Manual Transmission Technique (3-pedals)

[Danoff]

I don't quite understand what you're getting at, there's always a right gear to be in, you just need to be in it. It does seem like you're overthinking the complications of driving with a manual gearbox. I've had several cars that have done over 200,000 miles without requiring a gearbox change and with no obvious loss of gearbox quality. I've only ever had to change a clutch in one car (a geriatric Vauxhall that cost me £150, probably about £250 nowadays). Millions of other people have a similar experience, as far as I'm aware.

Worn out synchros and destroyed clutches are all I seem to find in used manuals. Even very nice ones - like my absolutely pristine all-stock, old man owned, never wrecked MR2. Ruined clutch (53k mi).

I've had to replace a PO destroyed clutch in all but one manual transmission car I've bought, the only one I didn't have to do that was the NSX (53kmi), where the PO had just finished replacing the clutch. 2nd gear synchro was destroyed on the RSX-S by 40k mi (by the PO). First gear synchros were not great the entire time I owned it.

Edit:

And don't get me started on the Beetle synchros. None of them were ever good.

Here's a bit on brake/gear overlap from IAM, and a guide to how passin their Advanced test. You'll see that "coasting" is a fail condition. Not many drivers take the Advanced test but it nonetheless represents the peak of all taught driving knowledge in the UK test curriculum.

Ok, explain why.

Coasting in neutral gives you the advantage of being able to perform a rev-matched double-clutched downshift very quickly when approaching a slow-down situation where you do not know which gear to select. Downshifting through the gears as you slow, constantly guessing which gear will be the one you need, gives the disadvantage of significantly greater wear and tear on the transmission, especially since you're not rev-matching each one of those (or you're constantly heel-toeing). Skipping gears to downshift as you approach a slow-down situation will leave you in a scenario where if you needed to accelerate quickly you're in the wrong gear, and so you're slightly more out of place for selecting a gear than you would have been if you had been coasting.

I certainly could pass a driving test which required rowing down during braking, but I'd immediately go back to doing what I do after completing the test.

 

[Turbotwin01]

I like to think I know how to be easy on the clutch in my Miata, but I often wonder how to be easier/more gentle on the syncros. I know some say double clutching does help but some say the difference is slim to none. Im used to double clutching in big trucks and find it sometimes helps.

Say your downshifting and making the revs match, does putting the gear lever in before you have the revs matched hard on it?

 

[Dennisch]

where you do not know which gear to select.

You really are an American.

 

[Greycap]

I probably don't want to know how a transmission or clutch gets killed in a performance oriented car with those mileages, especially if they haven't been driven hard.

I own two cars myself, around 350k and 270k km on them respectively, and both have original clutches. No issues. Both have zero shifting problems (worn stick bushings aren't considered a problem here) and both have been owned by people who have had absolutely no idea about any technicalities going on in the car. The latter even spent the first 15 years of its life in nearly constant stop and go traffic in our capital.

Adding to those, I've driven quite a lot of cars with around half a million km on the clock and no transmission issues of any kind. The transmission is one of the sturdiest parts of the car, probably only losing out to the differential and engine, and getting it destroyed in less than a fifth of that can only mean two things - horrible quality or a totally incompetent driver. On the other hand we're talking about USA here so the latter is probably true. With the average Finnish driver such issues simply don't seem to exist because everyone learns to drive in a manual car.

 

[Danoff]

You really are an American.

I did not know that non-Americans could see the future. What's going to happen in the next US election? I'm dying to know.

I probably don't want to know how a transmission or clutch gets killed in a performance oriented car with those mileages, especially if they haven't been driven hard.

I own two cars myself, around 350k and 270k km on them respectively, and both have original clutches. No issues. Both have zero shifting problems (worn stick bushings aren't considered a problem here) and both have been owned by people who have had absolutely no idea about any technicalities going on in the car. The latter even spent the first 15 years of its life in nearly constant stop and go traffic in our capital.

Adding to those, I've driven quite a lot of cars with around half a million km on the clock and no transmission issues of any kind. The transmission is one of the sturdiest parts of the car, probably only losing out to the differential and engine, and getting it destroyed in less than a fifth of that can only mean two things - horrible quality or a totally incompetent driver. On the other hand we're talking about USA here so the latter is probably true. With the average Finnish driver such issues simply don't seem to exist because everyone learns to drive in a manual car.

Congratulations on your national superiority.

Here's a breakdown of my manual transmission cars, and cars whose maintenance history I'm very familiar with. All of these are previously owned cars and this is the condition that the cars were purchased in:

- 1971 Beetle (unknown mileage), wasted synchros
- RSX-S 40k mi wasted (2nd gear) synchro wasted clutch.
- Jeep (unknown year and mileage), replaced transmission
- NSX 53k mi, replaced clutch
- MR2 53k mi, replaced (horrific) clutch
- E46 M3, 90k mi, replaced (horrific) clutch

Those cars are either all mine or owned by family members. They represent the sum total of my detailed knowledge of manual transmission success. There were a few other cars (neon, k-car, older MR2s, some E36s) but I couldn't attest to the history of the maintenance on them. These are the ones I know about, and all of them had worn out clutches and several had synchro problems.

