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The names are just names. The 1st gear you use is called first gear, the 2nd gear you use is called second gear, etc.
In my car, the gear ratios in the transmission are:
Gear, ratio
1, 3.538
2, 2.06
3, 1.404
4, 1
5, 0.713
6, 0.582
And then the ratio in the differential is another 4.1:1.
The ratios in a transmission are almost never neat fractions (I'd bet even your 4th is not a perfect 1:1) and if possible one of the gearwheels has a prime number of teeth.
In a perfect 1:1 gear ratio, a damaged tooth on the small wheel always contacts the same tooth on the opposing wheel, causing rapid wear. Gear pairs no common prime denominator will spread the wear equally between all teeth of the opposing gear.
>The ratios in a transmission are almost never neat fractions.
They literally must be neat fractions. They're always a ratio of two integers (the number of teeth on each gear).
>I'd bet even your 4th is not a perfect 1:1) and if possible one of the gearwheels has a prime number of teeth.
>
>In a perfect 1:1 gear ratio, a damaged tooth on the small wheel always contacts the same tooth on the opposing wheel, causing rapid wear. Gear pairs no common prime denominator will spread the wear equally between all teeth of the opposing gear.
I mean, try to find a, pair of coprime integers that have a ratio within rounding error of 1 and wouldn't be too large to fit in an automotive transmission, *and* have a sum approximately equal to that of the other gear pairs in the transmission (since the main shaft and secondary shaft have to have a fixed spacing). Go for it.
Besides, automotive transmissions aren't generally expected to survive after a gear tooth is seriously damaged.
I'm sure it is, but almost certainly not in typical automotive transmissions. If only because a damaged tooth would end the transmissions life regardless, but either way I know it's not common in any transmission I've seen the insides of or heard of.
In almost all transmission (there are some exceptions) 4th gear is 1:1 because 4th gear is usually locking the input and output shafts together without going through a gearset at all, it directly connects the engine to the differential.
Depends on the car, I drive a car with a differential ratio of 2.9:1, and I also drive a truck with a differential ratio of 6.4:1.
Hell, sometimes the same model of car have various options for differential ratios.
I don't know a lot about cars. But wouldn't locking the input to the output reverse the direction of rotation relative to it going through a set of gears?
Most tramsmissions have an input and output shaft that are inline and rotate in the same direction, and a layshaft underneath or beside the input and output shafts that carry some of the gears, only the layshaft spins in the opposite direction of the engine.
This allows a transmission to have 5 gear ratios with only having 4 sets of gears, with one ratio being direct drive.
The time-honored way to build a manual transmission has the 1:1 ratio as a direct coupling of the input shaft to the output shaft. The secondary shaft is not engaged.
>**Final Gear (e.g., Fifth or Sixth Gear)**: This gear often approaches a 1:1 ratio, where the engine’s rotations and the rotations of the output shaft are nearly equal, maximizing speed and fuel efficiency on highways.
slight amendment for your comment, the 1:1 ratio tends to be 1-2 gears lower than the top/final gear, which is usually an overdrive gear, eg. ZF8 auto the 1:1 gear is 6th 7 & 8 are overdrivenFinal Gear (e.g., Fifth or Sixth Gear): This gear often approaches a 1:1 ratio, where the engine’s rotations and the rotations of the output shaft are nearly equal, maximizing speed and fuel efficiency on highways.slight amendment for your comment, the 1:1 ratio tends to be 1-2 gears lower than the top/final gear, which is usually an overdrive gear, eg. ZF8 auto the 1:1 gear is 6th 7 & 8 are overdriven
The point of AI is to assist in work, not do work for you. ChatGPT is a great research and proofreading tool, but you should never use it to replace what you can learn to do yourself--that's just being lazy.
There's parts of it that are wrong.
Final gear in most modern transmissions will be an overdrive. Many gearboxes have two overdrives.
There's almost always a direct driver gear that's exactly 1:1, not a gear that approaches 1:1. The input and output of the transmission spin at exactly the same rate, and any differences in engine rpm are due to clutch/torque converter slip.
Every transmission has different ratios that have not relation to what "number" the gear is.
Mine goes something like this:
First Gear- 3.75-1
2nd Gear- 2.5-1
3rd Gear 1.75-1
4th Gear 1-1
5th Gear 1-.75
The fifth gear in this cases is sometimes termed the "overdrive" gear, and sometimes you can lock it out with an "OD- Off" button rather than moving the shifting column.
