Why does the rear of my vehicle sink when I apply the handbrake on a downward gradient?
This is something that I've always wondered. I'm no mechanic (web developer, actually) with very basic knowledge of vehicle mechanics so I can only guess at something like brake pipe pressure being involved, but that's about as far as I could guess. I can't find any article on the subject either, though I admit it's quite a niche question.
Case in point; I'm leaving the motorway via a downhill off-ramp and come to a stop in the queue using the foot brake (still downhill) - I shift into neutral, apply the handbrake and release the foot brake. As I release the foot brake the rear of the car sinks, as though the suspension was being elevated by the foot brake, though I've no idea how this is possible.
I apologise in advanced if this is rudimentary to those versed in vehicle mechanics and may be obvious. I've come to the assumption that it's normal behaviour and not an issue, but I can't remember whether or not this occurred with my previous two cars.
If it's relevant, here's my vehicle information:
Citroen Xsara Picasso Exclusive, 2006 (06),
1.6 HDI (Diesel) - 92HP,
Manual Transmission
manual-transmission handbrake stopping
edited 26 mins ago
motosubatsu
4,2151826
asked 1 hour ago
Kallum TantonKallum Tanton
1084
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
This is something that I've always wondered. I'm no mechanic (web developer, actually) with very basic knowledge of vehicle mechanics so I can only guess at something like brake pipe pressure being involved, but that's about as far as I could guess. I can't find any article on the subject either, though I admit it's quite a niche question.
Case in point; I'm leaving the motorway via a downhill off-ramp and come to a stop in the queue using the foot brake (still downhill) - I shift into neutral, apply the handbrake and release the foot brake. As I release the foot brake the rear of the car sinks, as though the suspension was being elevated by the foot brake, though I've no idea how this is possible.
I apologise in advanced if this is rudimentary to those versed in vehicle mechanics and may be obvious. I've come to the assumption that it's normal behaviour and not an issue, but I can't remember whether or not this occurred with my previous two cars.
If it's relevant, here's my vehicle information:
Citroen Xsara Picasso Exclusive, 2006 (06),
1.6 HDI (Diesel) - 92HP,
Manual Transmission
manual-transmission handbrake stopping
edited 26 mins ago
motosubatsu
4,2151826
asked 1 hour ago
Kallum TantonKallum Tanton
1084
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
This is something that I've always wondered. I'm no mechanic (web developer, actually) with very basic knowledge of vehicle mechanics so I can only guess at something like brake pipe pressure being involved, but that's about as far as I could guess. I can't find any article on the subject either, though I admit it's quite a niche question.
Case in point; I'm leaving the motorway via a downhill off-ramp and come to a stop in the queue using the foot brake (still downhill) - I shift into neutral, apply the handbrake and release the foot brake. As I release the foot brake the rear of the car sinks, as though the suspension was being elevated by the foot brake, though I've no idea how this is possible.
I apologise in advanced if this is rudimentary to those versed in vehicle mechanics and may be obvious. I've come to the assumption that it's normal behaviour and not an issue, but I can't remember whether or not this occurred with my previous two cars.
If it's relevant, here's my vehicle information:
Citroen Xsara Picasso Exclusive, 2006 (06),
1.6 HDI (Diesel) - 92HP,
Manual Transmission
manual-transmission handbrake stopping
edited 26 mins ago
motosubatsu
4,2151826
asked 1 hour ago
Kallum TantonKallum Tanton
1084
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
This is something that I've always wondered. I'm no mechanic (web developer, actually) with very basic knowledge of vehicle mechanics so I can only guess at something like brake pipe pressure being involved, but that's about as far as I could guess. I can't find any article on the subject either, though I admit it's quite a niche question.
Case in point; I'm leaving the motorway via a downhill off-ramp and come to a stop in the queue using the foot brake (still downhill) - I shift into neutral, apply the handbrake and release the foot brake. As I release the foot brake the rear of the car sinks, as though the suspension was being elevated by the foot brake, though I've no idea how this is possible.
