A big thank you to whoever created this video. The visualization makes all the difference. I've read so many forums and articles that just repeat the same words over and over without adding to any actual understanding.
Spot on with your description. So many people misunderstand ABS Traction Control. I have a Volvo XC90 with this kind of traction control, and I'm amazed at how many Volvo owners are confused about this. (They also confuse Spin Control with Traction Control--two different things completely. Volvo recommends turning off Spin Control when in low traction situations.) I don't have a button for Traction Control though--it's all automatic.
Great video - I am 52 and never understood the differential fully. It's hard for most people to understand how things were BEFORE the differential came along - try one of those off-road vehicles or go-karts without this device - it judders on a bend and of course, has better grip on the straight for acceleration. It's fair to say, it was probably made to improve the comfort of some posh bloke in a big limousine - should look it up I guess! This is the perfect animation, I sat and 'paused' the action, and thought through how it works - so now I know that in normal operation, driving straight ahead on a good road with no tyre slip, the 'twiddly bits' in the core of the action sort of act as 'locked up'. Then come a bend or tyre slip on one wheel say, that situation changes. Such a straightforward vid to view and think about how it works. Good work. Also, for further thought people out there could figure how to limit the slip for extra traction on snow etc? Obvs, lots have tried it and there are umpteen variations both involving the differential itself, freewheel-type devices on each axle (like bicycle, one way it's turned it provides drive, not the other, think about it!), aand the old standby now, using ABS system to jam the wheel that's spinning free, to 'force' the wheel with grip to turn a bit. Yes, food for thought, great vid.
My cousin has an FJ Cruiser. I pressed the "lock differential" button and went offroading with it...upon coming back to the road, the car felt very very weird on turns, i thought i have ruined something in the suspension...after several hours, my brother pointed out that i still had my "Lock Differential" button activated.../facepalm
MrSakninsh Only if it is an incredibly weak and poorly built one, but I'm assuming he actually meant rear diff lock and not transfer case lock because I don't think FJ's are full time all wheel drive, in which case it's a completely different part he is talking about.
MrSakninsh Well, depending on what you want to mean, pretty much every differential has to be "interaxial" by design. While the only "Toyota" I've owned had almost no Toyota parts on it, Toyota's reputation would indicate that neither a transfer case mounted or rear axle mounted locker should break ever in that circumstance. Also, a rear diff lock should disengage automatically above about 15 MPH for safety reasons. All OEM ones that I'm aware of do that.
sleekitwan I don't believe it was made for limousines, from what I've gathered early cars used to be only 1 wheel drive, but that was terrible since most roads were very rough and definitely not paved, which made cars really tedious to drive. Making cars two wheel drive was a necessity at the time, therefore the differential was created to allow both rear wheels to have power.
@89Silhouette Again, the brakes are pulsed via an ABS type system to not stop the wheel from turning but to create some drag to transfer power to the opposite axle. That type of system is a low-speed only system. There seems to be a misunderstanding that the brake "holds" the wheel from turning but it's rapidly pulsed only to the extent needed to transfer power. It has to be manually engaged via a button also.
Awsome ! After many failed attempts consisting of sites , forums and hours of googling, I finally find in a 5 min package and understand everybit of it :D :D !!!
To be fair, its very difficult to explain this to someone without pictures or a video. Either way you cant describe it correctly or even if you do, the person you are talking has not the required abilities of imagination. :)
There are a number of different but related software packages that control wheel slip via use of the brakes but they are actually technically independent. VSC (skid control), TRAC (traction control) ALSD (auto LSD), ABS (anti-lock-brakes), and Brake Assist (BA) all utilize wheel slip/brake control to accomplish a task but they are independent and were not always included as a full set of installed software. Some of the systems reduce engine power, some change brake pressure etc.
Locking differential at 3:28...Do both axles actually receive equal power (P)? Since they are locking the angular velocities (w) are equal, and the torque (T) on the side with more traction should be greater? P=T*w so T=P/w. If P is equal on both axles and so is w then T would be as well which is not the case correct?
@thebluecommet The video states that ALSD(aka brake based traction control) does a better job of trasfering torque then other differentials. And it does. Mechanical LSDs can't really change the torque distrabution, they just limit how much of the torque can go to the wheel with the least amout of traction. Brake based traction control can make the wheel with the least amount of resistance the wheel with the most amout of resistance. This why many modern cars use it.
Might not be supposed to be a high budget movie.. never the less, it looks very professionally done. And is well done and pretty illustrated. Ty for clearing my thoughts on how a LSD works.
@Jesus45U I wrote the script and it was for training sales consultants not for marketing. The primary disadvantage is that it's designed for low speed situations where the vehicle is likely to get stuck. It's not designed for all driving situations like, say, a mechanical LSD.
