8 inch 4ls front brake
There are also other brakes for Vincents on the market, but I decided against them. The weight gain is counter-productive and the ‘looks’ of others do nothing to complement the beautiful image of a standard Vincent. Having said this, maybe I am just too traditional and old fashioned.
Consequently, I have spent 18 months designing a completely new 8-inch braking system using all modern German casting and CNC machining techniques to very tight tolerances. My design minimises weight and keeps all of the “workings” internal to the aluminium alloy brake drums/plates while using the standard iconic balance-beam.
A prototype variant of the new brake has been in use for rigorous testing for a while now and the first production batch of components is currently being delivered. Read on for more detail.
- First of all the drums are composite, which means they are not as original made from cast iron but are cast in aluminium with a cast iron liner to work as the brake surface.
(Similar to Series A racing brakes!)
- The drum is more than 1.1 kg lighter a piece than the 8 inch cast iron drum that is available from another source, therefore vastly reducing unsprung mass at the front of a Vincent compared to this other 8 inch brake.
- The drum is even 0.4 kg lighter than a 7 inch shadow drum.
- Aluminium alloys can only store about a quarter of the heat of cast iron and alloy dissipates heat much better than cast iron. Therefore the risk of brake fading is also vastly reduced in a composite drum compared to a cast iron one.
- Due to the increased diameter the leverage of the braking force applied at the contact point of the brake compound to the drum is creating a bigger brake momentum which results in better breaking.
- The surface of the breaking compound is enlarged over a standard brake by about 60 % due to an increase in width as well as arc length of the breaking compound, while keeping the same lining angle as original.
- Brake plates are also cast aluminium and fully heat treated with very substantial webbing inside. They are far more rigid and practically flex free compared to standard steel plates.
- They have an integral machined water excluder which is more substantial than the original and therefore less likely to bend.
- Brake cams turn in sintered bronze bushes, in case of excessive wear those bushes can be replaced.
- Everything fully CNC machined to very fine tolerances , less than half a thou.
- The brake shoes are also cast from high spec aluminium alloy and fully heat treated before getting jig machined.
- Contrary to the original design they have five stiffening ribs each side as well as a very hefty central spar. The rigidity is far exceeding the original design with practically no flex compared with the very weak original design.
- To increase longivety and to overcome the potential risk of metallurgic oxidation between the alloy and the stainless anchor pin, the shoes pivot in sintered bronze bushes as well.
- On the brake cam end the shoe has a detachable wear pad. After using up some of the breaking compound, the wear pads can be removed and shims placed underneath to restore the original free movement on the brake lever. There is no need to adjust the brake cable and thereby tilting the brake cam to pre-engage the shoes. Therefore there should be no brake lever return springs and no balance beam stop necessary.
Brake cam, linkage, pins, etc
- All innards are CNC machined or laser cut from stainless steel.
- Pins are fitted into the bridge plates by a combination of a heatshrink and press process. They are drilled to reduce weight.
- All pins are deeply spigotted into the alloy plates.
- The geometry of the brake cam and lever angles as well as the inner connecting links are guaranteed by jigwelding of all components. There is no need for any adjustment.
- Every cam rotates in sintered bronze bushes.
- The hubs are fully machined from solid and the visible parts have the original measurements.
- Hubs have the necessary centering flange for the spoke flanges as well as the drums.
- Fitted with German branded metric bearings which are proven and readily available.
- Supplied completely with hollow axle, taper rollers, shims, wheel nuts and Nilos rings.
- Bearings already fitted and shimmed.
- Made from stainless steel and bought in from supplier.
- Every flange get finished by reaming hole diameters, rectifying possible concentricity runout between pcd and center hole.
Special hub bolts (longer) are CNC machined from stock in V70 stainless quality, supplied with stainless lock nuts.
Also supplied are hub spacers in different thicknesses. Due to different sources of spokes today, sometimes the spokes touch the rear of the drum exiting the spoke flange. This way you cannot mount the drum properly on the hub. These spacers help you to solve this problem should it occur to you.
- due to the increased brake diameter, the brake cables need to be about 3/4 on an ich longer than the standard cables. We are still waiting for a quotation of first class brake cables, they will hopefully be available soon.