[speedfinn]

I don't agree with the loading. Your tieing max brake force being directly portion to load it's not

Unless your rear is off the ground you don't have 100% of the load on the front.

If you start with 50/50 and add rear brake would it not be more like 65r/35f

Aaaaand back to the circle...
Braking with front or rear brake causes deceleration, and deceleration causes load transfer, and load transfer increases load on front.
Brake/ Deceleration > Load transfer > Increases load on front

Simplified model does not include engine brake, drag, rolling resistance, etc.

If you start with 50/50 and add rear brake 0...max, then load will be 50...33.3% r / 50...66,7% f.

That is also the reason why rear brake has only max 33.3% (0.33G) of the "stopping power" what front brake (1.0G) has.
That is why stopping distance (100-0 kmh ~120 m) with rear brake is three times longer than with front brake (100-0 kmh ~40 m).

Do you agree?

 

[Dylan Code]

Regarding the rear brake's effect on the rear suspension, here is a bicycle video that can be useful to the discussion:

 

[z00]

Simplified model:
Wheelbase 1400 mm
CoG height 700 mm
Weight distribution 50% / 50%
Friction coefficient 1.0

1. When traveling at constant speed:
Load on rear 50%, load on front 50%
Do you agree? Modern sportbikes are front biased 51-53%F to 49-47%R, but for the sake of simplicity 50/50 is fine.

2. Maximum front braking:
Load on rear 0%, load on front 100%
Do you agree? For stable braking, rear needs to be on the ground, so load won't be 100% on front. You don't see pro riders raising the rear at the end of every straight. So for realistic track riding disagree, from a theoretical physics perspective agree.

3. Maximum rear braking:
Load on rear 33.3%, load on front 66,7%
Do you agree? Your ratios are for stopping power, not load. Look at your 50/50 weight distribution above. Load on rear will be more than 33.3% with max rear braking.

Why do you assuming load on front/rear is equal to stopping ratio of front/rear brakes? Braking stopping power is not equal to load on wheels. Did you mean to say the load transfer amount not total load? To make your simple model work, can you specify if bike is leaned or upright? And separate brake stopping power ratios from load. But go on, I'm curious to see where you are going with this.

Regarding the rear brake's effect on the rear suspension, here is a bicycle video that can be useful to the discussion:

How do you see this affecting mid corner and load transfer?
It goes against from what I observed from dyno video I posted. Does this mean the rear compresses under both acceleration or braking? I thought only under acceleration. It pulls down under braking.

 

[speedfinn]

Why do you assuming load on front/rear is equal to stopping ratio of front/rear brakes? Braking stopping power is not equal to load on wheels. Did you mean to say the load transfer amount not total load? To make your simple model work, can you specify if bike is leaned or upright? And separate brake stopping power ratios from load. But go on, I'm curious to see where you are going with this.

You should first understand longitudinal forces; the connection between front brake, load transfer and rear brake, before we add lateral forces to the simplified model. Otherwise you are totally lost.

You don't see pro riders raising the rear at the end of every straight.

Well, you would be surprised, if you check some data from a pro.

Load on rear will be more than 33.3% with max rear braking.

From where does this magical load "more than 33.3%" come from?
Why rear brake has only max 33.3% (0.33G) of the "stopping power" what front brake (1.0G) has?
Why stopping distance (100-0 kmh ~120 m) with rear brake is three times longer than with front brake (100-0 kmh ~40 m)?

Or why you have two big brake disks in front, and a small single brake disk at rear?
Or why you use front brake only in track riding?

 

[speedfinn]

And if someone wants to be even more confused, here is simplified model front/ rear braking ratio vs maximum deceleration.

How to read;
First choose friction (black)
Then braking ratio F/R (red)
Then check maximum deceleration (blue)

For example:
Rear tyre friction 1, braking ratio 0/100, result max 0.33g.
Rear tyre friction 1, braking ratio 25/75, result max 0.4g.
Rear tyre friction 1, braking ratio 50/50, result max 0.5g.
Rear tyre friction 1, braking ratio 75/25, result max 0.66g.
Rear tyre friction 1, braking ratio 100/0, result max 1.0g.

