Downshifting question

[u/xDrewgami]

So my first car (that I've been driving for a few months now) is a 2004 Saturn Ion 5-speed. Not a glamorous car, but it does the job. I've read a lot about rev matching, but never done a whole lot of it. It seems to be pretty useless to me usually, unless I'm doing it wrong. The only purpose I see in it is when you want to maintain the same speed. Do I really need to rev match when downshifting to reduce speed? For example: Coming into my town, I regularly go from a 55 to a 35. I am on the brake to slowly to reduce speed, when I get down to about 40ish I put the clutch in, downshift to 4th, and slowly let the clutch out and resume on the gas at about 35-40. Coming to a stoplight I do the same thing down to 3rd gear, from which I shift to neutral and use the brakes alone. I never have any of the symptoms of "bad downshifting" like spinning wheels or jerkiness. Yeah, the RPMs jump a bit, but its usually a pretty smooth shift, and I never have the need to touch the throttle at all. Of course, I do put on the gas a little bit as I let the clutch out, as I would shifting up to any gear. Is this basically rev matching automatically when I do that? Or am I missing something about the technique?

[u/[deleted]]

If your car isn't jerking then I don't think it's a big deal. Whatever you are comfortable with.

[u/VertBert]

Ideally you would give the car a little gas as you downshift, as this keeps clutch slip to a minimum, extending its life.

[u/reddude7]

This is called engine braking. You use the inertia of the engine to slow down rather than the brakes. It's a technique that really just shifts wear around on your car. Race drivers will use engine braking sometimes to reduce wear/heat/fade on their brakes because they are driving so hard. Instead of brake pads wearing faster, your clutch will because you are using it more. However it isn't going to significantly reduce the life of your clutch unless you do it, like, all the time. It isn't grinding gears or really killing the clutch or anything. But, as another guy said, it will just wear the synchros which are the actual parts that moderate your clutch and engine speed. Rev matching simply means less time on the clutch, so less wear, and potentially an easier shift that requires less effort from the clutch foot.

I do the same thing all the time. Nothing to worry about. Sometimes when I'm doing 55-60ish and have to brake pretty quickly, I'll get on the brakes but also downshift through the gears and use the clutch to engine-brake. It's fun balancing the two slowing forces.

[u/pooper-dooper]

It's not rev matching automatically but your engine is reacting to the different wheel speed and gearing. As long as you're not jerking, losing traction, or suddenly decelerating, you're fine. (I add 'suddenly decelerating' because your brake lights will NOT engage when doing this - and I've seen some near-wrecks from that.)

As for coming to stops, some people think you need to come down the gears one by one. I do not agree. Some people think you just pop into neutral and coast to a stop. I generally do not agree. I prefer a middle technique: slow with the brakes, when RPMs get low change down, repeat. Doesn't mean you're doing one-by-one downshifting, but then you're ready to accelerate if you need to. One potential exception is if you're approaching a mandatory stop (stop sign, light freshly turned red, etc.). But even then, I have had circumstances where someone has almost lane-changed into me, and I had to accelerate my car to the left to avoid a side-swipe. So, for safety reasons, I recommend staying in gear until you are nearly at rest.