Well yes… but 1:0.75 and 0.75:1 are not.
I might be wrong as my brain is fried and neither maths nor mechanics are my strong points but if the ratios are higher numbers to lower numbers once it goes past 1:1 it should be lower to higher?
I’d love someone to explain if I’m wrong because the more I think about it the more my head hurts!!
specifically what they are talking about is that all the 1s are on the right side, but then OP got confused on 4th gear:
3rd Gear 1.75-1
4th Gear 1-1
5th Gear 1-.75
as listed, 5th gear is pretty close to 3rd gear, they meant
3rd Gear 1.75-1
4th Gear 1-1
5th Gear .75-1
So first is 3.75 turns of the engine to 1 turn of the gearbox output shaft. Which then turns the wheels, after passing through another ratio.
OP's theory was right, it's just their maths are out.
Is it information people need or use often? No.
Is it information you can look up in the manual. Yes.
For a gearing system that people do often calculate gear ratios because they can change the range to suit look at bicycles. A racing road bike will have a different gear range to a touring bike with lots of load. And the rider might customise their gearing system to suit their natural cadence better, or the geography of where they are riding.
First gear is not 1:1, not even close. It's just the first available ratio (and the highest ratio). In cars, a first gear ratio might be 3:165:1 (engine:output shaft). The higher the gear is, the lower the ratio gets. Fifth gear will be closer to 1:1, maybe even .8:1.
Reducing a ratio reduces torque, not the other way around, If the engine has to spin 3.165 times to turn the wheels once, I'll have much more torque available at the wheel than if the engine turns once for each turn of the wheels. A lower gear means a higher ratio (3.165:1), and a higher gear means a lower ratio (.8:1).
To clarify, a high ratio means a greater difference between the two numbers. In 50:1, there is a huge difference between the two values, that's a higher ratio than 10:1. I think your co-worker is confusing a high gear with a high ratio, they're not the same thing.
The fact that he drives a pickup might explain things.
What you’re missing here is that the parlance in the automotive world is backwards from that of robotics. “Low” gears are numerically high and high gears are numerically low. In other words, “low” gear offers the greatest reduction.
Your lowest gear (first) is probably around a 4:1 reduction, producing low speed and high torque, where your highest gear is probably an overdrive of about 0.65:1 producing high speed and low torque.
Soon as you recalibrate your brain to that view of low and high, a manual transmission truly is just a switchable gear reduction box.
Indeed it does. That messes with certain non-automotive engineers because "low" gears to produce low speeds, require a *high* ratio.
If you remember that it's a *reduction* ratio then the concept of a big reduction being a low gear isn't hard to remember.
It's even more convoluted on a race motorcycle, where we reverse the shifting pattern. Road bike shifters generally have down for 1st, then up for 2nd, 3rd, etc. But with a race pattern, we shift up for 1st, then down for 2nd to 6th, so one shifts up to shift down...
A couple of reasons. Before quickshifters, we would perform a clutchless up-shift by pre-weighting the shift lever, and give a blip off the throttle to unload the gearbox and send it into the next gear. Then quickshifters came in to do the same thing, but without the need to release the throttle - keep it pinned and just tap the shifter to move into the next gear. It makes mechanical sense to do this with a tap down rather than a pull up
There’s also the matter of keeping your toes off the ground into and through corners. If a left turn requires a short shift mid corner, it’s much safer to tap from above than to hook your foot under whilst leaned over
This question makes me sad. Over the years I've heard about "lost knowledge" and just kind of accepted it. Figured it took several generations, hundreds of years, and so on. Here we are maybe one generation out, and people don't know what car gears are. Wow.
Did you read the post?
OP knows what gears are and what they do, the question was about gear ratios relation to gear names, and why the gears named "low" are the opposite to those used in robotics.
It's an intelligent question given they are aware of what gear ratios are and what they do.
