as fast as a car! That is why a bike has gears.

Guys i've tried hard to understand things and it seems that am getting confused more and more .

Also if possible please tell me difference between Manual Gear box and Automatic Gear box ( how gear is selected in Automatic Gear Box )

Thanks in Advance.....!

hi Abhi....
Ans in bold
u"l get most f these on google n wiki!!
this link shud help:HowStuffWorks "Understanding a Gear Ratio"

**jd666** · 02-21-2011, 05:35 PM

Hey guys i want an little help on this(as i am confused and very few people around me has any interest discussing about Gear Box.) topic as am completely non technical guy . My question is as follows :-

1> What is Gearing ...?
Utilization of the engine power in the most efficient way to ensure proper performance and operation of the engine.

2> How it is Designed to Synchronize with various Speeds in Different Gear at same RPM ( for expml my RTR Dose max 40kmph @ 9k RPM in 1st gear where as in Top(5th Gear) RTR touches 120kmph aprox @ 9k(same RPM)

Thats due to different gear ratios.

3> What is an Overdrive Gear ..? Why it is needed ...? ( i often heard 6th Gear of R15 is an Overdrive Gear..? what is it about)

The overdrive gear is when the drive gear is bigger than the driven gear. So for a given speed the engine is turning at a lower rpm than it would in any other gear.

Its ideally suited for cruising, and for fuel efficiency ( for eg, in the old Zen, 4th and 5 gears, and also in the esteem, 4th and 5th gears were overdrive gears, the engine turns at a lower speed, sacrificing torque, for better efficiency, your acceleration will suffer in overdrive, but cruising at a steady 100-110 kmph ( even on the R15 ), you will get a more efficient performance from the engine at that speed ).

4>Why P220 being 21bhp has 5 Speed gear box where R15 being 17.5 Bhp uses 6 Speed gear box..?

Thats where R&D and road usage comes into play. Every engine has a different power and torque curve across the rev range. The pulsar makes more torque lower in the rpm band, so it can be better utilized with having lesser gear ratios. For a peaky engine like the R15 ( peaky being the power delivery ), more gear ratios help extract better performance and allows for an option of more than one gears for a given speed. For eg, you can hold 80kmph in 4th, 5th or 6th, depending on your acceleration, traffic, road conditions etc. In pulsar you can either hold it in 4th or 5th. Plus costing also plays a factor ( more gears, more expensive the gearbox ).

5> and Final query What is Gear Ratio (3.05:1 ..? )

Thats the ratio of rotation for the gears, for ever turn of the driven gear, the drive gear will turn 3.05 times.

Guys i've tried hard to understand things and it seems that am getting confused more and more .

Also if possible please tell me difference between Manual Gear box and Automatic Gear box ( how gear is selected in Automatic Gear Box )

By actuators which are operated electrically or hydraulically. The controller decides the ideal gear ratio as per the engine speed and vehicle speed. So its an automated pre decided operation.

Thanks in Advance.....!

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**abhiwar** · 02-22-2011, 06:16 PM

thanks for the reply guys...

**psr** · 02-23-2011, 03:00 PM

Originally posted by abhiwar View Post

thanks for the reply guys...

Here is a link with photos to explain

Tech Tips - Gearbox Operation.

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Gear Ratio and Gearing or Gear Desining

Gear Ratio and Gearing or Gear Desining

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