Downshifting or not with manual transmission in city?

[JulesMaximus]

I only downshift for a corner where I will be turning without stopping or if I am in very slippery conditions. If all I'm doing is stopping, and there is no issue of compromised traction I just put the clutch in and brake. Once the car is stopped, I am in neutral until it's time to start moving again.

I do this too sometime but just out of laziness... not because of some notion that I'm decreasing wear on my clutch.

 

[Don Vito Corleone]

I do this too sometime but just out of laziness... not because of some notion that I'm decreasing wear on my clutch.

In what sense is it laziness? To me there is no utility whatsoever in downshifting two or three times while rolling up to a red light, and it does in fact create at least a marginal amount of wear on the clutch and syncros where none is necessary. Even if this wear is insignificant, it's still some, when none is required. I pretty much stopped downshifting into first within a year of learning to drive stick (which was in 1989 - I have driven manual cars pretty much exclusively since that time).

 

[pauldun170]

Really the only good reason to downshift is if you want to exit the corner faster. Brakes are less than a clutch period.

Downshifting feels and sounds cool, but if you are using it to stop it's just wasted money.

I still do it though, even though I know it will cost more. heh

VERY few people can perfectly match the revs so that argument about matching perfectly is moot. Look out there at all the drivers you think many of them are that good. They have enough trouble not crashing into each other. I am sure many people on here will claim to be able to perfectly match though. They do that while driving their supermodel girlfriend in their Bugattis.....

When was the last time you replaced a clutch?

I've always heard about this "brakes are cheaper than a clutch".
Since I've never replaced the clutch my experience is that I've spent more money on brake jobs than I have on clutches.

Rev matching, or just easin out the clutch (prior to learning how to goose the the throttle for rev matchin) is better than "tossin it in nuetral".

If the driver is to lazy or un involved to figure out how to downshift properly, they might as well drive an automatic.
This way they can have a hand free to put on makeup or hold a phone or something.

 

[JulesMaximus]

To me there is no utility whatsoever in downshifting two or three times while rolling up to a red light, and it does in fact create at least a marginal amount of wear on the clutch and syncros where none is necessary. Even if this wear is insignificant, it's still some, when none is required. I pretty much stopped downshifting into first within a year of learning to drive stick (which was in 1989 - I have driven manual cars pretty much exclusively since that time).

Exactly...

In what sense is it laziness?

In the sense that you don't do it. Why else would you not downshift?

You put wear on a clutch primarily when accelerating from a stop. If you ride the clutch or rev the engine and slip it excessively you will wear out a clutch prematurely. You will not wear it out by downshifting unless you are letting the engine revs drop to idle before you let the clutch out in a lower gear, in which case you're doing it wrong.

My first car had a manual transmission (early 80s) and I put 60,000 miles on that car and never had to replace the clutch (it had 91,000 miles on it when I got it-clutch may have been replaced before I bought it, I don't remember). Between 1990 and 2001 I owned 2 manual transmission cars, both of them were Mustang GT's, and I put almost 100,000 miles on both cars. I replaced the clutch on both of them once during the time I owned them after around 70-80,000 miles on them.

I've also owned a few motorcycles, all of them have/had manual sequential gearboxes. Never replaced a clutch on any motorcycle I've owned.

 

[JulesMaximus]

When was the last time you replaced a clutch?

I've always heard about this "brakes are cheaper than a clutch".
Since I've never replaced the clutch my experience is that I've spent more money on brake jobs than I have on clutches.

Rev matching, or just easin out the clutch (prior to learning how to goose the the throttle for rev matchin) is better than "tossin it in nuetral".

If the driver is to lazy or un involved to figure out how to downshift properly, they might as well drive an automatic.
This way they can have a hand free to put on makeup or hold a phone or something.

