Use of secondary brakes

[carryfast]

Carryfast:

jakethesnake:
I don’t know what to say other than the worlds gone nuts. I can just about understand why it would be easier to train that way from an instructors point of view

this training vid.In which I’m shouting at the screen downshift the zb thing properly on the approach.Credit where it’s due at least he’s gone for manual training.

youtube.com/watch?v=xZnCvcM3ipM

Check out the comments at least that’s answered your question.
I think it’s a combination of less work for trainers and not wanting nor intending to wash out the no hopers who just can’t drive won’t drive.
The rot set in with synchro boxes the rest is history.

[carryfast]

switchlogic:
Exhaust brakes are an old fashioned waste of space, not bothered with them for years. When it comes to modern trucks brake fade is generally a thing of the past anyway

Either something has changed ? in that retarders were the rare exception not the rule.Expensive to buy and maintain and payload penalty.
Exhaust brakes are generally ok so long as you know how to keep the engine well into the yellow band while the truck is slowing down.Which brings us back to the stupidity of brakes to slow gears to go.
Modern trucks can’t possibly have much more brake heat capacity than older ones.Other than the relative advantages of disc brakes the space required for larger brake areas hasn’t changed that much.Especially 32t on 4 let alone 18t on two axles.

[switchlogic]

Something has changed. Well a lot has changed. Truck brake efficiency has increased dramatically in the 20 + years I’ve been driver and yes retarders and engine brakes are very common now, things have moved on rather a lot since you were in the industry Carry, they have moved on a lot since I started driving. Would be very interesting to do a brake test with trucks of various ages actually, to see how much quicker a modern truck can stop

[franglais]

See if we agree on terms first?

Exhauster-
flap covers exhaust to improve engine braking.

Engine Brake (Jake Brake)
Alters valves yo turn engine into an air compressor, increases engine braking more than an Exhausted.

Retarder (Intarder on DAF)
Fluid pump on back of gearbox that converts energy from prop shaft (hence the rear wheels) into heat.

Let’s ignore Electric Retarder such as Telma as UK truck rarities?

The first two, using modified engine braking, work best at higher revs, in lower gears. The retarder work a best at high road speed and isn’t dependent upon gear or engine speed.

As brilliant as Retarder are, they are expensive and heavy. (I think France allows 500kg gross extra, if fitted, so no penalty for safety) In the mostly flat UK they aren’t common, but although not universal, are found around Alpine countries and Iberia.

If you’re not fitting a retarder, then an engine brake is better than an exhauster. If fitting a retarder, than an engine brake isn’t so necessary, and an exhauster will suffice.

Discs should dissipate heat better than drums.
I don’t know off hand if current lining/pad material is much less temp sensitive than previous asbestos based types?
We can’t use F1 type materials as, although they work well at high temp, they don’t work well when cold.

Tyre grip is likely to be the limiting factor in simple braking tests, rather than the brakes themselves?*
Repeat stops or hill descents is where overheating and fade occurs.

Be aware that it takes a lot more to slow from 90kph to 80kph than it does from 20 to 10.

*Edit to add
The electronic anti lock systems have been a major improvement over anything before. They must, I agree, have made stopping distances less.

[carryfast]

switchlogic:
Something has changed. Well a lot has changed. Truck brake efficiency has increased dramatically in the 20 + years I’ve been driver and yes retarders and engine brakes are very common now, things have moved on rather a lot since you were in the industry Carry, they have moved on a lot since I started driving. Would be very interesting to do a brake test with trucks of various ages actually, to see how much quicker a modern truck can stop

Firstly I was taught to drive trucks on the BTSGTG method in 1980 and argued with the instructors just the same.So this argument has nothing to do with brake development then to now.
I’ll look into the retarder issue but it just means a different type of auxiliary braking where fitted regardless.

The issue remains that teaching drivers not to instinctively use engine braking when slowing down is wrong.It has nothing to do with how well a truck can stop.It’s all about conserving the limited finite amount of heat capacity in the brakes for when you might need it.
Especially in the case of a typical well used drum braked tipper working in hilly terrain.It’s new enthusiastic driver won’t be asked do you know how to keep the brakes cool on this heap when he gets the job.