@PayDroification DRE (driveshaft rotation effect) also means that if you attempt to back up quickly, you may spin the left rear wheel more than the right. It's not that only "one wheel drives", it's that your "go traction" is limited by the wheel with the least traction. One of the advantages of independent rear suspensions on rear driven wheels is the elimination of DRE.
You did happen to skip a very well-known differential, the 2-speed differential. I'm not sure if Toyota ever put one in any of their commercial trucks, but most all other manufacturers have, from 1-ton trucks up, at some point. To see how they work is truly ingenious and resolves the age-old question: gear for torque, or gear for speed. With a 2-speed, you can have both. In a truck, this is very helpful.
I wish I could do some more extensive videos like this. I had put this on the web for a single conversation on a forum with 6 people viewing it and next thing I knew it had all these hits. If I ever get the opportunity though, I'd make a more wide-ranging video. For instance, I was focused on low-speed differential characteristics because this was trucks. It would be good to do high-speed where LSDs and other mechanical diffs are superior to brake-diffs (which don't work at speed).
I have used all 3 type of Diff's and like the clutch pack lsd the best because Locking diff's come on suddenly and blow the entire truck sideways and can be downright scary when side hilling above rivers ect, the electronic ones dont work when rallying at speed and wait to kick in when you have already lost all speed. The clutch system is a constent manageble mesh that works great in the situations I drive.
Complicated question. There's the creative director (in this case me) who wrote and storyboarded it then a 3D animator, then a VO artist, then a video editor and this was part of a project that had a producer and other people so it's a big number even though in the scale of this type of project it was "low budget."
That's a good question. Normally in racing situations, of course, you'd want a limited slip diff. I would think with drifting that you'd still want some differential action but you'd want to really limit it so the amount of "slip" is low so that you can ensure lighting up both rear tires. If the car isn't actually drifted but is driven on curves, a locked differential would not only produce really bad handling but would also potentially damage the diff when turning so my guess is adjustable LSD.
1:35 A false claim is made; the power will remain the same! It is the torque and speed that will very. Of course assuming all frictional losses are comparable between the different gear ratios.
I don't see why not though the key to this is not just holding that brake but pulsing it so that wheel does still have some ability to turn. To do it "elegantly", the ABS sensor and electronic system works it but what you are describing would be like modulating the brake on that wheel as a driver would have done aggressively braking in the pre ABS times.
I did a little research, a humming noise is often caused by an incorrectly installed ring and gear pinion, which needs to be adjusted, the incorrect installation of ring and pinion gear prevents proper tooth contact and can cause rapid tooth wear and can cause gear failure. This humming noise converts into growling noise when the wear increases. Humming noise can also be caused due to worn out bearings, which needs to be replaced.
@PayDroification I'm not a Mustang expert but I know there was a friction-disc LSD on some Mustang rear ends and open diffs on others. If you find out you had an LSD on your particular model of Mustang, it's possible that the friction discs are worn out and it's not providing a limited-slip effect. If you have an open diff, the power tends to always go to the same axle so you would find "1-wheel drive" on the same wheel would be normal.
@allegroracing please demonstrate how it's possible for a differential to be placed on either left or right of an Axle instead of the center, like on the Toyota land cruiser 70 series. Thank you.
That's a tough question to answer. Remember it's the tires adhesion that ultimately determines if the car moves or the tires just sit there spinning (or skidding if the car is moving). The ability to control wheel slip and distribute power to any of the 4 wheels is very helpful in situations where one or more wheels are slipping but one or more have traction. However, if all 4 tires are on ice and there's no adhesion for any tire, no drive system will get the car moving.
@PayDroification You LIKELY have an open diff. There's probably some tag on the diff that would tell your Ford parts guy whether it's open or LSD. Ford used to call their LSD "Traction-Loc", GM called theirs "Positraction" and Chrysler called theirs "Sure Grip". Part of what you're noticing is "driveshaft rotation effect" (my term). DRE with a live axle setup like the shown Tundra or your Mustang tries to pick up the right rear wheel when going forward. This reduces it's traction and it spins.
Yes it would but the acceleration would suffer (check out Bonneville speed cars that have to be push started because they have such tall gears) because there would be no mechanical advantage from the differential. But you're correct, the axle ratio is a large component in both acceleration and top speed. However, in order to really make the car that much faster, it would need an exponential increase in horsepower because aerodynamic drag is the biggest issue at high speeds.
"Posi" is a term for a limited-slip differential. There are a variety of technologies used in limited-slip differentials but Posi refers to "Posi-traction" which was a brand name for an Eaton LSD unit.