:thumbsup::biggrin:

 

[pauldun170]

In what sense is it laziness? To me there is no utility whatsoever in downshifting two or three times while rolling up to a red light, and it does in fact create at least a marginal amount of wear on the clutch and syncros where none is necessary. Even if this wear is insignificant, it's still some, when none is required. I pretty much stopped downshifting into first within a year of learning to drive stick (which was in 1989 - I have driven manual cars pretty much exclusively since that time).

I only use first to take off from a standing start.
When approaching a stop, I've usually downshifted to second by then.
89 was when I first drove a stick. It was an Izuzu pup if I recall correctly.
Only automatic ever registered to me was one year with an 81 Monte Carlo.

I also ride so the habit of always being in a useable gear stems from that.

 

[slashbinslashbash]

It really just depends on how involved you want to be with your driving. As I said above, I do it largely as a mental exercise. When I'm busy or thinking about something else, I don't do it. But I enjoy driving, and I enjoy the technical nature of it, and I enjoy trying to "optimize" it. I drive a puny Saturn, so I've got to get my kicks somehow 🙂

Rev-matching is easy when you don't use the clutch. You can feel through the stick when you're close. A little pressure on the stick, and it slides right into gear when the revs are matched.

 

[OILFIELDTRASH]

What is rev matching? I drive a big rig for a living. I really don't remember a whole lot about car manuals as I haven't driven one daily since I was 17.
It sounds a lot like floating gears but don't car trans have synchro?

 

[kitatech]

Rev matching is increasing the engine's RPMs to where they would be in the lower gear at the road speed currently being run in the higher gear.

i.e. If running in 3th @ 30mph and the RPMs are, say, 2000, and you want to downshift to 2nd, the engine would find itself running at, say 2500rpm....so...

You would tap the accelerator to bring the engine up to 2500 during the shift process between gears (at the moment when the shifter is in N), so when 2nd is engaged, drag/friction/wear is thereby minimized in the clutch...

Many electronic accelerators "goose" acceleration and maintain the engine's RPMs a bit between gears during the UP-shift to minimize RPM drop for the same reason...

 

[OILFIELDTRASH]

Rev matching is increasing the engine's RPMs to where they would be in the lower gear at the road speed currently being run in the higher gear.

i.e. If running in 3th @ 30mph and the RPMs are, say, 2000, and you want to downshift to 2nd, the engine would find itself running at, say 2500rpm....so...

You would tap the accelerator to bring the engine up to 2500 during the shift process between gears (at the moment when the shifter is in N), so when 2nd is engaged, drag/friction/wear is thereby minimized in the clutch...

Many electronic accelerators "goose" acceleration and maintain the engine's RPMs a bit between gears during the UP-shift to minimize RPM drop for the same reason...

That's the same as floating the gears in a big rig. Doesn't a car have a sync or something that means it doesn't require that?

 

[JulesMaximus]

Rev matching is increasing the engine's RPMs to where they would be in the lower gear at the road speed currently being run in the higher gear.

i.e. If running in 3th @ 30mph and the RPMs are, say, 2000, and you want to downshift to 2nd, the engine would find itself running at, say 2500rpm....so...

You would tap the accelerator to bring the engine up to 2500 during the shift process between gears (at the moment when the shifter is in N), so when 2nd is engaged, drag/friction/wear is thereby minimizing in the clutch...

Many electronic accelerators "goose" acceleration and maintain the engine's RPMs a bit between gears during the UP-shift to minimize RPM drop for the same reason...

Nissan has a nifty rev-match feature in the 370Z that automatically blips the throttle on downshift to perfectly match engine speed for the gear you are selecting. I'd love to drive one with that feature to see how well it works. From what I've read though it works very well and it is an option I would probably select if I were to buy one of those cars. You can turn it off if you want to do it yourself of course.

 

[JulesMaximus]

That's the same as floating the gears in a big rig. Doesn't a car have a sync or something that means it doesn't require that?

The synchro just matches the gear speeds in the transmission so the gears don't crunch, it doesn't match engine speed to the gear being selected.

The synchronizer just eliminates the need for double clutching.

