First off on Thursday - and a pretty good one for a first!!

FoldingJoe

Had my first off on Thursday, and totally my own fault!!!

Approaching the Rotherhithe roundabout up Lower Road around 7.15-7.30am, following another cyclist and the traffic was stationary in the outside lane. As we approached the bus stop a black cab pulled out in front of us.

Cyclist in front of me managed to get on the brakes in time and stop before hitting the back of the cab, but by time I was on the anchors it looked like I would hit him, so in a vain attempt to stop from going into the back of the cyclist in front grabbed too much front brake and went straight over the bars!!!! :oops:

To the guy in front of me:

Thanks for not stopping to;

a.) check that I was OK
b.) thank me for not going into the back of your bike
c.) just have a laugh in my face for being an absolute knob.

The upshot was I was winded, so managed to pick myself up, catch my breath, and cycle into work.

Once in the office the whole of my right side started to stiffen up, and it was at that point when a colleague mentioned my hand was like a balloon that I thought it would be better to go to A&E.

Outcome is a fractured arm (radial head) and probable cracked ribs!!!

Anyway, probably best to get a good one out of the way first, hopefully the ones to come won't be so painful... :roll:

Off to take another couple of Co-dydramol.

FJ

mtb-idle

ouch, sorry to hear that..

Get well soon.

deptfordmarmoset

Does ''totally my own fault'' mean ''totally my own fault not to expect a taxi to pull a stupid manoeuvre with no consideration for the safety of any other road user?''

gllewellyn

Never mind your injuries - is the bike ok?

Seriously though, hope you're better soon

FoldingJoe

Well, I figured if the guy in front was able to stop without major incident then I should have been able to do the same.

Bike is it a bit scraped on the right, and probably needs a new rear mech as it is pretty bent.

Koncordski

Ouch, bad luck mate. I tend to brake more or less always with the front, just a spot of luck that i haven't had to clamp it on. After your story i'll do my best to try using the back stoppers!

davis

FoldingJoe wrote:

Bike is it a bit scraped on the right, and probably needs a new rear mech as it is pretty bent.

It's probably the (sacrificial) hanger that's bent, not the mech. Get a couple; they're not huge amounts of money but they're frame-specific so they might stop being made.

cloggsy

:shock: Ouch! :shock:

Get well soon fella!

pdw

Koncordski wrote:

I tend to brake more or less always with the front, just a spot of luck that i haven't had to clamp it on. After your story i'll do my best to try using the back stoppers!

On a dry road, front only is the fastest way to stop.

optimisticbiker

pdw wrote:

Koncordski wrote:

I tend to brake more or less always with the front, just a spot of luck that i haven't had to clamp it on. After your story i'll do my best to try using the back stoppers!

On a dry road, front only is the fastest way to stop.

Without wanting to detract from the OP's accident (get well soon btw) I disagree. On what do you base this 'fact'?

gb155

ouch, bad luck dude GWS

secretsam

I blame the woman in yellow.

(PS: GWS, bad luck mate, did you clock the taxi's number?)

mudcovered

OptimisticBiker wrote:

On a dry road, front only is the fastest way to stop.

Without wanting to detract from the OP's accident (get well soon btw) I disagree. On what do you base this 'fact'?[/quote]
Um. Physics.

http://sheldonbrown.com/brakturn.html covers it well.

Only time I ever use my back brake is on loose surfaces and when I'm just trying to maintain a speed on a downhill. The only real trick to using the front brake exclusively is getting your weight over the back wheel and ensuring that your arms are braced for the force required.

Why do you think cars and motorbikes (and a lot of MTBs) have much better front brake systems than on the back. The reason is that the payoff for the better system is much better there than on the back (where it just makes it easier to lock a wheel).

Mike

thecrofter

Hope you recover quickly.

To head off topic, the fastest way of stopping is to use both brakes, the majority of braking is done through the front with a touch of back brake to keep everything in line. Just ask any motorcyclist. Same rules apply.

EKE_38BPM

GWS FoldingJoe.

Optimisitic Biker, picture the scene:
You are riding along when something causes you to perform an emergency stop e.g. a dog runs into your path. You apply the brakes as hard as you can to avoid a collision. What happens next? Your back wheel lifts and only your supreme sense of balance/self preservation keeps you from flying over the handlebars.

While your back wheel was in the air, how much braking force was it providing? Thats right, none.

The back brake is good for regulating speed but in an emergency rely on your front.
Have a look at any car, truck, motorbike etc and you will see that the front brake is MUCH beefier than the rear. The front usually provides about 85% of the braking force in a motor vehicle and I would say it is at least the same on a bike.

BTW, on my fixie I only have a front brake. General speed regulation is provided with my legs (not leg braking, just not pedaling slower so that the bike slows). Stopping is done with the front brake.

And for clarity, anyone riding brakeless will probably win a Darwin award at the first emergency.

bails87

Yep, as others have said, when you brake your weight is shifted forwards, so the harder you're braking, the less your rear brake is doing.

I'm honestly suprised people who do any decent amount of riding don't know this stuff.

Maybe it's because it's more noticeable on MTBs, where wheels get off the ground more often. The quickest you can decelerate is with your back wheel hovering in the air. Brake any harder and you'll be eating tarmac, brake any less and...well, you could brake more.

On wet/greasy/icy surfaces it's obviously much easier to lock a wheel.

unixnerd

Also worth mentioning that in that situation I think a lot of folk;s reaction would be to sit up as high as possible whilst braking. This raises your centre of gravity making a trip over the bars more likely. What you want to do it lower your CoG and move it as far back as possible.

