[MEIN_VW]

Looking at a SL55 in the parking lot the other day, I could not get over the size of the brakes and calipers and it got me thinking just how much do these things weigh? The huge 6-pot calipers alone looked heavy.
Taking the new E63 as an example, just how much could the wheels + tires + brake discs and calipers weigh?
2007 E63
Front brakes - 14.2" discs, 6-pot calipers
Front wheels - 18" x 8.5"
Front tires - 245/40ZR-18
Rear brakes - 13" discs, 4-pot calipers
Rear wheels - 18" x 9"
Rear tires - 265/35ZR-18

 

[bc]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (MEIN_VW)

light. the calipers are sealed aluminum monoblock. Usually 6-9lbs per unit. Regular 1/2-piston sliding style caliper is 13-15lbs.
The two piece rotor you have in the pic is also a lot lighter than a conventional pig-iron unit. I have the 2-piece rotors on my scooby and they are at least 1/2 the weight of a regular rotor.

 

[schtebie]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (Y2KRICEBOY)

Quote, originally posted by Y2KRICEBOY »

light.

http://****************.com/smile/emthup.gif

 

[.:Rchild]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (MEIN_VW)

quick !, you should call AMG , Im sure it will be a revelation for them .....

 

[MixmasterNash]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (schtebie)

How much does it really matter in a 4000+lb 500+hp autobahn stormer?

 

[CBJ]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (MEIN_VW)

Interestingly, if you look at the spec for the M5 you'll see..... What's this twin piston brakes. My god doesn't BMW know that more is better (and that the Audi RS cars have eight pistons).

 

[MEIN_VW]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (MixmasterNash)

Quote, originally posted by MixmasterNash »

How much does it really matter in a 4000+lb 500+hp autobahn stormer?

It doesn't. But I'm just curious as to how much a 14.4" disc and 6-pot caliper weighs.

 

[SteveMcqueen]

Does the caliper wieght realy matter?

 

[Slipstream]

Re: (SteveMcqueen)

Quote, originally posted by SteveMcqueen »

Does the caliper wieght realy matter?

I was just thinking the same thing... Since it's not part of the rotating mass, does it really impact rotational weight?

 

[rpaller]

Re: (Slipstream)

Quote, originally posted by Slipstream »

I was just thinking the same thing... Since it's not part of the rotating mass, does it really impact rotational weight?

No it should not impact the rotational weight.

 

[CannuckCorradoVR6T]

Re: (Slipstream)

Doesnt make a diff in rotating weight, but it does in unsprung weight. Even the aluminum hat style rotors wont help that much in rotational inertia due to the fact that most of the disk's bulk is on the outer diameter - but it will help with unsprung weight.

 

[Juniper Monkeys]

Re: (rpaller)

Yeah, a high quality two-piece rotor can be made very light. I have 11" two-pieces at the front of my Miata, and they're quite a bit lighter than the original 9-ish" ones.

 

[MEIN_VW]

Re: (Slipstream)

Quote, originally posted by Slipstream »

I was just thinking the same thing... Since it's not part of the rotating mass, does it really impact rotational weight?

It's still unsprung weight.

 

[Dawg Dee-Lux]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (CBJ)

Quote, originally posted by CBJ »

Interestingly, if you look at the spec for the M5 you'll see..... What's this twin piston brakes. My god doesn't BMW know that more is better (and that the Audi RS cars have eight pistons).

And there's more, if you have a look at Best Motorings brake-test between the Mercedes-Benz CL55AMG and the BMW M5, you'll notice that the two-pot brakes on the M5 does a better job stopping the car too.

 

[Levish]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (vag-tan-klan)

Quote, originally posted by vag-tan-klan »

And there's more, if you have a look at Best Motorings brake-test between the Mercedes-Benz CL55AMG and the BMW M5, you'll notice that the two-pot brakes on the M5 does a better job stopping the car too.

A lot of factors contribute to how fast a car stops, # of pistons in a caliper is not one of the more significant ones
Tires are one of the key ingredients especially in relation to vehicle weight

 

[Viergang Fuchs]

BMW is the master of the cheap-ass brake system. Five laps of any full-sized track is enough to send any of their M cars crying for Mommy.
Hell, I overheated the brakes on a 550i during the God-dammed Drive For The Cure and that was only a 13.4-mile loop in traffic.
But, speaking of unspring weight, when I came out of Subway last night there was a Murcielago parked next to me. The owner had made the decision to pitch Lambo's properly engineered wheels and put some Davins or some garbage like that on. They were 22" or bigger. Nothing says "I've never operated this car past 3/10ths" like giant cast wheels.

 

[riceburner]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (CBJ)

Quote, originally posted by CBJ »

Interestingly, if you look at the spec for the M5 you'll see..... What's this twin piston brakes. My god doesn't BMW know that more is better (and that the Audi RS cars have eight pistons).

Tell me if I'm wrong- but I thought I read that the purpose of multiple piston calipers was to distribute the force evenly across the entire caliper, rather than provide more braking force.

 

[Viergang Fuchs]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (riceburner)

Quote, originally posted by riceburner »

Tell me if I'm wrong- but I thought I read that the purpose of multiple piston calipers was to distribute the force evenly across the entire caliper, rather than provide more braking force.

The entire pad, but yeah. However, a sliding caliper effectively accomplishes the same goal.

 

[riceburner]

Re: Big brakes + big wheels and tires - let's talk unsprung weight (Viergang Fuchs)

Thanks for the correction.

 

[chewym]

19 inch wheels usually weight above 25 pounds, the rubber weights a similar amount. Ceramic disk brakes will be lighter by a good amount compared to steel.