[franglais]

Carryfast:

switchlogic:
Something has changed. Well a lot has changed. Truck brake efficiency has increased dramatically in the 20 + years I’ve been driver and yes retarders and engine brakes are very common now, things have moved on rather a lot since you were in the industry Carry, they have moved on a lot since I started driving. Would be very interesting to do a brake test with trucks of various ages actually, to see how much quicker a modern truck can stop

Firstly I was taught to drive trucks on the BTSGTG method in 1980 and argued with the instructors just the same.So this argument has nothing to do with brake development then to now.
I’ll look into the retarder issue but it just means a different type of auxiliary braking where fitted regardless.

The issue remains that teaching drivers not to instinctively use engine braking when slowing down is wrong.It has nothing to do with how well a truck can stop.It’s all about conserving the limited finite amount of heat capacity in the brakes for when you might need it.
Especially in the case of a typical well used drum braked tipper working in hilly terrain.It’s new enthusiastic driver won’t be asked do you know how to keep the brakes cool on this heap when he gets the job.

Good post.

[dieseldave]

Carryfast:
… It’s all about conserving the limited finite amount of heat capacity in the brakes for when you might need it…

IMHO, this is probably the most spot-on part of what you’ve written so far.

Less is more in this case, because I don’t think that exact point can be argued.

[carryfast]

Franglais:
See if we agree on terms first?

Exhauster-
flap covers exhaust to improve engine braking.

Engine Brake (Jake Brake)
Alters valves yo turn engine into an air compressor, increases engine braking more than an Exhausted.

Retarder (Intarder on DAF)
Fluid pump on back of gearbox that converts energy from prop shaft (hence the rear wheels) into heat.

The first two, using modified engine braking, work best at higher revs, in lower gears. The retarder work a best at high road speed and isn’t dependent upon gear or engine speed.

As brilliant as Retarder are, they are expensive and heavy. (I think France allows 500kg gross extra, if fitted, so no penalty for safety) In the mostly flat UK they aren’t common, but although not universal, are found around Alpine countries and Iberia.
Repeat stops or hill descents is where overheating and fade occurs.

Be aware that it takes a lot more to slow from 90kph to 80kph than it does from 20 to 10.

I’ve never even seen let alone driven a truck with a retarder.

Also never driven one with a Jacobs engine brake.

But most were fitted with exhaust brakes.I had no issues with exhaust brakes they all seemed to do their job fine to me.So long as they were combined with the correct downshift regime on the approach.

The latest DAF MX seems to just be a modern version of exhaust braking.With it active ‘‘you downshift to keep in the blue ( yellow ) band’’.Which fits BTSGTG how ?.

youtube.com/watch?time_conti … e=emb_logo

Repeat stops or hill decents.Or the combination of both including stopping from 50 mph to zero and 30 mph to zero for roundabouts and traffic lights.( Like the run into Dewsbury from M1 or the Bath for example ).

[peterm]

Franglais:
See if we agree on terms first?

Exhauster-
flap covers exhaust to improve engine braking.

Engine Brake (Jake Brake)
Alters valves yo turn engine into an air compressor, increases engine braking more than an Exhausted.

Retarder (Intarder on DAF)
Fluid pump on back of gearbox that converts energy from prop shaft (hence the rear wheels) into heat.

Let’s ignore Electric Retarder such as Telma as UK truck rarities?

The first two, using modified engine braking, work best at higher revs, in lower gears. The retarder work a best at high road speed and isn’t dependent upon gear or engine speed.

As brilliant as Retarder are, they are expensive and heavy. (I think France allows 500kg gross extra, if fitted, so no penalty for safety) In the mostly flat UK they aren’t common, but although not universal, are found around Alpine countries and Iberia.

If you’re not fitting a retarder, then an engine brake is better than an exhauster. If fitting a retarder, than an engine brake isn’t so necessary, and an exhauster will suffice.

Discs should dissipate heat better than drums.
I don’t know off hand if current lining/pad material is much less temp sensitive than previous asbestos based types?
We can’t use F1 type materials as, although they work well at high temp, they don’t work well when cold.

Tyre grip is likely to be the limiting factor in simple braking tests, rather than the brakes themselves?*
Repeat stops or hill descents is where overheating and fade occurs.

Be aware that it takes a lot more to slow from 90kph to 80kph than it does from 20 to 10.

*Edit to add
The electronic anti lock systems have been a major improvement over anything before. They must, I agree, have made stopping distances less.

Pedant mode on. An exhauster is to be found on lorries with vacuum assisted brakes. Pedant mode off. I’m disappointed in you carryfast. I thought you’d have jumped straight on this.

[franglais]

peterm:

Franglais:
See if we agree on terms first?

