Skipping gears on downshifts

[amdhunter]

I've caught myself on occasion on the highway in 5th or 6th gear and slowing down really quickly, but havent really had the chance to downshift as fast as the braking motion... In order to for me to gain proper speed, I know I need to be in 3rd or 2nd, when the car is still in 5th, so I just go to that gear and rev match. It usually goes in smoothly, and no jerking or thumping occurs.

How bad is this? As long as I revmatch the downshifts I should be ok right? I've caught myself going from 4th to 2nd a few times also, but again, I revmatch perfectly and all goes well. (And never > 3000RPM, if its higher, I will downshift normally to 3rd.)

Am I killing my car?

EDIT: Also, a friend of mines swears that slowing the car down with gears is the best way to slow it down. I think that's retarded...doesn't it cause more wear to the gears if you do that, even if it's done properly?

Me and him have developed 2 totally different personalities when it comes to driving manual cars. I kinda like that though.

 

[Ragnarok2]

EDIT: Also, a friend of mines swears that slowing the car down with gears is the best way to slow it down. I think that's retarded...doesn't it cause more wear to the gears if you do that, even if it's done properly?

Actually, engine braking doesn't harm your car at all. If anything, it prolongs the life of your brake pads.

 

[JulesMaximus]

No, doing what you are doing isn't going to harm anything as long as you don't over rev the engine and rev match before letting the clutch out.

Also, downshifting or engine braking isn't going to harm anything either.

 

[woodie1]

When down shifting, as long as you won't exceed the engine red line, you can skip as many gears as you want.

When you engine brake there will be a very small amount of clutch wear if you don't match the engine speed perfectly but the gears could care less.

 

[amdhunter]

Originally posted by: Ragnarok2

EDIT: Also, a friend of mines swears that slowing the car down with gears is the best way to slow it down. I think that's retarded...doesn't it cause more wear to the gears if you do that, even if it's done properly?

Actually, engine braking doesn't harm your car at all. If anything, it prolongs the life of your brake pads.

Doesn't it wear down the gears, or cause damage to motor/transmission mounts? It just seems like a violent way to slow a car down.

 

[LS21]

Originally posted by: amdhunter
Doesn't it wear down the gears, or cause damage to motor/transmission mounts? It just seems like a violent way to slow a car down.

modern car, gear is already fully meshed

2 possible wear: 1) clutch ... if you dont rev-match
2) synchronizers ... if you dont double-clutch (or if you force the shifter lever for gear change)

since youre doing neither, theres no problem. if you ease the clutch engagement, theres no driveline "shock", so nothign bad to the mounts..

 

[JulesMaximus]

Originally posted by: amdhunter

Originally posted by: Ragnarok2

EDIT: Also, a friend of mines swears that slowing the car down with gears is the best way to slow it down. I think that's retarded...doesn't it cause more wear to the gears if you do that, even if it's done properly?

Actually, engine braking doesn't harm your car at all. If anything, it prolongs the life of your brake pads.

Doesn't it wear down the gears, or cause damage to motor/transmission mounts? It just seems like a violent way to slow a car down.

Accelerating causes much more stress to your drivetrain than engine braking ever will and you don't generally kick it up to redline for each downshift when doing this unless you are driving at the extreme limits of the car...in normal, day-to-day driving, downshifting and engine braking are not going to cause any significant wear on your drivetrain.

 

[Nyati13]

I skip gears up and down all the time, just shift correctly (ie clutch and revmatch, and with new syncros you don't even have to revmatch perfectly) and there's no problem.

Also, engine braking causes no damage unless you slip the clutch too much or over-rev.

 

[amdhunter]

Originally posted by: LS21

Originally posted by: amdhunter
Doesn't it wear down the gears, or cause damage to motor/transmission mounts? It just seems like a violent way to slow a car down.

modern car, gear is already fully meshed

2 possible wear: 1) clutch ... if you dont rev-match
2) synchronizers ... if you dont double-clutch (or if you force the shifter lever for gear change)

since youre doing neither, theres no problem. if you ease the clutch engagement, theres no driveline "shock", so nothign bad to the mounts..

meshed? <-- n00b, but trying to learn.

 

[amdhunter]

Originally posted by: Nyati13
I skip gears up and down all the time, just shift correctly (ie clutch and revmatch, and with new syncros you don't even have to revmatch perfectly) and there's no problem.

Also, engine braking causes no damage unless you slip the clutch too much or over-rev.