I'd think that the answer depends on how tight the tracks (or areas) you're going to run on would be. If you need to turn tightly and the vehicle is pretty wide, it will handle better with a differential than a solid axle. If traction isn't huge on the vehicle (like if it was an off-road RC truck) then it wouldn't matter much. Keep in mind, Karts run with solid axles and they handle great, their track and wheelbase are small.
I finally understand basic differentials now. I grew up thinking that a basic differential sent power to one dominant wheel (right side) 100% of the time and the other wheel part of the time. Turns out both wheels are treated exactly the same in relation to one another.
@mastersduhgree It doesn't "drag" the brake, auto LSD can pulse the brake a fraction of a second or several times per second and stops as soon as the other size gets traction. Trying to do this with the parking brake has a similar effect but is nothing like as sophisticated as the high-speed brake pulsing. It's also the basis of the CRAWL system which allows vehicles like the Lexus 460 to decline incredibly steep hills with both feet on the floor.
@bubub56 It operates exactly the same as a locked locking diff. Both rear wheels turn exactly the same RPM relative to each other. Great for a dedicated drag car, maybe an ice racer, or possibly a rock crawler. A spool would have way too many drawbacks for any other applications.
i have a question . when you want to rotate two front or rear wheels, with gears or differential, have you checked the precise rotations of both the wheels with digital meter. I guess, there can be difference.
does the differential add a reduction ratio? i mean internally, I know a reduction will be made having in mind the difference in the ring gear and in the pinion gear, but i do not now if its internal mecanism also add a reduction ratio
@Jesus45U Actually it's not a requirement that all passenger cars in the US have skid control...that means they also have ABS as standard so given that all new vehicles have ABS sensors, it's really just software to accomplish this and utilizes existing components. If the diff was being used for high-performance driving (ALSD disengages at low speed) then you would, in fact, tend to cook the brakes as often happens at track days with skid control.
Because it uses an already existing ABS sensor and is just software. There's no additional hardware or wear components added to a simple open differential. In some cases, mechanical systems require frequent maintenance due to the normal wear caused by their operation.
ALSD's work great for the average driver who seldom goes off road, but for serious off road you need locking front & rear diffs. If you have full time 4WD you also need a locking center diff. Brake activated ALSD systems overheat with continuous usage & waste engine power.
You answered your own question. Because ALSD only operates at low speeds, the brake friction is low and the brake wear is negligible. Some truck LSDs require frequent oil changes (as frequently as 12 or 20,000 miles) and there are more mechanical components that wear. Changing brake pads is cheaper and easier than differential parts.
Look up the difference between part-time and full-time 4wd. Your center differential is there to allow you to use 4wd on pavement, and it works between your front and rear driveshafts the same way an axle differential works between the wheels. Locking the center differential makes your truck behave like any other part-time 4wd rig, unlocking it makes your truck behave more like a Subaru or other all wheel drive vehicle. Lock it when you're offroad if you're worried about traction.
oh sorry one more question. if a car is already in motion then LSD might not be needed right? if one (or even both) rear wheels lose traction the car already has momentum, so the front wheels would keep moving the car forward losing speed, but hopefully before you reach 0 your rear wheels have regained traction and can move the car forward again right? but if you are already stopped and your rear wheels don't have traction then that's when you are screwed right?
Hi, i have a 1987 ford scorpio which has a limited slip differential but the differential has backlash and i need to change it. I have found an open differential that fits perfectly. But i want to know if an open differential would affect the car's handling in a negative way or not. For example, in a rainy day, driving on a curved road, would the car get out of control easier? The car is mostly being used in highway. Thanks.
A welded diff is basically a jerryrigged locking differential. It forces the rear axles to turn at the same speeds at all times by welding the differential together, giving the benefits of extra traction of a locked differential, without the benefits of an open, limited slip, or electronic (streetability) differential at a very low cost. Welded diffs cause axle hop during cornering and are almost unusable on a daily driver.
Welding a differential takes another design of diff (like an open diff) and creates a "LOCKED" differential. So the explanation of a locking differential basically applies to welded diffs. The goal of welding a diff is to cheaply convert it into a full-time locked differential. This is nearly always for off-road use.
I hear ya. . As for brake diffs not working at speed, check out Ford's torque vectoring setup, pretty sure it's near identical to the auto LSD or whatever (it's a brake diff) - it's on the new Focus ST's. It's performance oriented for that setup :). . Glad your video took off, hope someday you get the time and resources to do an addition ^_^.