 

[OILFIELDTRASH]

I really don't see the benefit of rev matching a car transmission. I'd imagine there is much more wear when you don't rev match perfectly and you grind your stuff. Or does a car tranny not grind?

 

[slashbinslashbash]

What is rev matching? I drive a big rig for a living. I really don't remember a whole lot about car manuals as I haven't driven one daily since I was 17.
It sounds a lot like floating gears but don't car trans have synchro?

What I do when rev-matching is usually floating gears (hadn't heard that term before, had to look it up, but that is what I do). Yes, cars have synchro, doesn't mean you can't float gears. The synchros will grind if you don't have it matched just right, but a good feel for the stick will keep this from happening.

 

[OILFIELDTRASH]

What I do when rev-matching is usually floating gears (hadn't heard that term before, had to look it up, but that is what I do). Yes, cars have synchro, doesn't mean you can't float gears. The synchros will grind if you don't have it matched just right, but a good feel for the stick will keep this from happening.

Good feel for the stick? What do you mean exactly?
The synchros grinds? In a big rig you miss floating gears and your grinding gears/transmission. That's why they don't want just anyone driving their 150k tractor.

 

[Ferzerp]

VERY few people can perfectly match the revs so that argument about matching perfectly is moot.

 

[OILFIELDTRASH]

And nobody rev matches/floats gears perfectly every time. Sorry it's not true. As truck drivers we drive all day most days floating gears. Some guys 30 years + and we all miss gears. And I guarantee we've probably floated more gears in a week than you have your entire driving history.

 

[FuzzyDunlop]

If they're learning I would just go with stay in gear, brake, change to neutral when stopped and then go again. This keeps things most simple but is only for straight forward scenarios but again if they're learning they will have time later to pick up the extra stuff about when to downshift. Mainly this is just to keep things simple and not have them over think the situation when they're learning.

As for city driving, typically I will stay in gear until I am almost stopped and then switch to neutral. If traffic is picking up again before full stop then I'll typically drop down to 2nd. I'll rev match if I'm going something like from 4th to 3rd about to go around a corner/curve. Usually if I have to switch to 2nd I'll be braking to the point where it'll be at the right speed for 2nd to engage without needing to rev match.

In driver training I was taught that you shouldnt put your car into neutral ever, until parked. Never coast in neutral, dont sit at lights in neutral. The reason being that if an emergency occurs where you need to move your vehicle quickly then its easier to get moving without having to fumble for the stick and put it into gear.
They also taught me that I should leave a full cars length between myself and the car infront of me, so that I then have room to pull over to the curb, or make room for the vehicles around you, if need be. I guess the two go hand in hand.

 

[Knowing]

OBD2 includes decell fuel cut, why wouldn't you?

 

[JulesMaximus]

And nobody rev matches/floats gears perfectly every time. Sorry it's not true. As truck drivers we drive all day most days floating gears. Some guys 30 years + and we all miss gears. And I guarantee we've probably floated more gears in a week than you have your entire driving history.

It's not that hard to do and as long as you're reasonably close it isn't going to cause any appreciable wear on the clutch. You will create far more wear on the clutch moving the car from a stop in 1st or reverse gear than you ever will from downshifting.

I think it is easier to get it right with a motorcycle though as you are using your hands for throttle and clutch control vs your feet. I haven't driven a stick in a few years but even after almost 6 years since I last owned one it only took a few miles to get a feel for the clutch and transmission and get my downshifts fairly precise the last time I drove one. By the end of the day I was downshifting like a pro.

Proper pedal placement and good shoes helps a great deal too. If you're wearing boots or high heels you might as well forget it.

 

[OILFIELDTRASH]

It's not that hard to do and as long as you're reasonably close it isn't going to cause any appreciable wear on the clutch. You will create far more wear on the clutch moving the car from a stop in 1st or reverse gear than you ever will from downshifting.

