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

[DucATIRadeon]

there's an interesting side-step emerging here and, although everything is connected I do wish to keep it to the brakes for now.

just a note before moving onto the brakes:
got some info on the steering head from outside the forum (from a VOC member, don't panic) and it shows 2 graphs of the front axle movement in stock config and modified.
took some triple reading to understand what is said but the graph actually speaks for itself. indeed the front moves vertically in a lens-like curve where the "average" axle postion is along the vertical.
with the mod, the lens-like curve is inclined and the average axle position is along an incline approx 30-40 degrees. someone called it "telescopic forks behaviour"? it does show similarities to that yes, I agree.
with the altered movement: does the mudguard stay wel clear from the head and magneto cowl at full upward travel?
heard of the term trail but never got me head around it. havent had a tank slapper either but have noticed mentioned above on my first ride on this machine when going over bumps and braking (read as: added resistance to engine braking) there is hardly any front-end dive. and yes the forks can move freely up and down, and a lot more after slightly easing off the lower damper bolted connection and of course greasgun then lot.

I've had my racing days on old Ducati's (albeit with disc brakes) with the odd frame flexing and highsider, all on TT Assen, and not keen on riding the same level with this machine so I don't expect to get slappers and such for now (ride like an old lady at the moment on my 1959 Ducati 175 bevel single). it is worth considering the changeover to the mod and damper bit, its just Id have to find reconciliation between keeping it original and modded for modern day riding.

not a VOC member so much of this info already on this forum is behind closed doors for me. do appreciate all the hints and info provided so far!

on with the brakes then?

 

[timetraveller]

Hello. I am the chap who supplies the modified steering heads. I am not sure exactly what you can see or not see as a non member but if you are able to get onto the other forum which is at theVincent .org then at the bottom left of the home page you will see a heading labelled 'Bike Modifications'. There are several articles in there and there is a photograph of the front of two bikes with the new system fitted. One is a Patrick Godet racer and the other a road bike from Australia. You will see that it is hard to see the change.
Regarding whether the front mudguard stay can hit something on the engine; that is not the problem. I know of one person who hit his front mudguard on the exhaust pipe while going over a kerb with the handlebars turned to the left. The dent in the mudguard was about 5 mm deep. One other person got the imprint of the three socket headed screws which hold the steering damper onto the base of the modified steering head when hitting a severe pothole. Changing to dome headed sockets solves that problem. There might be others but I have supplied about 320 kits so far so it is not a common problem.
The problem is that not all Vincents are the same. One of the most mystifying problems comes when fitting the AVO damper to the front with the new steering head. On some bikes there is no problem. On my own bike and many others one has to remove metal from below and behind the front part of the upper link. This is not as drastic as it might sound as it was done on the series 'D's. It is the increased diameter of the shroud over the AVO damper compared with the original damper which causes the problem but why some bike have to be modified and some do not I cannot explain.
In case you think that my response to your questions is an attempt to get you to spend money then that is not the case. This is not a commercial exercise and although I try not to loose money I also do not aim to make a profit. If I charged my time at the national minimum wage here in the UK I would by now be many thousands of pounds/euros out of pocket. The aim it to make the bikes safer, and incidentally. more comfortable. The kit has evolved over the years from originally just supplying the steering head and springs to now supplying in addition an AVO damper, which was developed by Hadronuk, on here, with AVO to provide a modern damper and fitting ball races into the rear of the lower link to replace the original Oilite bushes. That idea came from Greg Brillus in Australia when he was racing a Vin with the original suspension. Thus the ideas of several people have been incorporated and all I have done is to try to make them available to as many people as possible. I should warn you however that several kits have been sold to people after they had had tank slappers, never expecting to ever get into that state.

 

[DucATIRadeon]

regarding the brakes a small update:
still not done yet. as it happens a close family member is taken very ill into hospital and as such literally everything that was sorted has gone done the shoot.
what has been done: the holes in the brake plates have been reamed to same size and pillars made to suit. then found that 1 hole turned out skew (not parallel to the axle axis and other pillar hole), that one has to be corrected (oversize) and 1 oversize pillar made.

when I rode the bike after turning the shoes square with the axle it did brake better in the beginning then slightly back to less better. upon inspection it was clear the rubbing marks had shifted again to 1 side i.e. the shoe pillars are bending.

when family matter clears up (tbh I expect a funeral in the very near future) I hope to carry on with this, as the weather is exceptional the past few weeks and still havent ridden the bike properly yet!
many things done and can't test. oh well, riding the Enfield Bullet and the Ducati 175 isn't a punishment either!

 

[Chris Launders]

What I have done in the case of a similar layout on a vintage Enfield brake is a 2mm plate across both pillars fastened to each with countersunk Allen screws.

 

[DucATIRadeon]

I've designed the pillars such that they can accept a plate if need be; seen similar constructions on several BAS and Norton brakes.

the pillars I designed have a large base (26mm dia) that rest fully on the brake plate. when the pillars are tightened on the outside "as usual" they pull the pillars into the flats. additionally, as the base flats are large they foul each other, so filing a flat on both where they foul also act as locks when tightening the nuts on the outside.

I got the idea from our CNC fixtures for clamping castings, and the operators really have to exceed the parameters when milling (increase the feedrates manually unto 150% possible) before they become "unstable". so I've good hope this approach might actually work.
worst case: going back only requires original pillars with oversize shafts that fit into the brake plates (I try to do everything in such a mannor it an be reversed, just for sake of it, using as many original fasteners/parts as possible).

 

[erik]

To my mind it is wasted time to improofe the original brakes. It is a little like to revive a mummy. Luckily there are two exellent brakes to upgrade your bike .The Speet brake and the Schmitz brake! With this brakes you have the ultimative solution! Regards Erik

 

[vibrac]

The original 7" drums are still required for racing here is our twinleading shoe arrangement for the goodwood racer
If I was looking to improve road brakes (which I am on my Comet) the Girdraulics are more than man enough for a disc brake, The cost is low and they dont look out of place. I believe something like a small Honda single brake is quite enough....

Picture bskspeedworks.co.uk

 

[erik]

@ Vibrac . If you live not on this lucky island and you have to deal with the german TÜV forget the disc brake modification . Erik

 

[ericg]

The original 7" drums are still required for racing here is our twinleading shoe arrangement for the goodwood racer
If I was looking to improve road brakes (which I am on my Comet) the Girdraulics are more than man enough for a disc brake, The cost is low and they dont look out of place. I believe something like a small Honda single brake is quite enough....

Picture bskspeedworks.co.uk

Sorry Tim but to me Honda (or any other brand) discs are definitely totally out of place on a Vincent or any other classic British bike. Same with Mikuni carbs.

 

[DucATIRadeon]

ay +1 to that!
rather have European carbs (like dellorto) and preference to those that are fuel regulating than air regulating.
disc brake wise, it works a treat, outlives a drum, lighter than a drum but not always cosmetically pleasing on pre-disc era bikes.

anyway, I'm off to improving existing brakes rather than replacement, reviving mummies or not.