@thebluecommet Nowhere in that video does it claim that ALSD (which is far from a unique application of that technology in the auto industry) is superior to anything other than an open diff. ALSD has two benefits over other LSDs, it's lighter and it's cheaper to maintain. That is the only statement in the video. The reason so many differential designs exist is that each is suited to a specific need and have advantages and disadvantages depending on how the vehicle is going to be used.
Can you think of a way of doing this using simple mechanics? Sophisticated mechanical parts can wear even faster than electronics and can be much more destructive to itself. Power going to the path of least resistance is universal. Even in electronic circuits.
What would happen if i put a 265/75 R16 in one side and the other side a 31x10.50 R15 stock tire size my is limited split differential by the way. What would it damaged the diffrential??
Already done. they are referred to as "torque-biasing" differentials, and use helical or worm gears(2 different things, not 2 names for 1 thing). they're pretty good, but they have drawbacks as well. I won't get into the mechanics but: -both wheels have to have at least some traction, or it does nothing. -less efficient torque transfer compared to other options -it never actually 'locks', and so it acts against both drive wheels spinning/being broken loose(this is bad in certain situations).
hey you guys seem to know your lsds well. could you help me out with a question maybe? I'm am considering purchasing a subaru wrx because I feel it is an excellent choice of car for a daily driver, especially for winter months of snow. I understand the wrx is awd and has a rear lsd. this means when power is transferred to rear is can be further divided between the left and right rear wheel. the wrx does not have a front lsd. so my question is when traction is lot on both rear wheels
So then when turning to the right, the left wheels will be moving faster than the right wheels. Does this mean that since the more of the engine's power is going to the left wheels to keep them turning faster that the left wheels have less resistance in this scenario?
It depends what sort of diff the vehicle has. If it's an open diff, it depends which wheel is providing the most resistance. Usually the outside one (due to weight transfer) so it's common that the inside tire has the power and the outside one is just coasting. Not really what you want though because the outside tire has more potential traction so could handle more power. A LSD would try to put a lot of power to the loaded outside tire while still keeping some power to the inside as well.
I don't claim to be a mechanic but when it was stated the LSD system via brakes provided fewer parts and less maintenance, are they assuming the *maintenance* was only concerning the immediate LSD system and excluding the brakes? I'm having a hard time assuming the brakes wouldn't wear down sooner....increasing the maintenance frequency? Or am i getting caught up on the word *less as apose to more and they are not refering to time but volume?
@PayDroification TO test if you really have a "limited slip" or a "positrack"(power goes to both wheels); when you turn a corner, step on the gas to lay some rubber.If the outside tire spins too;you have a posi or limited slip.(just look for the fry marks when you go around the block to check out the rubber you layed.
Drift cars typically use very limited slip differentials to fully locked differentials. Since the rear is sliding, the differential effect of the turn is irrelevant. It's more important to get power to both rear wheels to keep them spinning. "Normal" handling is degraded due to a reduction in differential wheel speeds.
Hey, could you please tell me what simulator you used ? I'm doing a project for one of my exams and I can't accomplish the physical part so I want to simulate it. Thanks.
A big thank you to whoever created this video. The visualization makes all the difference. I've read so many forums and articles that just repeat the same words over and over without adding to any actual understanding.
i think i have learnt more in 4:44 than i have in my life :) thanks , really good vid
This video really grinds my gears
You did this on a budget. Proof that expense doesn't necessarily equal quality. Great video!
Spot on with your description. So many people misunderstand ABS Traction Control. I have a Volvo XC90 with this kind of traction control, and I'm amazed at how many Volvo owners are confused about this. (They also confuse Spin Control with Traction Control--two different things completely. Volvo recommends turning off Spin Control when in low traction situations.) I don't have a button for Traction Control though--it's all automatic.
Incredible, I turned 345 last Wednesday and even at my age I understood this video easily.
Never heard of the Auto LSD till this video. But I just thought about in my head it right before I saw it. Nice job Toyota. Practical simplicity.
Great video - I am 52 and never understood the differential fully. It's hard for most people to understand how things were BEFORE the differential came along - try one of those off-road vehicles or go-karts without this device - it judders on a bend and of course, has better grip on the straight for acceleration. It's fair to say, it was probably made to improve the comfort of some posh bloke in a big limousine - should look it up I guess! This is the perfect animation, I sat and 'paused' the action, and thought through how it works - so now I know that in normal operation, driving straight ahead on a good road with no tyre slip, the 'twiddly bits' in the core of the action sort of act as 'locked up'. Then come a bend or tyre slip on one wheel say, that situation changes. Such a straightforward vid to view and think about how it works. Good work. Also, for further thought people out there could figure how to limit the slip for extra traction on snow etc? Obvs, lots have tried it and there are umpteen variations both involving the differential itself, freewheel-type devices on each axle (like bicycle, one way it's turned it provides drive, not the other, think about it!), aand the old standby now, using ABS system to jam the wheel that's spinning free, to 'force' the wheel with grip to turn a bit. Yes, food for thought, great vid.
