Floating Rear Brake

Its a totally legit thing that Dave is talking about. I wonder if the teams don't do this because unless the bikes come stock with this system, the teams would have to modify the swingarm which is against AMA rules for pro racing. 

You wouldn't have to modify the swingarm, the caliper mount, if the caliper is above the swingarm, moves away from any existing  std caliper bracket locator.

I think (some of) the first production KTMs with rear discs had floating rear brakes.

And, you saw quite a few early Works bikes with Floating rear disc brakes, in the early years of the brake change over.

Honda even had the "linkaged"  / "Rocker Armed" floating rear brake.

They all just disappeared. 

You saw floating rear brakes on many of the Drum Brake set ups. Mainly, I think, because it helped, somewhat, but Not enough, with the brake  actuation differences created by the cable or brake rod and brake lever interface / pivot always moving / not being anywhere near the center line of the swingarm pivot. Hydraulic brakes, got rid of that problem. 

Now, on any of my Road Racers / Tar Track day bikes, I run a floating rear brake. By comparison to a Dirt Bike, you are dealing with near 100% traction ( of, course  that's Not 100% true) , so you really do get significant  'drag' on the rear wheel, thus compressing the rear suspension. And, if you do lose  rear traction, the swingarm can then viciously extend. Not a good thing.

I've made full suspension Bicycle frames for decades now. My own DH and Enduro frames, are simple ( but simple can be hard ) single pivot bikes. I make much of my money, from designing far more complicated systems for companies .  MTBA mag, years ago, just labelled single pivot bikes (and others) as "Brake Jackers" . Well, yes indeed, bad designed ones do - but so many of the incredibly complicated designs that are out there in Bicycle Land, have utterly dreadful, Idiotic caliper mountings, that are so, so much worse. But, in MTB, it's all about marketing BS.

I offer a floating rear brake set up for my frames - at a considerable, but fair price. And, for those interested, I let them ride my bike, with and without it. The vast majority, Don't take it on after that. And my set up is a full, equal sided and length parallelogram set up, not some sort of lash up. 

Thing is, yes, you can hold the bike still - generally with the front wheel against a wall, and see how the rear end is 'free' to move without the brake on, then stiffening / locking up with it on. Put a Floating rear brake on (if it's done properly, and Many are Not) , and it moves freely. 

But, when riding, you are moving forward - not stationary , and, under brakes, you are transferring the load to the front. And, a Dirt Bike / Bicycle has anything but near perfect traction, to create much rear end compression whilst going forward.

On my DH  / Enduro bikes, you mainly notice the effects of the floating rear brake at Very low speeds - with just a bit of pace on, You really don't. 

I'm Not a hater of FRBs, as I said, they have always been on my tar bikes, and I have used them extensively on my DH bikes - but my sponsored, incredibly fast (top 5 to 10 riders in OZ at their time, with UCI rankings nearer to 50th, than a 100) riders, never felt the need of them (indeed, disliked them), after doing a lot of testing. I might one day, put one on my CRE500, as I use it in very nasty, tight , extreme terrain. But, mostly for the 'kicks' of having yet another different thing on the old Teddy Bear of a bike. Same as I may just do a 'funny front end' for it. 

Some here might remember how Fabien Barel  used a Cross Over Torque Armed Floating rear brake on his Konas. Said set up, induces rear end Squat. He must have liked it, or, as I think it was a feature on one of the Kona DH bikes, he may have just used it because he was required to use it. I've seen such 'Squat inducing set ups on Road Racers, years ago, but they were quite rapidly removed, usually. 

PS - as I noted in another post, I'm feeling 'loopy' and bored after getting some hardware out of my spine last night, so I have a lot  of boring, and painful time on my hands, at the moment. 

There are pros and cons to everything, and in my opinion the cons outweigh the pros here.

The modern setup reacts the brake torque into the swingarm in a way that compresses the suspension a bit. Some says this is bad because it makes the rear that much more harsh through braking bumps, but they forget to consider that with the 'floating' setup, more weight will be transferred to the front and be more harsh there. 'Rob Peter to pay Paul'. Basically the modern design acts as a bit of anti-dive, which I think is preferable.

Maybe for it to truly be beneficial you would have to pair it with a similar anti-dive linkage on the front brake. 

Not sure why he claims it 'binds' the suspension. Maybe just a poor word choice. I tried the experiment mentioned in the article and I didn't notice anything. 

Aside from that, it's an extra part that can get damaged and adds cost. I wouldn't mind riding a bike setup this way to see for myself.

