Classic cars forum & vehicle restoration.
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peter scott
Joined: 18 Dec 2007 Posts: 7124 Location: Edinburgh
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Posted: Mon Feb 05, 2024 11:37 am Post subject: |
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Ray White wrote: |
I couldn't be sure because hydraulic brakes were fitted to some cars in 1935/36. Somewhat surprisingly thereafter - for some reason - the Company reverted to cable operated brakes.! |
_________________ http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon |
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Penman
Joined: 23 Nov 2007 Posts: 4765 Location: Swindon, Wilts.
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Posted: Mon Feb 05, 2024 11:43 am Post subject: |
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Ray White wrote: | Yes.
I think tyre adhesion is what matters.
If the wheels lock up on a dry surface then that is about the best one can hope for.
How you get to that point is almost immaterial. |
As an Instructor, I always maintained that MAX adhesion is just before the wheels lock up. _________________ Bristols should always come in pairs.
Any 2 from:-
Straight 6
V8 V10 |
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Ray White
Joined: 02 Dec 2014 Posts: 6342 Location: Derby
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Posted: Tue Feb 06, 2024 11:11 am Post subject: |
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Penman wrote: | Ray White wrote: | Yes.
I think tyre adhesion is what matters.
If the wheels lock up on a dry surface then that is about the best one can hope for.
How you get to that point is almost immaterial. |
As an Instructor, I always maintained that MAX adhesion is just before the wheels lock up. |
That, of course, is why ABS is so clever. It knows before you do when the max grip has been found. |
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alastairq
Joined: 14 Oct 2016 Posts: 1956 Location: East Yorkshire
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Posted: Tue Feb 06, 2024 5:25 pm Post subject: |
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Thus, takes longer to stop you then a skilled driver would...!
ABS does have limitations though.....For example, when driving off tarmac/concrete [''off road'' is the commonly used description]...Which is why many 'proper' off road vehicles using today's technologies actually disable the ABS once an off-highway mode is selected.
Another issue with ABS is that it ceases to function below a certain speed. {Albeit at quite low speed]
I have found that most ''skidding'' on ice and snow actually occurs at very low speeds....
Whilst on the buses, it was noted that nearly all damaging 'skids' occurred when the vehicle had almost stopped..or was travelling incredibly slowly.
Nothing worse than coming to a very careful halt at a bus stop, in ice or snow...only to thave the last few feet, as a halt is about to be achieved, going sideways down a gutter camber, and ending up leaning against a lamp post.
No amount of ABS technology is going to help...because it doesn't!
ABS actually is more helpful in allowing one to steer when trying to stop.....
Also very helpful to those driving LGVs......{Which was the most common usage back in the 80's]
Trying to cadence-brake with an air braked vehicle requires a huge amount of bottle and concentration.
This is because, when the brake pedal on an air braked vehicle is released, there is a small, but noticeable delay in the brakes, at the wheels, actually releasing.
Thus, immediately stamping down on the brake pedal [as one would in a car] has the effect of not allowing the brakes to release......all rather counterproductive.
Hence , one released the pedal, waited until one felt the brakes release, then stamped down on the brake pedal, almost immediately releasing it again, to pause....and so on.
All very distressing to one's nerves when trying to perform a quick stop from 30 mph, and there's some kiddie in the middle of the road....ABS took a lot of the strain off drivers.
[Used to be an MoD Skid Instructor, on many occasions, mainly to the RAF, using Bedford TM [8 tonner, 18 tonnes gross] in a Cedergrens skid frame..no ABS, first drill was the 'stop'.....A lot of cones died back in those days, to prove a point.
Nowadays used by those training on blue light bomb disposal courses.... _________________ Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces. |
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Ray White
Joined: 02 Dec 2014 Posts: 6342 Location: Derby
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Posted: Tue Feb 06, 2024 6:30 pm Post subject: |
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...which brings us nicely to those drivers who rely too much on their brakes..
If the Hotchkiss cable brakes system would be a problem then it probably isn't the car for you. |
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alastairq
Joined: 14 Oct 2016 Posts: 1956 Location: East Yorkshire
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Posted: Tue Feb 06, 2024 7:37 pm Post subject: |
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Quote: | If the Hotchkiss cable brakes system would be a problem then it probably isn't the car for you. |
I am used to cable/rod brakes...especially with the Dellow.
SOme old cable/rod brake systems had their drawbacks [Ford Model Y, for example?], but Girling systems, etc were probably on a par with hydraulic systems for effectiveness. Much maligned, rod/cable systems worked very effectively when correctly set up & adjusted.
Issues may well focus more on the modern lining materials, and how they differed from the older, {softer?] asbestos-based linings[or cork, or grannies old knickers, etc?}
I still come across old car owners complaining about a lack of brakes when compared to today's stuff, then discover they are using modern hard lining materials instead of softer linings which are available for older cars.
I do wonder whether hydraulic braking as much came about for cheapness of manufacture, self adjustment, etc than because of any increase in efficiency? _________________ Dellow Mk2, 1951 built, reg 1952.
Fiat 126 BIS
Cannon special [1996 registered. Built in 1950's]
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Ford Pop chassis, Ashley 1172 bodyshell, in pieces. |
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Ray White
Joined: 02 Dec 2014 Posts: 6342 Location: Derby
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Posted: Tue Feb 06, 2024 10:22 pm Post subject: |
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I don't yet know how it will fare ...but I have added a mild servo to the MG TC hydraulic brakes. They are Alfin drums with soft linings.
The two most common complaints about TC brakes are fade ...and the sheer effort required.! Admittedly, the antiquated single leading shoe design is inefficient - a problem not addressed until the TD was introduced - but I am hoping my "reversible" work will pay dividends. |
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