My cousin has an FJ Cruiser. I pressed the "lock differential" button and went offroading with it...upon coming back to the road, the car felt very very weird on turns, i thought i have ruined something in the suspension...after several hours, my brother pointed out that i still had my "Lock Differential" button activated.../facepalm
MrSakninsh My cousin uses the car pretty much everyday, there aren't any problems
MrSakninsh
Only if it is an incredibly weak and poorly built one, but I'm assuming he actually meant rear diff lock and not transfer case lock because I don't think FJ's are full time all wheel drive, in which case it's a completely different part he is talking about.
MrSakninsh
Well, depending on what you want to mean, pretty much every differential has to be "interaxial" by design.
While the only "Toyota" I've owned had almost no Toyota parts on it, Toyota's reputation would indicate that neither a transfer case mounted or rear axle mounted locker should break ever in that circumstance.
Also, a rear diff lock should disengage automatically above about 15 MPH for safety reasons. All OEM ones that I'm aware of do that.
sleekitwan I don't believe it was made for limousines, from what I've gathered early cars used to be only 1 wheel drive, but that was terrible since most roads were very rough and definitely not paved, which made cars really tedious to drive. Making cars two wheel drive was a necessity at the time, therefore the differential was created to allow both rear wheels to have power.
@89Silhouette Again, the brakes are pulsed via an ABS type system to not stop the wheel from turning but to create some drag to transfer power to the opposite axle. That type of system is a low-speed only system. There seems to be a misunderstanding that the brake "holds" the wheel from turning but it's rapidly pulsed only to the extent needed to transfer power. It has to be manually engaged via a button also.
Awsome ! After many failed attempts consisting of sites , forums and hours of googling, I finally find in a 5 min package and understand everybit of it :D :D !!!
I was workin on a Lego model truck with deferential,this vedio helped me to figure out few tricks to modifie it!thanks for such a great video
Very informative! Sales people at off-road stores can’t even explain it like this. Using Laymen’s term is the secret!
To be fair, its very difficult to explain this to someone without pictures or a video.
Either way you cant describe it correctly or even if you do, the person you are talking has not the required abilities of imagination. :)
There are a number of different but related software packages that control wheel slip via use of the brakes but they are actually technically independent. VSC (skid control), TRAC (traction control) ALSD (auto LSD), ABS (anti-lock-brakes), and Brake Assist (BA) all utilize wheel slip/brake control to accomplish a task but they are independent and were not always included as a full set of installed software. Some of the systems reduce engine power, some change brake pressure etc.
You have really done some hard work, thank you, its informative.
Locking differential at 3:28...Do both axles actually receive equal power (P)? Since they are locking the angular velocities (w) are equal, and the torque (T) on the side with more traction should be greater? P=T*w so T=P/w. If P is equal on both axles and so is w then T would be as well which is not the case correct?
@thebluecommet The video states that ALSD(aka brake based traction control) does a better job of trasfering torque then other differentials. And it does. Mechanical LSDs can't really change the torque distrabution, they just limit how much of the torque can go to the wheel with the least amout of traction. Brake based traction control can make the wheel with the least amount of resistance the wheel with the most amout of resistance. This why many modern cars use it.
Might not be supposed to be a high budget movie.. never the less, it looks very professionally done. And is well done and pretty illustrated. Ty for clearing my thoughts on how a LSD works.
@Jesus45U I wrote the script and it was for training sales consultants not for marketing. The primary disadvantage is that it's designed for low speed situations where the vehicle is likely to get stuck. It's not designed for all driving situations like, say, a mechanical LSD.
Really cool video. Easy to understand and follow. Well done!
@PayDroification DRE (driveshaft rotation effect) also means that if you attempt to back up quickly, you may spin the left rear wheel more than the right. It's not that only "one wheel drives", it's that your "go traction" is limited by the wheel with the least traction. One of the advantages of independent rear suspensions on rear driven wheels is the elimination of DRE.
Voice Over artist. Someone who professionally does voice recording work.
thanks for the vid. basically summed up half of my course and simplified the components.
Very informative video! I knew about slip differential because of my truck but I never knew whats really going on in the rear end.
Have had my tundra for 10 years, had no idea what Auto LSD does. Ty!!!
Nice! also helped to answer my question about the difference between a truck and a sports car
God bless you man. 5 stars for the video.
LOCKING DIFF. are widely used in Tractors.
Excelent vid. Animtation is pretty clear, don't need enough.