So yes, I do pay attention to how much I consume my synchros and clutches. It's wonderful that you've had luck with it, but I have gotten to the point where when I buy a car I assume the clutch is worthless. I've never created a problem in a manual transmission car that I know of (except for that one time that I hit a rock and broke the linkage), but that does not stop me from taking mechanical wear into account since I know that they can be so easily destroyed.

 

[homeforsummer]

I do think there's a bit of overstatement going on as to how much wear certain driving styles will cause to transmission components. Some vehicles will naturally be more susceptible to wear than others, and certain types of vehicles (sports cars, for instance) may be subject to more wear from driving style.

But expecting significant synchro wear from say, changing into first while doing less than walking pace, or significant wear to gearbox components from a theoretically unnecessary gearchange now and then, seems like unnecessary caution. These are actions that might have small differences in wear rates over probably hundreds of thousands of miles, but not things that will significantly alter the reliability of a transmission if the driver is otherwise competent and mechanically sympathetic. And probably not something you could identify as being caused by particular behaviour when the time eventually comes to replacing something.

Nor is teaching someone to drive stick necessarily tantamount to burning through a clutch. A decent teacher should be able to instruct a student in not just the basics but also in such a way that wear and tear differs little from a regular competent driver. Even a couple of weeks of teaching someone low-speed manoeuvres with lots of clutch usage is unlikely to cause a noticeable difference in wear unless the person learning has a serious lack of ability. It's certainly not gonna be the difference between replacing a clutch after ten years rather than after fifteen.

 

[Dennisch]

I did not know that non-Americans could see the future. What's going to happen in the next US election? I'm dying to know.

It has been said before, but I'll repeat it. You are severely overthinking the whole manual driving situation. You should know what gear to use after 10 minutes of driving, in pretty much any manual car. Coasting in neutral is great if you go hypermiling, or just like to see your car idling, but in any other situation it is nonsense.

And about the wear, nonsense. Again.

 

[nobuffalo]

If coming to a stop I generally remain in the gear I'm in, or maybe shift down one, and then when the engine gets to a low rpm I will shift into neutral for the remaining few mph before the stop. I rarely heel toe in public. I don't usually find it necessary and also under casual driving I'm just not too good at it. Also from my experience most cars have no problems accelerating in 2nd at low speeds without lugging the engine as long as you're already rolling and you're not moving uphill or pulling a lot of weight.

 

[Danoff]

Say your downshifting and making the revs match, does putting the gear lever in before you have the revs matched hard on it?

It's using the synchros. If you rev-match while in (clutch out) neutral you do not use the synchros. If you don't, you do. I use my syncrhos, but I try to minimize wear on them. I'm extra cautious with 1st gear, and I'm even more cautious with the clutch. So I heel-toe downshift without double-clutching for most of my shifts on the street. I use the synchros for those downshifts, but not as much clutch.

If you're going to perform a downshift with a large rpm differential, double-clutching would save some synchro wear. It's why I prefer to be in neutral when coasting to a down-shift.

But expecting significant synchro wear from say, changing into first while doing less than walking pace, or significant wear to gearbox components from a theoretically unnecessary gearchange now and then, seems like unnecessary caution.

It's a lot of additional mechanical usage to row your gears down through every braking situation. Granted it could be done with almost no wear if the driver is double-clutching and rev-matching perfectly. Hell it could theoretically be done without a clutch or synchros. Most people don't do that though. Most people don't rev-match and don't double-clutch. So it's hard on 2nd gear especially, and uses up the clutch.

It has been said before, but I'll repeat it. You are severely overthinking the whole manual driving situation.

I do think about it yes. I even made a thread about it.

You should know what gear to use after 10 minutes of driving,

Unless you can see the future, you don't know what your future speed will be in many instances on the road. You can guess, and many times you'll guess wrong.

And about the wear, nonsense. Again.

Explain why. From what I can tell, manual transmissions get trashed by people who don't pay attention.

I rarely heel toe in public. I don't usually find it necessary

It's not necessary. At least it shouldn't be. The only time heel toe is necessary is in threshold braking where you're going to be on the accelerator as soon as you're done braking (ie: on track). If you don't heel toe then you'll spin (or just lock the wheels depending on the car and whether you've initiated the turn).

Also from my experience most cars have no problems accelerating in 2nd at low speeds without lugging the engine as long as you're already rolling and you're not moving uphill or pulling a lot of weight.

Depends on your definition of lugging. I think every car I've owned could be started from a stop in 2nd gear. Of course I don't prefer to do it.

 

[Dennisch]

Unless you can see the future, you don't know what your future speed will be in many instances on the road. You can guess, and many times you'll guess wrong.

Pretty sure you are supposed to take note of what is happening around you, and shift accordingly. And what does it matter if you're in a gear too high or low for a future situation? You are supposed to be in the gear your current situation demands, and if that situation demands a gearshift, changing gears is a simple and quick procedure.

Explain why. From what I can tell, manual transmissions get trashed by people who don't pay attention.

