Question for Weeksy.
 

Hello mate,

After seeing the pics of your bike with the wavey discs. I wanna know one thing.

Are they any good/worth having?
;)

Allo mate,

Who made em and what sort of price are we talking?

I have seen a few adverts in the bike mags but i am interested if you know of any places that do em for a good price.:roll:

Go for the original " Braking " ones - the cheapies don't last.
Speak to Neil at Cornerspeed - my rear one was about £65...I don't know how much the fronts were as they were fitted as a warranty item.
Andy

do you think the rear make a difference cos I am sure you must have noticed the rear brake is so poor and might aswell stick wood in the wheel to stop I have run alsorts of pads and gone for dot 6 fluid but I wouldn't like to depend on it. never found a problem with the front. maybe its my style of riding. :sing:

ah ah well then not a lot I can say to that! :sing:

I think that they do perform better than the standard disks - but who cares when they look as good as they do!!!!:D:D:D:D:D:D:D:D:D



Tim:frog:



[Edited on 5-6-2004 by Rattler]

Tart :bouncy:

tart or poof.....?

wheres Vman when you need him!




Only jokin' tim

Hi mate,

Nice discs........... On and nice carbon rims............ Oh and nice calipers.......... Oh and nice ohlins forks. ;)

Very nice front end in deed!!!!:cool::lol:

You're just jealous!!!:D:D:D:D

[Edited on 7-6-2004 by Rattler]

me too!! :smug:

Ah - but can material things make you happy????

---------- you bet your arse!!!:lol::lol::lol::lol:

Still not a yorkshireman.Ah,well,can't have it all!!:D

A technical question for you about wavy discs:

Brakes basically work by converting the kinetic speed of your vehicle into heat, the more efficiently they do this the better the braking performance. So in the same way that a larger contact patch of tyre on the road gives better grip wouldn't a larger contact patch of brake pad on the disc give better braking performance? Taken to its extreme, the disc should be solid with no holes, shapes etc. just like they were 25 years ago !!

I realise that there was a trade off (I think started by BMW) to put holes in the discs to dissipate water and thus improve wet weather braking - but it seems logical (to me) that cutting down on the contact area would decrease braking efficiency.

So do wavy discs really work better or is it just for show ? :puzzled:

The real key to brake performance is the swept area of the braking pads. Yes bigger pads would give a better brake, but one problem, under heavy use is the heat. This shows it's head as fade and one of the contributors to this is the gases created between the braking surfaces. These can create a sort of "aquaplaning" of the pad surface, between it and the disc face.
Drilled discs, slotted discs and Waveys, all use the holes etc. to dispel these gases. Another thing these discs do is to clean the pad faces to maintain clean friction material is always present.
Disc wear shouldn't be any worse, but you'll certainly see a reduction in pad life, mainly due to the "cleaning" effect.

The Waveys produced by Braking are about £176 each. These are the ones on Tims bike and the ones Rushjob has. Also available with Carbon centres (missed those Tim!!)
There is a new kiddie on the block in the shape of Galfer. These are really good quality to and come, initially as a kit (2 x discs and pads) for £387.

As Andy said, stay away from the cheap stuff. Brakes must never be a compromise, and with Waveys, stick with the boys that have been doing it for a while and know what they are doing.

Spot on reply Neil.

I was also led to believe (but I'm easily led!!) that the waveys did disperse heat more effectively due to their larger edge surface area - if that makes any sense.

They even look good on a Suzuki!!!!



Tim:frog:

I know that it's counterintuitive, but the frictional force developed between two surfaces is independent of contact area. It depends only on the coefficient of friction and the force pushing the two surfaces together. The force developed between the road and a tyre is different because the soft rubber interlocks into the road surface, so a tyres grip is contact area dependent.

Yes BUT.............IF the coefficient of friction and force pushing the two surfaces together was equal for two systems with different size contact patches wouldnt the one with a greater surface area develop a greater braking force? :puzzled:

No. Physics 101. F=uN. Surprisingly, area doesn't enter into it.

But............the stress on the contact patch would be lower for the larger area...thus wear would not be so severe..........

Interesting point about tyres. I still think (but I may well be wrong) the CoF is important. After all the fastest corner speeds at Gp's come from the 125's, which have the smallest tyres. Although wheelbase etc comes into it.:puzzled:

Shazaam is correct,it's a physics thing!! The only other thing that would improve the braking is the radius of the disc!! The larger the radius the greater the braking effect,the surface area of the pad makes no difference!!

But isnt force also related to area?? :puzzled:


Force = pressure/area

Therefore pressure = force X area

or something :puzzled::puzzled:

Its been too many party night since my A-levels 7 years ago :lol:

[Edited on 9-6-2004 by DJ Tera]

DJ - The force you mention is the force pushing the pads together, determined by how hard the lever is squeezed - the harder you squeeze the quicker you slow down ( as Shazaam states ) The rate at which you slow would still be the same for a given lever pressure no matter what the size of pad/disc area. A small pad/disc area would just get very hot quickly and the brakes would fade.

My head hurts now!

DJ,
From the above, I assume you got a "D" in A Level physics :saint:
You are 100%......wrong!

Pressure (stress) = force/area
Do not get confused with the pressure on the brake pad backing plate and the area of the friction material.
Take the following:
1. Brake Pad "A": Backing plate area = "1", friction material area = "1"
2. Brake Pad "A": Backing plate area = "1", friction material area = "0.5"

Force applied due to hydraulic pressure will be the same for "1" and "2".
Friction force generated between 1 and 2 will therefore be the same.
However, STRESS on friction material "2" will be 2 x stress on friction material "1"...therefore the heat generated wqill be more and the wear rate will be worse.........
Enough.

DJ,
From the above, I assume you got a "D" in A Level physics :saint:
You are 100%......wrong!

Pressure (stress) = force/area
Do not get confused with the pressure on the brake pad backing plate and the area of the friction material.
Take the following:
1. Brake Pad "A": Backing plate area = "1", friction material area = "1"
2. Brake Pad "A": Backing plate area = "1", friction material area = "0.5"

Force applied due to hydraulic pressure will be the same for "1" and "2".
Friction force generated between 1 and 2 will therefore be the same.
However, STRESS on friction material "2" will be 2 x stress on friction material "1"...therefore the heat generated will be more and the wear rate will be worse.........
Enough.