You did happen to skip a very well-known differential, the 2-speed differential. I'm not sure if Toyota ever put one in any of their commercial trucks, but most all other manufacturers have, from 1-ton trucks up, at some point. To see how they work is truly ingenious and resolves the age-old question: gear for torque, or gear for speed. With a 2-speed, you can have both. In a truck, this is very helpful.
I wish I could do some more extensive videos like this. I had put this on the web for a single conversation on a forum with 6 people viewing it and next thing I knew it had all these hits. If I ever get the opportunity though, I'd make a more wide-ranging video. For instance, I was focused on low-speed differential characteristics because this was trucks. It would be good to do high-speed where LSDs and other mechanical diffs are superior to brake-diffs (which don't work at speed).
i just discovered differentials today, and this stuff is very, very interesting. is there anywhere i can learn more about stuff like this?
I have used all 3 type of Diff's and like the clutch pack lsd the best because Locking diff's come on suddenly and blow the entire truck sideways and can be downright scary when side hilling above rivers ect, the electronic ones dont work when rallying at speed and wait to kick in when you have already lost all speed. The clutch system is a constent manageble mesh that works great in the situations I drive.
Complicated question. There's the creative director (in this case me) who wrote and storyboarded it then a 3D animator, then a VO artist, then a video editor and this was part of a project that had a producer and other people so it's a big number even though in the scale of this type of project it was "low budget."
That's a good question. Normally in racing situations, of course, you'd want a limited slip diff. I would think with drifting that you'd still want some differential action but you'd want to really limit it so the amount of "slip" is low so that you can ensure lighting up both rear tires. If the car isn't actually drifted but is driven on curves, a locked differential would not only produce really bad handling but would also potentially damage the diff when turning so my guess is adjustable LSD.
1:35 A false claim is made; the power will remain the same! It is the torque and speed that will very. Of course assuming all frictional losses are comparable between the different gear ratios.
I don't see why not though the key to this is not just holding that brake but pulsing it so that wheel does still have some ability to turn. To do it "elegantly", the ABS sensor and electronic system works it but what you are describing would be like modulating the brake on that wheel as a driver would have done aggressively braking in the pre ABS times.
I did a little research, a humming noise is often caused by an incorrectly installed ring and gear pinion, which needs to be adjusted, the incorrect installation of ring and pinion gear prevents proper tooth contact and can cause rapid tooth wear and can cause gear failure. This humming noise converts into growling noise when the wear increases. Humming noise can also be caused due to worn out bearings, which needs to be replaced.
@PayDroification I'm not a Mustang expert but I know there was a friction-disc LSD on some Mustang rear ends and open diffs on others. If you find out you had an LSD on your particular model of Mustang, it's possible that the friction discs are worn out and it's not providing a limited-slip effect. If you have an open diff, the power tends to always go to the same axle so you would find "1-wheel drive" on the same wheel would be normal.
It just clicked! Hell yeah. I've been curious forever about this topic.
awesome job guys! great video even though i knew how a diff works this video makes it easier for me to explain what i know to others
@allegroracing please demonstrate how it's possible for a differential to be placed on either left or right of an Axle instead of the center, like on the Toyota land cruiser 70 series. Thank you.
That's a tough question to answer. Remember it's the tires adhesion that ultimately determines if the car moves or the tires just sit there spinning (or skidding if the car is moving). The ability to control wheel slip and distribute power to any of the 4 wheels is very helpful in situations where one or more wheels are slipping but one or more have traction. However, if all 4 tires are on ice and there's no adhesion for any tire, no drive system will get the car moving.
@PayDroification You LIKELY have an open diff. There's probably some tag on the diff that would tell your Ford parts guy whether it's open or LSD. Ford used to call their LSD "Traction-Loc", GM called theirs "Positraction" and Chrysler called theirs "Sure Grip". Part of what you're noticing is "driveshaft rotation effect" (my term). DRE with a live axle setup like the shown Tundra or your Mustang tries to pick up the right rear wheel when going forward. This reduces it's traction and it spins.
Yes it would but the acceleration would suffer (check out Bonneville speed cars that have to be push started because they have such tall gears) because there would be no mechanical advantage from the differential. But you're correct, the axle ratio is a large component in both acceleration and top speed. However, in order to really make the car that much faster, it would need an exponential increase in horsepower because aerodynamic drag is the biggest issue at high speeds.
"Posi" is a term for a limited-slip differential. There are a variety of technologies used in limited-slip differentials but Posi refers to "Posi-traction" which was a brand name for an Eaton LSD unit.