 

[z00]

No one is denying front brake has the most braking power. You are going off topic on your own tangent. The purpose of this thread is rear brake applications, not Front Vs rear brake stopping power.
Plenty of videos and data show pro riders don't lift the rear into every hard braking corner. It happens on occasion, not intentional. Breaking the rear loose is expected when load is on the front. Not the same as having the rear completely off the ground.

Let's stay on topic. What about front, rear, load transfer in your simple model in regards to rear brake?

 

[corkgsxr]

Ride down the road press rear brake the rear end squats. How does it squat and still manage to make the rear lighter?

 

[speedfinn]

No one is denying front brake has the most braking power. You are going off topic on your own tangent. The purpose of this thread is rear brake applications, not Front Vs rear brake stopping power.
Plenty of videos and data show pro riders don't lift the rear into every hard braking corner. It happens on occasion, not intentional. Breaking the rear loose is expected when load is on the front. Not the same as having the rear completely off the ground.

Let's stay on topic. What about front, rear, load transfer in your simple model in regards to rear brake?

Aaaaand back to the circle...
Braking with front or rear brake causes deceleration, and deceleration causes load transfer, and load transfer increases load on front.
Brake/ Deceleration > Load transfer > Increases load on front (easyer to break the rear loose)

 

[speedfinn]

Ride down the road press rear brake the rear end squats. How does it squat and still manage to make the rear lighter?

So you are asking why Brake/ Deceleration > Load transfer > Increases load on front (makes the rear lighter) ?

 

[Elk]

Let's stay on topic.

Keep up the good fight, z00. Perhaps at some point you will obtain some useful information.

 

[TampaS1KRR]

https://c.tenor.com/cz4tOBk-HK0AAAAM/rowing-boat.gif

 

[TampaS1KRR]

https://c.tenor.com/cz4tOBk-HK0AAAAM/rowing-boat.gif

 

[z00]

We are not getting anywhere @speedfin. You keep repeating yourself. We covered that part.

I already bought the thumb brake system, no foot lever. First test at the end of March at VIR.

 

[corkgsxr]

So you are asking why Brake/ Deceleration > Load transfer > Increases load on front (makes the rear lighter) ?

That's not what I sed. Rear squats with rear brake. Does this increase or decrease the % weight towards front or rear.

The hint rear squats.

 

[speedfinn]

That's not what I sed. Rear squats with rear brake. Does this increase or decrease the % weight towards front or rear.

The hint rear squats.

The hint; there are multiple forces/ mechanics acting in rear, which causes multiple different things.
One of them is Brake/ Deceleration > Load transfer > Increases load on front (makes the rear lighter).

And yes, rear brake also causes other forces and things, not only load transfer.

You can also confuse yourself more with opposite action, throttle/ acceleration, when load transfer increases load on rear, but also some other magical force causes rear to anti-squat.
OMG, how is that possible?

 

[bmwbadboy]

Keep up the good fight, z00. Perhaps at some point you will obtain some useful information.

Unlikely

 

[bmwbadboy]

We are not getting anywhere @speedfin. You keep repeating yourself. We covered that part.

I already bought the thumb brake system, no foot lever. First test at the end of March at VIR.

Congrats!
Just make sure you don't pay double to that silly mechanic of yours to fit it

 

[speedfinn]

We are not getting anywhere @speedfin. You keep repeating yourself. We covered that part.

Load on rear will be more than 33.3% with max rear braking.

If you want to proceed, can you explain;
From where does this magical load "more than 33.3%" come from?

 

[corkgsxr]

The hint; there are multiple forces/ mechanics acting in rear, which causes multiple different things.
One of them is Brake/ Deceleration > Load transfer > Increases load on front (makes the rear lighter).

And yes, rear brake also causes other forces and things, not only load transfer.

You can also confuse yourself more with opposite action, throttle/ acceleration, when load transfer increases load on rear, but also some other magical force causes rear to anti-squat.
OMG, how is that possible?

Well we have finally got you to admit there's more than just load flying to the front at every action. That's a tiny bit of progress.

So riding in a straight line and apply rear brake does rear load increase

 

[speedfinn]

Well we have finally got you to admit there's more than just load flying to the front at every action. That's a tiny bit of progress.

So riding in a straight line and apply rear brake does rear load increase

Riding in a straight line and applying rear brake does not increase rear load.
Braking causes deceleration, and deceleration causes load transfer, and load transfer increases load on front.

And yes, rear brake also causes other forces and things, not only load transfer.