Indeed, people who still need to learn how to use a 3 pedal car, something most people learn in a couple of days. And there are probably people out there who would benefit from driving a slushie instead of manual, we call them pedal knights (pedaalridders) because they butcher their cars. And as you make it seem, pretty much every American is a pedal knight. There is nothing special or difficult about learning to drive stick. Perhaps the USA needs a different training program? I just can't imagine that so many people are so terrible at learning something so simple.

I told you before, destroyed synchros are pretty much non existent here. Perhaps it has something to do with manual being the gearbox of choice for almost every learners car here. The gearboxes I take apart are because of faulty bearings, design faults, and once in a blue moon, and it really is a very blue moon, a syncro job because the car drove to that blue moon and back.

 

[homeforsummer]

It's a lot of additional mechanical usage to row your gears down through every braking situation. Granted it could be done with almost no wear if the driver is double-clutching and rev-matching perfectly. Hell it could theoretically be done without a clutch or synchros. Most people don't do that though. Most people don't rev-match and don't double-clutch. So it's hard on 2nd gear especially, and uses up the clutch.

My point is that you're hugely overstating how much wear results from doing things that the transmission is designed to do. This for instance:

It's using the synchros.

Of course it's using the synchros. That's literally what synchro rings are for. It's their job to match the speed of the selector and gear, and it does so through friction. Wear is part and parcel of them, but it's not an unusual part of it - it's designed into the remit of the device.

Changing down a gear without rev matching will cause more wear to the clutch than it will the synchros. The speed differential between the engine and input shaft will be more significant than that between the synchro ring and whatever gear you're selecting. And again... the clutch is literally a friction device. You're not asking anything of it that it isn't designed to handle, even if some drivers will wear it at a faster rate than others.

But what we're talking here is small differences in technique, not the difference between a competent and an incompetent driver. Someone ham-fisting everything will obviously cause more wear than someone doing everything perfectly by the book. But some of the aforementioned things in this thread - like selecting first at 2mph rather than at zero - are not big wear accelerators, even if they're not strictly ideal.

Trying to avoid using synchros by unnecessarily double-declutching makes little more sense than driving around at night with your headlights off to save on lightbulb wear.

 

[Danoff]

Pretty sure you are supposed to take note of what is happening around you, and shift accordingly. And what does it matter if you're in a gear too high or low for a future situation? You are supposed to be in the gear your current situation demands, and if that situation demands a gearshift, changing gears is a simple and quick procedure.

...and often unnecessary and stupid and causes significant wear. I've literally watched people row down through 5th, 4th, 3rd, 2nd, and into 1st in order to reach a stopsign!

Perhaps you've just been too sheltered from bad manual drivers to appreciate the basic points I'm making. Or perhaps when I get into the weeds of manuals you're thinking I'm more worked up about it than I am.

Indeed, people who still need to learn how to use a 3 pedal car, something most people learn in a couple of days.

Psssshhhhhhh

Manual transmissions are a seemingly never-ending offering of complexity and nuance. Almost everyone can refine their technique a little more. Case in point, 99% of people (Edit: ok that's probably hyperbole, it's probably more like 90%) I have known who drive stick (not including this website) have never even heard of heel-toe. Let alone attempted it.

And there are probably people out there who would benefit from driving a slushie instead of manual, we call them pedal knights (pedaalridders) because they butcher their cars. And as you make it seem, pretty much every American is a pedal knight. There is nothing special or difficult about learning to drive stick. Perhaps the USA needs a different training program? I just can't imagine that so many people are so terrible at learning something so simple.

It's a case of not knowing the difference I think. In some cases, just not being able to understand it.

My point is that you're hugely overstating how much wear results from doing things that the transmission is designed to do. This for instance:

Of course it's using the synchros. That's literally what synchro rings are for. It's their job to match the speed of the selector and gear, and it does so through friction. Wear is part and parcel of them, but it's not an unusual part of it - it's designed into the remit of the device.

Agreed. And I even indicated that I use mine:

It's using the synchros... I use my syncrhos [sic]

I don't double-clutch every downshift. I do think that it is particularly hard on the car to row down through the gears for every braking scenario though. That's a bad habit. I've had to explain to one person that they even could skip gears. One person thought it was necessary to take the gears in order on the way up, and again on the way down.

Changing down a gear without rev matching will cause more wear to the clutch than it will the synchros.

That's why I put more emphasis on rev-matching than double-clutching. I really only double-clutch when it's convenient.

But what we're talking here is small differences in technique, not the difference between a competent and an incompetent driver.

For the most part yes (it's all a matter of degree), and I'm constantly searching to refine mine. I wouldn't consider heel-toe a requirement for competency. I wouldn't even necessarily consider rev-matching a requirement for competency. But some of the things I'm talking about are required for competency. Some of the things I'm talking about are big wear items - like shifting into first at speed, or rowing all the way down every time you slow. And they compound. If you're doing something 20 times more often than necessary and doing it in a way that causes extra mechanical wear as well, then it spirals.

Someone ham-fisting everything will obviously cause more wear than someone doing everything perfectly by the book. But some of the aforementioned things in this thread - like selecting first at 2mph rather than at zero - are not big wear accelerators, even if they're not strictly ideal.

