This was my solution to stealthily and securely fitting a Hall effect brake sensor attachment to Sram guide lever. This would be suitable for types R, RS, RE, DB5. Perhaps RSC. A similar arrangement may be applicable to other brands of levers.
When I looked at the lever assembly there didn’t appear to be an easy, neat or really secure way to fix either the magnet or the sensor to the Sram Guide RE brake lever assembly on my electrified Boardman with Bafang BBS02, the reach adjustment of this lever really gets in the way and the master cylinder body has no decent flat surfaces.
My solution was to make a new pivot pin with integrated arm to hold the magnet. This way the sensor can be mounted with epoxy resin (having removed the sticky tape) on to the underside of the master cylinder, almost totally hidden from view and protected from damage. The pin and arm were made in the lathe from a solid piece of non magnetic stainless steel I had in stock. In my case I used a 3mm screw to retain the magnet but epoxy would do I’m sure.
In the Guide lever design the pivot pin is locked and retained to the piston push rod rocker assembly by a grub screw and as such the angle of the pin and thus the new arm is adjustable by loosening this screw, once set in position it is not effected by any change in angle set with the reach adjustment setting. This makes the subsequent setting up and locking of the sensing point relatively easy. An advantage being that no great precision is needed when fixing the sensor to the brake master cylinder body as it is adjustable after assembly. Apart from the pivot pin diameter the dimensions are not critical, in my case dictated only by the size of the piece of stainless I had lying around. The pictures should make this clear I hope.
When I looked at the lever assembly there didn’t appear to be an easy, neat or really secure way to fix either the magnet or the sensor to the Sram Guide RE brake lever assembly on my electrified Boardman with Bafang BBS02, the reach adjustment of this lever really gets in the way and the master cylinder body has no decent flat surfaces.
My solution was to make a new pivot pin with integrated arm to hold the magnet. This way the sensor can be mounted with epoxy resin (having removed the sticky tape) on to the underside of the master cylinder, almost totally hidden from view and protected from damage. The pin and arm were made in the lathe from a solid piece of non magnetic stainless steel I had in stock. In my case I used a 3mm screw to retain the magnet but epoxy would do I’m sure.
In the Guide lever design the pivot pin is locked and retained to the piston push rod rocker assembly by a grub screw and as such the angle of the pin and thus the new arm is adjustable by loosening this screw, once set in position it is not effected by any change in angle set with the reach adjustment setting. This makes the subsequent setting up and locking of the sensing point relatively easy. An advantage being that no great precision is needed when fixing the sensor to the brake master cylinder body as it is adjustable after assembly. Apart from the pivot pin diameter the dimensions are not critical, in my case dictated only by the size of the piece of stainless I had lying around. The pictures should make this clear I hope.
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