IMA THUMB BRAKE?

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B Topp said:
So I ran into the issue with the similar Brembo PS13 master with the integrated reservoir. I started with the thumb brake reservoir mounted next to the clutch reservoir but found that if I hit the foot brake it would just push the fluid up to the thumb brake reservoir and if I hit the thumb brake it would push the fluid into the foot brake reservoir. Turns out there is no valve installed on the PS13 to prevent that. So I had to get the different foot master cylinder and use just the thumb brake reservoir to supply fluid to both the thumb and foot brake.
View attachment 42410View attachment 42411View attachment 42412

Now I have both thumb brake and foot brake. Just don't hit them both at the same time as fluid can get past the seal in the foot master cylinder.
Click to expand...

I never use the foot brake so I think we’ll just save the weight and take it off.

man’s yeah I was bummed we wouldn’t be using that cool ass $1500 rear master cylinder….that’ll probably go for sale to some old school track rat.

I think right now we are running two IMA rear brake MC’s.



I take that back, the one instance where I use the foot brake is stopped at a light on a hill
 
B Topp said:
So I ran into the issue with the similar Brembo PS13 master with the integrated reservoir. I started with the thumb brake reservoir mounted next to the clutch reservoir but found that if I hit the foot brake it would just push the fluid up to the thumb brake reservoir and if I hit the thumb brake it would push the fluid into the foot brake reservoir. Turns out there is no valve installed on the PS13 to prevent that. So I had to get the different foot master cylinder and use just the thumb brake reservoir to supply fluid to both the thumb and foot brake.
View attachment 42410View attachment 42411View attachment 42412

Now I have both thumb brake and foot brake. Just don't hit them both at the same time as fluid can get past the seal in the foot master cylinder.
Click to expand...

good info, we toyed with the idea of using both the PS13 and IMA MC’s but scrapped it on complicated mock up.

didn’t even know about the fluid back flow issue, I’m sure there is a plumbing work around that would work, but just not worth sorting through a solution without a problem with so little use of that foot brake
 
That's an option for sure and I was initially going to do that, but the thumb brake (at least the HEL unit I am running) does not generate nearly the same braking force that the foot brake can generate. Your foot can apply a shitload of more leverage to the foot peddle compared to just your thumb. So I find that the thumb brake will provide little braking performance when compared to the foot unit (at least on my bike with the available mounting space is limited and the lever needed to be modified/ shortened which would definitely effect the available leverage able to be applied to the thumb master cylinder.).
 
There is a “one way” check valve for the PS13 if you’re using the additional master. Without it, the dual port 13 is a pass through system. There is a force multiplier equation for the foot and thumb brake application based on MC size and lever arm so in comparison, (foot pressure vs finger pressure) that would have to be factored to draw a conclusion on system effectiveness.

In general, precision and sensory modulation is more accurate with hands than feet. I am at the moment playing with a very non intrusive push button auto shifter. It is extremely fast and obviously for ergonomic considerations, potentially beneficial for some which I gather is the main benefit of the thumb brake setup. These options allow adjustability for the variability in the individuals biomechanics
 
B Topp said:
That's an option for sure and I was initially going to do that, but the thumb brake (at least the HEL unit I am running) does not generate nearly the same braking force that the foot brake can generate. Your foot can apply a shitload of more leverage to the foot peddle compared to just your thumb. So I find that the thumb brake will provide little braking performance when compared to the foot unit (at least on my bike with the available mounting space is limited and the lever needed to be modified/ shortened which would definitely effect the available leverage able to be applied to the thumb master cylinder.).
Click to expand...

agreed, but then I was thinking how much brake force do you actually need in the rear?

no matter how good I ever become at the track on this bike I can’t see using the rear brake for more than wheelie control and maybe some light touch trail braking into a corner.

the rear brake for me is for finesse, and needs to be able to be easily modulated, not so much for raw stopping power, but for light touch applications.
 
Steven31371 said:
agreed, but then I was thinking how much brake force do you actually need in the rear?

no matter how good I ever become at the track on this bike I can’t see using the rear brake for more than wheelie control and maybe some light touch trail braking into a corner.

the rear brake for me is for finesse, and needs to be able to be easily modulated, not so much for raw stopping power, but for light touch applications.
Click to expand...