That one's just me being picky. I haven't developed a technique that I'm personally satisfied with yet.

Trying to avoid using synchros by unnecessarily double-declutching makes little more sense than driving around at night with your headlights off to save on lightbulb wear.

It costs nothing. All I have to do is let the clutch out in neutral when I'm slowing down. I was going to rev-match anyway.

 

[Dennisch]

...and often unnecessary and stupid and causes significant wear.

The only thing I can make of this is that the American way of teaching how to drive stick needs an update and perhaps an injection of interest.
I can understand have to replace a clutch more often because of the hills and mountains compared to the flatlands, but the whole gearbox destruction lifestyle that surrounds you, I mean, I have been a mechanic for pretty much 20 years now, it all seems a bit weird to me.

 

[nobuffalo]

Depends on your definition of lugging.

What's yours?

I think every car I've owned could be started from a stop in 2nd gear. Of course I don't prefer to do it.

Did you miss where I said already rolling or are you trying to make a point?

 

[Danoff]

The only thing I can make of this is that the American way of teaching how to drive stick needs an update and perhaps an injection of interest.
I can understand have to replace a clutch more often because of the hills and mountains compared to the flatlands, but the whole gearbox destruction lifestyle that surrounds you, I mean, I have been a mechanic for pretty much 20 years now, it all seems a bit weird to me.

Maybe it's just me. Nobody seems surprised though when it happens. For the type S with the sync and clutch replacement, nobody was saying "wow this is really weird". I still had the temp tags on the MR2 so they knew they wouldn't be offending me by saying that it was odd to have a clutch go at such low mileage. But they didn't seem to think that was odd either. It's all anecdotal though, so it's possible that I just happen to pick bad apple clutches.

What's yours?

Good question. I try not to go below like... I dunno... 1200 in 2nd. I'll pay attention next time I drive and give you a better answer. Maybe its 1000.

Did you miss where I said already rolling or are you trying to make a point?

I was making a point, which was that lots of stuff works... just not necessarily is preferable.

 

[Turbotwin01]

It's using the synchros. If you rev-match while in (clutch out) neutral you do not use the synchros. If you don't, you do. I use my syncrhos, but I try to minimize wear on them. I'm extra cautious with 1st gear, and I'm even more cautious with the clutch. So I heel-toe downshift without double-clutching for most of my shifts on the street. I use the synchros for those downshifts, but not as much clutch.

If you're going to perform a downshift with a large rpm differential, double-clutching would save some synchro wear. It's why I prefer to be in neutral when coasting to a down-shift.

So even if the engine is running at the rpm you need before the gear lever is in the gear you want, unless you let the clutch out in neutral (double clutching) the syncro is still being used?

I feel I over think the wear and tear of it anyway, but in my case the only 2 manual things are drive are an NA Miata and an 18 Speed Dump Truck where double clutching is required because there are none.

Another thing ive wondered is how many of you have tried/can/do shift without the clutch? Once I got familiar with the big trucks I drive Ill upshift certain gears without the clutch at all. In my Miata I cant bring my self to do it all, partly because im scared to and partly because I know its more difficult to get the shift timing right at 3-4000 RPM than the 12-1600 RPM of a big truck.

 

[homeforsummer]

I don't double-clutch every downshift. I do think that it is particularly hard on the car to row down through the gears for every braking scenario though. That's a bad habit. I've had to explain to one person that they even could skip gears. One person thought it was necessary to take the gears in order on the way up, and again on the way down.

The reason to block-change up or down though is more about convenience than reducing wear. I'm sure it does reduce wear, but not to a measurable degree in the life of a transmission (even in your 20 times more often than necessary example).

The way I'd view it is which elements of a car's entire transmission (everything from the clutch to the driveshafts) would you expect to have to replace over time, all other things being equal? Gearbox and differential fluids would probably be fairly high on the list. Probably a few CV joints and dust boots. A few seals here and there - oil always finds its way out eventually. Perhaps bushes or cables in the selector mechanism. And if the car has been used hard or has significant mileage, the clutch and flywheel.

Realistically though, I'd not expect to have to replace or rebuild the gearbox itself, nor any component within the casing unless the transmission was particularly known for fragility*. Probably not in the entire lifetime of the average car. Rust, or a broken engine, or dodgy electronics will almost certainly end a vehicle's life before anything has a chance to go wrong with the transmission.

There are variables obviously. In a car you intend to keep for a lifetime - your NSX, say - then you might want to do things to mitigate wear and tear over a much longer period of ownership. Though equally, I imagine you don't do commuter mileage in your NSX every day, so any wear and tear will accumulate much slower.

That one's just me being picky. I haven't developed a technique that I'm personally satisfied with yet.

The only thing I can say here is that it varies from car to car.

In a very general way, I've noticed that modern manual transmissions are much happier doing something like shifting from second into first while in motion, or shifting from reverse to first or vice-versa where selection is forcing the gearbox internals to quickly stop, than older transmissions.

