Naked Science Forum

Non Life Sciences => Technology => Topic started by: neilep on 13/05/2008 16:03:07

Title: Why Does My Auto Jolt When Handbrake Is Applied ?
Post by: neilep on 13/05/2008 16:03:07

Dear Hand Jobs...sorry...I mean Handbrakeologists !


Why does my car jolt when I apply the handbrake WHILST the car is in Drive !

I can't recall if it jolts up or down.....(I think it's up)...do you know what I mean ?......surely you've seen it........You would think that the handrake would ' set ' the car where it is...but it does not.....I apply the handbrake, take my foot of the break and the car lifts a few inches !!!

What is happening that makes it jolt ?


Thanks



neil
Jolt Asker

Title: Why Does My Auto Jolt When Handbrake Is Applied ?
Post by: Karen W. on 14/05/2008 15:40:58

I wonder if it has to do with where the handbrake is hooked,front or back tires?? Seems that if the handbrake is hooked up to the front it would cause that lunge or jolt!Like when you are running or hit something with your foot and jolts you in effort to stop you. Same when a tire hits a curb you get that jolt.. I think it is hooked to the front end tires so instead of a slow stop its more like a sudden braking of the front tires.

Title: Why Does My Auto Jolt When Handbrake Is Applied ?
Post by: lyner on 14/05/2008 22:52:30

I think you are referring to the effect you get with front wheel driven cars with a rear handbrake. The wheelbase 'stretches' or 'compresses' a tiny bit as the front wheels are driven relative to the braked back wheel.
The rear suspension trailing links pull the back of the car up or down a bit, as a consequence.
I had a 2CV (don't you dare laugh!!!!) and it had a front (disc) handbrake and front wheel drive. It didn't produce the effect you seem to be describing. The mini was the first car I heard of to do it.

Title: Why Does My Auto Jolt When Handbrake Is Applied ?
Post by: turnipsock on 14/05/2008 23:22:15

Could it be that you are doing something wrong? Have you read the instruction manual?

I don't use the handbrake at all in my car, other than the MOT. In traffic light situations, I just keep one of my feet onthe brake pedal. If it looks like I may be there for a bit, I just put it into P.

Title: Why Does My Auto Jolt When Handbrake Is Applied ?
Post by: lyner on 15/05/2008 10:16:10

With a (real!) stick shift, it is not good practice to use different feet for accelerator and brake because there is the clutch to control with your left foot.
In your driving lessons they tell you to use the handbrake for hill starting and not to hop from brake pedal to accelerator. Of course, we all get sloppy and do just that - slipping backwards by a few cm every time.