I apologise in advanced if this is rudimentary to those versed in vehicle mechanics and may be obvious. I've come to the assumption that it's normal behaviour and not an issue, but I can't remember whether or not this occurred with my previous two cars.
If it's relevant, here's my vehicle information:
Citroen Xsara Picasso Exclusive, 2006 (06),
1.6 HDI (Diesel) - 92HP,
Manual Transmission
manual-transmission handbrake stopping
manual-transmission handbrake stopping
edited 26 mins ago
motosubatsu
4,2151826
asked 1 hour ago
Kallum TantonKallum Tanton
1084
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 26 mins ago
motosubatsu
4,2151826
asked 1 hour ago
Kallum TantonKallum Tanton
1084
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 26 mins ago
motosubatsu
4,2151826
edited 26 mins ago
motosubatsu
4,2151826
edited 26 mins ago
motosubatsu
4,2151826
4,2151826
asked 1 hour ago
Kallum TantonKallum Tanton
1084
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 1 hour ago
Kallum TantonKallum Tanton
1084
asked 1 hour ago
Kallum TantonKallum Tanton
1084
1084
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Kallum Tanton is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
When you stop the car using the footbrake, all four wheels are held stationary by the brake. When you apply the handbrake, this locks the rear wheels only (in most cars) - as you then release the footbrake, this releases the front wheels, allowing them to turn ever so slightly. Gravity is still trying to pull the whole car downwards, and so it settles down on the rear suspension - it's something that's hard to describe!
answered 1 hour ago
Nick C♦Nick C
25.3k44190
Ah, that makes perfect sense and, while I agree that is difficult to describe, I understand you. I was thinking the suspension was expanded and was settling back to rest, however you've shown that it was at rest and the cars front moving forward slightly is actually compressing the rear suspension - if I've got that right! Thanks again.
– Kallum Tanton
1 hour ago
add a comment |
With the handbrake on, the rear wheel is not able to rotate. When the foot brake is released the car will try to move forward. This will cause a rotational force on the rear tire. Since the rear tire cannot turn, the rotational force will be transferred to the axle mounting point 'A' which will cause the road spring to compress, hence lowering the car body. If you did the same thing going up hill, you will find that the body raises instead.
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
add a comment |
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2 Answers
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2 Answers
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When you stop the car using the footbrake, all four wheels are held stationary by the brake. When you apply the handbrake, this locks the rear wheels only (in most cars) - as you then release the footbrake, this releases the front wheels, allowing them to turn ever so slightly. Gravity is still trying to pull the whole car downwards, and so it settles down on the rear suspension - it's something that's hard to describe!
answered 1 hour ago
Nick C♦Nick C
25.3k44190
Ah, that makes perfect sense and, while I agree that is difficult to describe, I understand you. I was thinking the suspension was expanded and was settling back to rest, however you've shown that it was at rest and the cars front moving forward slightly is actually compressing the rear suspension - if I've got that right! Thanks again.
– Kallum Tanton
1 hour ago
add a comment |
When you stop the car using the footbrake, all four wheels are held stationary by the brake. When you apply the handbrake, this locks the rear wheels only (in most cars) - as you then release the footbrake, this releases the front wheels, allowing them to turn ever so slightly. Gravity is still trying to pull the whole car downwards, and so it settles down on the rear suspension - it's something that's hard to describe!
answered 1 hour ago
Nick C♦Nick C
25.3k44190
Ah, that makes perfect sense and, while I agree that is difficult to describe, I understand you. I was thinking the suspension was expanded and was settling back to rest, however you've shown that it was at rest and the cars front moving forward slightly is actually compressing the rear suspension - if I've got that right! Thanks again.
