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Old 07-29-2013, 07:26 PM   #1
Ivyleague OP
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Question Do hot brakes stop faster?

First I have to define"HOT"
I bought a new Triumph Bonnieville this past April, the purpose of which was to get a bike big enough for a sissy bar so my wife might want to ride more. Well, it hasn't worked out, in part due to some brake problems. My son borrowed it for a short ride right after the bike had its' first service and when he came back, the rear brake squealed loudly. I took it to the dealer who said he probably "rode the brake pedal" and heat-glazed the rear pads. The dealer had the bike for a month and I just got it back weekend before last. But my son borrowed it again and took it for a shorter ride to the store - less than 2 miles - and the back wheel caught on fire! The brakes were causing enough friction to melt the brake line causing a fire when the brake fluid ignited. Nobody I have talked to has ever heard of anything like this. This is a 2013 Triumph T-100 with about a thousand miles on it.

So my son says, if the back wheel is on fire, you can stop really fast. Any thoughts?
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Old 07-29-2013, 07:39 PM   #2
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Ceramic type pads need some heat to operate correctly. Too much heat for any brake system causes fading, and as you saw: fire

There appears to be a common denominator here with your brake problems.
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Old 07-29-2013, 07:45 PM   #3
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Originally Posted by k5mitch View Post

There appears to be a common denominator here with your brake problems.
I was thinking the same thing. If the brakes are fine when you ride but overheat when the boy is riding, it might not be a bike problem.
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Old 07-29-2013, 07:46 PM   #4
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Flammable brake fluid? NOT ! You've been TROLLED.
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Old 07-29-2013, 07:49 PM   #5
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Originally Posted by Ivyleague View Post
So my son says, if the back wheel is on fire, you can stop really fast. Any thoughts?
If the back wheel is on fire, you'd WANT TO stop REALLY FAST.

Seems like your son is using the brake pedal like it's a footpeg.

Oh yeah, and brake fade from overheated brakes is a cause of loss of brake performance. (Seems like you're not, ya know, Ivy League material there, Scout.)
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Old 07-29-2013, 07:51 PM   #6
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Do something to his mom.
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Old 07-29-2013, 07:55 PM   #7
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Do something to his mom.
Apparently he already did, but it was years ago....
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Old 07-29-2013, 08:15 PM   #8
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Dunno 'bout hot brakes, butt I stop purdie fast fer hawt chicks.

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Old 07-29-2013, 08:15 PM   #9
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Yeah, first thought is your son owes you some money.

Long ago a friend of mine loaned out a nice vintage TY250 for a trail ride. Quite a ways into the ride the rider went through a water puddle and steam boiled off of the rear brake hub. I witnessed that and had the group stop. He was riding the brake peddle the whole time. My friend was almost in tears. At least no hydraulics were involved.


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Old 07-29-2013, 08:49 PM   #10
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Did you bother to tell your son the difference between the brake peddle and the foot peg?
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Old 07-29-2013, 09:01 PM   #11
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If the brake fluid has been exposed to the atmosphere (rubber seal improperly installed, fill ups with contaminated fluid, etc.), it could have absorbed some humidity.
When this happens, after some hard braking, that water becomes steam inside the lines, putting pressure on the pistons and pads.
Due to that reason, even if the rider is not pressing the lever, the pads can keep dragging for miles, generating more heat and expanding the steam even more, which creates more force over the pistons, and so on.
........... just a possibility.
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Old 07-29-2013, 09:06 PM   #12
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Originally Posted by lnewqban View Post
If the brake fluid has been exposed to the atmosphere (rubber seal improperly installed, fill ups with contaminated fluid, etc.), it could have absorbed some humidity.
When this happens, after some hard braking, that water becomes steam inside the lines, putting pressure on the pistons and pads.
Due to that reason, even if the rider is not pressing the lever, the pads can keep dragging for miles, generating more heat and expanding the steam even more, which creates more force over the pistons, and so on.
........... just a possibility.
This makes no sense , if the master-cylinder is working properly and he really wasn't dragging the brake. Any pressure would release into the MC reservoir.
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Old 07-29-2013, 11:46 PM   #13
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If the back gets hot enough to weld the moving parts together...ya..you'll stop real fast
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Old 07-29-2013, 11:49 PM   #14
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This makes no sense , if the master-cylinder is working properly and he really wasn't dragging the brake. Any pressure would release into the MC reservoir.
The MC reservoir has very little headroom in it. The brake system is closed to atmosphere (mostly; moisture finds it's way into the system by migrating through the seals during normal operation). Steam takes up a FUCKING HUGE (science term) volume in comparison to that of water. Makes perfect sense.
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Old 07-30-2013, 12:22 AM   #15
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And for the record, DOT 3/4 fluid IS flammable.

Don't know what happened with the Bonnie, but theoretically if it got hot enough to cook the piston seals, and fluid leaked out, flames could very well happen.

If the caliper was misaligned, or there was moisture in the fluid, or the pedal was misadjusted, it could very well have been dragging enough to heat things up without Junior's foot on the pedal.
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