Double sided front brake

[Adler]

Hello Nourish,
... looking forward to see news from your project.
BR, Manfred

 

[Nourish]

Well my thoughts were whilst sat in my arm chair was to remove the rivets from two hubs and remove the hub centres. cut these centres in half, weld the two splined halves together and slip on the two larger outer crinkle halves and re-rivet them. But of course now that have a hub in my hand and found this picture I can see that the two outer halves wouldn't fit over the double ended splined centre!!!

[Adler]

Hello Nourish,
hm, understand. I did not think of that. Liked the idea of yours to create a duo brake ala Vincent. I just thought maybe using two 8" front hubs and make a duo brake setup - but it turns out that the distance between the fork legs is much too small to have a decent distance between the lower ends of the spokes to have a good triangle section setup ... here are some quickly made powerpoint sketches ...

Maybe another hour in the arm chair and you will have the right idea you want to have. Good luck.
Best regards, Manfred

[Joolstacho]

Precious little space between the flanges. Not much angle for the spokes. Would that be an issue?

[muskrat]

G'day Jools.
Short answer YES.
The wider you can get the triangulation the better. With a narrow hub it wouldn't take much of a bump to throw the rim out of kilter.
Cheers

[chaterlea25]

Hi All,
I'm sure I remember that "Rocket Racer" has a double sided brake front wheel on his outfit,
using the later 8inch drums that have the spokes laced to the drum

One thing to remember when doubling up the drums is that they must be offset to each other to ensure the spoke angles are equal

John

[Adler]

Hello Nourish, maybe you could be interested in a TLS instead of a duo sls:

https://www.a7a10.net/forum/index.php?topic=7691.0

Cheers
Manfred

[Adler]

Hello John,
you were right - found it:


https://www.a7a10.net/forum/index.php?topic=1998.msg145792#msg145792

https://www.a7a10.net/forum/index.php?topic=1998.msg32533#msg32533

https://www.a7a10.net/forum/index.php?topic=5488.msg80612#msg80612


BR, M.

[Nourish]

Thank you Manfred - that could be an option.
 I'm now thinking that I could cut off the splined section of an inner hub and weld/braze in a tube to the centre of this and cut a thread onto its jhhjprotruding end to match that of the bearing retaining ring - i would then in effect have a combined retaining ring/splined drive. My concern would be that the thread length would only be a 1/4" or so long. It would have a L/H thread - I think that would be correct for the L/H side wouldn't it? What are your thoughts on this engineering wise?

[Nourish]

Oh bugger - I don't have any stanchions but the yokes are 6.750" between centres, The sliders are 1.620" in diameter that allows 5.130" for the wheel to fit in - not enough for the double brake    -  Or have I got the '49 on yokes? - are they narrower?

[Nourish]

No! - We're back on. I have the wrong yokes - they should be 7 1/4" according to Dragonfly and I didn't realise that the spigot on the 47/48 brake plate fits inside the fork leg. 

[Adler]

Thank you Manfred - that could be an option.
 I'm now thinking that I could cut off the splined section of an inner hub and weld/braze in a tube to the centre of this and cut a thread onto its jhhjprotruding end to match that of the bearing retaining ring - i would then in effect have a combined retaining ring/splined drive. My concern would be that the thread length would only be a 1/4" or so long. It would have a L/H thread - I think that would be correct for the L/H side wouldn't it? What are your thoughts on this engineering wise?

Good Morning Nourish, I honestly do not really like the Idea, that the securing nut acts as the element which carry the brake load (half of the total brake load). When braking, the nut would be screwed in and when braking at rolling backwards it potentially would be unscrewed.
My favourite design is the one from Dick Casey for his AMC single

https://youtu.be/0SFpoixKnDg?si=j52lodVBFRFl5Ubn

He welded the second drum to the hub. But the AMC hubs are different to your BSA hubs ... Could you probably imagine to use AMC hubs?
But also here the flanges on the brake drums are far inboard. It obviously would be better the flanges were more outside as for pressed steel hubs (Not cast steel hubs) but I assume, he used wider fork yokes.
Unfortunately I have no better ideas at the moment.
Cheers, Manfred