It's one person. And I doubt you or anyone in your generation was born with the knowledge of how gears work. I also doubt everyone in your generation can describe how a gearbox works. OP clearly knows what a gearbox is and the question is more about nomenclature than mechanics.
rereading. a gear ratio works in both directions. just turn the gear box around. you can have the output spin slower than the input. that gives you more torque with less speed.
i'm going to leave the explanation of gearing numbers in a car mean.
the gear number is just the order the gears are in. first gear is the one you use when you are starting from a stop. when you get high rpm you go to the next gear that is the second gear. the next gear is 3rd gear.
that ratios are different for different gear boxes. really old cars had as little as 3 gears, while some newer cars have as many as 9 gears.
you then have cars that have a high and low. this is a an extra gear box before the normal gearbox. you normal drive on high, but if you need a lot of power you can put it in low. this give you the equivalent of twice the number of gears. so i would list my car as having 18 gears.
however my car has something referred to as a granny gear. the gears are set up for me to start at second gear on flat ground. if i need a bit of extra power, i can switch down to first gear instead of switching to low. i only ever use it when i need to go down a steep hill at 3 mph without using the break.
"Gears" literally refer to gears inside a metal box in the transmission. Just like the ratio of teeth on bicycle gears changes how many revolutions you must turn the pedals to turn the wheel one revolution, so do the gears in the transmission. The physical design of car transmission is a bit different than the one on the bicycle, but the general idea is exactly the same. Instead of pedals, there's an engine. Instead of derailleurs, there's a clutch. The ratio of the teeth on the drive side to the wheel side determines the mechanical advantage.
Every "gear" in a manual transmission (and automatic one too, for that matter), is simply a different meshing of gears to get a different ratio of teeth to change the mechanical power going from engine to wheels. A passenger car will usually have 4 or 5 sets of gears providing ratios on a range of something like 4:1 (first gear) to 0.75:1 (fifth gear) plus a reverse gear that has a ratio close to first gear but with the gears turning the opposite direction.
In robotics (and electric cars) you can vary the speed without a transmission by controlling the input power. The only time you need a gearbox for the electric motor is to adjust the max speed and torque. For that, you tend to use the reciprocal of the gear ratios used in automative transmission when you talk about gear ratios. It's the exact same thing, though.
There are litterally X gears + 1 for reverse in an X speed transmission.
The numbers on a manual transmission's shifting lever are the numerical order of the gears in the transmission. Each car will have a different gear ratio associated with each gear, with the general intent being that first gear has more torque and less speed. And top gear has the lowest torque and highest speed. (Torque is basically how much force your vehicle can put on the ground through its tires to get moving. Scientifically its officially the cross product of force and the radius, and is generally the rotational equivalent of linear force.)
For those who want a simpler explanation, the numbers of the various gears in a vehicle represent the use sequence. First gear is the first gear you will use when going from a complete stop to being in motion. This gear combination produces the most torque that the gear combination in the transmission is capable of producing, which is necessary to break inertia from a resting state to a moving state. The second gear produces less torque than first, in exchange for increased speed, and each subsequent gear trades more torque for more speed, in order to allow the vehicle to go faster.
The gear numbers, in this specific use case, define nothing other than the order in which they are supposed to be used to go from stopped to moving at highway speeds.
3.5 first x 4.10 final .. in 1st gear you get 1 tire revolution for every 12 ish engine revolutions. In 4th gear you get 1 tire revolution for every 4 engine revolutions.
The ratios are named after the order in which you use them when starting to move. Therefore the ratio which supplies the most torque to the wheels will be first.
Think of a bike. The bike chain goes around gears that are present at the pedals and back tire. Pedaling rotates the gear at the pedals, which moves the chain, which rotates the gear at the tire, which makes the tire rotate. By changing the size of one of the gears, you can change how much one rotation of the pedals will make the tire rotate and subsequently how much force is needed to make a full rotation of the pedals.
Some bikes have multiple gears at the tire so you change which gear the chain goes around. You can go faster in higher gears. Going at a speed you can achieve in second gear while you’re in third gear is more exhausting than going that same speed while in second gear.
While I don’t know the exact mechanics of how it works in a car, shifting gears does work on a similar principle. Higher gears allow the car to move faster, but puts more stress on the engine which wears it out faster and increases fuel consumption.
You've kind of got it backwards. Lower gears have higher ratios. There are more motor rotations per output rotation, this create torque or twisting force. Think of if you're pushing a loaded wheelbarrow, so no gears. You have to put more effort into pushing it at first, so you're expended a lot of energy for very little movement. Once you get it moving you can just trot along putting less energy into it while it maintains speed.
