Downshifting can be important in SOME circumstances, but really, those circumstances don’t come about all that often and when they do, it won’t affect the life of the clutch or the transmission whether or not you rev match or double clutch. Most downshifting at speed is unnecessary.
Releasing the clutch on a downshift without any effort to match engine speed is just poor technique. It will cause some clutch wear. It is hard on the synchro’s in the transmission, it must be herky jerky for passangers, and in slippery conditions could cause the wheels to lose traction.
You don’t have to be perfect, or watch the tach for several seconds rather than the road. It is a simple process of applying a bit of gas and using your ears and seat of your pants to tell if you gave enough gas or too much. With just a bit of practice the OP can do it.
If you can’t or won’t downshift properly you are better off not down shifting and just using the brakes when stopping or slowing down. The put it in the proper gear for the speed you need when time to go or accelerate again. Then buy an automatic trans in the next car.
"If you can’t or won’t downshift properly you are better off not down shifting and just using the brakes when stopping or slowing down. The put it in the proper gear for the speed you need when time to go or accelerate again. Then buy an automatic trans in the next car. "
Umm, I’ve been driving manually cars exclusively for almost 20 years because I enjoy shifting and having direct control over the gear. I would never downshift to come to a stop. I’m talking about downshifting for added torque or because I’m no longer in an appropriate gear for a given speed.
When I downshift without rev matching it’s always at a slow enough speed for the intended gear that it ends up being smooth with no bucking. So in a way I am making an effort to match engine speed as RPMs never jump more than about 500.
If rev matching is required to drive a manual transmission properly than I’m guessing 95% of people who drive manual don’t drive it properly according to your definition.
UncleTurbo’s comments are absurd.
Downshifting without revmatching a few hundred rpm won’t hurt anything at all. No car company would design a car with either a clutch or synchros that couldn’t handle a few hundred rpm difference.
The majority of manual drivers never rev match. Ever. In their entire lives. Thus the presumption that rev-matching is a necessary skill is faulty thinking.
I’ve never routinely rev matched myself in any car I’ve ever owned and I’ve never had any clutch or transmission issues, even after more than 200k+ miles.
Yeah, I don’t rev match with either my car or my motorcycle, and my car’s clutch has lasted 224,000 miles so far (the bike only has 48,000 miles). The only vehicle I’ve ever done rev matching on was on a Volvo tractor with a Cummins diesel, and that was because the transmission didn’t have synchronizers.
Something to consider is that if rev matching was so important, your automatic transmission would do it for you (automatically). It doesn’t, because it isn’t.
Based on the OP’s original question about “a typical downshift from 4th to 3rd at 40 mph” I’ll stand behind my answer the OP didn’t like and another poster called absurd.
The OP then said he downshifts going into, during, and coming out of corners with no problems. Downshifting in these situations isn’t where precise speed matching is an issue. In the process of taking a corner the car is scrubbing off speed so the new lower gear is going to match the car’s speed without any input from the driver and then you have to accelerate coming out of the turn.
If you don’t want to downshift on off ramps, going down hills, or at other times to use engine braking properties then you don’t need to practice “speed matching”. If you do use engine braking properties and downshift in situations the OP originally asked about speed matching is appropriate and will benefit the clutch (less wear), the drivetrain (less stress), and the transmission (less wear on sychro’s). Will one bad downshift destroy a car - no.
Some of this answer depends on the car. A high powered, high compression muscle car will require much better driver control of speed matching than an old VW bug. If the OP is fine driving the way he has for 20+ years, it is working for him in his cars so no need to change anything.
Don’t know anyone who bothers bliping the throttle here in europe, where thanks to tax and gas prices, the manual is king.
If you “need” to dip and blip you might be driving a touch fast…
Don’t ride the clutch, don’t rest your foot near it and go easy on revs taking off and you will be fine.