[spincrazy]

And I still don't. I never really cared before, but I just decided it's probably something I should know.

I mean, I know what it does, but just how I never bothered to ponder. I'm sure this is a rudimentary part of bicycle tech, geek, engineering, blah, knowledge but I don't have it. Care to explain?

 

[SirChomps-a-Lot]

basically it is an anti-lock system operated by a frog or small gnome that lives inside your brake caliper.

 

[Fulton]

Originally posted by SirChomps-a-Lot
basically it is an anti-lock system operated by a frog or small gnome that lives inside your brake caliper.

LOL

 

[Fulton]

ok, the basics..........

on a single pivot bike, with out a floater, when the suspension compresses, the caliper rotates forward around the axle, in the same direction of the spinning wheel, due to the arc of the swingarm. This is why the suspension compresses and stiffens when the brake is applied while riding. The rotor "pushes" the caliper around the axle, in the same direction as the suspension compression, actuating the suspension.

A perfectly neutral floater, will be in a parrallelogram, with the swing arm pivot, axle, and the 2 brake arm pivots. This keeps the caliper in the same postition relative to the axle, no rotation, so it has no effect on the suspension.

 

[BMXman]

Originally posted by Fulton

A perfectly neutral floater, will be in a parrallelogram, with the swing arm pivot, axle, and the 2 brake arm pivots. This keeps the caliper in the same postition relative to the axle, no rotation, so it has no effect on the suspension.

so like a Yeti dh9???

 

[Fulton]

Originally posted by BMXman
so like a Yeti dh9???

sorry, that was a bit of a typo in my previous post, let me clarify, I meant to say:
" a neutral floater will be in a perfect parrallelogram.....", which the yeti is not. If the caliper on the yeti was mounted directly on the axle bracket thingy, ie, no floater, then the suspension would extend, or "jack" under braking. The caliper on that bike would rotate in the opposite direction of a caliper on a normal single pivot bike.

 

[thaflyinfatman]

Originally posted by BMXman
so like a Yeti dh9???

A Yeti DH9 isn't a parallelogram. Quadrilateral yes, but the links aren't parallel!

 

[- seb]

I'll say this much: A lot of you say floating brakes aren't necessary, but I noticably miss mine. Used to have one on my 222 and my GT DHi-drive is noticably worse under braking, find myself getting kicked about.

But on the flipside getting the back wheel in and out of my 222 was a MISSION because of the floating brake, and I don't miss it for that reason Also was increased weight, more noise, more slop.

 

[Tom Church]

Can't a floating brake also cause pedal feedback when doing drops and such in a low gear? Someone told me that once...

How come one of the freeriders use them...only the DHers?

Tom

 

[- seb]

No, unless you drop with the brake on, which sounds odd....

 

[Steve from JH]

Originally posted by Fulton
ok, the basics..........

on a single pivot bike, with out a floater, when the suspension compresses, the caliper rotates forward around the axle, in the same direction of the spinning wheel, due to the arc of the swingarm. This is why the suspension compresses and stiffens when the brake is applied while riding. The rotor "pushes" the caliper around the axle, in the same direction as the suspension compression, actuating the suspension.

A perfectly neutral floater, will be in a parrallelogram, with the swing arm pivot, axle, and the 2 brake arm pivots. This keeps the caliper in the same postition relative to the axle, no rotation, so it has no effect on the suspension.

Actually to be accurate you have to take into account the ground line. The floating brake parallelogram will only be neutral when the brake arm and swingarm are also parallel with the ground.

Neutrality occurs when the three lines--swingarm line, brake arm line, and ground line--all converge at the same point. Having them parallel is just a special case of that, with the convergence point being at iinfinity.

The best way to setup a brake to be neutral throughout travel would be to have a non-parallel floater aimed so that the convergence point of the brake arm line and swingarm line stayed very close to the ground line as the suspension moved.

 

[HTFR]

Originally posted by Tom Church
Can't a floating brake also cause pedal feedback when doing drops and such in a low gear? Someone told me that once...

How come one of the freeriders use them...only the DHers?

Tom

Am i a freerider? or am i a DHer?