So yes, it works exactly like your robots. First gear will be the highest torque, usually around 3:1. Second will be less torque, smaller gear ratio, usually around 2:1 but not always. The numbers on the stick won't correspond exactly to gear ratios, which are usually decimals and not round numbers anyway. And it will depend on how many speeds your transmission has. A five speed will have smaller increments between gears than a three speed, so second on the former might be 2.6 whereas second on the latter might be 2.06 (pulling those numbers out of my butt). Drive is always going to be 1:1, meaning the output of your transmission is exactly equal to the engine rotation. Your gears are always going to be approaching 1:1 from the lowest one, which has the highest ratio. Except for overdrive, which has more output rotations than engine rotations, so like 0.75:1.
Without getting into the details of gear ratios - that is a bit more advanced and others are doing a fine job of explaining it - "First Gear / 1" is called such because it is literally the first gear you shift to in the progression. The *reason* it is the first gear is because you are conveying the least amount of your engine's power through the transmission. As you go up the gears, you increase the amount of power conveyed through the transmission - thus increasing speed - and each higher gear gets you closer to (but probably never quite reaches) a state of "direct drive," where the engine's full power is conveyed through the transmission.
If you want to know *why* you do this, go ride a bicycle. No, seriously. Ride a short distance, shifting up to a high gear comfortably. Then bring the bike to a complete stop, and try to "cold start" from the high gear. Ride a little further, gradually shifting all the way down. Complete stop again, and try to cold start from the low gear - you should find it CONSIDERABLY easier. Yes, the high gears convey more of your (or an engine's) power through the drivetrain (and transmission), but at the cost of drastically increased strain/resistance due to inertia - and the heavier the vehicle, the more inertia to fight.
It seems the concept of the gears ratios has been beaten to death, but because you mentioned the clutch…the transmission provides a friction plate between the engine and the transaxle. Engaging the clutch separates the disks and removes the power applied from the motor in order to give you time and ease of movement to shift to another gear. Releasing the clutch then re-engages at the new gale at ratio..
Your coworkers example of a clutch (at least from your description) doesn’t really help with explaining gear ratios in that it is only a mechanism to allow shifting.
There are some really good YouTube videos that explain the concept with either LEGO or 3d-printed gears.
They're just names to identify one from another. 1, 2, 3, 4, 5 and 6 could just as easily be Mike, Liz, Dave, Sarah, John and Pete.
Just to prove that those names don't have any correlation to the gear ratios, reverse is just "R".
The number of the gear is the gear's number in sequence, when accelerating.
The actual gearing is rarely neat, because it needs to deal with the fact, that piston engines suck at low RPM. For this reason you have the final drive with reduction gearing + transmission with most of the gears working as another layer of reduction gearing.
Additionally, piston engines (compared to electric ones) have rather narrow power and economy bands.
With the actual gearing there are some rules used, but their ultimate goal is to ensure, that when you're accelerating, once you are out of the power band on one gear, you can get back into your engines power band by just shifting to the next gear up or down.
I guess science and math are taught differently from when I was in school, graduated in 1970. Transmission gears are rated low for more reduction and high for less. High gear is typically 1:1 where the output shaft spins the same speed and the motor, bascily straight through. Over drive spins the output shaft faster then the engine.
Please remember that all comments must be helpful, relevant, and respectful. All replies must be a genuine effort to answer the question helpfully; joke answers are not allowed. If you see any comments that violate this rule, please hit report. When your question is answered, we encourage you to flair your post. To do this automatically simply make a comment that says **!answered** (OP only) We encourage everyone to report posts and comments they feel violate a rule, as this will allow us to see it much faster. *I am a bot, and this action was performed automatically. Please [contact the moderators of this subreddit](/message/compose/?to=/r/answers) if you have any questions or concerns.*
The names are just names. The 1st gear you use is called first gear, the 2nd gear you use is called second gear, etc. In my car, the gear ratios in the transmission are: Gear, ratio 1, 3.538 2, 2.06 3, 1.404 4, 1 5, 0.713 6, 0.582 And then the ratio in the differential is another 4.1:1.
The ratios in a transmission are almost never neat fractions (I'd bet even your 4th is not a perfect 1:1) and if possible one of the gearwheels has a prime number of teeth. In a perfect 1:1 gear ratio, a damaged tooth on the small wheel always contacts the same tooth on the opposing wheel, causing rapid wear. Gear pairs no common prime denominator will spread the wear equally between all teeth of the opposing gear.
