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This is more out of curiosity than anything. I've driven both manual and automatic vehicles, and it seems to me, that the hardest part of driving a manual vehicle is starting on an incline. The rest is pretty manageable.

I know that modern vehicles have hill start or hold function, but I'm wondering, for older cars, why doesn't applying the brakes automatically apply the clutch? It seems like it would solve the dreaded "move back a few inches while you try to finagle throttle and clutch and brake position" issue, at least with a bit of left-foot driving in the worst situations.

In my very simplistic imagination, this could even be achieved by a simple horizontal bar that protrudes from the top of the brake pedal arm and rests on (but is otherwise not connected to) the clutch pedal arm, thereby allowing the clutch to be pressed independently, but would force it to be pressed in when you hit the brakes. Heck, put that bar on a swivel so that you can disable this "feature".

Am I under-thinking this? Is there a reason this wasn't implemented / thought of? Safety or emergency reasons? Additional clutch wear and tear?

I know some people use the parking brake, and so do I in some situations, but I can't help but feel that it's more of a band-aid; I am not "parked" after all, just stuck in traffic.

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  • I don't see how your device is supposed to help with hill starts. In UK the parking brake is called a hand brake and that is what you use to do a hill start with manual transmission. In US vehicles it is often operated by foot (so it's not a hand brake, duh) but a traditional auto allows easy hill starts anyway. However, the modern DSG box doesn't always hold the car on a hill, so you may still need to use the handbrake. Jun 17, 2023 at 18:29
  • @WeatherVane, in stop and go traffic on an incline, one wouldn't need to constantly pull up the hand brake and then put it down. You'd just hold the brake pedal, and in really steep situations you could even use your left foot for just the brake, and then immediately accelerate with your right. Same as an automatic (assuming I'm getting it right, hence the question). Jun 17, 2023 at 18:56
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    Have you ever tried using your left foot for the brake? You stop! because the action is totally different from the left foot's normal clutch use. It would be as much difficulty learning as using the handbrake for hill starts. Anyway, it's unlikely that a crude bar pressing the clutch would be the right amount of both brake and clutch for a hill start. Just get out and practice hand brake hill starts: a manual isn't an auto. Jun 17, 2023 at 19:07

2 Answers 2

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I think the main reason why is, every time you even touch the brakes you'd be slipping the clutch. This would destroy a clutch in short order from overheating, especially in stop/go traffic. If you were trying to start on a hill, I have no clue how you'd even try to attempt it. You'd have absolutely no control over the clutch while braking. Every time you tried to stop rolling backwards, you'd be slipping your clutch without any hope of motivating the vehicle to go forward. And if you wanted to simultaneously brake and engine brake while going downhill, you couldn't do it (as MTA was suggesting). Just would not be a good thing to have done and I'm sure is why it was never even considered in the past ... if it was considered, I'm sure it was shut down in short order.

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When driving down a long steep hill, it's sometimes advantageous to downshift and use engine braking instead of your service brakes, which can overheat if applied too long. With a device such as you suggest, one would lose engine braking whenever the service brakes are applied.

Also, it is illegal in many jurisdictions to travel with the clutch pedal depressed except while actually shifting gears. With your device, braking would automatically create a driving violation by depressing the clutch pedal.

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  • In UK it isn't actually illegal to coast, but if an accident occurs the driver might be deemed 'not in proper control'. But I don't see how this answers the question about hill starts. Jun 17, 2023 at 18:21
  • @WeatherVane Yes, true but he didn't ask how to do hill starts. He asked, "why doesn't applying the brakes automatically apply the clutch?" and "Is there a reason this wasn't implemented". So I answered the questions that he asked. :-)
    – MTA
    Jun 17, 2023 at 18:38
  • Perhaps, I highlighted what the OP says is the most difficult thing. The rest of their post seems to concern their other difficulty: stopping, which is quite easy with a little practice, and much easier than hill starts. Jun 17, 2023 at 18:41
  • My apologies, I intended to say stop and start traffic on an incline, but somewhere along typing the question it turned into "stopping at an incline". I've edited the question to remove that part. Jun 17, 2023 at 19:00

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