That’s all that’s needed since there’s hardly any weight on the rear during corner entry.


Sent from my iPhone using Tapatalk
 
True. It has not been an issue for me as I really don't use the rear brake much. I cant wheelie for .... anyway so I'm not that concerned about using it for that. I do find it easier to use though than the foot control. I do like the ergonomics of the thumb brake and find it easy to actuate. Definitely cant lock the rear with the one I'm using in its current configuration. Overall I like it but have to admit it might be a bit of a novelty on my bike as I'm a 99.5% front brake guy.
 
Alkhater said:
That’s all that’s needed since there’s hardly any weight on the rear during corner entry.


Sent from my iPhone using Tapatalk
Click to expand...

what I’m IMAGINING doing is going hard on the front brakes entering a braking zone, while simultaneously lightly to moderately on the rear brake, then instead of trail braking the front brake deep into the curve lightly release it on turn in WHILE keeping the rear brake on to trail brake.

if done properly with the right timing it might prevent a novice rider like me from messing up front trail braking, overloading the front wheel going down, and from years of dirt bike riding when I was younger I’m much more confident recovering a rear wheel slide than a front wheel slide lol

having said all that, I’ve watched as many videos as I can find of professional riders using the Thumb brake, they never use it on corner entry or in the braking zone leading up to the corner, only coming off the Apex for light touch anti-wheelie control.
 
endodoc said:
There is a “one way” check valve for the PS13 if you’re using the additional master. Without it, the dual port 13 is a pass through system. There is a force multiplier equation for the foot and thumb brake application based on MC size and lever arm so in comparison, (foot pressure vs finger pressure) that would have to be factored to draw a conclusion on system effectiveness.

In general, precision and sensory modulation is more accurate with hands than feet. I am at the moment playing with a very non intrusive push button auto shifter. It is extremely fast and obviously for ergonomic considerations, potentially beneficial for some which I gather is the main benefit of the thumb brake setup. These options allow adjustability for the variability in the individuals biomechanics
Click to expand...

that would be cool, though I have to admit I actually like blip shifting with the foot, I have it in reverse GP style, which for me always felt more intuitive than standard up down.

still though, I think ultimately the less you have to do with your feet other than positioning to lean the bike the more efficient things would be. Easier and ultimately faster.

I’m thinking of an E-Bike where you never have to even consider shifting, and can focus solely on your line, braking, lean etc.

IF you decide to have some limited gearing in an E-bike a push button would be a good option, but usually in electric applications there is only one additional gear, an overdrive sort of function for high end top speeds…so essentially two gears
 
endodoc said:
There is a “one way” check valve for the PS13 if you’re using the additional master. Without it, the dual port 13 is a pass through system. There is a force multiplier equation for the foot and thumb brake application based on MC size and lever arm so in comparison, (foot pressure vs finger pressure) that would have to be factored to draw a conclusion on system effectiveness.

In general, precision and sensory modulation is more accurate with hands than feet. I am at the moment playing with a very non intrusive push button auto shifter. It is extremely fast and obviously for ergonomic considerations, potentially beneficial for some which I gather is the main benefit of the thumb brake setup. These options allow adjustability for the variability in the individuals biomechanics
Click to expand...

What shifter are you running?
 
Steven31371 said:
what I’m IMAGINING doing is going hard on the front brakes entering a braking zone, while simultaneously lightly to moderately on the rear brake, then instead of trail braking the front brake deep into the curve lightly release it on turn in WHILE keeping the rear brake on to trail brake.

if done properly with the right timing it might prevent a novice rider like me from messing up front trail braking, overloading the front wheel going down, and from years of dirt bike riding when I was younger I’m much more confident recovering a rear wheel slide than a front wheel slide lol

having said all that, I’ve watched as many videos as I can find of professional riders using the Thumb brake, they never use it on corner entry or in the braking zone leading up to the corner, only coming off the Apex for light touch anti-wheelie control.
Click to expand...

My advice, forget about rear brake finesse. If you can train yourself to lightly use it whenever you brake it will maybe help keep the rear in line but its not going to be an issue until you are really pushing it. You also are not going to flip the bike without using it, nor are you going to overload the front tire no matter how hard you work it unless you are really cranked and trailbraking super late (i.e panic mode).