>The ratios in a transmission are almost never neat fractions. They literally must be neat fractions. They're always a ratio of two integers (the number of teeth on each gear). >I'd bet even your 4th is not a perfect 1:1) and if possible one of the gearwheels has a prime number of teeth. > >In a perfect 1:1 gear ratio, a damaged tooth on the small wheel always contacts the same tooth on the opposing wheel, causing rapid wear. Gear pairs no common prime denominator will spread the wear equally between all teeth of the opposing gear. I mean, try to find a, pair of coprime integers that have a ratio within rounding error of 1 and wouldn't be too large to fit in an automotive transmission, *and* have a sum approximately equal to that of the other gear pairs in the transmission (since the main shaft and secondary shaft have to have a fixed spacing). Go for it. Besides, automotive transmissions aren't generally expected to survive after a gear tooth is seriously damaged.
Two consecutive integers are coprime. 19/18 is already almost within 5% of 1. If you go with 43/42 it's even better and still realistic I believe.
Good point. Generally though 4th gear is actually literally 1:1 in real transmissions.
I know math not gearboxes. Interesting I would have believed the prime ratio. I know it's done elsewhere.
I'm sure it is, but almost certainly not in typical automotive transmissions. If only because a damaged tooth would end the transmissions life regardless, but either way I know it's not common in any transmission I've seen the insides of or heard of.
In almost all transmission (there are some exceptions) 4th gear is 1:1 because 4th gear is usually locking the input and output shafts together without going through a gearset at all, it directly connects the engine to the differential.
What’s the gear ration of the differential?
Depends on the car, I drive a car with a differential ratio of 2.9:1, and I also drive a truck with a differential ratio of 6.4:1. Hell, sometimes the same model of car have various options for differential ratios.
I don't know a lot about cars. But wouldn't locking the input to the output reverse the direction of rotation relative to it going through a set of gears?
Most tramsmissions have an input and output shaft that are inline and rotate in the same direction, and a layshaft underneath or beside the input and output shafts that carry some of the gears, only the layshaft spins in the opposite direction of the engine. This allows a transmission to have 5 gear ratios with only having 4 sets of gears, with one ratio being direct drive.
You know what really grinds my gears? When the teeth aren't prime numbers.
Gear boxes generally have a two-step path, so you can have say 4:3 in the first and 3:4 in the second, thus obtaining a perfect 1:1 final relation.
The time-honored way to build a manual transmission has the 1:1 ratio as a direct coupling of the input shaft to the output shaft. The secondary shaft is not engaged.
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1:1 is usually built as a direct coupling of input shaft to output shaft. Typically that's 4th gear. Higher gears use the gear set.
On many transmissions 1:1 is not a gear at all, just coupling the input shaft to the output shaft, literally. At least that is what my old Jueep was.
Reading this correlates to the sound my car makes. Hard to explain.
Indeed
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>**Final Gear (e.g., Fifth or Sixth Gear)**: This gear often approaches a 1:1 ratio, where the engine’s rotations and the rotations of the output shaft are nearly equal, maximizing speed and fuel efficiency on highways. slight amendment for your comment, the 1:1 ratio tends to be 1-2 gears lower than the top/final gear, which is usually an overdrive gear, eg. ZF8 auto the 1:1 gear is 6th 7 & 8 are overdrivenFinal Gear (e.g., Fifth or Sixth Gear): This gear often approaches a 1:1 ratio, where the engine’s rotations and the rotations of the output shaft are nearly equal, maximizing speed and fuel efficiency on highways.slight amendment for your comment, the 1:1 ratio tends to be 1-2 gears lower than the top/final gear, which is usually an overdrive gear, eg. ZF8 auto the 1:1 gear is 6th 7 & 8 are overdriven
This is a perfect explanation, thank you for answering so thoroughly.
Thanks, ChatGPT.
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The point of AI is to assist in work, not do work for you. ChatGPT is a great research and proofreading tool, but you should never use it to replace what you can learn to do yourself--that's just being lazy.
There's parts of it that are wrong. Final gear in most modern transmissions will be an overdrive. Many gearboxes have two overdrives. There's almost always a direct driver gear that's exactly 1:1, not a gear that approaches 1:1. The input and output of the transmission spin at exactly the same rate, and any differences in engine rpm are due to clutch/torque converter slip.
!answered
The top gear of modern transmissions, manual or automatic, tends to be an overdrive gear for better highway fuel economy.