 

[Tom Church]

I'm just saying that you don't often see them on bikes other than those 100% dedicated to DH. Even long travel bikes that are being used to ride bridges and drops don't have them. It's not even an option on the normal Gemini from cannondale but it is on the Gemini DH.

Why is that?

Tom

 

[buildyourown]

Originally posted by Fulton
ok, the basics..........

on a single pivot bike, with out a floater, when the suspension compresses, the caliper rotates forward around the axle, in the same direction of the spinning wheel, due to the arc of the swingarm. This is why the suspension compresses and stiffens when the brake is applied while riding. The rotor "pushes" the caliper around the axle, in the same direction as the suspension compression, actuating the suspension.

A perfectly neutral floater, will be in a parrallelogram, with the swing arm pivot, axle, and the 2 brake arm pivots. This keeps the caliper in the same postition relative to the axle, no rotation, so it has no effect on the suspension.

I think you have it backwards. The rotor pushes the caliper around the axle and stiffens the suspension, not actuating. That is why bikes with out floaters brake jack, not squat. Basically, the linkage arm resolves the braking force into the frame instead of the swingarm. To be a perfect floater, the geometry gets pretty complicated but you don't need it to be perfect. That is why Brake Therapy can you the same floater on lots of different bikes. You only have to get close to notice an improvement. The higher the pivot, the more you need it.

Bikes that need it alot:
Super8
Bullit
BB7
Yeti
Original Tomac

Bikes where it would help, but not much:
Rocky Mountain
Turner
Rotec

Bikes that don't need it at all:
FSR

 

[Slugman]

Originally posted by Tom Church
I'm just saying that you don't often see them on bikes other than those 100% dedicated to DH. Even long travel bikes that are being used to ride bridges and drops don't have them. It's not even an option on the normal Gemini from cannondale but it is on the Gemini DH.

Why is that?

Tom

IMO - b/c Freeriders are not doing the speed and rapid hits of a DH run, so the effect is felt a lot less. Yeah we go fast, but not as fast as a pure DH.

We also go off much taller (personal experience only) stuff than you would in a typical DH run. When you're hucking a 10+ drop - you don't want to touch the brake until you've stuck the landing, so you don't need it as much.

 

[Fulton]

Originally posted by buildyourown
I think you have it backwards. The rotor pushes the caliper around the axle and stiffens the suspension, not actuating. That is why bikes with out floaters brake jack, not squat. Basically, the linkage arm resolves the braking force into the frame instead of the swingarm. To be a perfect floater, the geometry gets pretty complicated but you don't need it to be perfect. That is why Brake Therapy can you the same floater on lots of different bikes. You only have to get close to notice an improvement. The higher the pivot, the more you need it.

Bikes that need it alot:
Super8
Bullit
BB7
Yeti
Original Tomac

Bikes where it would help, but not much:
Rocky Mountain
Turner
Rotec

Bikes that don't need it at all:
FSR

actually..........

you have it backwards. Single pivot bikes do squat under braking, it is a comon misconception that they jack. There's been alot of discussion on this subject. The reason high single pivots squat considerably more has as much to do with axle path as it does caliper rotation.

 

[Jm_]

screw it all, just turn your bike upside down, put it in the highest gears possible, spin the cranks and get the wheel going about a billion mph, then lock up the rear brake and watch the suspension...

 

[Fulton]

Originally posted by Jm_
screw it all, just turn your bike upside down, put it in the highest gears possible, spin the cranks and get the wheel going about a billion mph, then lock up the rear brake and watch the suspension...

oh, but your experiment will be comprimised by the influence of gravity.......

we did this with my super 8 in a stand, pulled the spring off the shock, got the wheel spinning hella fast, grabbed the brake, and it blew thru half it's travel

 

[Jm_]

Originally posted by Fulton
oh, but your experiment will be comprimised by the influence of gravity.......

we did this with my super 8 in a stand, pulled the spring off the shock, got the wheel spinning hella fast, grabbed the brake, and it blew thru half it's travel

naw..its STIFF...

 

[DRB]

Originally posted by Jm_
screw it all, just turn your bike upside down, put it in the highest gears possible, spin the cranks and get the wheel going about a billion mph, then lock up the rear brake and watch the suspension...

Don't do this test..... it'll cause tidal waves. Tidal waves are bad.