Having read through many replies, all I can say is I’ve lived it & have fitted this system to my own stuff & it’s better.

Do the static test in your garage.

In my long Career, I’ve seen every color have failures. Radiators, electrical stuff, shifters, brake pedals, chain guides, etc., costing Wins & Championships.

I can’t recall any color doing such from this system. Bent rods, sure, but failures I don’t recall, & I had a long Career with every1 every color using them.

I will go as far to Guarantee faster times especially for Pros Outdoors.

It makes to much sense & is certainly no worse than anything bolted or added on the bikes currently, shoot more radiators fail. 
 

Cool article and something very interesting that I’ve been learning more about the last few years. Moto definitely doesn’t talk much about the anti-rise or anti-squat curves of the bikes much…
 

In my opinion, I do believe there are a lot of benefits to the floating brake arm on certain tracks with long braking sections, maybe GH, Thunder Valley, Millville you could be braking and keeping a free feeling shock. There are some scenarios when you want drag the rear brake to help the rear end squat where the no floating brake can help. And how much time in a 3 minute lap are the top pros hard on their rear brake, 30%?

But I don’t believe that it could be a blanket statement that every bike needs a floating rotor because it depends on what the anti-rise curve is of each bike.

In mountain biking it’s a much different scenario with anti-rise and braking characteristics because when riding a DH track you’re on the brakes probably more than 50-60% of the 3 minute race, or maybe more. 

I've converted bikes to and from FF, mostly from, and all drum, though the principles are the same as disc.

Rider input and sensitivity will make a lot more difference to the rear brake, and overall chassis balance, than if it is floating, or not.

Bearuno's right, it DID exist.

I had that on my '89 KTM.

Quite a few factory Hondas had it earlier, including the funky articulated version, and it was common on drum braked RMs and YZs.

They were around. No one understood it. Disc rear brakes came in. Floating rear brakes disappeared just like that. Not one magazine or rider I know of questioned it or missed them. And now all of a sudden they are cool again 

It is not as important to modern 450 riders because they don't use the rear brake as much with all the engine braking these bikes have.

Another thing to think about during that switch from drum brakes to disc, was the advancement in linkage/suspension kinematics.  With the advancement in suspension technology, the engineers were able to separate anti squat, anti-rise, leverage ratio.

Again, i'm not saying the floating rotor isn't an advantage in some scenarios and it is interesting not 1 team has found it to be a slight edge over the competition. 

It would be interesting to get some answers from chassis engineers or something like Decoster who is a do it all guy. 

My 1971 Yamaha DT1 had one...

There was even a floating FRONT set up. I think it was Preston Petty that put it out. Never caught on. I recall see a photo with the rider locking up the front wheel and there was almost no dive in the forks. Interesting how ideas come and go and come back, wash, rinse, repeat.

MXA article:

https://motocrossactionmag.com/forgotten-motocross-tech-how-to-make-a-f…

Here is a floating rear disc carrier I found a picture of , 1987 Byron motor sports park 1987 NSR CR500

I'm pretty sure you have to wear a kidney belt for floating brake setup to work properly. I just don't think we are going to see any meaningful advancements in floating brake setups until every riding gear company has a full rainbow of kidney belts in their lineup again. 

My understanding is the purpose was to get a consistent brake feed back. When a rod was used, as the suspension articulated, the feel varied on a non-floating brake. The full floating of it helped reduce the variance of the pedal feel. Once the Japanese went to cable brakes, this became a mute point as the cable flexed by design. With the advent of disc brakes, this issue went into the vault. This is of course applicable only to the rear brakes. 

(It helps to be fossilized sometimes!)

I remember my first bike with a non-floating rear disc...  a 1986 KX250.     I have always been sensitive to bike changes, and this was one of them.

While I was happy that the rear disc was more powerful than the drum it replaced, and also didnt require constant adjustment.... I did notice in some braking situations with large braking bumps that the rear suspension did not react the way I expected.   So the two positives outweighed the negative to me.   Probably why nobody complained about it at the time.   I've always wondered what a modern floating rear brake would feel like.

^I have never been very sensitive to bike changes, but I remember rear disc brakes seemed like the trickest, most factory thing around. I remember the advent of water cooling, disc brakes, piggyback shocks, USD forks and carbon fiber as the age of supreme advancement. Oh, and tiger-striped seat covers. Gotta have a hot orange and white tiger-striped seat cover. 😎

Bob Hannah was using it. On his Works Honda.