I'd think that the answer depends on how tight the tracks (or areas) you're going to run on would be. If you need to turn tightly and the vehicle is pretty wide, it will handle better with a differential than a solid axle. If traction isn't huge on the vehicle (like if it was an off-road RC truck) then it wouldn't matter much. Keep in mind, Karts run with solid axles and they handle great, their track and wheelbase are small.
I finally understand basic differentials now. I grew up thinking that a basic differential sent power to one dominant wheel (right side) 100% of the time and the other wheel part of the time. Turns out both wheels are treated exactly the same in relation to one another.
@mastersduhgree It doesn't "drag" the brake, auto LSD can pulse the brake a fraction of a second or several times per second and stops as soon as the other size gets traction. Trying to do this with the parking brake has a similar effect but is nothing like as sophisticated as the high-speed brake pulsing. It's also the basis of the CRAWL system which allows vehicles like the Lexus 460 to decline incredibly steep hills with both feet on the floor.
the powertrax no-slip is the best auto locker ever made and best set up for on or off-road.
تفاعلات تكوانسا حركة ممتازة بدون عطل حركة
Just watched all your vids and I must say pretty interesting. Nicely done
@bubub56 It operates exactly the same as a locked locking diff. Both rear wheels turn exactly the same RPM relative to each other. Great for a dedicated drag car, maybe an ice racer, or possibly a rock crawler. A spool would have way too many drawbacks for any other applications.
i have a question . when you want to rotate two front or rear wheels, with gears or differential, have you checked the precise rotations of both the wheels with digital meter. I guess, there can be difference.
This video gave me a great help to update my knowledge thank you.
does the differential add a reduction ratio? i mean internally, I know a reduction will be made having in mind the difference in the ring gear and in the pinion gear, but i do not now if its internal mecanism also add a reduction ratio
so LSD and driving go hand in hand?
Depends on what kind of trip you want.
Yeah, it's when you go on a trip and never leave the farm.
I hope you ain't talking about lysergic acid diethylamide!
Go out of Town and never leave the driveway! Lol
@Jesus45U Actually it's not a requirement that all passenger cars in the US have skid control...that means they also have ABS as standard so given that all new vehicles have ABS sensors, it's really just software to accomplish this and utilizes existing components. If the diff was being used for high-performance driving (ALSD disengages at low speed) then you would, in fact, tend to cook the brakes as often happens at track days with skid control.
Because it uses an already existing ABS sensor and is just software. There's no additional hardware or wear components added to a simple open differential. In some cases, mechanical systems require frequent maintenance due to the normal wear caused by their operation.
ALSD's work great for the average driver who seldom goes off road, but for serious off road you need locking front & rear diffs. If you have full time 4WD you also need a locking center diff. Brake activated ALSD systems overheat with continuous usage & waste engine power.
Great vid. Easy to follow
Are the diameters of the differential gears also need to compensate for the width of the car?
such a superb video
You answered your own question. Because ALSD only operates at low speeds, the brake friction is low and the brake wear is negligible. Some truck LSDs require frequent oil changes (as frequently as 12 or 20,000 miles) and there are more mechanical components that wear. Changing brake pads is cheaper and easier than differential parts.
easy to understand, this was great learning tool.. thanks for the good video
excellent, very concise and informative. thank you.
This was amazing. I learned about differentials
Look up the difference between part-time and full-time 4wd. Your center differential is there to allow you to use 4wd on pavement, and it works between your front and rear driveshafts the same way an axle differential works between the wheels. Locking the center differential makes your truck behave like any other part-time 4wd rig, unlocking it makes your truck behave more like a Subaru or other all wheel drive vehicle. Lock it when you're offroad if you're worried about traction.
helpful educational videos. I am very happy.
oh sorry one more question. if a car is already in motion then LSD might not be needed right? if one (or even both) rear wheels lose traction the car already has momentum, so the front wheels would keep moving the car forward losing speed, but hopefully before you reach 0 your rear wheels have regained traction and can move the car forward again right? but if you are already stopped and your rear wheels don't have traction then that's when you are screwed right?
Hi, i have a 1987 ford scorpio which has a limited slip differential but the differential has backlash and i need to change it. I have found an open differential that fits perfectly. But i want to know if an open differential would affect the car's handling in a negative way or not. For example, in a rainy day, driving on a curved road, would the car get out of control easier? The car is mostly being used in highway. Thanks.
hi guys i needed this
A welded diff is basically a jerryrigged locking differential. It forces the rear axles to turn at the same speeds at all times by welding the differential together, giving the benefits of extra traction of a locked differential, without the benefits of an open, limited slip, or electronic (streetability) differential at a very low cost. Welded diffs cause axle hop during cornering and are almost unusable on a daily driver.