I'd love a thumbbrake as you can do "experiments" in handling with it, a lot of the time the rear is not giving much feedback via the boot.
 
Steven31371 said:
what I’m IMAGINING doing is going hard on the front brakes entering a braking zone, while simultaneously lightly to moderately on the rear brake, then instead of trail braking the front brake deep into the curve lightly release it on turn in WHILE keeping the rear brake on to trail brake.

if done properly with the right timing it might prevent a novice rider like me from messing up front trail braking, overloading the front wheel going down, and from years of dirt bike riding when I was younger I’m much more confident recovering a rear wheel slide than a front wheel slide lol

having said all that, I’ve watched as many videos as I can find of professional riders using the Thumb brake, they never use it on corner entry or in the braking zone leading up to the corner, only coming off the Apex for light touch anti-wheelie control.
Click to expand...

What you’re imagining will cause the bike to run wide and miss the apex once you release the front brakes.

You’re on the right line of thought up until turn in where you want the rear break to aid in the angle of corner entry… any use of the rear brake after this point will cause the bike to run wider than it would without its use unless the rear is sliding.

Riding style also plays a big factor in this… a point and shoot style for example may utilize the rear brake further into the entry of a corner, inducing a moderate slide to angle the bike for the exit. In any case it’s in concert with the front brakes.

In no case should the rear be used alone at or pre-apex as it will cause a wider line.


Sent from my iPhone using Tapatalk
 
bp_SFV4 said:
This.
Click to expand...
Ha, yes this is a modified version of the Translogic PSR. A few mechanical and electronic mods. Should be on the bike in the next 30 days. I’m currently using a Nova gearbox and Nova gearbox component group with a modified RS drum and selector assembly. This is an extremely smooth gearbox and a vary precise operation. I’m hoping to achieve somewhat of seamless gearbox from an operational perspective with instantaneous up/down sequencing while negating much of a weight penalty by using light weight materials.

It’s just another project with potential benefits. Currently, no matter what, you have to have a specific foot position for a gear change. With a Tip-Tronic setup, your left foot has options it normally wouldn’t have and the electro-mechanical actuator is lightning fast.
3F41A393-49B2-4211-994B-5ED1C378FA7E.jpeg
 
endodoc said:
Ha, yes this is a modified version of the Translogic PSR. A few mechanical and electronic mods. Should be on the bike in the next 30 days. I’m currently using a Nova gearbox and Nova gearbox component group with a modified RS drum and selector assembly. This is an extremely smooth gearbox and a vary precise operation. I’m hoping to achieve somewhat of seamless gearbox from an operational perspective with instantaneous up/down sequencing while negating much of a weight penalty by using light weight materials.

It’s just another project with potential benefits. Currently, no matter what, you have to have a specific foot position for a gear change. With a Tip-Tronic setup, your left foot has options it normally wouldn’t have and the electro-mechanical actuator is lightning fast.
View attachment 42413
Click to expand...

Very cool!
 
I just did a track day where Toni Elias was providing lectures and he said he uses his thumb brake all the time, with typical braking force at 60% F and 40% R. He does this to "settle" the bike.
When I asked him if a particularly "technical" track was the most appropriate place to have/use a thumb break, he looked at me oddly and stated, every track bike should have a thumb brake and it should be used on every track.
 
We're coming up on age 3. Just saying. I've got expectations keeping up with tradition.
🍈🍈
 
endodoc said:
Ha, yes this is a modified version of the Translogic PSR. A few mechanical and electronic mods. Should be on the bike in the next 30 days. I’m currently using a Nova gearbox and Nova gearbox component group with a modified RS drum and selector assembly. This is an extremely smooth gearbox and a vary precise operation. I’m hoping to achieve somewhat of seamless gearbox from an operational perspective with instantaneous up/down sequencing while negating much of a weight penalty by using light weight materials.

It’s just another project with potential benefits. Currently, no matter what, you have to have a specific foot position for a gear change. With a Tip-Tronic setup, your left foot has options it normally wouldn’t have and the electro-mechanical actuator is lightning fast.
View attachment 42413
Click to expand...

How is this going @endodoc almost a year later? I would love to see that.
 

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