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Brake temp

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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Baronbb
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Brake temp

Post by Baronbb » Tue Oct 07, 2014 8:01 pm

Hi, I have standard brakes with 18's on a 20i. I went out for a drive the other day in the country and there was a lot of acceleration followed by braking into corners.
When I got home I put my hand near the wheel and the heat was pouring off it.
So question is what temp could they get up to?
Anyone measured their own?

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KERMIT1970
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Re: Brake temp

Post by KERMIT1970 » Tue Oct 07, 2014 8:27 pm

Sounds like a sticky caliper ! Are both wheels of same temp or one worse than the other ?
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Re: Brake temp

Post by mad4slalom » Tue Oct 07, 2014 8:30 pm

did you expect to be able to touch them :? ?

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Re: Brake temp

Post by KERMIT1970 » Tue Oct 07, 2014 8:32 pm

mad4slalom wrote:did you expect to be able to touch them :? ?
You should be able to touch the wheel without getting burnt !
Cars: 2016 M4 vert YMB & X3m Comp. E30 325i Sport. Z3M

Gone
: 2014 z4 35is melbourne red & black leather
: 335d M sport Coupe Black with red leather
: z4 Coupe 3.0 si Red with Black Leather 18" CSL`s
: z3 2.2 sport

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Re: Brake temp

Post by Maniac » Tue Oct 07, 2014 9:09 pm

KERMIT1970 wrote:
mad4slalom wrote:did you expect to be able to touch them :? ?
You should be able to touch the wheel without getting burnt !
Did the OP say he got burnt? Discs can easily reach 100C under high load, you can see them glow when used on track if given significant hammer. Hence brake fade at high use. Of course you'll feel heat from them for quite a while after. The wheels will take some of this heat also, but nowhere near as much as they're alloy.
Last edited by Maniac on Tue Oct 07, 2014 9:15 pm, edited 1 time in total.

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Re: Brake temp

Post by Maniac » Tue Oct 07, 2014 9:11 pm

Did it look like this? ;)


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KERMIT1970
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Re: Brake temp

Post by KERMIT1970 » Tue Oct 07, 2014 9:46 pm

Maniac wrote:
KERMIT1970 wrote:
mad4slalom wrote:did you expect to be able to touch them :? ?
You should be able to touch the wheel without getting burnt !
Did the OP say he got burnt? Discs can easily reach 100C under high load, you can see them glow when used on track if given significant hammer. Hence brake fade at high use. Of course you'll feel heat from them for quite a while after. The wheels will take some of this heat also, but nowhere near as much as they're alloy.
What I ment was the wheel souldnt be hot with road use !
Cars: 2016 M4 vert YMB & X3m Comp. E30 325i Sport. Z3M

Gone
: 2014 z4 35is melbourne red & black leather
: 335d M sport Coupe Black with red leather
: z4 Coupe 3.0 si Red with Black Leather 18" CSL`s
: z3 2.2 sport

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Re: Brake temp

Post by Maniac » Tue Oct 07, 2014 9:50 pm

Op said; 'I went out for a drive the other day in the country and there was a lot of acceleration followed by braking into corners.'

I'd take that as a bit more than usual road use so I'd expect hot brakes after a more 'spirited drive'.

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Baronbb
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Re: Brake temp

Post by Baronbb » Wed Oct 08, 2014 7:49 am

Hey, thanks for responses.

Maybe I wasn't clear, I didn't actually touch them and don't think there is an issue, was just surprised at how hot they were when I put my hand near them.

It was as some would say a 'spirited drive' and I was just interested in how high the temp could get. If I had a fancy thermometer I would have checked, just wondering if others already had.

Cheers

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Re: Brake temp

Post by flybobbie » Wed Oct 08, 2014 8:50 am

Lidl have some cheap infra red thermometers on offer at the moment.
Ideal for checking disc temperatures.

When i first bought a Peugeot 106 i changed the brake pads.
Driving to work i could smell them burning. When i looked at the disc it was glowing orange and had cooked the pads, when i removed them at the side of the road. The calipers had jamned on.
I later discovered i had just copied the 'way round' the original pads had been fitted when i replaced them. Turns out the originals had been fitted wrong. I had fitted them in mirrored pairs, exactly as they came off. This was wrong as they should be fitted as odd pairs.

Just shows when fiiting parts, don't just copy as they come off, cross check with a diagram.

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Re: Brake temp

Post by SO8 » Wed Oct 08, 2014 10:04 am

Do not try touching the disc after any spirited drive - you will end up in A&E Lol !

I have seen car brakes on fire - literally pouring smoke ... but that was a police traffic car years ago and they had to uprate the brakes on them all. Police drivers are taught to brake very heavily and standard cars do not like it ! BMW 5 series as traffic cars are Ok though so either brakes have come a long way or BMW's are very, very good.

Do not worry too much - brakes can take a lot of abuse and be totally fine.

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Re: Brake temp

Post by Visionist » Sun Oct 19, 2014 8:39 pm

BMWs are, generally, derided for their brake fade, which is seen as disproportionately high compared to other marques.

i'm not sure why though. I haven't looked at an M Power car that wasn't criticised for its early brake fade. It seems the heavier cars suffer the most, which makes sense.

My friend won't track his M39 as a result; he's paranoid.
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