Great work. Thanks for sharing info.
Welding a differential takes another design of diff (like an open diff) and creates a "LOCKED" differential. So the explanation of a locking differential basically applies to welded diffs. The goal of welding a diff is to cheaply convert it into a full-time locked differential. This is nearly always for off-road use.
im a huge DRIFT nerd so i need to learn abotu this, nice video =D
I hear ya.
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As for brake diffs not working at speed, check out Ford's torque vectoring setup, pretty sure it's near identical to the auto LSD or whatever (it's a brake diff) - it's on the new Focus ST's. It's performance oriented for that setup :).
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Glad your video took off, hope someday you get the time and resources to do an addition ^_^.
@thebluecommet Nowhere in that video does it claim that ALSD (which is far from a unique application of that technology in the auto industry) is superior to anything other than an open diff. ALSD has two benefits over other LSDs, it's lighter and it's cheaper to maintain. That is the only statement in the video. The reason so many differential designs exist is that each is suited to a specific need and have advantages and disadvantages depending on how the vehicle is going to be used.
Great video! However with the Toyota Brake LSD, doesn't that causes uneven brake wear?
Brakes wear so slow, especially on the rear, if any uneven wear was occurring it wouldn't be a problem.until well past 100k miles
Can you think of a way of doing this using simple mechanics? Sophisticated mechanical parts can wear even faster than electronics and can be much more destructive to itself. Power going to the path of least resistance is universal. Even in electronic circuits.
Awesome Video! Had a small understanding, now I completely understand! Thanks! :D
What would happen if i put a 265/75 R16 in one side and the other side a 31x10.50 R15 stock tire size my is limited split differential by the way. What would it damaged the diffrential??
that is called diff lock. nice video; gotta tip my hat for you
Already done. they are referred to as "torque-biasing" differentials, and use helical or worm gears(2 different things, not 2 names for 1 thing). they're pretty good, but they have drawbacks as well. I won't get into the mechanics but:
-both wheels have to have at least some traction, or it does nothing.
-less efficient torque transfer compared to other options
-it never actually 'locks', and so it acts against both drive wheels spinning/being broken loose(this is bad in certain situations).
hey you guys seem to know your lsds well. could you help me out with a question maybe? I'm am considering purchasing a subaru wrx because I feel it is an excellent choice of car for a daily driver, especially for winter months of snow. I understand the wrx is awd and has a rear lsd. this means when power is transferred to rear is can be further divided between the left and right rear wheel. the wrx does not have a front lsd. so my question is when traction is lot on both rear wheels
So then when turning to the right, the left wheels will be moving faster than the right wheels. Does this mean that since the more of the engine's power is going to the left wheels to keep them turning faster that the left wheels have less resistance in this scenario?
It depends what sort of diff the vehicle has. If it's an open diff, it depends which wheel is providing the most resistance. Usually the outside one (due to weight transfer) so it's common that the inside tire has the power and the outside one is just coasting. Not really what you want though because the outside tire has more potential traction so could handle more power. A LSD would try to put a lot of power to the loaded outside tire while still keeping some power to the inside as well.
gfcb
I don't claim to be a mechanic but when it was stated the LSD system via brakes provided fewer parts and less maintenance, are they assuming the *maintenance* was only concerning the immediate LSD system and excluding the brakes? I'm having a hard time assuming the brakes wouldn't wear down sooner....increasing the maintenance frequency? Or am i getting caught up on the word *less as apose to more and they are not refering to time but volume?
Minimal wear on pads. Non issue.
@PayDroification TO test if you really have a "limited slip" or a "positrack"(power goes to both wheels); when you turn a corner, step on the gas to lay some rubber.If the outside tire spins too;you have a posi or limited slip.(just look for the fry marks when you go around the block to check out the rubber you layed.
very good video ....continue .
Great knowledge share. Thank you
This video really help me
Great explanation!
That's a pretty cool unit!
Drift cars typically use very limited slip differentials to fully locked differentials. Since the rear is sliding, the differential effect of the turn is irrelevant. It's more important to get power to both rear wheels to keep them spinning. "Normal" handling is degraded due to a reduction in differential wheel speeds.
Great video!
could you change the horizontal input (drive shaft) to a vertical in put? if so how?
Hey, could you please tell me what simulator you used ? I'm doing a project for one of my exams and I can't accomplish the physical part so I want to simulate it. Thanks.
Limited slip using braking very clever, thank you.
Do you allow me to use your video in making my videos on channel auto oprema?
Can you teach us about different types of four wheel steering.
excellent video! thanks!
awesome video, helps alot!
ya i no what a welded diff is now. i have know for quite some time, but thank u for the reply. i appreciate it.