I don't think I've ever skipped gears up...I couldn't really imagine any scenario where I'd do it either...lol

 

[LS21]

Originally posted by: amdhunter

meshed? <-- n00b, but trying to learn.

a common misconception is that when someone is changing gears, theyre bringing gear teeth together.. but theyre always fully linked.

what theyre linking together is the dog collar to the gears.. (dog collar splined to the driveshaft... ie spin dog collar = spin wheels) what the synchronizers do is ease this engagement between dog collar and gear

 

[fbrdphreak]

You do not need to double-clutch with a modern transmission. For explanation see ZV.

OP - you're doing fine. Just rev match and as long as you aren't jerky and you aren't forcing the shifter into gear, you're fine.

And you need a little something called torque to skip gears going up Although my wife does go from 3rd to 5th in her Accord four-banger.

 

[amdhunter]

Originally posted by: LS21

Originally posted by: amdhunter

meshed? <-- n00b, but trying to learn.

a common misconception is that when someone is changing gears, theyre bringing gear teeth together.. but theyre always fully linked.

what theyre linking together is the dog collar to the gears.. (dog collar splined to the driveshaft... ie spin dog collar = spin wheels) what the synchronizers do is ease this engagement between dog collar and gear

Don't they disengage to go to the alternate gear for that set? For example, when they change from 1-2 or 3-4 or 5-6? Or is the synchronizer what moves?

 

[amdhunter]

Originally posted by: fbrdphreak
You do not need to double-clutch with a modern transmission. For explanation see ZV.

OP - you're doing fine. Just rev match and as long as you aren't jerky and you aren't forcing the shifter into gear, you're fine.

And you need a little something called torque to skip gears going up Although my wife does go from 3rd to 5th in her Accord four-banger.

hah, I guess if I really gunned it, I can skip 2nd or 3rd...lol

 

[overst33r]

Originally posted by: amdhunter

Originally posted by: LS21

Originally posted by: amdhunter
Doesn't it wear down the gears, or cause damage to motor/transmission mounts? It just seems like a violent way to slow a car down.

modern car, gear is already fully meshed

2 possible wear: 1) clutch ... if you dont rev-match
2) synchronizers ... if you dont double-clutch (or if you force the shifter lever for gear change)

since youre doing neither, theres no problem. if you ease the clutch engagement, theres no driveline "shock", so nothign bad to the mounts..

meshed? <-- n00b, but trying to learn.

Syncromesh. It eliminates the need for double-clutching. It matches the speed of the gear and the particular shaft using clever mechanics. Look it up on wiki.

 

[Zenmervolt]

Originally posted by: fbrdphreak
You do not need to double-clutch with a modern transmission. For explanation see ZV.

I'm flattered.

Your cheque is in the mail.

But yes, for modern transmissions the synchros are robust enough that they won't wear appreciably and you can count on them to work rather than having to double-clutch.

Of course, double-clutching is still fun on the track when you get it just right.

ZV

 

[alfa147x]

Originally posted by: Ragnarok2

EDIT: Also, a friend of mines swears that slowing the car down with gears is the best way to slow it down. I think that's retarded...doesn't it cause more wear to the gears if you do that, even if it's done properly?

Actually, engine braking doesn't harm your car at all. If anything, it prolongs the life of your brake pads.

http://forums.anandtech.com/me...=2134595&enterthread=y

 

[LS21]

double

 

[LS21]

Originally posted by: fbrdphreak
You do not need to double-clutch with a modern transmission. For explanation see ZV.

whem im at high speed on 6th, and i want to drop it down to 3rd, im not a) waiting for the synchronizers to match up the dog teeth + gear b) forcing it in to grind the dog teeth

feel the resistance when youre performing a quick gear jump? hear the GRRRSSH when you pound the gear?

technically you dont need to use a clutch at all to shift, but ill double-clutch thanks

 

[jagec]

Originally posted by: amdhunter

Originally posted by: Ragnarok2

EDIT: Also, a friend of mines swears that slowing the car down with gears is the best way to slow it down. I think that's retarded...doesn't it cause more wear to the gears if you do that, even if it's done properly?

Actually, engine braking doesn't harm your car at all. If anything, it prolongs the life of your brake pads.

Doesn't it wear down the gears, or cause damage to motor/transmission mounts? It just seems like a violent way to slow a car down.

It's only "violent" if you don't rev-match. If you revmatch it's very smooth indeed.

