FAO Yeehaa
steelie600
Posts: 519
Cast your mind back to last week and we were discussing disc brakes and temperatures.
Well cos im a saddo with no life and a blue anorak (jedi level) I was watching some vids last night and came across this beaut. It shows how in about 10 secs of light brake dragging whilst bedding a set of pads in the guy got the disc over 120*f! From an ambient of 60*f.
Proof if ever there was one that disc brakes on mtb's can generate serious heat
Enjoy the anorak styled geekiness from about 5 mins in
http://www.youtube.com/watch?v=SZOJZA9ybag&feature=BFa&list=PL3293736101E7C6B3
Well cos im a saddo with no life and a blue anorak (jedi level) I was watching some vids last night and came across this beaut. It shows how in about 10 secs of light brake dragging whilst bedding a set of pads in the guy got the disc over 120*f! From an ambient of 60*f.
Proof if ever there was one that disc brakes on mtb's can generate serious heat
Enjoy the anorak styled geekiness from about 5 mins in
http://www.youtube.com/watch?v=SZOJZA9ybag&feature=BFa&list=PL3293736101E7C6B3
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Comments
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steelie600 wrote:about 10 secs of light brake dragging whilst bedding a set of pads
this not how to bed in pads0 -
No but puts a lovely glaze on things.I don't do smileys.
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Parktools0 -
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Quite.TwellySmat wrote:120 fahrenheit is only 48 celsius. I went to Dubai and the air was hotter than that.
So, what exactly is your point, steelie600?
Is your thinking, or my thinking right, or wrong?0 -
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There's no need for that, you clumpnugget.VWsurfbum wrote:
This is something we were talking about a few weeks ago, and we're both interested to find out more about it. I'm just not sure what conclusion he's drawing from this video, since it's not heavy usage, and it doesn't have particularly high temperatures involved.0 -
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Very interesting I wouldn't mind seeing some spreadsheets andcharts on this. I might try attaching a remote thermometer sensor.0
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If you've got one, go for it, I'd be very fascinated to find out.FocusZing wrote:Very interesting I wouldn't mind seeing some spreadsheets andcharts on this. I might try attaching a remote thermometer sensor.
I used to have access to all sorts of interesting things, like non-contact thermometers and so on, but I've since changed jobs, and have somewhat less interesting toys to mess about with.0 -
YeehaaMcgee wrote:
If you've got one, go for it, I'd be very fascinated to find out.FocusZing wrote:Very interesting I wouldn't mind seeing some spreadsheets andcharts on this. I might try attaching a remote thermometer sensor.
I used to have access to all sorts of interesting things, like non-contact thermometers and so on, but I've since changed jobs, and have somewhat less interesting toys to mess about with.
I have a weather station so I could strap it to my bars and the sensor to the disc. I could use the barometric for the rate of climb. I could record the results with my mobiles video camera.0 -
See, for a minute I thought you actually weren't being a knob. I'll know never to make such a ridicilous assumption ever again.0
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He's not called Focusmong for nothing.I don't do smileys.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools0 -
YeehaaMcgee wrote:
Quite.TwellySmat wrote:120 fahrenheit is only 48 celsius. I went to Dubai and the air was hotter than that.
So, what exactly is your point, steelie600?
Is your thinking, or my thinking right, or wrong?
Neither of us is wrong at the minute, but its just a quick demonstration of how quickly the discs will heat up.
As you recall my theory is theyll get to a couple hundred degrees and hotter no worries, and you dont think they will.
Unfortunately my bike is still in a pile of bits whilst I wait for some more bits to come (build thread imminent) so I cant prove either of us right, even though ive got the thermometer thingy doofer.
But I think with the discs gaining that much heat in ten seconds of light pressure 60*f or thereabouts, I might be on target for the few hundred degrees theory. BUT will buy ou a beer if im wrong0 -
No need to buy me a beer, I'm not actually arguing with you, I just have a different guess of how hot they get.
I still think they'll shed heat quite well, preventing them from getting to 200degrees.
I'm not sure exactly how hot to guess they'd get, but somewhere under 200 degrees I'd have thunk.0 -
I bet you get could get your obvious up 60f in 10 seconds with the right sort of pressure.
By the way, what's this f business. c makes much more sense.I don't do smileys.
There is no secret ingredient - Kung Fu Panda
London Calling on Facebook
Parktools0 -
I would be surprised with 200f with a bikes discs being so exposed to fast moving air. I guess anybody could touch them quick after a descent for a general idea. I've seen some road bikes start to use discs too, due to weight being a priority they might get pushed hard.0
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Depends what contaminants are on it, it's often the crap on the disc that changes colour, not the actual disc.sheepsteeth wrote:i have turned a disc blue before, doesnt that occur at over 200 degrees?
Also, if there's something on the disc that prevents them from working properly, then you'll have to use them much harder, this could I suspect lead to greater than normal heat buildup.
And yeah, I'm talking under 200C - Farenheit is just nonsense.0 -
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Isn't that the colour they glow whilst actually heated? Not the burnished colour that Sheepsteeth is talking about.FocusZing wrote:
For example, rally car brakes (easily observable on night stages in the past) often reached that bright orange colour which suggests they're at circa 875 degrees. But when they cooled down they didn't stay that colour.
I don't think anyone's MTB brakes have reached anything near hot enough to start glowing at all under any use.0 -
Agree with this ^
Thermal imaging probably whats needed here I guess, I'd be interested to find out more.
I've also recently procured a Shimano ice tech rotor for cheap, I'm also interested to see if this makes any difference whatsoever.0 -
Just for reference I too am concerned with *c not fahrenheit, its just that the yanks are a bit in the dark ages and thats how he measured his temps.
I personally think we should have a get together ride out at a trail centre, and send 1 rider (pref fast as fook one) down the fastest DH section on a variety of bikes with different brakes and take readings and compare and contrast over a pint or ten.
Anyone up for this?0 -
I've got a better, nastier hill to do it on. Right behind the "Halfway House Inn" in Port dinorwic. The hill is friendly enough to come to a stop right above the carpark, and is seriously feckin steep. It is one of the most demanding places for brakes that I've ridden, especially within easy reach of a pub!steelie600 wrote:Just for reference I too am concerned with *c not fahrenheit, its just that the yanks are a bit in the dark ages and thats how he measured his temps.
I personally think we should have a get together ride out at a trail centre, and send 1 rider (pref fast as fook one) down the fastest DH section on a variety of bikes with different brakes and take readings and compare and contrast over a pint or ten.
Anyone up for this?
Because of a hairpin bend halfway down, and a tight left hander near the bottom, and the slimy surface, and occasional car, you are ultimately forced to control your speed over the whole descent, or the latter half of it anyway. This leads to a hell of a lot of heat build up - more than I've encountered anywhere outside of the alps, or a particular (again, road) section of the Cowlyd loop near Capel Curig.0 -
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It would also be interesting to see how different brakes perform, and with different riders.0
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Aye, I wonder if we could get bikeradar to supply a fleet of test bikes, and a hooligan for testing duties so we get a fair result on the temperature tests and then say a few of us test the different types of brakes to give a laymans verdict??0
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I'm sure between the forum members there are a fair amount of bikes you could test and an equal amount of 'ooligans without needing help from bikeradar0
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If we had a few people interested, then we could all test each other's bikes.
For example, I'm a big guy, it would be interesting to see how the heat buildup varies between me, and a lighter rider, on the same bike.0 -
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