Discs
 

Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs don't. Why do
bicycle discs have them?

Discs
 

On Thu, 16 Nov 2017 07:47:19 +0100, Tosspot
wrote:

Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs don't. Why do
bicycle discs have them?

https://www.ebay.com/sch/Honda-Motor...i.html?_fsrp=1
https://www.boschautoparts.com/en/au...c-brake-rotors
http://www.aerobrake.com/?gclid=EAIa... AEgLxKfD_BwE
--
Cheers,

John B.

Discs
 

On Thursday, November 16, 2017 at 7:47:23 AM UTC+1, Tosspot wrote:
Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs don't. Why do
bicycle discs have them?

Weight is my guess.

Lou

Discs
 

On 11/16/2017 12:47 AM, Tosspot wrote:
Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs
don't. Why do bicycle discs have them?

Many do have slots or holes. Typical low-end auto discs have
a center air channel. Our researcher discovered this by
completely ignoring normal maintenance:

http://www.yellowjersey.org/photosfr...t/NRCTDISC.JPG

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

Discs
 

On 16-11-17 14:43, AMuzi wrote:
On 11/16/2017 12:47 AM, Tosspot wrote:
Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs
don't.Â* Why do bicycle discs have them?

Many do have slots or holes. Typical low-end auto discs have a center
air channel. Our researcher discovered this by completely ignoring
normal maintenance:

http://www.yellowjersey.org/photosfr...t/NRCTDISC.JPG


As a maybe related question: Why do bike discs allow for so little wear?
The Shimano Ice-Tech discs are 1.8 mm thick, and need to replaced when
they wear to 1.5 mm. Would there be an issue with cooling if they were
thicker? Or, in the worst case, is this just a way for Shimano to sell
more replacements?

Ned

Discs
 

On 16-11-17 14:43, AMuzi wrote:
On 11/16/2017 12:47 AM, Tosspot wrote:
Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs
don't.* Why do bicycle discs have them?

Many do have slots or holes. Typical low-end auto discs have a center air
channel. Our researcher discovered this by completely ignoring normal
maintenance:

http://www.yellowjersey.org/photosfr...t/NRCTDISC.JPG


As a maybe related question: Why do bike discs allow for so little wear? The
Shimano Ice-Tech discs are 1.8 mm thick, and need to replaced when they wear
to 1.5 mm. Would there be an issue with cooling if they were thicker? Or, in
the worst case, is this just a way for Shimano to sell more replacements?

Ned

The thinner, the lighter. Thicker discs do not cool worse as heat
dissipated is the same as the surface area.
And replacement rate goes up.

Discs
 

wrote in message
...
On Thursday, November 16, 2017 at 7:47:23 AM UTC+1, Tosspot wrote:
Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs don't. Why do
bicycle discs have them?

Weight is my guess.

Sometimes its about water clearance, but probably a "two birds with one
stone" kind of thing.

Discs
 

"Tosspot" wrote in message
...
Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs don't. Why do
bicycle discs have them?

Damn - I was just seeking crowd funding for a start up in motorcycle disc
locks.

Vaguely remember seeing a car disc with holes - but can't remember where.

its to a considerable extent, a trendy thing, and not many aircraft cruise
past the girlies on the high street. Aircraft probably use cast iron discs
because it works better and is lighter than stainless - and cast iron might
be too brittle to make loads of holes in it.

Discs
 

Tosspot wrote:
:Why do they have holes in them?

:Car discs don't, motorbike discs don't, aircraft discs don't. Why do
:bicycle discs have them?

Lots of high-performance car brake rotors are drilled or slotted.
Slotting is more common on better stuff, holes can crack. They serve
a couple of features. One, people think they're cool. two, they
allow the gasses that come off brake pads somewhere to go (this is a
non-issue with modern pads, but it was a problem in the dark ages).
Three, they give water somewhere to go. Four, they improve cooling
(increase surface area). five, the clean pads, and reduce wear.

--
sig 127

Discs
 

On Thursday, November 16, 2017 at 11:38:40 AM UTC-8, David Scheidt wrote:
Tosspot wrote:
:Why do they have holes in them?

:Car discs don't, motorbike discs don't, aircraft discs don't. Why do
:bicycle discs have them?

Lots of high-performance car brake rotors are drilled or slotted.
Slotting is more common on better stuff, holes can crack. They serve
a couple of features. One, people think they're cool. two, they
allow the gasses that come off brake pads somewhere to go (this is a
non-issue with modern pads, but it was a problem in the dark ages).
Three, they give water somewhere to go. Four, they improve cooling
(increase surface area). five, the clean pads, and reduce wear.

BTW, I have found that flaming skulls work better than lizards or space aliens. https://ep1.pinkbike.org/p4pb5960033/p4pb5960033.jpg
https://i.pinimg.com/736x/a8/a5/8f/a...2ba6b94a8f.jpg

-- Jay Beattie.