Have a look at 8:12 in http://www.youtube.com/watch?v=2E544BcanO4

pdw

EKE_38BPM wrote:

The front usually provides about 85% of the braking force in a motor vehicle and I would say it is at least the same on a bike.

Yep - you can't do a stoppie in a car. Wheelbase is too long, and CofG too low. In other words, the front wheels will lock before the car rolls over forwards, so even at the limit of traction on the front, there's still some weight on the rears that you can use for braking.

On a bike, that's not the case.

thecrofter wrote:

To head off topic, the fastest way of stopping is to use both brakes, the majority of braking is done through the front with a touch of back brake to keep everything in line. Just ask any motorcyclist. Same rules apply.

A locked up rear wheel won't keep you in line, so the quickest way to stop and keep in line is front only, but not enough to lift the rear.

A better reason to use a little bit of rear is that it allows you to feel how much traction you've got at the rear by feeling how much braking is required to get the wheel to lock.

optimisticbiker

thecrofter wrote:

Hope you recover quickly.

To head off topic, the fastest way of stopping is to use both brakes, the majority of braking is done through the front with a touch of back brake to keep everything in line. Just ask any motorcyclist. Same rules apply.

I agree... modelling it crudely in a simple structural modeling tool shows that as long as the rider can keep his arms braced so that he retains weight on the rear wheel there is a point where maximum deceleration occurs using both brakes which is greater than that achieved by the front wheel alone. Having said that, knowing where that point is in practice may be harder to judge than simple modulating the front brake enough to keep from going over the bars... so while Sheldon may be 'real-world' correct, his grasp of physics isn't as good as some might believe. I guess its easier to find the point on a motorbike as you have a lot more weight in the bike compared to the rider...

bails87

pdw wrote:

A locked up rear wheel won't keep you in line, so the quickest way to stop and keep in line is front only, enough to lift the rear, and use mad skillz.
.

FTFY

EKE_38BPM

bails87 wrote:

pdw wrote:

A locked up rear wheel won't keep you in line, so the quickest way to stop and keep in line is front only, enough to lift the rear, and use mad skillz.
.

FTFY

LOL

Kieran_Burns

The question is: which of your brakes wears out first?

optimisticbiker

bails87 wrote:

Yep, as others have said, when you brake your weight is shifted forwards, so the harder you're braking, the less your rear brake is doing.

I'm honestly suprised people who do any decent amount of riding don't know this stuff.
.

As I ride 150miles+/week and I replace front brakes pads twice as fast as the rear... I do know this

my issue was with the word 'only' in the assertion

pdw wrote:

On a dry road, front only is the fastest way to stop.

as to me intuitvely it wasn't right... if it were so why fit a back brake at all?

Anyway guys... subject is done to death probably for the 'n-th' time...

and to the OP - get well soon...

pdw

OptimisticBiker wrote:

I agree... modelling it crudely in a simple structural modeling tool shows that as long as the rider can keep his arms braced so that he retains weight on the rear wheel there is a point where maximum deceleration occurs using both brakes which is greater than that achieved by the front wheel alone.

Can you explain this further? I don't understand what you mean my "as long as ... he retains weight on the rear wheel". The point is that on a normal bike on a dry road, you can apply the front brake to the point where this simply isn't possible.

pdw

[quote="OptimisticBiker"

pdw wrote:

On a dry road, front only is the fastest way to stop.

as to me intuitvely it wasn't right... if it were so why fit a back brake at all?
[/quote]

Err, because roads aren't always dry.

Also, I'm pretty sure there's a legal requirement to have two independent ways to stop a bike.

bails87

OptimisticBiker wrote:

pdw wrote:

t;]On a dry road, front only is the fastest way to stop.

as to me intuitvely it wasn't right... if it were so why fit a back brake at all?

Anyway guys... subject is done to death probably for the 'n-th' time...

and to the OP - get well soon...

Front brake + corner = bad idea. Use the front brake to stop in a straight line, use the back brake to feather speed and when turning. Plus the legal requirement to have two seperate braking mechanisms.

As said before, due to the shape and weight distribution of a typical bike, braking hard enough to just lift the wheel off the ground is the fastest way to stop. If the back wheel's on the ground, you can brake harderand the extra braking makes up for the 5% loss of traction caused by lifting the (practically unweighted) back wheel off the ground.

It's amazing just how quickly you can stop on a MTB with fat tyres and disc brakes btw.

And good point, get well soon OP

unixnerd

Front brake + corner = bad idea

Braking at all and cornering = bad idea. A tyre can do 100% of something. Ask it to brake OR corner with 100% of it's grip and you're fine. Do both at the same time and you can't apply as much force to the brake without skidding.

Braking should be done in a straight line before cornering.

Gussio

Fit some cantilever brakes to your bike - no way you'll be locking up then

bails87

Yes, braking while turning isn't ideal, but in that situation, the back brake is better than the front.

graham.

I always understood that the front brake was to do the "Stopping" bit, and the back brake was to do the "Controlling " bit.
Graham.

thecrofter

As soon as you get the back wheel in the air you are raising the CoG in relation to the pivot point and will have to ease off the front break to prevent going over the handlebars. As I said before, given a dry, clean road surface, the fastest way to stop is mainly front brake with a touch of back to keep everything in line. I really can't see why some people have difficulty understanding this. :roll: