The Ultimate Brakeless/Front/Rear/How many brakes? thread

Dr. Metal,

The problem is that you are only considering what is mechanically most effective to stop you ina straight line, on impulse, in an emergency.

Have you ever experienced an experienced bike rider, somebody who can ride down a mountain, 360 down a set of stairs or jump over another bike, stop by slowing down in a straight line?

Think outside the box, your not going to have to do such a thing because an experienced rider contantly scans his lines and exits. Faced in an awkaward situation you avoid it.

For instance, im riding my bmx with a front brake only. Need to avoid an obstacle.I pull on the front brake, now I cant turn, but i've slowed down significantly, but I still hit the object at much slower speed.

This time i'm in the same situation but my bmx has a rear brake fitted. I have an obstacle to avoid. I slam by back brake, use my elgs to push the rear out sideways, slowing down But ultimately changing direction, then I bunny hop up the curb.

Much safer. You just gotta know how. Which is why faux fixies are ridiculous.

Sammy, I see exactly what you mean, but please keep in mind what I set out to do. To elucidate the mechanical efficiency of a breaking system. I dont know if you have ever done research or anything in a scientific field. It is almost impossible to get to the point where you can made a decision which holds true. All you can do is make some assumptions about your system and go from there. These are general principles, which will apply 90% of the time.

So, all I am saying, and all I have said, is that if you need to come to a safe stop asap, which translates to the shortest stopping distance there are certain systems which work better than others.

Thus the original caveat "for a equal level of skill"

Think of it this way... when can a fixie with no front brake be a better breaking system than a dual disc systen? I would imagine that there is no time you would rather a fixie with a front over a dual disc. So, the dual disc must be a better braking system, right?

Just trying to bring a little logic to this post.

R

You can't use 'logic' or pure engineering methodology on a process that involves human thought and actions.

That's what happened when ABS equipped cars were introduced and everyone was told they stopped quicker than non ABS equipped cars. They were proved wrong pretty quickly.

so... NurseHolliday

How exactly do you think that anything that was ever manufactured, designed or engineered came about?

You make informed logical decision which fit observation.

I think you need to have a better understanding of what exactly science is before you come up with a rebuttal like "you can't"

Think of it this way... when can a fixie with no front brake be a better breaking system than a dual disc systen? I would imagine that there is no time you would rather a fixie with a front over a dual disc. So, the dual disc must be a better braking system, right?

8 Pot Brembo racing calipers with ceramic discs are fucking amazing car brakes. Slightly overkill for a 100 bhp Ford Focus however. I would much rather have the standard brakes because I'd be less likely to be rear-ended by some dozy bint with normal brakes behind. The Brembos stop me quicker, and mechanically, they are the better braking system but you won't see me pining for them to drive around on the road.

so... NurseHolliday

How exactly do you think that anything that was ever manufactured, designed or engineered came about?

You make informed logical decision which fit observation.

I think you need to have a better understanding of what exactly science is before you come up with a rebuttal like "you can't"

Mate, I have knowledge, thanks. I am also an engineer, an Aerospace Engineer.

I know exactly how designs and engineering works, and I also understand the application of design, there's a difference between designing something that is mechanically amazing, and designing something that is mechanically amazing and can be used by humans.

No thats completely illogical to a serious cyclist.

I may not have spent any time scientifically testing which brake works best to slow a numpty down in a straight line, but I have for many years ridden bmx, cross country, downhill, 24", 26", road, singlespeed road, fixed front brake and brakeless. So i'd say i've got a pretty good opinion n what kind of braking systems work when you need to avoid something.

Have you seen the effects on your balance, when a rear disc locks up onto a fixed drivetrain, with your feet physically attached to the pedals. So your legs would stop or get shuddered about. You need your legs in control so you can balance correctly over the bike in order to stop or avoid. what if they lock at 12 and 6 oclock, your gonna hit the deck.

Anyway, disc brake on a road bike? that'll just make you lock out and slip anyway. 23c tyres don't have enough grip for sucha powerful system.

where did 90% of the time come from?

why stop, why not avoid?

I think this advice is only really valid for beginners.

1) Nurse,

Well done on being an engineer, an aero no less. Should point out that engineering is not a science, so you may not fully grasp the simplicity of what I am saying here. Anything in nature is a complex system, we will never be able to understand nor calculate the interactions of a multi variable system. All we can do, and all we have ever done, is make simple assumptions about the system and tailor them as best we can to the given initial conditions. This is a long way of saying... we cant measure or calculate the exact system.... but what we can tell you is thay if you want to stop a bike which is going fast, a very efficient and safe way is with a good breaking system which leaves the rider in control of the bike. There is a hierarchy of systems. Thus the list...

2) Sammy

I have been a serious cyclist for over 10 years, that includes bmx (rear and breakless), dh, ss road, road and for a short period fixie. So I am not coming from this from an abstract maths perspective. While your own idea of a good method is valid, it is subjective, and thus very difficult to quantify.

As for a disc ever locking up, thats not using it correclty. A "lock-up" on any breaking system is bad news. You can lock up on any breaking system, from breakless fixie to discs.

Think of it this way.... can you think of a single situation where a fixie with no breaks would be safer than any other breaking system. Think hard now...

And what I'm trying to say is that your list is based entirely on mechanical reasoning and not taking into account application or human interaction therefore it is pointless.

I submit references to other types of transport for your approval.

