Car Gears - Explained

Answering the question:

"I have a question about gears. How do gears work? Why is it that the first gear gives you the most torque and hence the most acceleration? Since the first gear gives me the most acceleration why do I need to switch gears. Wouldn't it be ideal to stay in first gear. Essentially my question is why switch gears and what is the concept behind this point. Your help understanding this would be greatly appreciated."

Hope this helps.

Category:

Autos & Vehicles

Tags:

• Car
• gears
• explained
• how
• it
• works
• transmission
• torque
• acceleration

[bloximonkey]

This may sound stupid, but why not stay in the top gear when you get higher speeds and better fuel economy?

[EngineeringExplained]

@bloximonkey Well, for example, if I were to be in my car going 35 mph uphill, and I was in 5th gear, I'd be turning about 1500 rpms, and would have to floor it to produce enough power to go up the hill, where as if I was in 3rd I'd be closer to 3k rpms, and could climb the hill easily. You need lower gears to accelerate up to speed, and then you can switch up to a high gear to save gas (by lowering rpm).

[EngineeringExplained]

@EngineeringExplained Flooring it in a high gear at a low rpm will end up being less efficient, and put lots of strain on the engine, when a gear with a better torque advantage could be selected, use less gas, and get the job done easily.

[HawaiiJackJr]

Could you do another video about how a gearbox works, physically like how a gear is selected etc.

[EngineeringExplained]

@HawaiiJackJr Thanks for the idea. Check out my video on automatics vs. manuals. For manuals, I explain in detail how this process works. Automatics use a system of clutches to transfer between planetary gears, which are fairly more complicated. I will add planetary gears to the pending list of videos to make!

[jy0408]

Would this apply to rotary engines? I think it would but I was just curious since the eccentric shaft of the rotary engine rotates once every three rotor rotations. Thus, the n_cycle for the engine is 3 while for the piston engines, it's 2 assuming they are all four stroke engines.

[EngineeringExplained]

@jy0408 Yes, this applies to rotaries. And the shaft of the rotary rotates 3 times for every one rotation of the rotor. Regardless, this shaft will have a certain rpm, and will manipulate the wheel speed through gearing in the same manner. The "transmission" I've shown is very simplified, but its principles apply to all transmissions.

[antoniomarquezramos]

3.14 x 24" (diameter of tire) = your tire travels 75.36" per spin.

75.36" /(divided) by 12 (12 inches in a feet) = 6.26ft per tire spin

1st gear is10.5 revolutions for 1 tire spin

6000rpm /(divided) by 10.5(10.5 revolutions for one tire spin) = 571 spins per min

571(tire spins per minute at 1st gear) x 6.26ft (one spin distance)

571 spins per min x 6.26ft= 3574ft per min

3574ft /(divided) 5280ft(a mile) = .67 miles per min

.67 miles per min x 60 minutes = 40.2mph

[daveweckl7]

I would like to watch a video about car steering, if possible please

....!

[u2ubeguy11]

wow...i cant believe i just understood everything he said.

[3gh2]

@EngineeringExplained I have got heaps of question for you but I ask those that related to your video here!

1- Could you explain Limited Slip Differential?

2-Also what is Final Drive?

3-In AWD vehicles if front tyres don't have a same diameter as rear tyres how do you calculate each gear's max speed?

[nephthysuk]

This is wonderful, I am trying to get my head around gears for my driving test, I am no good at learning bare facts, need to know the theory behind it.

[MsSisylana]

You are very good at explaining, thanks for doing that!

[TeclaLD]

Awsome videos