180 ver 160 brake discs up front ?

[Steven Knoetze (sk27)]

Don't know who wrote that, but he is wrong - the distance will be shorter, BUT - you will have much less control over steering/direction - possibly none.

 

Works for cars too - ABS does not shorten braking distances (wet or dry) but it does allow you to change direction when braking hard - this is why race cars with configurable race ABS systems allow you to push through the ABS to get it to lock - you just have to REALLY stand on the pedal (although cutover pressure is configurable)

 

Useful feature if needed as a last resort - rather learn to drive AROUND things.

 

I agree with you mostly, but what you stated is only true if the rider has the technical riding skills to actually pull it off.

 

Most of the guys I have seen just stand up on the peddles, weight forward and lock the back from 100m out of the turn. They usually come off of the brakes before they are even close to tipping into the corner. So it's not helping them stop quicker or assisting with getting some oversteer to turn quicker through the bend. Pointless and rips up all sorts of stones and rock which makes that corner particularly interesting when you get there on the next lap and suddenly it's like rolling on ball bearings!!!

[ThePubSA]

Don't know who wrote that, but he is wrong - the distance will be shorter, BUT - you will have much less control over steering/direction - possibly none.

 

Works for cars too - ABS does not shorten braking distances (wet or dry) but it does allow you to change direction when braking hard - this is why race cars with configurable race ABS systems allow you to push through the ABS to get it to lock - you just have to REALLY stand on the pedal (although cutover pressure is configurable)

 

Useful feature if needed as a last resort - rather learn to drive AROUND things.

I see it diff on 2 wheels without ABS.. it also boils down to rider weight and they way in which he rides that affects braking on a bicycle.. bit diff to a car with 4 wheels and much wider chassis.. back end of a car wont jump around near as much and your contact patch is way less on a bicycle.

When pros slightly lock up back brakes to 2x slide through a shacain there steering isnt compromised infact they make it through both corners easier and with more speed out of it.. ?

[ThePubSA]

Skidding makes your braking distance further, as there is less traction on the tyre (thus less resistance to stop), than when you gradually braking, keeping traction (More resistance on the ground)

 

Edit: As soon as the wheels lock, the resistance coefficient is that of the Tyre to ground, in stead of Brake pad to rotor

 

Spose thats what i wanted... idk all the tech.. i just learn with my eyes

Edited March 19, 2014 by 2Nutz

[V12man]

I see it diff on 2 wheels without ABS.. it also boils down to rider weight and they way in which he rides that affects braking on a bicycle.. bit diff to a car with 4 wheels and much wider chassis.. back end of a car wont jump around near as much and your contact patch is way less on a bicycle.

When pros slightly lock up back brakes to 2x slide through a shacain there steering isnt compromised infact they make it through both corners easier and with more speed out of it.. ?

 

Cornering technique is a different thing to braking distance - not close to the same thing - it's a long and complicated bit of mathematics - I have the math in a book.... but the bottom line is pretty much that when a tire is locked, you have very little direction change capability with it (and because of rolling circumference diameter differences on bike/motorbike tires when you lean them over, you have more capability to turn locked with a bike) but still - locked tires (ALL of them you might have) give you the shortest possible stopping distance (and the least control - which on a bike may well mean you fall off... which does not help shorten the stopping distance... )

[Cassie]

I just took off my 180mm rotors and went to 160mm, which has more then enough stopping power for me that is ( XT Brakes & Ice-Tech Rotors)

 

Care to part with a 180mm?/ I'd be interested in getting one....

PM me...

[NotSoBigBen]

My laaitie rides with a 160/140 combo and once finished an XCO race a few years ago at 'Fambili' with the back brake caliper tape to the rear chainstay and on the podium nogal .......... I wouldn't try that though

[Brian Fantana]

Another aspect that influence braking is your body position. The lower you can have your COG the harder you can pull your front brake. This is where a dropper post will come in handy, as it will allow you to lower your torso further than with an XC height seatpost.

 

The low COG will decrease the MOI of the system (you and your bike) around the front axle which which allows you to brake much harder.

 

Since MOI is a function of distance squared, a small reduction of distance between the COG and the rotating axis can have a significant effect. In this case the axis is the front axle.

 

Your body is the biggest contributor to the mass of the system which also means that your body position has a significant influence on the position of the COG of the system.

 

MOI ---> Moment of Inertia

COG---> Centre of Gravity

[DR ◣◢]

So much wrong in this thread it's not even funny.

 

Thank goodness for good advice with scientific backup

[droo]

So much wrong in this thread it's not even funny.

 

Thank goodness for good advice with scientific backup

 

Haha... so unlike the Hub to have opinions with no backup.

[Bizkit031]

If you a big guy then go big,but lots of guys go with 180 front and 160 rear. I have 180 front and rear less fade when bigger due to the heat issue.

[Wuzzie]

XC bikes for stage races or general mucking about with decent brakes like Shimano XT or XTR 160 front 160 back.

Specialized sworks coem standard with 160F X 160B they must know something.