Now maybe this is just a sign that the transmission is okay "for now" doing such things, but I also think it's indicative that technology has improved enough that techniques that were problematic before are simply no longer an issue. I think manufacturers do a lot of fool-proofing anyway, and components are also designed to minimise a driver's mechanical connection to things like gearboxes (think clutch release delay valves, cable rather than rod changes, electronic torque limits to limit wear on engines and transmissions). So what might have been problematic before is probably less so today.

An older car will generally tell you when you're doing something it doesn't like, I've found! I'd very much not change from second to first at anything other than either standstill or an absolute crawl in my old Miata, or my current Peugeot, and I sub-consciously double-declutch in such situations to ease the passage between gears. I'd not be particularly concerned about the long-term health of either car's transmission really - the Miata had just under 100k miles, the Peugeot's on about 115k, and both feel/felt absolutely fine - but it's more of a feel thing. If something I'm doing results in a clunk or graunch from transmission components, that's a fairly good indication not to do that thing.


* I can't think of a car off the top of my head whose manual is known for significant reliability issues to the extent a used purchase would require very careful consideration of the gearbox's state.

There are certainly a few cars with dubious automatics that fit that definition, but seeing as it's very difficult to use an automatic in a way it shouldn't be used, we can assume that's a manufacturing issue rather than user error.

And, admittedly, I have heard of gearboxes with synchro issues (my old Honda Insight and Fiat Panda among them) but it's so infrequent and so randomly applied across the market I have to imagine that's more of a manufacturing issue too than an example of widespread bad driving technique.

 

[TenEightyOne]

I rarely heel toe in public. I don't usually find it necessary and also under casual driving I'm just not too good at it.

Genuine question - why would you ever heel-and-toe? I can't think of any situations on the road when you might need to, unless you're trying to outrun a police BMW.

...and often unnecessary and stupid and causes significant wear. I've literally watched people row down through 5th, 4th, 3rd, 2nd, and into 1st in order to reach a stopsign!

There's nothing wrong with that if that's what the situation demands. It seems like you're trying to re-invent and re-think the whole system for driving a manual, and I would expect that anybody reading your musings is going to think that it's something that's really hard to do. It isn't.

The other thing I notice is that you seem to be terrified of being in the wrong gear a bit further down the road. So change gear, you need to be in the right gear for where you are in that moment, not the right gear for further down the road.

Another thing ive wondered is how many of you have tried/can/do shift without the clutch?

The answer in almost all manual cars is No. Your MX-5 will particularly hate it.

Good question. I try not to go below like... I dunno... 1200 in 2nd. I'll pay attention next time I drive and give you a better answer. Maybe its 1000.

Another good tip for manual learners is to ignore the rev counter (if the car even has one). Use your ears and leave your eyes on the Big Window.

a syncro job because the car drove to that blue moon and back.

I want to see that job sheet when it happens

 

[MatskiMonk]

Definitely not. And you'd fail your driving test if the examiner spotted you doing it, at least in the UK.

Quite. I was taught when approaching a junction to always be ready to stop. I'd picked up the habit of block shifting down into first but keeping my foot on the clutch when approaching a junction, if I didn't need to stop I'd slide it back into second before releasing the clutch. This was never an issue for my instructor but on my first driving test it was one of the two majors I got, which of course failed me (the other was lane discipline on a tiny roundabout)

So yes, I do pay attention to how much I consume my synchros and clutches. It's wonderful that you've had luck with it, but I have gotten to the point where when I buy a car I assume the clutch is worthless. I've never created a problem in a manual transmission car that I know of (except for that one time that I hit a rock and broke the linkage), but that does not stop me from taking mechanical wear into account since I know that they can be so easily destroyed.

Maybe the problem is a lot of Americans can't use a manual properly, so these cars are already knackered by the time you get them. Not sure how it works in the USA, but over here, the vast majority of people are driving manuals from day 1.

My experience is like 1081's, and I mostly just buy old nails from eBay. The only transmission issue I've ever had was in my E34 525i, whose clutch started going at 252,000 miles - bare in mind this car was given to me and had been used as a courier delivery vehicle for 12 months prior to me getting it. The most I've ever spent on buying a car is £4000. I think my 635CSi is the only car that's had only one owner prior to me, but that was an auto. I'm not saying transmissions don't get knackered, but I don't think they're inherently as fragile as your experience has shown.

The rest of my MT history;
Rover 214SLi, Rover 216GSi, Toyota Paseo ST, Peugeot 106 Diesel, BMW E28 528i, BMW E28 520i, BMW E34 525i (clutch was going, taken off the road, crushed for unpaid tax), BMW E46 320d, BMW E87 120d. Transmission wise, aside from the 525i, none of these cars even required so much as a clutch during ownership.

Another thing ive wondered is how many of you have tried/can/do shift without the clutch?

I practiced this a few years ago just to see if I could. If I needed to 'limp home' doing this I could, but I've never had to, fortunately.

edit:

Another good tip for manual learners is to ignore the rev counter (if the car even has one). Use your ears and leave your eyes on the Big Window.

I'd agree with this a lot! I used to practice pulling away in the Rover, in the end I got used to doing it watching the tach, of course, when I got into the instructors Corsa - that didn't even have a tach - it all went out the window.