Exhauster-
flap covers exhaust to improve engine braking.

Engine Brake (Jake Brake)
Alters valves yo turn engine into an air compressor, increases engine braking more than an Exhausted.

Retarder (Intarder on DAF)
Fluid pump on back of gearbox that converts energy from prop shaft (hence the rear wheels) into heat.

Let’s ignore Electric Retarder such as Telma as UK truck rarities?

The first two, using modified engine braking, work best at higher revs, in lower gears. The retarder work a best at high road speed and isn’t dependent upon gear or engine speed.

As brilliant as Retarder are, they are expensive and heavy. (I think France allows 500kg gross extra, if fitted, so no penalty for safety) In the mostly flat UK they aren’t common, but although not universal, are found around Alpine countries and Iberia.

If you’re not fitting a retarder, then an engine brake is better than an exhauster. If fitting a retarder, than an engine brake isn’t so necessary, and an exhauster will suffice.

Discs should dissipate heat better than drums.
I don’t know off hand if current lining/pad material is much less temp sensitive than previous asbestos based types?
We can’t use F1 type materials as, although they work well at high temp, they don’t work well when cold.

Tyre grip is likely to be the limiting factor in simple braking tests, rather than the brakes themselves?*
Repeat stops or hill descents is where overheating and fade occurs.

Be aware that it takes a lot more to slow from 90kph to 80kph than it does from 20 to 10.

*Edit to add
The electronic anti lock systems have been a major improvement over anything before. They must, I agree, have made stopping distances less.

Pedant mode on. An exhauster is to be found on lorries with vacuum assisted brakes. Pedant mode off. I’m disappointed in you carryfast. I thought you’d have jumped straight on this.

Vacuum brakes!
At the start of my driving career I did drive some old trucks with them, but only on local coal rounds, so never got into any real experience of them.
I doubt young C-F will have much experience of them either?
(He’s only 32yrs old really, but has an attitude older than that of Jacob Rees-Mogg!)

[carryfast]

Franglais:

peterm:

Franglais:
See if we agree on terms first?

Exhauster-
flap covers exhaust to improve engine braking.

Engine Brake (Jake Brake)
Alters valves yo turn engine into an air compressor, increases engine braking more than an Exhausted.

Retarder (Intarder on DAF)
Fluid pump on back of gearbox that converts energy from prop shaft (hence the rear wheels) into heat.

Let’s ignore Electric Retarder such as Telma as UK truck rarities?

The first two, using modified engine braking, work best at higher revs, in lower gears. The retarder work a best at high road speed and isn’t dependent upon gear or engine speed.

As brilliant as Retarder are, they are expensive and heavy. (I think France allows 500kg gross extra, if fitted, so no penalty for safety) In the mostly flat UK they aren’t common, but although not universal, are found around Alpine countries and Iberia.

If you’re not fitting a retarder, then an engine brake is better than an exhauster. If fitting a retarder, than an engine brake isn’t so necessary, and an exhauster will suffice.

Discs should dissipate heat better than drums.
I don’t know off hand if current lining/pad material is much less temp sensitive than previous asbestos based types?
We can’t use F1 type materials as, although they work well at high temp, they don’t work well when cold.

Tyre grip is likely to be the limiting factor in simple braking tests, rather than the brakes themselves?*
Repeat stops or hill descents is where overheating and fade occurs.

Be aware that it takes a lot more to slow from 90kph to 80kph than it does from 20 to 10.

*Edit to add
The electronic anti lock systems have been a major improvement over anything before. They must, I agree, have made stopping distances less.

Pedant mode on. An exhauster is to be found on lorries with vacuum assisted brakes. Pedant mode off. I’m disappointed in you carryfast. I thought you’d have jumped straight on this.

Vacuum brakes!
At the start of my driving career I did drive some old trucks with them, but only on local coal rounds, so never got into any real experience of them.
I doubt young C-F will have much experience of them either?
(He’s only 32yrs old really, but has an attitude older than that of Jacob Rees-Mogg!)

To be fair I just took it for granted that it meant exhaust brake.
I know the Matador had vacuum brakes and if you used the brake pedal it seemed to stop the thing somehow as usual combined with the gears to slow mantra.That’s all I know about it but, like the 30 years later Clydesdale , no exhaust brake from memory.

As for JRM my guess is he’s a BTSGTG type of driver.He puts on a good act climbing into the cab but he can’t drive when it comes to it out on the road.