Brake rotor not fitting 240Z vs 280Z hub?

[Zealous]

Hey All,

While I have the suspension out and replacing more bits and bobs on the car, I decided to refresh the rotors and brakes while changing the shocks and springs. I went to install some new 240z rotors I picked up but they are much taller in the hat then the old rotors I have. After looking around here and hybridz I am wondering if I have had my hubs replaced by 280z hubs some where in the cars life, or that I have the wrong new rotors. How I can tell the difference? The photo below show the difference in rotor hat sizes, even taking into account the wear of the rotor~2mm or so the hat is ~8-10mm taller than the old one. I am wondering if I had 280z rotors on the car? Does anyone have a 280z rotor with measurements so that I can compare? Or if there is a way to look at the hubs and know for certain if it is a 240z or 280z hub? I searched for this information all over but I could not find anything. If I missed it please send me to that thread.

[Zed Head]

They look like aftermarket rotors. What is the distance, compared between the two, from the bearing seat to the rotor face? And the dust seal seat. That will determine if the rotor is centered in the caliper, assuming the bearing diameters and other critical dimensions are the same.

[Zealous]

The difference is enough that the back of the rotor rubs up against the dust backing plate once mounted. The rear of the hub used to stick behind the rotor but with the new rotor it does not stick behind anymore. The hubs and bearings are exactly the same I have not changed them just the rotors and the rotor appears to be too tall. Moving the rotor back about 10mm up agains the dust cover.

[Zed Head]

Apparently, the rotors are different, starting with the 260Z, which you apparently already know. But if you have 280Z rotors on your 240Z, you must also have the 280Z front struts and hub assembly, I believe. Maybe you should check those dimensions.

That's all I know. Good luck.

[Zealous]

Thanks Zed Head, that is what I am asking what are the dimensions and difference of the hubs?

Maybe it is time I pulled the other Z apart too to check.

[Zealous]

Does anyone know the offset difference for the brake rotors between the 240z and 280z hubs? Just talked to part manufactures and they have sold many of the rotors and never had a problem with fitment reported.

[Zealous]

Ok so I think I have worked out that I do have 280z hubs on the front now looking at these two hybridz threads. My rotors are of the 280z height.

http://forums.hybridz.org/index.php/topic/88361-need-some-s30-brake-info/

240z rotor info.

# of Bolt Holes : 4

Bolt Circle Diameter : 103 mm

Brake rotor Diameter : 10.67"

Brake rotor Discard Thickness : .41"

Brake rotor Thickness New : .49"

Brake rotor Type : Disc Brake rotor Only

Center Hole Diameter : 3.19"

Height : 2.02"

Maximum Lateral Runout : .004"

Mounting Type : Type L - rotor Only. The rotor Is Mounted Inboard Of The Hub. The Hub & rotor Sections Are Bolted Together. Replace The Complete Assembly If Hub Flange Is Bent Or Damaged. See Diagram For More Information.

Vented / Solid : Solid

260-280z rotor info.

# of Bolt Holes : 4

Bolt Circle Diameter : 103 mm

Brake rotor Diameter : 10.67"

Brake rotor Discard Thickness : .41"

Brake rotor Thickness New : .49"

Brake rotor Type : Disc Brake rotor Only

Center Hole Diameter : 3.19"

Height : 1.7"

Maximum Lateral Runout : .004"

Mounting Type : Type L - rotor Only. The rotor Is Mounted Inboard Of The Hub. The Hub & rotor Sections Are Bolted Together. Replace The Complete Assembly If Hub Flange Is Bent Or Damaged. See Diagram For More Information.

Vented / Solid : Solid

guess the height is the differnce between the two. that is why the Hub spacers are also different in thickness when converting to vented z31 rotors depending on hubs being used.

More information in:

http://forums.hybridz.org/index.php/topic/52174-280z-vs-240z-front-offset/

Hope this helps someone else. Now off to source 280z rotors.