I need new discs for my M4's (bent whilst wedged in the back of the car- doh!) and was wondering whether floating discs had any benefit, and were worth the extra cost?
Cheers
The braking surface is allowed to expand at a different rate to the alloy carrier, so it's less likely to warp at high temperatures... or something along those lines.
They look rad.
They make a sweet ticking noise when cooling down.
Thay look dead sexy.
Bling
The main benefit is that Hope can charge you more money for them. Do you regularly ride hour long downhills? if not, then you're probably not going to see much performance gain
Dey is Pimp Daddy mac, innit.
Like.
Scienceofficer - Member
Dey is Pimp Daddy mac, innit.Like.
Good point, well made.
Bling only AFAICS
Only tend to ride xc/ trails... Normal rotors for me then
cheers guys
I reckon there's a slight advantage with BB7s where only one pad moves.
But they need to be set up carefully.
They go ping, ping, ping when they cool down.
THREAD CLOSED.
Magnified bling. Oh, and reduced compatability.
My Magura floaters have a huge flange on the rotor, they're much stiffer I think than the standard items.
less rubbin
+1 - less rubbing
after issues with rubbing and warping etc i switched to floating, they havent warped since and always feel solid and not flexy....
i also noticed that they seem much much much quieter in the wet too, seem to get rid of the water alot quicker and generate less noise, which is always worth it 🙂
a) clicky cooling noise
b) you can get them in gold
c) bigger flanges
d) extra bling
+2 - less rubbing, especially with my Juicy 5's.
They look good.
They will make you a phalic love god.
Generally lighter although there are lighter rotors about (although usually at the expense of your pads). Look ace, Go ping ping ping, and annoy people who don't see the point in them, so my 140mm, hard tail, 1x9, tubeless wheeled bike annoys a fair amount of people mehehhe!
annoy people who don't see the point in them
^this and therefore worth every penny 😀
the "being a bit lighter" is nice too
http://www.singletrackworld.com/forum/topic/floating-disc-rotors
As an engineer who has worked on brake development including 'floating' rotors please see my post here...
+2 annoy people who don't see the point in them
if you fall in a pond/river you can use them as liferings
Generally lighter although there are lighter rotors about (although usually at the expense of your pads). Look ace, Go ping ping ping, and annoy people who don't see the point in them, so my 140mm, hard tail, 1x9, tubeless wheeled bike annoys a fair amount of people mehehhe!
Do you leave it in the middle of the trail in blind spots at Glentress or something? coz that sounds like exactly the sort of bike most on here seem to want.
At £8 difference it is not a biggie either way when compared to the price of frames, forks, etc.
Slightly lighter but not that you would notice. Get coloured centres with lots of extra bling for very little extra dosh
Lighter? Really? My Magura ones are anything but lighter!
ok, so i'll copy in here what I wrote in there:
As someone who worked for Ferodo R&D many moons ago here's my tuppence worth.
Floating rotors were used originally on racing motorbikes because steel was (is) rubbish compared to cast iron for friction purposes. To save unpsrung mass and overall weight AND to reduce cracking caused by thermal expansion and warping on large diameter disks. they were mounted on pins so that they could move slightly. you can actually waggle the disk. The disk does 'auto align' under braking and it reduces the drag on the pads off brake, but this is secondary.
Cast iron starts to glow red at about 600degC, and bright toward 850degC. Racing brakes achieve this temp quite easily under repeated stops, but settle at about 450degC otherwise fade is experienced with most pad materials. A floating brake does not cool better (the cooling area is reduced) but it does isolate the hub from the extreme heat allowing different materials to be used where appropriate.
Racing brakes rarely use steel as it warps and is rubbish at friction compared to iron. F1 brakes are a totally different game, and racing bikes now often use carbon reinforced carbon disks and pads fro the same weight reasons as F1.
I don't know much about MTB brakes, but the thermal split in the disk to spider, will allow the disk to get hot and keep the hub cooler, there were several cases of failed bearing in racing mbikes due to excess heat build up. it might help with alignment, but i have seen waggly ones and very tight ones so I'd be surprised if that was the design intention!
Cynically it might actually be just a 'looks cool' but I'll bet the DH boys can see some serious disk surface temperatures and so this will help.
Running a large diameter steel or iron disk is a lot of heavy material you don't need, so just keeping th efriction surface as a good material and using lighter spider improves stiffness and reduces unsprung mass, more important that overall weight I'd guess in a DH bike.
part 2
Temperature depends entirely on the pad material, soem like heat others do not. Most car and m-bike pads are what MTB world refers to as sintered,ie they are iron powder based, or metallic. what we call organic pads (ie carbon or aramid {we know as kevlar} flake based) are very rare in the car world due to excessive pad wear.
I have never doen any scientific testing of MTB brakes so this is only extrapolation of the work I did on m-bike and racing car brakes:
a really cold disk tends to squeal and you get some 'creep-groan' at very low speed. the mu (coefficiebnt of friction) is also reduced slightly. thsi improves from 50deg- approx 450 deg, when fade starts to set in. pad material is a balance of four things: noise (squeal as we know it), fade performance and pad/disk wear Vs maximising (or rather keeping constant through a stop) the coeff of friction. You can't have all four at once, usually wear versus friction and noise versus fade, but they are all interrelated.
So my point is that you want a warm but not hot disk 50-450degC (linked directly to pad temp), so the float helps acheive both, faster warm up and isoplation from heat.
Waggle on a floating disk is as expected, but too much movement rotationally around the common axis signifies wear. a proper floating disk willhave some axial and radial play. But it is the weight and thermal benefits that they are designed for.
Thats as mibbe andyfb78, but it's all about the ping, ping, ping.
I wish I got mine hot enough to get ping ping ping....
Just bought vented V2 for the tandem, crossing the alps into Italy this summer, I may achieve that pinging this year heres hoping.
🙂
LOL @ GW
+2 annoy people who don't see the point in them
And that makes you better than them?
Lighter my ar5e...Floating hope rotor = 170g, Braking Wave rotor = 166g, Alligator Aeries rotor = 134g, all in 203mm. 🙄
I've not bent one throwing em in the back of my car!? and the ting ting noise is pretty cool - even if it's there to remind you you've been a pussy and on the brakes too much!
I've broken two floating discs. One when i lent my front wheel against the bumper of the car - drove forwards over it, then reversed over it again to see what I'd hit. The disc partially cut two spokes and the axle got pushed through a bit but the wheel, with a new disc, is still true and still in use.
The other was on road in London when someone cycled into my front wheel - slow speed, pretty much 90 degrees, neither of us came off (blind corner around a high wall). Again bent the spider. Aprobos of nothing really. Both times would probably have bent a standard rotors as well.
I was amused by someone at a demo day who told me that one reason never be ride a Rohloff because you can't fit floating rotors to them.