SR71 Blackbird. Mach 3.2. It flew high enough to see the curvature of the Earth, and the pilots had to wear space suits. The aircraft leaked on the ground because the panel gaps had to allow for expansion during the intense heat build up while flying at over 3 times the speed of sound. Is it better than a Boeing 747? In terms of engineering and mechanical hardship in designing and manufacturing, yes! Would I want to fly in one to go on holiday? No.

Radical SR8. Quickest production car around the Nurburgring. Immensely lightweight despite V8 engine. Ridiculous levels of mechanical grip and downforce. Is it a mechanical marvel? Is it a feat of engineering? Yes! Would I drive one to the shops? No.

10 years ago, someone once rocked up at Rom skatepark with a rear disc brake on his BMX. As a 14 year old boy I was amazed, thinking why don't more people use disc brakes on a BMX rather than these shitty U Brakes. 10 minutes later it was lying in pieces on the ground. Both he and I found out rather quickly why people don't use disc brakes on a BMX.

can you think of a single situation where a fixie with no breaks would be safer than any other breaking system. Think hard now...

Well my tiny non-science brain, didn't have to think very hard.

Rear brake is safer because you can steer out of the way.

So your list -

1) front and rear discs
2) front and rear dual pull
3) front disc
4) front dual pull
5) rear disc
6) rear dual pull
7) front & fixie
8) front & ss
9) no break fixie

Should look like this

1) front and rear discs (on a freewheel bike, offroad)
2) front and rear dual pull
3) front and fixed
4) rear disc
5) rear dual pull
6) no brake fixed
7) front dual pull
8) front disc
9) front + SS

because 7, 8 and 9 don't allow you to avoid, and if people don't know how to avoid, then I would cosnider them to be a novice cyclist. And novice cyclists can't modulate their brakes very well, so they'd also have a tendency to go over the bars (thats why front disc is worse than front dual pull)

And if your gonna talk about disc brakes, you forgot v - brakes...

Freewheel brakeless is the best.

with no tyres preferably

Much as I hate to join in here do have one question- why do people think that it is impossible to steer whilst using a lot of front brake?

Certainly if you lock the wheel up then you are buggered, but up to the point of slip/lock-up you can certainly pick which direction you are going in.

I've done a number of stoppies now in response to Londons famous Londons excellent road users, never once lost control or skidded, despite lifting the rear wheel into the air for the duration of the braking period.

Also, see Troy Bayliss round Silverstone in the pissing rain a few seasons back. LOADS of braking and steering at the front end!

because most people are wrong.

I could ride perfectly safely with a front brake on a single speed, i barely use the back brake on my roadie. Can also ride perfectly safely brakeless fixed.

A lot of people like to perpetuate rumours!

I dont see the problem with faux fixie, its your own decision.

A lot of people try to argue that brakeless fixed is just as safe or safer than other styles of riding... I don't get this, just admit, it is a bit dangerous, yes, but you do it anyway because you enjoy it. Ofcourse a front brake would make the bike safer, there is no argument.

I have riden a fixie. The most common method of stopping is a fixie skid.
According to what source? I want citations as I find this to be a woefully inaccurate statement.

1)Well done on being an engineer, an aero no less. Should point out that engineering is not a science, so you may not fully grasp the simplicity of what I am saying here
You really are a sanctimonious fuckwit aren’t you?

I am not an engineer or a scientist. I am however a mathematician and challange you to do your "science" without utilising my subject as a tool. Or, being more realistic about it, acknowledge that pure "science" isn't an adequate enough guide to make the decisions/observations that are attempting to make.
Accept the fact that as a mathematician I can provide you not only with the results that you have but also the calculations based around situation and human response, i.e. probability.
I also highly doubt that your study (Show us your proofs and calculations and we may pay a little more attention) takes into account anything as abstract as temperature fluctuation, degradation of the braking compounds used in the pads, friction between the brake cable inners & outers or poorly bled hydrolic lines.

By The way, it would help your cause if you would call it physics not just "science". MacroBiology is a science but wouldn't be very helpful in this area.

Originally Posted by dr.metal
*1)Well done on being an engineer, an aero no less. Should point out that engineering is not a science, so you may not fully grasp the simplicity of what I am saying here*

coming from the man who reckons a front brake ss is more effective at stopping than a front brake on a fixed wheel bike

you are a genius as clearly you can create stopping power from nothing, all the worlds energy problems have been resolved by Dr Metal

or perhaps the complexity of the situation is a little too much for you to grasp

barber

i have reservations about any bike with only one braking system

i had a brake cable failure on my fixed gear bike a few weeks ago, if i had not had the ability to skid as well i would have piled into the car in front of me.

its about being safe and having a failsafe/backup option, two simulataneous catastrophic failures are less likely than one.

I thought your backup option was to run into german bankers?

^ They're a bit heavy, you can only really carry one.

its threads like this that remind me why I got the internet

There's goat porn in the thread? What breed?

if you can't tell, you don't deserve internet

I wonder if dr.metal has ever told a bike mechanic that he knows more about bikes because he's an engineer.

Sounds more like a first year engineering student...

Much as I hate to join in here do have one question- why do people think that it is impossible to steer whilst using a lot of front brake?
.

It is easier to lock-up/skid the front if you trurn it away from the direction of your momentum. Wether or not this actually happens is depend on the conditions, your brakes, and you i suppose.

Bit busy, but this should do

BSc Theoretical Physics
MSc Computational Physics
PhD “Maximizing braking efficiency of commercial jets with novel systems architectures”
4+ years experience in R&D

Thus,

me>you