Engine braking - OK or not OK?

[roxburd]

Hi all,

Do you use engine braking in your motorhome? I find myself using it a little from time to time and I suspect it's frowned upon by HGV instructors... but I've never had any instruction so I'm curious. I'd never driven a big diesel before last month. I've done the IAM motorcycle advanced test and they have a saying - brakes to slow, gears to go. It basically means that you shouldn't use engine braking. They also advise block-changing - changing to the gear you want all in one go, rather than changing one gear at a time and declutching between. And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

I try to drive my MH at a very leisurely pace - but I'm still occasionally tempted to use a little engine braking - for example, as I'm entering a roundabout with a little more speed than I'd like to carry round and the gear I want will give some braking.

I realise this might seem a bit 'who cares' to some but I've found myself wondering and so thought I'd see what people think... I suppose the important question is this: can gentle engine braking cause any mechanical issues?? I wouldn't have thought so...

Cheers
(let the disagreements commence)

 

[Guigsy]

Son currently has his eye on one of those, either the Stone Ten or the Special Edition. I’m more semi-old skool with a 1997 Cali EV, LM1000, project Dr John LM1100 replica 1985 AMA Endurance racer, and this beast:
View attachment 938664

The fun of a longitudinal bike engine is your throttle position affects the roll-in to a corner. My R1200GS dropped to the right a bit easier as I backed of the gas.

 

[dunnah01]

Sorry but that statement could not be further from the truth if you tried.

They may look similar BUT 1950's cars had solid rod operated brakes, no hydraulics only servo assist (if you were lucky)

No discs or pads, all drums and no ABS.

The shoes often included asbestos particles which was inhaled by the mechanic in the dust when he changed the shoes.

There is a lot more but I think that's enough to start with?

Disc brakes were first introduced in the 50's and everything since has-been small refinements. We're still relying on friction between pad and disc to stop us. Very little has really been done to reduce the heat created which is why engine braking is still as important as it ever was. ABS won't help you if you've cooked the brakes. Asbestos is really nasty stuff but it was great at dissipating heat which is why it took many years to get back to the level if performance it provided. You could argue rods would prevent brake fade due to hydraulic fluid boiling which is basically what lorries are fitted with

 

[gus-lopez]

Bloke I worked for in Devon did grass track racing, as did his daughter. He worked out that front wheel drive would give him far more acceleration exiting corners. So he built a front wheel drive bike. Daughter made it work well but he used to roll of the throttle so quick he threw him over the handle bars.

So if you slam on the brakes you are almost always braking in the optimum point just before locking. Another bonus is that all four wheels keep their maximum grip, if for example the road surface is different under the wheels.

I had to do that this morning to save a pigeon who had left it late taking off.

 

[Figaro]

I think a better term to use than engine braking, would be engine restriction.
The guy I referred to earlier in this thread that mangled his almost new clutch, was, I believe doing just that, using the clutch and gears to slow the vehicle on a steep decent.
This left his clutch as shredded fibre and swarf falling out through the ventilation holes in the bell housing.

It should of course be the brakes used to slow the vehicle, then the clutch and gears used to select appropriate gear and restrict the speed as far as possible, before braking firmly for a short period when speed has built up to a level where rpm are getting too high.

Just my thoughts anyway

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[JJ]

Many moons ago a good mate of mine was a driving instructor.

He taught that the brakes were designed to slow the car down whereas the engine was designed to speed it up...

JJ

 

[Barriesimpson]

My last company car, a Skoda Octavia, went back at the end of its 100,000mile stint, with its original brake discs and pads, along with its original clutch and dual mass flywheel. Not relevant to this discussion, but it also had its original battery, exhaust and never needed so much as a new bulb.

Geoff

My Rover 75 2.0 diesel also, but with over 200,000km.

 

[wireman]

I smashed my bike at 80+ just after I found some T**T had taken my brake lever off and engine braking had little effect until I reached a false neutral still doing 70+ and the next thing I remember is coming round for a couple of minutes to have a question from the guy who reached me first to tell him my back really hurt and went out for the next 3 weeks with odd waking times only. Lots of hospital stuff for 8 weeks when they let me home only just able to walk a few feet with lots of help. Engine braking is the last thing you should rely on; period.

 

[dunnah01]

Engine braking is the last thing you should rely on; period.