 

[nobuffalo]

Genuine question - why would you ever heel-and-toe? I can't think of any situations on the road when you might need to, unless you're trying to outrun a police BMW.

I don't know, I was just answering some of questions in this thread. I should have said very rarely as I can't recall the last time I did or needed to. Thinking about it I've maybe done it in my old Camry on a hill start where the ebrake was barely functional.

Do you guys heel-toe on the street?

 

[homeforsummer]

Genuine question - why would you ever heel-and-toe? I can't think of any situations on the road when you might need to, unless you're trying to outrun a police BMW.

This comes under @Danoff's goal of mechanical sympathy. If you're bringing the revs up to meet road speed in the next gear down before you re-engage the clutch, then you're causing minimal clutch wear and sending minimal extra load through the drivetrain from things spinning at different speeds.

While it's not strictly necessary, it definitely has application on the road. The mechanical benefits extend to stability benefits when you start driving a bit quicker - heel and toe means you aren't suddenly introducing extra engine braking to driven wheels when you're slowing down (enough to lock wheels if you've misjudged a change) and it also means minimal time with drive disengaged (another stability benefit) as to make a smooth downchange without heel and toe you have to spend an extra few moments slipping the clutch to try and slowly match road speed to engine speed.

If pedal spacing and weighting allows it, I virtually always heel and toe on the road. It has the aforementioned benefits above, particularly in quick driving. Unlike conventional rev-matching separate from braking, it allows you to cover the brake pedal the whole time rather than braking in stages.

And, y'know... it's fun. It's a driving technique you can practice virtually everywhere that makes driving a little smoother, more efficient and more mechanically sympathetic. Some cars don't make it easy with pedal weight/spacing, and others make it very easy by giving you an auto rev-match function (which in turn is quite useful in cars with poor pedal weight/spacing), but in general I'd say that if you can, there's little reason why you shouldn't.

 

[Danoff]

In case you guys haven't noticed, I'm a bit of a perfectionist and a nit-picker. It's just me, it doesn't make me unhappy or stressed, so try to read my posts from that perspective.

The reason to block-change up or down though is more about convenience than reducing wear. I'm sure it does reduce wear, but not to a measurable degree in the life of a transmission (even in your 20 times more often than necessary example).

Thinking about how often the clutch really gets... "used" significantly, if one were avoiding block downshifts I think it would represent if not the majority of clutch consumption, at least a big portion of the pie. Unless you're drag racing frequently or somesuch. For normal operation, the virtually all of the clutch use is starting in 1st or a non-matched downshift. So if you're doing a non-matched downshift for every gear every single time you're slowing, the amount of clutch material used for it could be quite a lot.

That all depends on how generous the person is with 1st gear takeoffs though. As you can imagine, I'm not very generous with it. I'm usually off the clutch very quickly on start, and with as little engine rpm as possible.

The only thing I can say here is that it varies from car to car.

Sure, but I like your phrase "mechanical sympathy". That's all I'm going for here. Just trying to refine my technique so that I can be smooth and not wasteful of my car's components.

In a very general way, I've noticed that modern manual transmissions are much happier doing something like shifting from second into first while in motion, or shifting from reverse to first or vice-versa where selection is forcing the gearbox internals to quickly stop, than older transmissions.

Up until like 2 days ago I basically treated 1st gear as though it had no synchros. I know it does, but that was how I drove. I'm becoming convinced that I should ease off on that just a bit.

Genuine question - why would you ever heel-and-toe? I can't think of any situations on the road when you might need to, unless you're trying to outrun a police BMW.

As @homeforsummer said above, I don't do it for speed. I do it to be smooth and spare my clutch (and to practice, and it gives me a grin).

There's nothing wrong with that if that's what the situation demands. It seems like you're trying to re-invent and re-think the whole system for driving a manual, and I would expect that anybody reading your musings is going to think that it's something that's really hard to do. It isn't.

There aren't many situations that demand rowing down on approach to a stopsign. I guess if your brakes failed.

I would expect someone reading my thoughts to think it was difficult, yes. I know it's not hard to drive a stick. But I thought I gave a rather detailed and illustrative example of 4 different approaches, none of which look different from the outside, and each of which might become a habit, and yet when you really think about it, 2 of those approaches are far superior to the others. I'm trying to promote a little analysis and thought behind stick shift technique, and that's partially motivated by the number of appalling manual drivers I have encountered.

The other thing I notice is that you seem to be terrified of being in the wrong gear a bit further down the road. So change gear, you need to be in the right gear for where you are in that moment, not the right gear for further down the road.

Definitely not terrified. If it seems that way, I think you're reading a degree of emotion into it that it wasn't written with. I don't mind being in the wrong gear, it's why gears exist. But I do like to be thoughtful about how often I engage a gear and why I'm doing it.

Another good tip for manual learners is to ignore the rev counter (if the car even has one). Use your ears and leave your eyes on the Big Window.

Agreed. My very first (1971 bug) didn't even have a tach.

I'd picked up the habit of block shifting down into first but keeping my foot on the clutch when approaching a junction, if I didn't need to stop I'd slide it back into second before releasing the clutch.