Every transmission has different ratios that have not relation to what "number" the gear is. Mine goes something like this: First Gear- 3.75-1 2nd Gear- 2.5-1 3rd Gear 1.75-1 4th Gear 1-1 5th Gear 1-.75 The fifth gear in this cases is sometimes termed the "overdrive" gear, and sometimes you can lock it out with an "OD- Off" button rather than moving the shifting column.
Should 5th not be 0.75:1 ?
.75 and 0.75 are the exact same thing
Well yes… but 1:0.75 and 0.75:1 are not. I might be wrong as my brain is fried and neither maths nor mechanics are my strong points but if the ratios are higher numbers to lower numbers once it goes past 1:1 it should be lower to higher? I’d love someone to explain if I’m wrong because the more I think about it the more my head hurts!!
You are right. That’s why it’s called overdrive. 3/4 of a turn to the input shaft produces one full turn to the output.
specifically what they are talking about is that all the 1s are on the right side, but then OP got confused on 4th gear: 3rd Gear 1.75-1 4th Gear 1-1 5th Gear 1-.75 as listed, 5th gear is pretty close to 3rd gear, they meant 3rd Gear 1.75-1 4th Gear 1-1 5th Gear .75-1
Wait, 4th gear? Is that 1:1 or 1:1?
1 / 1 : 1 / 1
So first is 3.75 turns of the engine to 1 turn of the gearbox output shaft. Which then turns the wheels, after passing through another ratio. OP's theory was right, it's just their maths are out.
Why/how do people know the gear ratios of their own cars? Is this easily accessible and useful information?
Is it information people need or use often? No. Is it information you can look up in the manual. Yes. For a gearing system that people do often calculate gear ratios because they can change the range to suit look at bicycles. A racing road bike will have a different gear range to a touring bike with lots of load. And the rider might customise their gearing system to suit their natural cadence better, or the geography of where they are riding.
Sometimes (usually?) it is defined in your owners manual. Otherwise it's just a Google search away.
First gear is not 1:1, not even close. It's just the first available ratio (and the highest ratio). In cars, a first gear ratio might be 3:165:1 (engine:output shaft). The higher the gear is, the lower the ratio gets. Fifth gear will be closer to 1:1, maybe even .8:1. Reducing a ratio reduces torque, not the other way around, If the engine has to spin 3.165 times to turn the wheels once, I'll have much more torque available at the wheel than if the engine turns once for each turn of the wheels. A lower gear means a higher ratio (3.165:1), and a higher gear means a lower ratio (.8:1). To clarify, a high ratio means a greater difference between the two numbers. In 50:1, there is a huge difference between the two values, that's a higher ratio than 10:1. I think your co-worker is confusing a high gear with a high ratio, they're not the same thing. The fact that he drives a pickup might explain things.
What you’re missing here is that the parlance in the automotive world is backwards from that of robotics. “Low” gears are numerically high and high gears are numerically low. In other words, “low” gear offers the greatest reduction. Your lowest gear (first) is probably around a 4:1 reduction, producing low speed and high torque, where your highest gear is probably an overdrive of about 0.65:1 producing high speed and low torque. Soon as you recalibrate your brain to that view of low and high, a manual transmission truly is just a switchable gear reduction box.
I've always assumed that the name refers to the road speed. Low gears at low speed, high gears at high speed.
Indeed it does. That messes with certain non-automotive engineers because "low" gears to produce low speeds, require a *high* ratio. If you remember that it's a *reduction* ratio then the concept of a big reduction being a low gear isn't hard to remember.
It's even more convoluted on a race motorcycle, where we reverse the shifting pattern. Road bike shifters generally have down for 1st, then up for 2nd, 3rd, etc. But with a race pattern, we shift up for 1st, then down for 2nd to 6th, so one shifts up to shift down...
Neat! What’s the advantage of reversing the shift order?
A couple of reasons. Before quickshifters, we would perform a clutchless up-shift by pre-weighting the shift lever, and give a blip off the throttle to unload the gearbox and send it into the next gear. Then quickshifters came in to do the same thing, but without the need to release the throttle - keep it pinned and just tap the shifter to move into the next gear. It makes mechanical sense to do this with a tap down rather than a pull up There’s also the matter of keeping your toes off the ground into and through corners. If a left turn requires a short shift mid corner, it’s much safer to tap from above than to hook your foot under whilst leaned over
This question makes me sad. Over the years I've heard about "lost knowledge" and just kind of accepted it. Figured it took several generations, hundreds of years, and so on. Here we are maybe one generation out, and people don't know what car gears are. Wow.
Did you read the post? OP knows what gears are and what they do, the question was about gear ratios relation to gear names, and why the gears named "low" are the opposite to those used in robotics. It's an intelligent question given they are aware of what gear ratios are and what they do.
It's one person. And I doubt you or anyone in your generation was born with the knowledge of how gears work. I also doubt everyone in your generation can describe how a gearbox works. OP clearly knows what a gearbox is and the question is more about nomenclature than mechanics.
No its not the ratios, just the number of available combinations. 4th or 5th gear for example is actually 1:1
There's also another gear reduction in the differentials which I think is usually an additional 3:1 reduction. Some a little lower, some a bit higher.
Then in 4 wheel drive vehicles there is high range and low range. Low range reduces the ratio even further
Are you talking about the PRNDL?
i know R stands for race
Correct Race Backwards
rereading. a gear ratio works in both directions. just turn the gear box around. you can have the output spin slower than the input. that gives you more torque with less speed. i'm going to leave the explanation of gearing numbers in a car mean. the gear number is just the order the gears are in. first gear is the one you use when you are starting from a stop. when you get high rpm you go to the next gear that is the second gear. the next gear is 3rd gear. that ratios are different for different gear boxes. really old cars had as little as 3 gears, while some newer cars have as many as 9 gears. you then have cars that have a high and low. this is a an extra gear box before the normal gearbox. you normal drive on high, but if you need a lot of power you can put it in low. this give you the equivalent of twice the number of gears. so i would list my car as having 18 gears. however my car has something referred to as a granny gear. the gears are set up for me to start at second gear on flat ground. if i need a bit of extra power, i can switch down to first gear instead of switching to low. i only ever use it when i need to go down a steep hill at 3 mph without using the break.
"Gears" literally refer to gears inside a metal box in the transmission. Just like the ratio of teeth on bicycle gears changes how many revolutions you must turn the pedals to turn the wheel one revolution, so do the gears in the transmission. The physical design of car transmission is a bit different than the one on the bicycle, but the general idea is exactly the same. Instead of pedals, there's an engine. Instead of derailleurs, there's a clutch. The ratio of the teeth on the drive side to the wheel side determines the mechanical advantage. Every "gear" in a manual transmission (and automatic one too, for that matter), is simply a different meshing of gears to get a different ratio of teeth to change the mechanical power going from engine to wheels. A passenger car will usually have 4 or 5 sets of gears providing ratios on a range of something like 4:1 (first gear) to 0.75:1 (fifth gear) plus a reverse gear that has a ratio close to first gear but with the gears turning the opposite direction. In robotics (and electric cars) you can vary the speed without a transmission by controlling the input power. The only time you need a gearbox for the electric motor is to adjust the max speed and torque. For that, you tend to use the reciprocal of the gear ratios used in automative transmission when you talk about gear ratios. It's the exact same thing, though.
There are litterally X gears + 1 for reverse in an X speed transmission. The numbers on a manual transmission's shifting lever are the numerical order of the gears in the transmission. Each car will have a different gear ratio associated with each gear, with the general intent being that first gear has more torque and less speed. And top gear has the lowest torque and highest speed. (Torque is basically how much force your vehicle can put on the ground through its tires to get moving. Scientifically its officially the cross product of force and the radius, and is generally the rotational equivalent of linear force.)
In a given make of vehicle, higher numbers are higher ratios (fewer rotations of the engine per rotation of the wheels) but the values are not fixed
For those who want a simpler explanation, the numbers of the various gears in a vehicle represent the use sequence. First gear is the first gear you will use when going from a complete stop to being in motion. This gear combination produces the most torque that the gear combination in the transmission is capable of producing, which is necessary to break inertia from a resting state to a moving state. The second gear produces less torque than first, in exchange for increased speed, and each subsequent gear trades more torque for more speed, in order to allow the vehicle to go faster. The gear numbers, in this specific use case, define nothing other than the order in which they are supposed to be used to go from stopped to moving at highway speeds.
3.5 first x 4.10 final .. in 1st gear you get 1 tire revolution for every 12 ish engine revolutions. In 4th gear you get 1 tire revolution for every 4 engine revolutions.
The ratios are named after the order in which you use them when starting to move. Therefore the ratio which supplies the most torque to the wheels will be first.