I hope a few people don't take that too literally. Coming down any alpine pass just on your brakes with no engine assistance will get you slowly down the first mile but the next ten will be a lot more interesting

 

[Sdrawde]

Back in the day, they taught us that although gear selection was important to quell an engines freedom to roam downhill, the use of engine braking in more 'normal conditions' was very much frowned upon - cost of new brake pads Vs cost of new clutch.
Obviously reading the road ahead is part of that equation, but I'm guessing most of us are pretty good at that anyway, though if you've not already done a course on Advanced Driving, it is highly recommended.

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[DBK]

Back in the day, they taught us that although gear selection was important to quell an engines freedom to roam downhill, the use of engine braking in more 'normal conditions' was very much frowned upon - cost of new brake pads Vs cost of new clutch.
Obviously reading the road ahead is part of that equation, but I'm guessing most of us are pretty good at that anyway, though if you've not already done a course on Advanced Driving, it is highly recommended.

I don't understand that argument. Engine braking shouldn't wear the clutch, you should have changed down a gear long before any sort of emergency action is needed which might cause anything jerky.

 

[Sdrawde]

If you don't understand the argument it's cos I've not explained it well enough

 

[bigtwin]

I don't understand that argument. Engine braking shouldn't wear the clutch, you should have changed down a gear long before any sort of emergency action is needed which might cause anything jerky.

If you substitute the word gearbox for the word clutch, it all makes sense.

Ian

 

[DBK]

If you substitute the word gearbox for the word clutch, it all makes sense.

Ian

Sorry, but I don't understand that either. The gearbox won't suffer any more wear from going down a hill than it might have suffered going up the hill.

Those suggesting you should use brakes instead of changing down a gear have never descended an Alpine pass.

 

[Yorick]

I did a bike safe course and you'll rarely see police motorcyclists use their brakes, even when they're hussling pretty fast. If you needed to brake for a corner, you judged it wrong. Which is the ultimate sin as far as they are concerned. But then it is easier to slow on a bike just by rolling off the throttle.

Many years I was instructing at Donington and 2 police riders turned up and I was assigned to help them
They kept arguing with what I said and the police way was better.

So next session I lapped them both, twice

I passed them in paddock with big smile

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[L' Hobo]

In my mind, it was the crash box that required the anticipation.
One HAD to be in the right gear at the right time because the alternative was to stop and start in first gear all over again and doing this halfway up a steep hill was not the place to do it!
That's when one burnt out the clutch!

 

[Guigsy]

Many years I was instructing at Donington and 2 police riders turned up and I was assigned to help them
They kept arguing with what I said and the police way was better.

So next session I lapped them both, twice

I passed them in paddock with big smile

Braking for corners is leagues faster on a track. The difference is that when road riding, you aren't trying to find the limits of lateral adhesion on every corner. You're going as fast as you can to allow you to brake within the forward distance you can see. So it makes much less of a difference. And the "no brakes" technique does mean your bike is more settled, so you can probably react to the unexpected a lot more easily than if you're nose down and about to elbow it into a bend.

 

[bigtwin]

Sorry, but I don't understand that either. The gearbox won't suffer any more wear from going down a hill than it might have suffered going up the hill.

Many moons ago, it was the message that the Police used to give out on their driving courses.

I have some sympathy with your point of view however it would be fair to say that a gearbox is designed primarily to aid acceleration and not deceleration so, it might be argued, that in normal driving conditions minimising loadings on deceleration is beneficial?

That said, I agree entirely that it would be foolhardy to not use the gears to retard speed on downhill sections.

Ian

 

[Roby2008]

On my Morris Minor ( first car) if you didn’t use engine braking you didn’t stop

Mine too, plus the joys of drum brakes and skinny cross plies

 

[L' Hobo]

Many years I was instructing at Donington and 2 police riders turned up and I was assigned to help them
They kept arguing with what I said and the police way was better.

So next session I lapped them both, twice

I passed them in paddock with big smile

It does make one wonder where they get some of these Police instructors from?

Many years ago while living in Surrey near Hampton Court, I was attending a Council committee meeting discussing speed and a senior instructor stated that "drivers could get across London, as fast by sticking to the law as breaking it".