I think it is easier to get it right with a motorcycle though as you are using your hands for throttle and clutch control vs your feet. I haven't driven a stick in a few years but even after almost 6 years since I last owned one it only took a few miles to get a feel for the clutch and transmission and get my downshifts fairly precise the last time I drove one. By the end of the day I was downshifting like a pro.

Proper pedal placement and good shoes helps a great deal too. If you're wearing boots or high heels you might as well forget it.

I think it's completely different than a big rig. From re reading it sounds like you have the clutch in the whole shifting process while rev matching. Floating a gear you never touch the clutch.

 

[JulesMaximus]

I think it's completely different than a big rig. From re reading it sounds like you have the clutch in the whole shifting process while rev matching. Floating a gear you never touch the clutch.

That is correct. I've never heard the term floating a gear but if you are shifting without using the clutch that is completely different than what we are talking about here.

I have done that though with my first car. I drove it around for a couple days with no clutch (cable broke) before I could get it fixed. Start it in gear to get moving and then slip it out of gear with no load on the transmission and then match revs to slip it into the next gear.

 

[slashbinslashbash]

Good feel for the stick? What do you mean exactly?
The synchros grinds? In a big rig you miss floating gears and your grinding gears/transmission. That's why they don't want just anyone driving their 150k tractor.

I mean, the stick moves into and out of the gear very easily when the revs are matched perfectly. (This is all without using the clutch, BTW.) If you are in gear and the revs are not matched, pulling the stick out of gear is hard.... very hard if there is a lot of torque being transmitted through the gearbox. If you match the revs (usually just blip the throttle a bit and then back off immediately while pulling the stick out of gear) then there is no torque being transmitted; the gears are spinning freely at the same rate as the engine. The stick pulls out of gear with no resistance at all.

Same with going into gear. If you are in neutral and trying to shift into gear, if the revs are not matched then it will have a lot of resistance, and if you force it and push hard enough then it will grind the synchros. If the revs are matched then you can push it into gear with no sound and no resistance; it slips right in.

So you have to get a feel for the stick and be able to put a moderate amount of pressure on the stick, enough to be able to feel the resistance but not enough to actually move things and grind the synchros. Any resistance = not matched. Slides right in/out = matched.

The synchros have little teeth on them too. As far as I can tell, this is what grinds in manual transmission cars. The synchros protect the power gears in a sense. The synchros grind, but the power gears don't. Because if the teeth don't line up on the synchro, the power gear is still disengaged.

 

[OILFIELDTRASH]

That is correct. I've never heard the term floating a gear but if you are shifting without using the clutch that is completely different than what we are talking about here.

I have done that though with my first car. I drove it around for a couple days with no clutch (cable broke) before I could get it fixed. Start it in gear to get moving and then slip it out of gear with no load on the transmission and then match revs to slip it into the next gear.

Yeah that second paragraph is basically it for a big rig. Except a lot more gears and since your load is pushing or pulling on your tractor you not only need to factor in rpm and speed you also must heavily factor in the grade of the road you are currently on. Uphill, downhill, slight grade, etc. all factor in to how fast or slow you can shift. It took me about 3 months of steady driving to get to a point where I could go a full day without missing a gear. I basically can look at my speedometer and tell you which of the 13 speeds you need to downshift to and the rpm you should be at when you do it.

 

[JulesMaximus]

Yeah that second paragraph is basically it for a big rig. Except a lot more gears and since your load is pushing or pulling on your tractor you not only need to factor in rpm and speed you also must heavily factor in the grade of the road you are currently on. Uphill, downhill, slight grade, etc. all factor in to how fast or slow you can shift. It took me about 3 months of steady driving to get to a point where I could go a full day without missing a gear. I basically can look at my speedometer and tell you which of the 13 speeds you need to downshift to and the rpm you should be at when you do it.

I feel for you guys and I try to make it easy for truck drivers trying to merge onto a busy freeway by slowing down and flashing my lights on and off to let them know they can move over into my lane. Usually I will get a flash of the tail lights on and off as a thank you for this.