I'm glad that they pinged you on that because it's hard on 1st. But this kind of thing goes rampantly unchecked in the US. It will be passed down from generation to generation as the right way to do it.

Maybe the problem is a lot of Americans can't use a manual properly, so these cars are already knackered by the time you get them.

I'm confident that you're right.


Edit:

So even if the engine is running at the rpm you need before the gear lever is in the gear you want, unless you let the clutch out in neutral (double clutching) the syncro is still being used?

Yup. Think of it as 3 spinning bits. The engine, the transmission, and the wheels. If the engine is running at the right rpm prior to releasing the clutch, the clutch has to do virtually nothing to match the spin. But the synchronizers don't exist for that purpose. They exist for the purpose of matching transmission to wheels. So whatever speed the transmission is going (previously engaged gear probably), that's the spin differential that the synchros have to accommodate when you slot it into the next gear.

So, for example, let's say you're doing 2k rpm in 6th and you want to be doing 5k rpm in 3rd (I don't know how realistic this is, just throwing out numbers). You clutch in in 6th, and move the gear lever to 3rd. As you engage 3rd with the clutch in, you're bringing the speed of the transmission up to 5k rpm in order to connect the wheels and the transmission. Your 3rd gear synchronizers are performing that task. Syncing up 3k rpm differential is not huge for synchronizers, but it's a lot more than... say... a 0-500 rpm differential if you had double-clutched while rev-matching.

Full disclosure here, I do not double-clutch the above shift in most circumstances. Especially not in heel-toe. I'm just explaining why it is that the synchronizers get used. The only time I double clutch this is if I'm doing a lazy coast in neutral. In which case I clutch-out by default prior to rev-matching because that's just how I coast.

 

[daan]

Maybe the problem is a lot of Americans can't use a manual properly, so these cars are already knackered by the time you get them. Not sure how it works in the USA, but over here, the vast majority of people are driving manuals from day 1.

Not only that, but we grow up in the back of our dad's car watching him changing gear. It's ingrained.

I would also be confident that after @Danoff has replaced a clutch due to the previous owners "abuse," he's never had to replace it again.

 

[MatskiMonk]

I'm glad that they pinged you on that because it's hard on 1st

So I calculated a scenario where a block shift from 4th to 1st takes place at 2000 rpm in my 120d, road speed of ~47mph. At the point the clutch goes in, the input shaft is doing 2000rpm, and the output shaft is doing 1587rpm. The unengaged 1st gear gear at this point is being driven at 389rpm, so as the synchro engages it, it has to bring that gear speed up by 1198rpm. For simplicity let's assume nothing's lost any rotational momentum. Since the output shaft is doing 1587rpm and now connected to the input shaft at 5.14:1, the input shaft (clutch is still disengaged) is brought up to ~8158rpm. Let's assume, the clutch isn't then re-engaged until an appropriate road speed so the engine re-engages at about 2000rpm (11.5mph).

... so the periods of high stress... I assume are therefore: engaging the 1st gear synchro with a speed differential of 1198rpm, and the force associated with spinning up the gear itself, and, in spinning up the (undriven) input shaft from 1587rpm to 8158rpm.

Now.. I wanted to get a better understand of the forces involved, but other than these rotational speeds, I don't know what it translates to force wise - but I'd have thought, since it's only dealing with bits and pieces with masses of a few kg's, they'd be able to withstand it given the forces the gearbox undergoes when, say, accelerating the car from standstill.

Just a thought really, not drawing any conclusions myself.

 

[Danoff]

So I calculated a scenario where a block shift from 4th to 1st takes place at 2000 rpm in my 120d, road speed of ~47mph. At the point the clutch goes in, the input shaft is doing 2000rpm, and the output shaft is doing 1587rpm. The unengaged 1st gear gear at this point is being driven at 389rpm, so as the synchro engages it, it has to bring that gear speed up by 1198rpm. For simplicity let's assume nothing's lost any rotational momentum. Since the output shaft is doing 1587rpm and now connected to the input shaft at 5.14:1, the input shaft (clutch is still disengaged) is brought up to ~8158rpm. Let's assume, the clutch isn't then re-engaged until an appropriate road speed so the engine re-engages at about 2000rpm (11.5mph).

... so the periods of high stress... I assume are therefore: engaging the 1st gear synchro with a speed differential of 1198rpm, and the force associated with spinning up the gear itself, and, in spinning up the output shaft from 1587rpm to 8158rpm.

Now.. I wanted to get a better understand of the forces involved, but other than these rotational speeds, I don't know what it translates to force wise - but I'd have thought, since it's only dealing with bits and pieces with masses of a few kg's, they'd be able to withstand it given the forces the gearbox undergoes when, say, accelerating the car from standstill.

Just a thought really, not drawing any conclusions myself.

8000 rpm doesn't sound totally right for 47 mph for a 120d, but I guess it's not out of the question. Redlining (I assume that's around redline) at almost 50 mph in 1st gear seems tall for that car. You're sure about that number?

Yes, though, that is what I'm talking about. Needing to go from 2k to 8k (or something similar). You can feel it too, when you push through the synchro, how much work it's having to do. Heat builds up the longer it takes too, but then force is greater if you make it go faster. Being patient with it and letting it do its job is better than forcing it, but it doesn't completely solve the problem because of heat.

