H: Hubs, Wheels and Tyres (Front) Brake improvements

[DucATIRadeon]

my Rap C has ribbed front drums and aluminium brake plates (BS type?), and to be honest they don't brake as well as "claimed"nor as I had hoped.
compared to the (Indian) Royal Enfield Bullet brake plates they share the same (forgive my wording) flaw: there is little to no real support on the pins. this is demonstrated when the nuts are loosened and the pins can be literally pushed back and fro; more in the direction of wheel rotation than opposite.
on one of the brake plates, with the nut undone and dial gauge touching it, it has deflection of 0 against rotation and a whopping 1mm in the direction of wheel rotation. 2 items are jointly responsible for this:
1- the pin(s) resting only on the hex flange (which is small, 15mm across the flats and 17 at the corners)
2- the hole in the brake plate is oval, and gets more oval with the braking experience it gains.

result are brake shoes that do not run square with the drum, holes get more oval and braking efficiency drops. not taking into account the flexing of the brake plates themselves.

anybody tackled this without getting replacement drums or fitting 2LS brake plates?

made a dummy pin with round 20mm flange and that already drops the movement from 1mm to just under 0.4mm (without any nut pulling it). pondering on reaming the holes from 9.51mm (⅜") to 10mm then fit new oversize pins with slight interference fit and larger flange (26mm) and filing a flat so that 2 pins adjacent each have the flats touching to act as a stopper when tightening the outside nuts.

what are your thoughts on this? again: NOT replacement 2LS stuff (with all respect to those that made them).

 

[Chris Launders]

Another fix for the flex I have done on another type of machine is drill and tap the inner ends of the pins and fit a plate with countersunk Allen studs, not sure is there's room in the Vincent brake but losing a bit of shoe width there might be worthwhile.

 

[stu spalding]

Hi Duc,
You might like to check out the Bert Weitz brake mod in MPH 821, June 2017. I think this as good as it gets with SLS. Cheers Stu.

 

[Cyborg]

If the holes in the plates are oval, to me that suggests the pivot bolts were a sloppy fit to start with. If it were mine, I’d set the plates up in a mill just to make sure the holes end up where they should be. I’d make oversize pivot bolts that are a snug fit in the plates…. either that or bush the holes back to size. Add some appropriate loctite to the pivots where they go through the plates as well as on the threads. Unless you are a youngster who rides like you stole it, the brakes should last you.
What brake shoes are in there? If stock, you could swap them for Neal’s. They don’t flex. Turn the shoes on the brake plates before installing them in the bike. The alloy plates are definitely an improvement when they are made properly. It seems lots weren’t.

I machined a set of alloy plates relatively recently. They were cast by a company that does work for the USAF and they were heat treated. I can’t imagine them flexing.

 

[DucATIRadeon]

Hi Duc,
You might like to check out the Bert Weitz brake mod in MPH 821, June 2017. I think this as good as it gets with SLS. Cheers Stu.

would you care to share the article here, or explain what was done?
not a VOC member, but I am member of the VOC Dutch Section, so limited access and hurdles everywhere.

 

[DucATIRadeon]

If the holes in the plates are oval, to me that suggests the pivot bolts were a sloppy fit to start with.

or... the hole become oval due to the stresses involved with little support and tiny surfaces.

If it were mine, I’d set the plates up in a mill just to make sure the holes end up where they should be. I’d make oversize pivot bolts that are a snug fit in the plates….

as I suggested. anything to make them proper fitment!

either that or bush the holes back to size. Add some appropriate loctite to the pivots where they go through the plates as well as on the threads. Unless you are a youngster who rides like you stole it, the brakes should last you.

well I am a youngster compared to the lot of you I suppose, my rapide is almost double my age...
I don't want to ride like I stole it, they have to work properly as advertised and I should have absolutely no worries my better half gets scared shitless (again).

What brake shoes are in there?

I was told from a Black Shadow, its aluminium and has cast air scoops on them with fine wire mesh glued to the back. hubs are 10 holes but 5bolts used, ribbed with drainage holes.

If stock, you could swap them for Neal’s. They don’t flex. Turn the shoes on the brake plates before installing them in the bike. The alloy plates are definitely an improvement when they are made properly. It seems lots weren’t.

I machined a set of alloy plates relatively recently. They were cast by a company that does work for the USAF and they were heat treated. I can’t imagine them flexing.

ow yes have turned the shoes too before fitment, all little bits help. notice the brake lining has a higher edge on the outside, almost like the shoes aren't far enough inside.

 

[chankly bore]

There is a post of mine on the Britbike Vincent Forum dated 26/02/2022, entitled "Adjusting Vincent brakes." The post is #872865. Saying that however, in my opinion if you want to ride your Vincent you really need some improvements- at least good shoes and brake plates. I personally went with the German 8" twin leading shoe ones because they are functional and have no external belts, springs or pulleys. Remember, if you can't stop as well as the car you're behind it is your fault if you hit it. Good luck mate!

 

[bmetcalf]

Good reading here:

https://www.vincentownersclub.co.uk/resources/categories/2-1-brakes.42/

 

[stu spalding]

would you care to share the article here, or explain what was done?

Hi Duc, see post 8, page 2, item 43.

 

[Chris Launders]

I have the rear brake arms on the front of mine, they are about 50% longer and turn out instead of in so clearing the air scoops, they also line up with the balance beam better, you would need to make special trunnions, and it is advisable to use extra heavy duty cables.