– Kallum Tanton
1 hour ago
add a comment |
When you stop the car using the footbrake, all four wheels are held stationary by the brake. When you apply the handbrake, this locks the rear wheels only (in most cars) - as you then release the footbrake, this releases the front wheels, allowing them to turn ever so slightly. Gravity is still trying to pull the whole car downwards, and so it settles down on the rear suspension - it's something that's hard to describe!
answered 1 hour ago
Nick C♦Nick C
25.3k44190
When you stop the car using the footbrake, all four wheels are held stationary by the brake. When you apply the handbrake, this locks the rear wheels only (in most cars) - as you then release the footbrake, this releases the front wheels, allowing them to turn ever so slightly. Gravity is still trying to pull the whole car downwards, and so it settles down on the rear suspension - it's something that's hard to describe!
answered 1 hour ago
Nick C♦Nick C
25.3k44190
answered 1 hour ago
Nick C♦Nick C
25.3k44190
answered 1 hour ago
Nick C♦Nick C
25.3k44190
answered 1 hour ago
Nick C♦Nick C
25.3k44190
25.3k44190
Ah, that makes perfect sense and, while I agree that is difficult to describe, I understand you. I was thinking the suspension was expanded and was settling back to rest, however you've shown that it was at rest and the cars front moving forward slightly is actually compressing the rear suspension - if I've got that right! Thanks again.
– Kallum Tanton
1 hour ago
add a comment |
Ah, that makes perfect sense and, while I agree that is difficult to describe, I understand you. I was thinking the suspension was expanded and was settling back to rest, however you've shown that it was at rest and the cars front moving forward slightly is actually compressing the rear suspension - if I've got that right! Thanks again.
– Kallum Tanton
1 hour ago
Ah, that makes perfect sense and, while I agree that is difficult to describe, I understand you. I was thinking the suspension was expanded and was settling back to rest, however you've shown that it was at rest and the cars front moving forward slightly is actually compressing the rear suspension - if I've got that right! Thanks again.
– Kallum Tanton
1 hour ago
Ah, that makes perfect sense and, while I agree that is difficult to describe, I understand you. I was thinking the suspension was expanded and was settling back to rest, however you've shown that it was at rest and the cars front moving forward slightly is actually compressing the rear suspension - if I've got that right! Thanks again.
– Kallum Tanton
1 hour ago
add a comment |
With the handbrake on, the rear wheel is not able to rotate. When the foot brake is released the car will try to move forward. This will cause a rotational force on the rear tire. Since the rear tire cannot turn, the rotational force will be transferred to the axle mounting point 'A' which will cause the road spring to compress, hence lowering the car body. If you did the same thing going up hill, you will find that the body raises instead.
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
add a comment |
With the handbrake on, the rear wheel is not able to rotate. When the foot brake is released the car will try to move forward. This will cause a rotational force on the rear tire. Since the rear tire cannot turn, the rotational force will be transferred to the axle mounting point 'A' which will cause the road spring to compress, hence lowering the car body. If you did the same thing going up hill, you will find that the body raises instead.
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
add a comment |
With the handbrake on, the rear wheel is not able to rotate. When the foot brake is released the car will try to move forward. This will cause a rotational force on the rear tire. Since the rear tire cannot turn, the rotational force will be transferred to the axle mounting point 'A' which will cause the road spring to compress, hence lowering the car body. If you did the same thing going up hill, you will find that the body raises instead.
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
With the handbrake on, the rear wheel is not able to rotate. When the foot brake is released the car will try to move forward. This will cause a rotational force on the rear tire. Since the rear tire cannot turn, the rotational force will be transferred to the axle mounting point 'A' which will cause the road spring to compress, hence lowering the car body. If you did the same thing going up hill, you will find that the body raises instead.
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
answered 1 hour ago
HandyHowieHandyHowie
9,57011133
9,57011133
add a comment |
add a comment |
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Kallum Tanton is a new contributor. Be nice, and check out our Code of Conduct.
Kallum Tanton is a new contributor. Be nice, and check out our Code of Conduct.
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