First Look: 914-6 Alloy Rear Calipers, ...about 30 days out. Options

[Eric_Shea]

The time has come. We are beginning to take pre-orders on the 914-6 rear calipers.

As you know, us 914 owners have long been looking for a solution to a properly biased brake system. The fronts have been the easy part, bolt on a pair of Brembo's ...or a 3.5" 911 front suspension and you would have your choice of larger calipers with 48mm pistons up front. But, what about the rears? You need a 38mm piston to give you the correct bias. For 914 owners that meant a long and winding road of searching for the proper solution which usually boiled down to two things; uber-rare (and uber-expensive) original 914-6 calipers or 911 rear calipers and a confusing handbrake assembly or, worse yet, 911 rear calipers and no handbrake solution.

Well, you're looking at the true bolt on solution. Aluminum castings of the famous 914-6 rear calipers. Final weigh-in has yet to be established but, we think we'll be under 3lbs each with the aluminum pistons.

These simply bolt on and use stock handbrake cables and parts. Larger pistons and larger pads make this the prefect rear caliper solution for Brembo bolt-ons and S-Caliper or A-Caliper upgrades.

What you are looking at is a raw alloy assembled prototype prior to anodizing.


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[Eric_Shea]

Sorry Rob. These will flex way too much for you. (IMG:style_emoticons/default/biggrin.gif)

The Brembos were cast copies of ATE steel A-Calipers. Hey Rob, how are your Brembos working out?

Tensile Strengths Steel and Aluminum

Structural steel ASTM A36 Steel
Yield strength (MPa) = 250

Carbon steel 1090
Yield strength (MPa) = 250

Aluminium
Yield strength (MPa) = 414

Human skin (mine is getting thicker with all this Internet philosophic discussion) (IMG:style_emoticons/default/biggrin.gif)
Yield strength (MPa) = 15

Aluminum
(IMG:http://www.914world.com/bbs2/uploads_offsite/upload.wikimedia.org-1110-1345214481.1.png)

1. Ultimate strength
2. Yield strength
3. Proportional limit stress
4. Fracture
5. Offset strain (typically 0.2%)

Steel
(IMG:http://www.914world.com/bbs2/uploads_offsite/upload.wikimedia.org-1110-1345214481.2.png)

1. Ultimate strength
2. Yield strength
3. Fracture
4. Strain hardening region
5. Necking region
A: Engineering stress
B: True stress

The Yield Strength of aluminum will always be the same regardless of the "caliper design". Now, let's get into real world observations: I've "NEVER" seen a broken aluminum caliper but I've seen "innumerable" steel calipers with mounting ears fractured off and sealing flanges fractured. Steel is much more brittle than aluminum. The aforementioned Brembos have been in use since the mid-70's and again, I've "never" seen one broken or fractured. Same material depth on the mounting ears and around the piston flanges. Again, an aluminum copy of an ATE steel caliper that was used on virtually every European make sedan and sports car. Finally, virtually all modern calipers are all made of aluminum now as it's lighter and stronger and better suited for the application of being hung off a cars suspension. They're using computers now and... they're using aluminum to manufacture calipers. Some "slide rule" designs were ahead of their time (Porsche seems to be famous for this).

Brembo, Alcon, PFC, Wilwood, etc all spend huge amounts of resources on trying to make their calipers stiffer.

Back it up. Can you tell me how you could possibly know these companies spend huge amounts of resources to make their calipers stiffer or is this a general claim? If I were to make a general claim it would be that their engineers look at the numbers I posted because modern (computer) design practices dictate the use of the "Yield Strength" figures.

All the brake companies will tell you the flex is in the caliper design, not the fasteners.

Again, back it up. You've spoken to "All the brake companies"? I've searched for your "flex design" criteria. I think you're making general statements that people could easily confuse with facts and even those are wrong. E.G.: with 4 M8 fasteners running from the nose to back... the fasteners "definitely" do play a factor in flex or no flex. If the fasteners were made out of rubber; would the caliper flex? Aluminum? Now steel? Steel is used where it is needed in modern computer designed aluminum calipers.

So Matt... are you worried about actual "Strength" or are you concerned that these will literally "Flex" their way off the car? Or is there another point that you feel needs to be made?

[MDG]

Human skin (mine is getting thicker with all this Internet philosophic discussion) (IMG:style_emoticons/default/biggrin.gif)
Yield strength (MPa) = 15

Okay.

If your skin continues to thicken at the rate this chart suggests, thereby becoming less flexible and losing elasticity, as a precaution, have you now forbidden your Venezuelan maids from wearing those short skirts? You know, in case you have any, um, flex?

[scotty b]

Human skin (mine is getting thicker with all this Internet philosophic discussion) (IMG:style_emoticons/default/biggrin.gif)
Yield strength (MPa) = 15

Okay.

If your skin continues to thicken at the rate this chart suggests, thereby becoming less flexible and losing elasticity, as a precaution, have you now forbidden your Venezuelan maids from wearing those short skirts? You know, in case you have any, um, flex?

But wouldn't the flexing technically result in a stiffer piece (IMG:style_emoticons/default/confused24.gif)

[SLITS]

Human skin (mine is getting thicker with all this Internet philosophic discussion) (IMG:style_emoticons/default/biggrin.gif)
Yield strength (MPa) = 15

Okay.

If your skin continues to thicken at the rate this chart suggests, thereby becoming less flexible and losing elasticity, as a precaution, have you now forbidden your Venezuelan maids from wearing those short skirts? You know, in case you have any, um, flex?

But wouldn't the flexing technically result in a stiffer piece (IMG:style_emoticons/default/confused24.gif)

Not in Erc's case ... you can't stiffen what is already flaxen. (IMG:style_emoticons/default/poke.gif)