I’ve seen websites that say “Lower Gears in Cars means more power”, Which is what I’m guessing, means more rpm, but then I see other people say that if you increase the gear, then it makes the rpm higher… Which one is it?
In: Engineering
Both.
When you shift up gears your rpm drops and you starting gaining higher rpm again until you need to shift into the next gear .
Then then you shift ,rpm drop and start to build as you accelerate again
You’re mixing two different things.
Gears regarding power or speed refer to the drivetrain aka the rear end or simply the axle, the bar which turns the tires.
Upshifting refers to changing gears at the transmission aka gear box (different from gears in the axle)
Upshift just changes which gears your using in the gear box.
So the engine increases rpm and using a different gear allows for the engine to turn the wheels faster.
Upshifting doesn’t create more time it allows for more rpm.
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Your rpm rises as you apply gas. But it doesn’t translate directly to power or vehicle speed.
E.g. let’s say you have a gas car with an engine that goes up to 5000 rpm. The thing is, it provides the most power at about, say 2500 rpm. So you want to keep the engine somewhere around those rpms.
Now the transmission comes in and it serves 2 main purposes:
1) to provide the most power onto the wheels. E.g. if you want to go uphil you may need more power even for low speed, just like on a bike. Even if your rpm goes outside the good zone.
2) so you (on manual trans) or the automatic can keep the engine near its most effective rpms. E.g. if you’re cruising at 70 kph (~50 mph I think?), you’re most likely in 4th gear on most cars. You can technically be in 3rd, where you’ll get higher rpm, but you won’t get anything extra out of it. In fact if you keep the engine in high rpm unnecessarily, you can blow the engine. Or on the other hand you can be in 5th or 6th, but you better downshift again if you need to accelerate or go uphill.
So, you upshift in these cases:
A) you’re accelerating to a speed where lower gear is no longer effective
B) you don’t need the power, e.g. going downhill
When you upshift, the rpm drops momentarily, and then it depends what you’re doing. When you apply gas, rpm goes back up. How fast depends on the load. If your rpm is low and the load is high, the engine dies.
You downshift when:
A) need to go slower (e.g. entering a lower speed zone) while also applying brakes
B) going uphill, and your current gear isn’t effective, i.e. either rpm is too low or you’re losing speed
C) you’re already cruising and want to accelerate rapidly: this will increase rpm and thus power, but not in an effective manner because the engine will be out of its comfort zone. Note you’ll need to upshift again to keep up the acceleration.
When you downshift, rpm goes up momentarily. Then it depends on what you’re doing. If you keep rpm too high, you may blow the engine, especially with low load.
You have the [same RPMs in every gear. You have the same power in every gear. ](https://qph.fs.quoracdn.net/main-qimg-a69447cd5dc3409a047fcc11d1eb950c)
Get on a 10-speed bike and try to start riding in 10th gear. Now try to start driving in first gear. Higher gears only work when you’re already going fast.
OR, play a game like Forza Horizon or Ridge Racer with manual shifting. And drive around with manual shifting. And watch the RPMs. You can even turn on “telemetry” and watch how the power level changes (which will match the diagram I linked earlier, roughly).
When you upshift, RPMs will drop but only for a moment until you move up through the RPMs again. And again…in every gear.
If someone says “lower gear means more power” just ignore that, they may have meant that you have more usable power *when going slow* or starting from a stop.
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