Zen and the art of changing gear.

[R_U_LOCAL]

GreenV8S said:

Playing devil's advocate for a moment, what's your position on coasting either with the clutch down and/or out of gear, while approaching a hazard? There's a follow-on question that you can probably guess, but I won't ask it yet because I don't want to presuppose your answer.

ETA: this was really a response to instructormike's post, not Vonhosen's.

Edited by GreenV8S on Friday 10th August 18:05

I'm anticipating a "what happens if the revs drop to the point where the engine starts to judder?" question - am I right?

The braking should be dome in the higher gear right down until the engine revs approach tick-over speed in that gear. Once you've reached that speed, then you should dip the clutch to prevent judder. This is different from coasting in the accepted sense, which is more a case of dipping the clutch as soon as you start to brake, or even putting the car in neutral whilst braking.

Even in top gear, you'll be down to 10-15mph before you have to dip the clutch, so the distance travelled with the clutch down is generally only a few yards.

[R_U_LOCAL]

I have to agree with VH. The main problem in that video is when the driver approaches roundabouts which have three lanes on the approach, and uses the lane marked left turn only in order to go straight on. There are advantages with regards to vehicle balance in taking the roundabout this way, but I feel this is outweighed by the possibility that another road user will be confused by your positioning. If I were approaching those roundabouts from the left, I would be quite within my rights to expect someone in the left lane to turn left, although I think the approach speed would be a giveaway.

Other than that, from a system and gearchange timing point of view, that was a reasonably good example. I'll try to film some similar footage in a couple of weeks.

[R_U_LOCAL]

GreenV8S said:

R_U_LOCAL said:

I'm anticipating a "what happens if the revs drop to the point where the engine starts to judder?" question - am I right?

Not what I was leading up to. Back to the question: coasting with the clutch dipped and/or out of gear, views for / against and why?

It takes away the engine's assistance in slowing the car down. This assistance is obviously less in higher gears and more in lower gears, but it's always there when the clutch is out.

Acceleration sense is a very important aspect of advanced driving. Used correctly, the ability to vary vehicle speed through accurate use of the accelerator(1) can smooth a drive considerably and helps to improve observation skills.

(1)Yes, I know - straight lift from roadcraft. Shoot me.

[R_U_LOCAL]

uriel said:

One thing I've never seen discussed when reading discussions on gear changes and engine braking is the effect of the engine impeding the braking progress. It seems like common sense to me, so I'm wondering whether I'm looking at things wrongly.

If you are in gear with the clutch engaged, wanting to slow down at a rate greater than that at which the car would engine brake without the brakes being applied, then if you were to slow at that rate using the brakes, aren't the brakes working against the motion of the engine as well as the forward motion of the car? When reading discussions on engine braking, it seems as though people consider the effects of the brakes and the engine braking as a cumulative affect. But the way I see it, that's only true if the engine braking is slowing the car more than the brake pads? I hope that makes some sense!

I don't see how the engine is hindering the brakes. If you lift off the accelerator, the compression of the engine starts to slow the car down. Pressing the brakes slows the car more quickly, but the engine is still helping, albeit in a very small way. It would only be going against the brakes if there was still some throttle applied.

[R_U_LOCAL]

Maybe, but surely, if the brakes are capable of reaching the point of lock-up, then this would be irrelevant.

[R_U_LOCAL]

MX5.

[R_U_LOCAL]

R_U_LOCAL said:

MX5.

Sorry - couldn't resist that. It seemed like the most appropriate comment with which to return to the PH forums after a 7 year break!

To whoever resurrected this thread - thank you. Glad it's still being read and that some people still find it useful. I posted some other stuff on here around the same time and it kept me busy for a while.

I've been an occasional lurker on PH over the last couple of years, but a change in career took up a lot of my time and I decided to have a break from actually posting. Not sure if I'll go back to posting regularly, but a friendly phone call from a PH member a few weeks ago made me aware that this thread was still running so I thought I'd bob in and say hello.

So hello.

And MX5.

[R_U_LOCAL]

waremark said:

Welcome back Reg, the stuff you wrote and your videos were all great - well, maybe not the knees but all the rest! Do you still have MX5 and M3? Is your new career driving related?

Thanks! The M3 became somewhat uneconomical to run following a three month period when the SMG gearbox needed a rebuild and then the VANOS decided to let go, so I ended up cutting my losses & selling it on. I still miss it every day though! I've currently got a BMW 120d coupe as my daily driver and although I'm not really a diesel fanboy, it's a very nice drive and you can't argue with 50+mpg and 170bhp.

I've still got the MX5! It's SORNed at the moment but I've been slowly modifying it into a road-going track day car. I've done quite a few track days in it at Oulton Park, Anglesey, Cadwell Park and Blyton Park. Still learning new skills!

