A forum member has kindly lent me one of the front brake rod assemblies so I can check the measurements with a view to reproducing it.
However, the sample piece is not quite complete. I have the rod and the complete lower assembly that attaches to the brake arm. I also have the fitting at the other end of the rod that the cable connects to.
What I don't have is the piece that screws into the fork leg and other associated parts from the upper end....
Does anyone have a drawing of these parts?..Alternatively, original pieces that I could borrow to make the drawings from...Ian

email (option): ian@wright52.plus.com

Ian
I have the part that screws into the fork which the cable runs though, however it is on my R35-17 I believe this would be the same
Cheers Darren

email (option): Darrenacartwright@yahoo.com.au

I'm not sure about that Darren. Pre war models aren't my speciality...Hopefully Leon or someone else will confirm one way or t'other....Ian

email (option): ian@wright52.plus.com

parts books between 35 & 38 show about 4 variations across models but the different part numbers don't explain what the differences are.
the main difference is some have an external thread (to enter the fork bracket) halfway down the part & others have that thread at the top.
Bikes with a left side brake in the late 30's like G14 /Y13 show a different part number as well.
But I'm 99% sure that the one you want for the latest bikes with M20 type forks is this one pictured which (forgetting the cable adjuster screw) is 2" long.

Hello Ian. I have one on my table, what dimensions do you need?



PS damper knob arrived ok.

Kalle

Hi Kalle..I need the thread size for the cable adjuster..is it 1/4" or 5/16" cycle thread?...Also the overall length of the fitting, the length of the plain section and the length of the hexagonal section...The size of the hexagon across the flats.
The bore size inside the lower part and the depth of that bore. Also, is there a spring inside or is it just the upper end of the rod (that the cable connects to) that goes inside?...It might be best if you mail me the dimensions when you have time..thanks.....Ian

email (option): ian@wright52.plus.com

As you can see from my picture I've set the rod length to almost expose the nipple when the brake is off because the design of those brakes would allow a badly worn brake to cause the rod to "top out" before the brake comes on fully, its possibly why they ditched it. .(literally).

hi ian,
i've got a copy of one you can borrow ?

email (option): chris.astinbarker@btinternet.com

Hi All..Thanks for your input and offers of help...Kalle has now sent me the dimensions for the top part...and I also have the opportunity to borrow one...Tim W. kindly lent me the rest, so I think I now have enough information/parts to sort it all out...Ian

email (option): ian@wright52.plus.com

Hi Ian, would you be looking at manufacturing the rod assembly?, if so, I would be interested as I am missing a complete assembly for my 1938 M20.

Rgds Dave

See what size fork you have. I have found a complete original brake rod and it doesn't fit my bike as it has the later type longer fork. I have to replace my front fork to make it fit. Luckily I have such a short fork so I will replace it one day but until that is done I can't fit the brake rod.

Henk.

email (option): ahum@quicknet.nl

Hi Dave...Yes, I am looking at the viability of making the complete assembly though I would make it all in stainless. I can see just by the number of individual components and their overall specs. that this wouldn't be a cheap assembly to reproduce...I'll make a decision once it's all priced up...
Henk..Was this assembly fitted with the short forks only?...Ian

email (option): ian@wright52.plus.com

Hello
The one I have is 52.75mm long and the thread fits my Wm20 B30-4 w34-7 and the R36-17 which it came off.
Darren

email (option): Darrenacartwright@yahoo.com.au

Darren, they do look the same but that R17 one is 24-7824 & a few years later on M20 etc the number is 24-7825 so something changed.
I like discovering the reasons but can't see what changed,... maybe internal depth of the drilling.

Fred
The R35-17 has forks that are longer than the ones on my Wm20 by about 1 1/4"(measured from the axle to the centre of the bottom link. However I did piece the Wm20 from spare parts. It appears they use a similar piece from 1930 to 1942 as it fits on all of the forks I have the part no for 1930 is 24-7824 and the same for most 1935 models.

email (option): Darrenacartwright@yahoo.com.au

Yes, they are all similar but there's at least 4 different part numbers during the thirties, some as I mentioned earlier have the external thread & nut at the mid point rather than at the top. but BSA changed the part number to 24-7825 for all the heavyweights from 1937 & that surely was because of a change to the part ?

I noticed before that although those R type forks have a similar overall length to M20 they do, as you say have a high bottom yoke, I would imagine its extra clearance for the 20" wheel competition models with off road tyre.

Ian,

The brake rods have been made before and were all around the GBP 100.00 mark. Derek huyton used to make the tob tube and the top piece of the rod for the cable fitting and sold those assemblies for GBP 8.00 (2 pieces). In some models there is a return spring fitted in that tube.

The top tube comes in various specifications as Fred explained. Some have a nut on the tube and on top of that the standard cable adjuster with the knurled ring nut.

The cable fitting piece is locked by a very tiny lock nut as well. The rod itself is 3/16". I can bring a complete M20 brake rod asembly if you like from my Dunkirk M20 which was more or less a timemachine because all the hard to find bits were on it untouched.

Regards,
Leon

email (option): leonhop3@planet.nl

Hi Leon...I'm only looking at the M20 variant at the moment (and that should fit a few other late 30s models as well I think)..As it turned out, someone I know is a friend of the chap that bought the 1940 frame/fork assembly without wheels, tank engine etc. that was on e bay last week...He has loaned me the complete assembly as a pattern...Also Tim Walker loaned me a partially complete assembly minus the fork fitting...I have also had various dimensions provided off an original...Thanks for the offer of help never the less..Without people lending the original parts or providing the information there would be no accurate replicas of anything made....See you at Stafford....Ian

email (option): ian@wright52.plus.com

Hi Ian,

Did you have already more info for the front brake rods??

regards,

Bram

email (option): bram@ockhuizen.com

Hi Bram..From two different sources I now have a complete assembly that is suitable as a pattern. I am looking at this to determine whether I should simply replicate it as it is or look towards 'simplifying' the design for remanufacture but without altering its appearance...
I suspect, due to the complication and number of individual parts that a straight replica would be pretty expensive to produce.
A recent family illness and bereavement put this and a number of other projects on hold for a while but I am now picking some of them up again...
This one won't be completed quickly and like anything, not at all if it isn't financially viable...
I'll post some info. on the forum when I have a clearer picture regarding the outcome....Ian

email (option): ian@wright52.plus.com

OK Ian,

Thanks, I think the most will have it like the original.
Looking forward for the info.

regards,

Bram

email (option): bram@ockhuizen.com