Clutch wear is (kinda) similar in that the related forces are higher if you just drop it, but heat builds up if you feather it slowly. RPM differential makes a big difference there as well. The clutch has to deal with more mass, but it's also much beefier.

 

[MatskiMonk]

8000 rpm doesn't sound totally right for 47 mph for a 120d, but I guess it's not out of the question. Redlining (I assume that's around redline) at almost 50 mph in 1st gear seems tall for that car. You're sure about that number?

Sorry, just to clarify, I referred to the 8k rpm as being the output shaft, I meant the input shaft whilst the clutch is disengaged. The engine tops out a 5500rpm, but I assume there's nothing to govern the input shaft speed whilst the clutch is disengaged. Max speed in first would be 31mph.

Yes, though, that is what I'm talking about. Needing to go from 2k to 8k (or something similar). You can feel it too, when you push through the synchro, how much work it's having to do. Heat builds up the longer it takes too, but then force is greater if you make it go faster. Being patient with it and letting it do its job is better than forcing it, but it doesn't completely solve the problem because of heat.

I've not thought about it in this much detail before, so the issue is the friction in the synchro? Hmm...

 

[Danoff]

Sorry, just to clarify, I referred to the 8k rpm as being the output shaft, I meant the input shaft whilst the clutch is disengaged. The engine tops out a 5500rpm, but I assume there's nothing to govern the input shaft speed whilst the clutch is disengaged. Max speed in first would be 31mph.

Ok fair enough. You're right that 1st gear could be spinning well above redline in that case (another reason to be careful about doing it, because releasing the clutch accidentally, or in case of a heart attack or car accident would destroy the engine). I don't drive diesels often so I forgot about the low redline.

Yea 6k seems like a lot of work for the synchro to do, and I think first gear is often a weak one. Or at least it used to be.

I've not thought about it in this much detail before, so the issue is the friction in the synchro? Hmm...

Friction is how it does its job. But friction produces heat, which is the enemy of most things mechanical.

Edit:

Most of this is clutch-preservation, which is where I'd place the priority. Still it's interesting:

https://jalopnik.com/heres-how-to-destroy-your-manual-transmission-and-how-1828403150

 

[Danoff]

What's yours?

Seems like around 1500 in the NSX. It doesn't like going very low in RPM.

 

[Danoff]

Someone was sitting at a stoplight this morning with a fart cannon on a beater Subaru. I'm listening to it "blatblatblatblat" and the light turns green. Fart note rises with engine rpms, and then pauses, and then picks up where it left off, does a quick dive, and starts climbing from a low tone again up through the rpms. It pauses again for another shift, picks up where it left off, does a quick dive, and starts climbing again from a low tone up through the rpms.

The driver was slipping the clutch for each shift. I can only imagine how much wear that is going to create over the life of the car. Every single shift as if it were 1st. I wish I could say this kind of thing was uncommon, but people learn it and then just keep doing it. If you have an explanation as to why this was somehow the right thing to do (barring impending clutch failure), let me know.



So the gentleman in the video is demonstrating (at after a minute or so) how a proper upshift does not include catching the engine note where it used to be and letting it drop through the clutch release. He's actually trying something related to the above, with a great deal more finesse, which is to rev-match the bottom of the upshift . He misses slightly high quite a bit, and it's a very deliberate blip. It's because his flywheel is faster than his shifting technique - which is because his car is tuned a little more for aggressive driving than laid back road driving, which is one of the many annoying tradeoffs for driving a track-oriented car for the road.

I do something somewhat similar to what he's doing, but I try to make it smoother. When I know that I'm going to be slower through the shift gate than the flywheel, I tend to linger my foot on the gas. It's almost a full release, but not entirely. If I do it just right, it's enough gas to land the engine rpm at the right spot for the clutch release. It's a single smooth motion, instead of a blip like he's doing in the video.

 

[homeforsummer]

The post above has reminded me, actually. I was watching this video the other day:

​

Now I know how fashionable it is to pick faults in driving technique on the internet, but the driver's heel and toe technique is... frustrating to watch.

Notice it? On every single downshift? WAM...WAAAAAAAOOOOOOO. The rev blip is too quick, so when he releases the clutch the road speed still drags the engine revs up. WAM...WAAAAAAAOOOOOOOO. Now giving him the benefit of the doubt, it's presumably running a light flywheel so the revs rise and fall quickly. But that's where you compensate for it as a driver, by either making the blip later before you engage the clutch, or by giving the gas a firmer or longer press so the revs are high enough to meet the output shaft speed before the clutch re-engages.

I don't expect everyone to get it right all the time (certainly not myself, and not even professional racing drivers - if there are any series still using manual transmissions these days - NASCAR maybe?) but I know I mentally kick myself every time I misjudge a heel-toe blip and get the same awkward non-rev-match, so I couldn't help but wince at that video.

It's all about practice, ultimately. If there's any solid reason for heel-toe on the street it's that it's actually quite easy to practice, almost all the time. By the time you then get on a track doing it with a reasonable success rate will hopefully then be second-nature...