The helical gears in the gearbox are constantly engaged and spinning. As long as they are lubed, they should last well beyond the lifetime of the car. The dog gears may experience wear if you grind the gears when downshifting, but once you're in gear they are locked to the layshaft and again will not wear.
Engine braking is no worse for your motor/transmission mounts than accelerating. IMHO these, too, should be lifetime parts, although not all manufacturers get it, and sometimes the rubber wears out and you get "clunking" as the engine assembly shifts under acceleration/engine braking transition. It's more annoying than anything else...your engine isn't about to leap right out of the hood in a big oily mess.

Originally posted by: amdhunter

Originally posted by: Nyati13
I skip gears up and down all the time, just shift correctly (ie clutch and revmatch, and with new syncros you don't even have to revmatch perfectly) and there's no problem.

Also, engine braking causes no damage unless you slip the clutch too much or over-rev.

I don't think I've ever skipped gears up...I couldn't really imagine any scenario where I'd do it either...lol

Freeway onramp, run it up to redline in 1st and 2nd, then shift straight to the top gear for cruising. Weee!

 

[Vic]

The only way engine braking could harm the drivetrain is if you're doing it wrong. Double-clutching is not necessary. Rev-matching is smoother and better for your clutch in the long run but still not necessary.
And most importantly, you brake with the brakes, not the engine. Saving the life of your sub-$100 brakes pad with your expensive drivetrain is the stupidest idea ever, not to mention poor driving skill. The purpose of downshifting as you brake is so that you are in the appropriate gear at all times.

 

[Zenmervolt]

Originally posted by: LS21

Originally posted by: fbrdphreak
You do not need to double-clutch with a modern transmission. For explanation see ZV.

whem im at high speed on 6th, and i want to drop it down to 3rd, im not a) waiting for the synchronizers to match up the dog teeth + gear b) forcing it in to grind the dog teeth

feel the resistance when youre performing a quick gear jump? hear the GRRRSSH when you pound the gear?

technically you dont need to use a clutch at all to shift, but ill double-clutch thanks

Most people aren't trying to speed-shift. Hell, a 5-3 downshift on my old 951 (160,000 miles) doesn't even strain the synchros. There's no undue resistance, and there's certainly no grinding/groaning sound.

Unless you're trying to turn a fast lap at Buttonwillow, there's absolutely no need to double-clutch a modern transmission. None.

ZV

 

[Zenmervolt]

Originally posted by: Vic
And most importantly, you brake with the brakes, not the engine. Saving the life of your sub-$100 brakes pad with your expensive drivetrain is the stupidest idea ever, not to mention poor driving skill. The purpose of downshifting as you brake is so that you are in the appropriate gear at all times.

I'm going to have to disagree with you on this one Vic. I downshift all the time to slow the car. It saves fuel and allows for a much smoother control over the car's speed. Done right, I don't need the brakes at all while I'm on the freeway.

Engine braking is one of the best ways to control speed if you do not need to stop. If you need to stop, yes, that's what the brakes are there for, but if you just want to scrub off 10 mph, then dropping into 4th and engine braking is just fine. As you say though, when coming to a stop, just use the brakes.

ZV

 

[spidey07]

Originally posted by: LS21

Originally posted by: fbrdphreak
You do not need to double-clutch with a modern transmission. For explanation see ZV.

whem im at high speed on 6th, and i want to drop it down to 3rd, im not a) waiting for the synchronizers to match up the dog teeth + gear b) forcing it in to grind the dog teeth

feel the resistance when youre performing a quick gear jump? hear the GRRRSSH when you pound the gear?

technically you dont need to use a clutch at all to shift, but ill double-clutch thanks

You need practice then. Rev-match. It should be smooth as butter, the shifter will literally move itself into gear.

 

[LS21]

Originally posted by: Zenmervolt
Most people aren't trying to speed-shift. Hell, a 5-3 downshift on my old 951 (160,000 miles) doesn't even strain the synchros. There's no undue resistance, and there's certainly no grinding/groaning sound.
ZV

theres no resistance if you do it slowly...thats because youre doing it casually, allowing the syncros to do their job. when you want to drive spiritedly, not casually, then there becomes a need. its analogous to saying "theres no need to rev-match, just let the clutch up slowly and let it do its job in mating to the flywheel".

Originally posted by: spidey07

You need practice then. Rev-match. It should be smooth as butter, the shifter will literally move itself into gear.

youre mistaken. youre blending the 2 independent/exclusive processes of the actual gear shift, and the clutch engagement. double-clutching help ease the gear change. rev-matching help eases the engagement.