As my daily commute to my Coach Depot crossed Hampton Court Way between the Scilly Isles roundabout and Hampton Court Bridge, I asked him to show me how was that possible when, in the 'rush hour' (which lasted most of the morning,) when was the road clear, without vehicles, for 100+ metres, simultaneously in BOTH directions, so that I could cross from one minor road to the other on the opposite side? (It was ALWAYS busy in both directions)
(The law states something like 'sufficient distance' and, in my estimation, on a 30mph road, that would be, at least, 100 metres?)

He said he didn't have time but insisted it was possible and had no answer to "Why do Police Cars use blues & two's then to achieve the same manoeuvre"?

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[Pausim]

It does make one wonder where they get some of these Police instructors from?

Perhaps Police driving needs different techniques from motorhome driving.

 

[L' Hobo]

Perhaps Police driving needs different techniques from motorhome driving.

No perhaps about it, of course it does and vice versa.
We can all learn something from every situation!

 

[gilbaro]

This has developed into an interesting discussion. I go back to one of my earlier points.
"The only fixed rule is no fixed rules"
There can always be a reason to do things differently.
I am unusual (many who know me will agree!)
I was Police trained but also raced cars at National and International level. I used and taught different techniques depending on whether on track or road.
On the road I would I would generally promote "brakes to slow gears to go". This would invariably involve block chang
ing of gears with careful matching of revs.
Racing was different, braking very late and very hard, downchanging sequentially using 'heel and toe' to match revs (this was before the current sequential boxes used now in racing)
Both techniques worked in their particular domain.
On the road anticipation is key, method can be flexible. What works for a person, vehicle or situation can and will vary.

 

[Cheese Monster]

And not changing gear at all until you've finished braking. It all depends on circumstance but they are general guidance points.

My understanding is that while you are braking and the braking is controlling your loss of speed, you can change gear as this isn't having influence on your speed.

This is on a motorcycle which has a sequential gearbox and the theory is taken from the cars and they could go from 4th to 1st.

 

[Jev88]

Driving an RV I use the on/off Overdrive switch for engine breaking.

Modern hybrid engines use electronic trickery before applying the brakes themselves and grab that slow down charge. If hybrid engines make it to Motorhomes I guess this would help protect brakes?

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[Richard n Ann]

Some modern motorcycles have the engine ecu and timing designed to massivley reduce or even entirely remove engine braking and also use slipper clutches . Some are aweful to ride , as you approach a corner and shut off throttle and the bike does not slow down unless you use the brakes ,, its horrible and Triumphs Bonneville range is worst offender ... lovely looking bikes but terrible engines .... A few Hondas do the same as do the new HD sportster ..
Slipper clutches can be Ok my2022 kawasaki Z900 and my Daughters Z650 have slipper clutches but still have great engine braking ..
When challenged about this idiotic no engine braking idea the designers and manufacturers say its to help new riders ????? How exactly ?????

My Honda has got 3 settings for engine braking, I have mine on minimum but it's still aggressive. Some say it makes the bike jerky but I don't mind it.

 

[dunnah01]

Anybody that's pulled a few cars apart and put them back together will soon realise that mechanical sympathy is the best way for normal driving.

 

[Yorick]

Many bikes like mine have a slipper clutch so you can bang down the gears into a corner as aggressively as you like. If you go daft, the clutch slips to forgive you.

So bike makers actively encourage engine braking.

 

[wireman]

I hope a few people don't take that too literally. Coming down any alpine pass just on your brakes with no engine assistance will get you slowly down the first mile but the next ten will be a lot more interesting

Yup, but note I said -rely on it- which is different from not using it by a long margin. Of course I agree with the engine braking being used but if you have to change gears you suddenly do not have it till you let the clutch back in and hope that uou have not missed the gear... that was my premise.

 

[jerryz]

Many bikes like mine have a slipper clutch so you can bang down the gears into a corner as aggressively as you like. If you go daft, the clutch slips to forgive you.

So bike makers actively encourage engine braking

.yes your right Yorick but certain bikes have had it deliberately designed out like Triumphs and its aweful

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[SpeedyDux]

- drum brakes vs radial tyres FTW. Shows that drum brakes were ‘good enough’ for the tyres available at that point!

Four locked up tyres ain’t helping the retardation...

My recollection was that on dry tarmac, four locked wheels gave the shortest stopping distance, although maybe with less control.

That was in a Mini. Those were the days.