Caliper Weights, Deciding where you want your un/semi-sprung weight Options

[Eric_Shea]

I finally had the time, the proper scale and all of the calipers varieties around to do a little comparison weighing. All calipers are without pins, springs and pads.

And the winners are:

Brembo Calipers = 4lbs. 6oz. (front 911 strut 3" spacing, or early 914 strut w/o caliper spacers, or late 914 strut with ClubHub 48mm pistons, #109 Pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360942664.1.jpg)

S-Calipers = 5lbs. 6oz. (front 911 strut with 3.5" spacing, 48mm pistons #45 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943317.1.jpg)

L-Caliper = 5lbs. 6oz. (rear early 65-68 911 caliper with 2.25" spacing 35mm pistons, #30 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943317.2.jpg)

Wide L-Caliper = 5lbs. 10oz. (rear early 911S 67-68, 38mm pistons, #30 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943318.3.jpg)

911 Rear M-Caliper = 6lbs. 2oz (rear 911 69-83, 38mm pistons, #31 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943318.4.jpg)

914 Rear Caliper = 6lbs. 10oz. (rear 914 All, 33mm pistons, #30 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943319.5.jpg)

914 Front Caliper = 6lbs. 14oz. (front 914 all, 42mm pistons, #31 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943319.6.jpg)

M-Caliper = 7lbs. 6oz. (911 & 914-6 Front, can be used on early 914 w/o spacers, 48mm pistons, #31 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943319.7.jpg)

A-Caliper = 9lbs. 2oz. (911SC all front 3.5" spacing, 48mm pistons, #45 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943320.8.jpg)

Wide A-Caliper = 9lbs. 4oz. (911 Carrera all 3.5" spacing, 48mm pistons, #45 pad)
(IMG:http://www.914world.com/bbs2/uploads_offsite/www.pmbperformance.com-1110-1360943320.9.jpg)
[same picture as above... just has 4mm wider spacers.]

Couple of things to note. The very lightest calipers and the very heaviest calipers share the same 48mm pistons and "almost" the same size pad. The 109 pad is the same pad as the BMW 320i... just as wide as the #45 pad but a couple of mm shorter.

Stands to reason a 3" 911T/914-6 strut with Brembo's is the lightest most effective system in this batch. Looking at the top and the bottom... you could shave almost 10lbs. of un-sprung/semi-sprung weight off your suspension and get the same performance!

[Eric_Shea]

These are the combined weight of two calipers, correct?

No... that's one caliper.

I never have been a fan of those calipers on a 914 for the weight reason. They are fine calipers and pretty much a staple in the Porsche line-up since 1978 but there's a couple issues that make me not want them on my car:

1. The rotors are the 24mm vented rotor. This adds weight beyond the 20mm standard vented rotor. Rotational Mass is the last place you would want to add weight. I have "never" heard of a 914 that is braking properly that has ever experienced fade on a 20mm vented rotor. If you check the historics and the HSR 2 Litre Challenge, all of those cars are wheel to wheel racing... HARD... on 20mm rotors and 908/S-Calipers.

2. The weight of the caliper - As you can see, the S-Caliper is a full 8lbs lighter (we're talking pair now) and it has the same piston and pad area. S-Caliper pads are actually thicker for racing purposes.

That said, some say the S-Calipers flex. I have yet to experience this on any S-Calipers that I've had. I've gone through pad bedding procedures that left the brakes smoking and I was "looking" for flex at the time. I dub thee an "Internet Myth"... YMMV

[DRPHIL914]

These are the combined weight of two calipers, correct?

No... that's one caliper.

I never have been a fan of those calipers on a 914 for the weight reason. They are fine calipers and pretty much a staple in the Porsche line-up since 1978 but there's a couple issues that make me not want them on my car:

1. The rotors are the 24mm vented rotor. This adds weight beyond the 20mm standard vented rotor. Rotational Mass is the last place you would want to add weight. I have "never" heard of a 914 that is braking properly that has ever experienced fade on a 20mm vented rotor. If you check the historics and the HSR 2 Litre Challenge, all of those cars are wheel to wheel racing... HARD... on 20mm rotors and 908/S-Calipers.

2. The weight of the caliper - As you can see, the S-Caliper is a full 8lbs lighter (we're talking pair now) and it has the same piston and pad area. S-Caliper pads are actually thicker for racing purposes.

That said, some say the S-Calipers flex. I have yet to experience this on any S-Calipers that I've had. I've gone through pad bedding procedures that left the brakes smoking and I was "looking" for flex at the time. I dub thee an "Internet Myth"... YMMV

@Eric_Shea i am sending you a PM , so as not to clog up this thread, but main question is for '75 car currently running stock calipers with 5 lug(drilled stock 4 lug rotor to 5 lug) - if i wanted to convert to the 20mm rotors and use these 3" space lighter S- caliper, what else would be needed to complete the conversion? any spacer at the mount on the strut?
- oh and i have 16" Fuchs 6'' front and 7'' rear.
Phil