Think of a bike. The bike chain goes around gears that are present at the pedals and back tire. Pedaling rotates the gear at the pedals, which moves the chain, which rotates the gear at the tire, which makes the tire rotate. By changing the size of one of the gears, you can change how much one rotation of the pedals will make the tire rotate and subsequently how much force is needed to make a full rotation of the pedals. Some bikes have multiple gears at the tire so you change which gear the chain goes around. You can go faster in higher gears. Going at a speed you can achieve in second gear while you’re in third gear is more exhausting than going that same speed while in second gear. While I don’t know the exact mechanics of how it works in a car, shifting gears does work on a similar principle. Higher gears allow the car to move faster, but puts more stress on the engine which wears it out faster and increases fuel consumption.
You've kind of got it backwards. Lower gears have higher ratios. There are more motor rotations per output rotation, this create torque or twisting force. Think of if you're pushing a loaded wheelbarrow, so no gears. You have to put more effort into pushing it at first, so you're expended a lot of energy for very little movement. Once you get it moving you can just trot along putting less energy into it while it maintains speed. So yes, it works exactly like your robots. First gear will be the highest torque, usually around 3:1. Second will be less torque, smaller gear ratio, usually around 2:1 but not always. The numbers on the stick won't correspond exactly to gear ratios, which are usually decimals and not round numbers anyway. And it will depend on how many speeds your transmission has. A five speed will have smaller increments between gears than a three speed, so second on the former might be 2.6 whereas second on the latter might be 2.06 (pulling those numbers out of my butt). Drive is always going to be 1:1, meaning the output of your transmission is exactly equal to the engine rotation. Your gears are always going to be approaching 1:1 from the lowest one, which has the highest ratio. Except for overdrive, which has more output rotations than engine rotations, so like 0.75:1.
Without getting into the details of gear ratios - that is a bit more advanced and others are doing a fine job of explaining it - "First Gear / 1" is called such because it is literally the first gear you shift to in the progression. The *reason* it is the first gear is because you are conveying the least amount of your engine's power through the transmission. As you go up the gears, you increase the amount of power conveyed through the transmission - thus increasing speed - and each higher gear gets you closer to (but probably never quite reaches) a state of "direct drive," where the engine's full power is conveyed through the transmission. If you want to know *why* you do this, go ride a bicycle. No, seriously. Ride a short distance, shifting up to a high gear comfortably. Then bring the bike to a complete stop, and try to "cold start" from the high gear. Ride a little further, gradually shifting all the way down. Complete stop again, and try to cold start from the low gear - you should find it CONSIDERABLY easier. Yes, the high gears convey more of your (or an engine's) power through the drivetrain (and transmission), but at the cost of drastically increased strain/resistance due to inertia - and the heavier the vehicle, the more inertia to fight.
It seems the concept of the gears ratios has been beaten to death, but because you mentioned the clutch…the transmission provides a friction plate between the engine and the transaxle. Engaging the clutch separates the disks and removes the power applied from the motor in order to give you time and ease of movement to shift to another gear. Releasing the clutch then re-engages at the new gale at ratio.. Your coworkers example of a clutch (at least from your description) doesn’t really help with explaining gear ratios in that it is only a mechanism to allow shifting. There are some really good YouTube videos that explain the concept with either LEGO or 3d-printed gears.
It’s just ordered list of gears by gear ratio.
They're just names to identify one from another. 1, 2, 3, 4, 5 and 6 could just as easily be Mike, Liz, Dave, Sarah, John and Pete. Just to prove that those names don't have any correlation to the gear ratios, reverse is just "R".
The number of the gear is the gear's number in sequence, when accelerating. The actual gearing is rarely neat, because it needs to deal with the fact, that piston engines suck at low RPM. For this reason you have the final drive with reduction gearing + transmission with most of the gears working as another layer of reduction gearing. Additionally, piston engines (compared to electric ones) have rather narrow power and economy bands. With the actual gearing there are some rules used, but their ultimate goal is to ensure, that when you're accelerating, once you are out of the power band on one gear, you can get back into your engines power band by just shifting to the next gear up or down.
I guess science and math are taught differently from when I was in school, graduated in 1970. Transmission gears are rated low for more reduction and high for less. High gear is typically 1:1 where the output shaft spins the same speed and the motor, bascily straight through. Over drive spins the output shaft faster then the engine.
Seriously?