Things that make you say "Hmmmm..." - Floating Disk Brakes?

[rohar]

OK TT experts. I did a search on this and nothing came up -at least not in the last 6 months.

Can someone explain to me the purpose of using a floating disk brake as opposed to a rigidly mounted one? I'm just curious since WR450 uses a floating front disk and a rigidly mounted rear disk and I was wondering why. Is it because the front disk usually runs hotter since it's used more and takes the brunt of the braking job? Inquiring, bored-at-work-on-the-day-before-the-long-weekend minds want to know...

I bow to your expertise ?

[Hick]

I don't know. But like most other things I'm totaly ignorant of, I have a theory. ?

When I change pads on my pickup (fixed rotor, floating caliper), one pad is always worn more than the other. So I'm thinking a floating rotor allows for more evenly applied pressure to both sides of the rotor, maximizing the stopping potential.

Anyone else?

[DesertChris]

I had an idea but couldn't find the words to explain it so I found this: http://www.vehiclecraft.com/Brakes/rot_ques.htm

Makes a little more sense to me now too.

[DesertChris]

Hick,

Your truck has floating calipers, that is why one pad wears more than the other. The piston pushes one pad and pulls on the other, the one in direct contact with the piston gets more wear.

[MOmilkman]

Anyone else?

I was always under the assumption the floating disc was so it has some flex to it so when you hit rocks its less likley to get bent. ?

Thats what I always thought anyways...

[Hick]

Hick,

Your truck has floating calipers, that is why one pad wears more than the other. The piston pushes one pad and pulls on the other, the one in direct contact with the piston gets more wear.

Umm, yeah, that is my point, but thanks for the help. Pickup w/ floating caliper exhibits uneven wear across pads, ergo floating disc idea is to allow equal pressure and better braking.

Just my theory, but there it is.

[SFO]

When the rotor is heated it wants to expand radially.

If it is rigidly mounted this will cause the rotor to distort or potato chip resulting in poor lever feel and pulsing.

The floating rotor allows the rotor to expand radially, independent of the rotor center, and stay flat when it is heated/expanded.

Hope this helps.

[John_H]

SFO,

That sounds like a reasonable explanation. I always wondered about this too. ?

[Mike_Hudson]

The link in DesertChis's post has it right. The caliper is fixed to the fork tube and the disk to the hub. By allowing the disk to move side to side it ensures the best contact between the two at all times.

[rohar]

Thanks to DesertChris and all those who replied. "castellated dog-drive"? That just sounds bad...

I knew someone on this forum would come up with the answer. Thanks again. ?