Quick brake size question

[rrubel]

What were the stock rotor sizes for early C4's with 16" wheels and later C4's with 17" wheels?

Thanks...
[RICHR]

 

[sothpaw]

I think for 17" from 88 up to '94 it is 12" dia. (front and back). I am unsure of the thickness but look up the specs here for a 1993 and you'll see my rotor specs. Now, all this excludes the ZR-1.

Now in 1995 they took the heavy duty (HD in catalog) brakes from the ZR-1 and but them on all vettes. That is a 13" front,
2 piston caliper. The HD conversion kit is $850 from vb and others.

 

[Ken]

From Michael Antonick's...

...new book Cor-vette specs, C4 1984-1996 comes this, a passage from the press release written in June, 1987, for August release, by Jane Eckhoff.

Wheels and Tires:
Wheel and tire lineup for 1988 is new; both standard and optional wheels have been restyled. The base wheel with standard suspension remains 16 x 8.5-inch with Goodyear P255/50ZR16 Eagle ZR50 tires, which obviously meet the new international "Z" rating system for "149 mph +" top speed tires, and 16 x 4-inch steel spare with T155/80D16 tire.

The new optional 17 x 9.5-inch wheels are fitted with Goodyear P275/40ZR17 Eagle ZR40 tires, while the 17 x 4-inch aluminum spare is Goodyear's T155/70D17 tire. The optional tires represent state-of-the-art tire technology for better wet and dry traction, braking and handling.

New 17-inch wheels with directional cooling fins are standard with the Z51 and Z52 options.

Brakes:
New twin piston front brake calipers and larger and thicker diameter rotors for 1988 provide increased braking capacity and longer pad life. Also for 1988, optional heavy-duty brakes are available with the 17-inch wheel option, including even larger rotor and matching caliper system.

All rotors are of integral construction. Standard front and rear rotor size is 305 x 20 mm, while the heavy-duty front rotor is 330 x 28 mm.

• Brakes--Service
• Description: Aluminum caliper with nodular iron reaction bracket; pad reaction thru braket.
• Brake type front: Disc with sliding-head caliper, low drag.
• Brake type rear: Disc with sliding caliper, low drag.
• Self adjusting: Standard
• Special valving type: Proportioning, integral with master cylinder.
• Power brake: Standard
• Booster type: Integral; lightweight with tru-bolt reaction system.
• Vacuum source: Inline (intake manifold)
• Anti-lock device type: Electronic 4-wheel, 3 channel (standard)
• Effective area: 27.0 sq. in. (front); 18.3 sq. in. (rear)
• Gross lining area: 27.0 sq. in. (front); 18.3 sq. in. (rear)
• Swept area: 96.4 sq. in. (front); 87.5 sq. in. (rear)
• Rotor outer working diameter: 11.5" (front); 11.5" (rear)
• Rotor inner working diameter: 8.42" (front); 8.75" (rear)
• Rotor thickness: 0.8" (front); 1.6" (rear)
• Rotor material and type: Vented; gray cast iron (front), damped iron (rear)
• Wheel cylinder bore: 2.1" (front); 1.6" (rear)
• Master cylinder bore: 0.862"
• Master cylinder stroke: 0.49"
• Pedal arc ratio: 3.5:1
• Line pressure at 100 lbs. pedal load: 1250 psi (front), 800 psi (rear)
• Lining clearance: Self adjusting
• Front brake lining bonding: Integral molded
• Front brake lining manufacturer: Japan Brake Industries
• Front brake lining code: CP26
• Front brake lining material: Semi-metallic
• Front brake lining size primary: 5.2" x 1.52" x 0.34"
• Front brake lining size secondary: 4.4" x 1.56" x .034"
• Front brake shoe thickness: 0.22" backing plate
• Rear brake lining bonding: Integral molded
• Rear brake lining manufacturer: Japan Brake Industries
• Rear brake lining code: CP26/B11
• Rear brake lining material: Semi-metallic
• Rear brake lining size primary: 4.25" x 1.38" x 0.34"
• Rear brake lining size secondary: 3.62" x 1.42" x .034"
• Rear brake shoe thickness: 0.2" backing plate

Probably way more than you care to know, but I had the time and energy so I figured why not share this.

 

[rrubel]

HOY! Definitely information overload! But thanks, and thanks also for the link to that Mike Antonick book. Winter holidays are coming, and that looks like a good resource to have (I've relied on his Black Book for years).

I'm trying to decide whether to spring for a Big Brakes kit or buy Sothpaw's current fronts when he upgrades to HIS bbk and use them as cores to just get new stock late-C4 brakes cheap.

Ken, as always you rock...

[RICHR]