Thumb brake

Fitting a thumb operated rear brake in place of the usual foot brake is simple in principle but in practice can be a bit of an exercise. The theory is that you fit a small lever operated master cylinder to your handlebars or fork legs, along with a fluid reservoir, then run a hydraulic pipe down to the rear caliper.... job done. The result is never as powerful as a foot operated lever but is often more than adequate.

The 961 Cafe has no fairing so the headlight sits on hefty brackets which rule out fitting a fork mounted thumb brake so I opted for a GP Tech handlebar setup which uses a Brembo 13mm master cylinder. The Cafe's clip-ons are quite cramped but I managed to find 12mm spare bar on which to mount the lever.... then came the real problem, avoiding having the lever crunch into that lovely sculpted tank at full lock, and avoiding the master cyl. and pipework of the existing hydraulic clutch. The result was that I had to cut and shape the GP Tech mount and fabricate an alloy extension mount in order to avoid all the obstacles and still give me a lever in an accessible position.

The 961 now has ABS so rather than run my hydraulic pipe straight down to the caliper I had to have it link up with the ABS unit. On my other bike (also ABS) I decided to route my new pipe down to the foot operated master cyl. pipe and 'join' the new/old pipes together using a simple union made from ally plate, drilled and tapped to take two hydraulic banjos (and the brake light switch) and shaped such that it is it's own bracket for mounting on the frame. This setup was a success so I deployed the same tactics for the 961. Doing it this way means that if I need to quickly revert back to standard then all the original pipework and wiring is undisturbed.

I think I got this one just about right and the view from the cockpit is still quite appealing

That looks like a very designed system.
Does the MOT hassle you when you have to take the bike to get an inspection?

BritTwit said:

That looks like a very designed system.
Does the MOT hassle you when you have to take the bike to get an inspection?

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They don't hassle about the positioning of the lever, they are only interested in the braking efficiency. These two bikes are my first venture using a thumb lever and I am hoping will pass the MoT but I must admit the efficiency of them is borderline, they wouldn't lock the rear wheel on tarmac.... but more than enough for everyday road use which is what I am interested in. If they fail a test then I will put the foot lever back on, bleed the brakes and offer it for a retest all in the same day

Very neat.

MxMartin said:

..I must admit the efficiency of them is borderline, they wouldn't lock the rear wheel on tarmac.... but more than enough for everyday road use which is what I am interested in.

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That really is all that is needed from the rear brake.

Well done. I've often wanted a thumb brake.


Those who discount the rear brake are missing a trick. I use it to (1) control chain snatch on entries, (2) to control wheel spin on exits, (3) to enhance damping and reduce wheel chatter, and to hold the bike upright when front wheel traction is dicey.

xbacksideslider said:

Well done. I've often wanted a thumb brake.


Those who discount the rear brake are missing a trick. I use it to (1) control chain snatch on entries, (2) to control wheel spin on exits, (3) to enhance damping and reduce wheel chatter, and to hold the bike upright when front wheel traction is dicey.

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Adding a thumb brake in addition to the foot brake is becoming popular with the circuit riders and stunt riders for just those reasons you state, especially when your body is positioned where you cannot physically make contact with the foot lever. There are simple tricks to link the hydraulic pipe from thumb brake into the reservoir port of the foot master cylinder, effectively the reservoir of the thumb brake then becomes the reservoir of the foot brake, but the parts aren't readily available and most folk machine their own adaptors. GP Tech make these adaptors but I don't know if they would be legal here in the UK (and void your insurance) so I simply discard the foot brake completely.

xbacksideslider said:

Well done. I've often wanted a thumb brake.


Those who discount the rear brake are missing a trick. I use it to (1) control chain snatch on entries, (2) to control wheel spin on exits, (3) to enhance damping and reduce wheel chatter, and to hold the bike upright when front wheel traction is dicey.

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Strewth. If I added that lot to the list of things I’m already concentrating on during cornering, I think I’d black out...!

Try it.

On hot entries, just before you chop the throttle, lightly "cover" the rear brake . . . . the rear wheel won't have that little slip when the chain throws compression braking at it. Covering the brake keeps the taught side of the chain on top.

On exits, if your engine hits hard and you're fighting spin, it's simpler to whack the throttle open and modulate how much power is put to the ground with your foot instead of your hand; I learned this riding peaky two strokes.

The rear brake can also be "the poor man's Konis;" this seems to work better if you don't have a floating rear brake, as "covering" the brake binds up the swing arm's up and down motion; I learned this riding Ducati singles where it seemed to help with wheel chatter.

As for helping with keeping the front wheel upright - dirt riding in the mud, when trying to turn but the front wheel's packed with mud, or going down steep slippery hills.

xbacksideslider said:

Try it.

On hot entries, just before you chop the throttle, lightly "cover" the rear brake . . . . the rear wheel won't have that little slip when the chain throws compression braking at it. Covering the brake keeps the taught side of the chain on top.

On exits, if your engine hits hard and you're fighting spin, it's simpler to whack the throttle open and modulate how much power is put to the ground with your foot instead of your hand; I learned this riding peaky two strokes.

The rear brake can also be "the poor man's Konis;" this seems to work better if you don't have a floating rear brake, as "covering" the brake binds up the swing arm's up and down motion; I learned this riding Ducati singles where it seemed to help with wheel chatter.

As for helping with keeping the front wheel upright - dirt riding in the mud, when trying to turn but the front wheel's packed with mud, or going down steep slippery hills.

Click to expand...

Are you female by any chance?

It’s just that you are clearly far better at ‘multi tasking’ than me...

I’d think myself into the gravel doing that !