Kyoto Wavy Discs

[Ashley M]

Try Nick at sales@allbikeengineering.co.uk very helpful
And will be less expensive then Mr Honda, if you ask they
Could fit them for you as well if you don’t have the time

[416cc]

I use Braking discs on several of my bikes & find that they are a much better disc than OEM & many aftermarket products. Braking pads are good as well.
Brake Discs for the HONDA XRV R AFRICA TWIN 750 (2001)

[416cc]

Try Nick at sales@allbikeengineering.co.uk very helpful
And will be less expensive then Mr Honda, if you ask they
Could fit them for you as well if you don’t have the time

Tried discs from Allbikes...once. Even Russ couldn't figure out why the discs were machined very badly. Got my money back & went elsewhere.

[digitalcaptive]

I do get things wrong... Just like I thought your IQ was in treble figures... I was way wrong on that one

You rat bag, spose I deserved that one

Hell you were way off there, unless you move the decimal point

You're the only person I know that insists on his height being measured in millimeters......mind you I can understand why .........3 feet 2 1/2 inches just dosn't sound as impressive as 977.9mm

[icenian]

Why does having more contact between pads and discs improve braking? If you halve the contact area, then it means you double the pressure.

If the contact area affects braking, it means that braking is not proportional (linearly) to the pressure exerted between pads and discs.

I'm willing to believe this is true, but I'm interested to know why!

Also, if non-wavy discs give better braking (because of more contact) and make pads last longer, shouldn't see we get rid of our discs with holes in, and fit solid (i.e. undrilled) discs?

[Lumiya]

Good question as it's not that easy to figure out..

It's not just to do with contact area and pressure but also the friction of the material. Friction produces heat (the energy has to go somewhere) on a small contact point at high pressure you might have the inability to spread the heat around (this is in the form of heat spreading to the surrounding material and also heat spreading to the air)

Also the heats produced by small points of contact can take the surface temp up beyond melting point. (Look at a grinder it doesn't just scrape the material away but melts it first and a thin disk (small contact area) is more efficient than a thicker disk)

It's complicated as to disk size, type, material, surface contact, air-flow...etc.. as to if a brake is efficient and also capable of doign the job..

[416cc]

There is also a question of the barrier gases given off by the pad with the friction. It has been shown in the past that having slots in the surface of the disc is another way to dissipate heat as well as these barrier gases.

[StumpyFingers]

The larger contact area the pads have the more the heat is spread out entering the disc.
Braking is transferring one form of energy into another, using friction (the rotational energy of the wheel into heat). The more surface area in contact the better the transfer takes place, imagine putting the pads from a pushbike on your bike the pads would melt before you stopped.

[icenian]

The larger contact area the pads have the more the heat is spread out entering the disc.

That would mean a big contact area is good for heavy, sustained braking: where heat may build up to the point it reduces effectiveness. A small contact patch could be better for lighter, infrequent braking: where brakes run cold, possibly too cold to work optimally. In reality, I should think that the road pads we use are fine when cold, and we don't build up enough heat to cause problems either.

FWIW I reckon that wavy shapes is of bugger all significance besides things like the material the discs and pads are made of, and whether they match. OE discs and pads look like the way to go to me, at least while the prices at David Silver stay sensible (75 per disc, 20 per set of pads).

Curiously, the Transalp 650 calipers I have on my AT just now (which are identical except the silver paint) came with slightly different pads. I wonder if Honda specify a different compound for XL... rather than XR... bikes.

[StumpyFingers]

I think the idea of wavy discs is similar to the idea of drilled holes, they are to allow more surface area contact with the air. This allows better cooling.
Could the pad differences be due to the mass needed to be stopped?