I now work as Licensing Manager for a local Authority. I've gone from working with some of the best drivers on the road to regulating some of the worst - taxi drivers! Along with pubs, clubs, bookmakers, pet shops, tattooists, scrap metal dealers etc. etc.

The taxi drivers love me! *

And the knees are still good thanks.

• The taxi drivers do not love me.

Edited by R_U_LOCAL on Saturday 15th March 12:41

[R_U_LOCAL]

DHB07 said:

Great read Reg, but a quick question...

Why do you recommend not blipping the throttle on downshift? Surely holding revs on is more likely to encourage the engine to hold speed, whereas a blip matches revs and as long as you nail a nice fast clutch release, you get them help of the engine on the way down.

I blip the throttle under normal driving (whether while braking or just down shifting) and find holding revs can even make things more difficult...

If blipping the throttle works for you then carry on blipping!

Don't forget this is road driving and my recommended method doesn't just involve raising (rather than blipping) the throttle, but also includes a slower, smoother shift action and a slower, smoother clutch operation.

I completely understand that it's more fun to drive in a sporty manner, heel-toeing and throttle blipping, but any change in technique from the one you're familiar with can feel odd or ungainly at first. In my opinion, my technique keeps any weight transfer during gear changes to a minimum and keeps the car as stable as possible at high speeds. It also reduces mechanical wear and feels nicer for passengers.

It's probably not, however, the ideal technique for competition or track days where you're looking for maximum performance over every other consideration.

[R_U_LOCAL]

Jon1967x said:

Like all the best advice is obvious when you think about it and you wonder why you never did think about it.

One of my cars has a flappy paddle single clutch automated manual gearbox and a fair bit of power. The gear changes are far from smooth if you either leave it to do its own thing or lift when changing up and in effect I've learnt to feather the throttle slightly when changing up and it's now pretty smooth. I'm not sure it's easier or grader to make it smooth in a car like this as the actual change is done in half a second when you pull the trigger but the advice here rings true in this instance.

For down shifts though it sounds like they need a different approach to lifting. While the gearbox auto blips on a downshift the throttle input needs to increase not decrease to raise engine speed? If I was downshifting to increase the ability to accelerate then this I imagine is true but if I was braking for a corner then maybe not needed? The zen of changing gear with flappy paddles would be welcome! Any thoughts?

Apologies to the true manual drivers who think I've sold my soul - the car in question was only available with that style of gearbox at the time.

I wrote a thread on this subject back in the day...

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Please bear in mind that this is now 7 years old and technology has moved on, but I think the principles are the same.

[R_U_LOCAL]

Martin A said:

If the revs are going up to 5000rpm, it seems that the idea is to make fairly brisk progress. If that's the case then why would you want the rate of acceleration to slow unnecessarily, it will obviously do so as soon as the clutch is depressed.

It would feel even smoother, except maybe with a dual mass flywheel that irons out failings in technique anyway, if the clutch were depressed at 4500rpm, while easing off the gas as the clutch passes through the biting point, with much the same final result.

I understand your point, but we're in danger of getting in to the "what EXACTLY is advanced driving?" debate and I suspect no-one wants this thread to go in that direction because, well, each to his own.

My technique produces very smooth - seamless at times - gearchanges and as we all know, smoothness is in no way incompatible with progress. Don't forget though - we're talking about smooth, advanced road driving here. We're not setting a lap time and we're not on a response run or pursuit - we're looking to make safe, unobtrusive progress and the "unobtrusive" bit counts just as much for your passengers as it does for other road users, so sacrificing a few tenths for a smoother change is perfectly acceptable.

And don't be distracted by the revs described in my example. They were just for demonstration purposes with an imaginary car and didn't relate to real life as every different car will have different gear ratios and different optimum rev ranges.

On the subject of advanced driving in general, I'm considering putting my writing cap back on soon and the question "what is advanced driving" was one of the subjects I was considering drafting a few paragraphs on. I've a few more ideas, but I'm also open to suggestions if anyone has any?

[Reg Local]

I had an interestng experience this week.

A thread I'd started in the Advanced Driving forum was deleted by an unknown moderator. I'd started the thread to discuss some videos I was planning to post on a well-known video hosting website, and the intention was to update the thread each time I posted a new video.

Alas, it seems I broke one of the PH posting rules. Which rule? Well, unfortnately, I've no idea - the email I received from an anonymous moderator said that my post had been removed because it "breaches the rules and regulations of the site".

It's a bit like being stopped by a police officer because you're "breaking the law Sir. Don't do it again".

Anyway, at the risk of breaching further rules and regulations of the site, if you were to search a popular video hosting site, it's possible that you may find an interesting new video about changing gear.