NEED measurement of gen3 rear brake disc

[hotsv1]

does anyone know the measurement of the rear brake disk of GEN3 mr2? i know the disk is 280mm X 22mm thick..but i need to know the measurement of actual bell, from the face of the hub to the face of the disk. any other helpful measurement would be nice. (need measurement to get 330mm aftermarket groved disc) if anyone knows exact depth and size of the bell for the 330mmx22mm rear disc would be great help

[welsha]

47mm I think is the height
:: EBC Brakes Direct Limited : Cars : Brake Discs & Brake Drums : TOYOTA : MR2 : 2.0 Turbo : 92-2000

[CJMR2T]

If the EBC info is correct, they are 23mm disc's not 22mm. Again, if all that info is correct, then the hat / bell section is 24mm.

Most manufactures list the Heigth as an overall height (Bell and disc) so take the 47mm height and subtract the 23mm disc thickness and 24 is the resulting height of the bell.

Something else that needs to be taken into account for is the thickness of the bell flange. The thickness of the flange will through the disc centerline off if it is not the same thickness as the original. Also, it can effect the offset of the wheel.
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Oh btw. I may be new here to the MR2 boards and forums, but I am in no way a newbie to the industry (especially when it comes to brake)

[hotsv1]

u do sound like u know a lot . the measurement from different companies varies, i got measruement of 281x22mm, 46.3 disc height, and 5x114.3 pcd. the only measruement i cannot get is the thickness of flange as u mentioned. anyone knows the measurement of that. i am taking it would be around 7to 8mm.

[CJMR2T]

Im pretty sure that the bell flange thickness is 6.5mm. Im designing my own BBK (F&R) at the moment, and from what all I can find, the gen 3 brakes are the same as the 93-95 gen 2 brakes here (U.S.). That being said, All of them here (again, U.S.) have a 6.5mm flange thickness.....

Side note... In the past, I have found that DBA (Disc Brakes Austraila) is very accurate with thier rotor specs and them matching specs that I have personally measured myself and list the rear for 93-00 as being 280mm dia, 46.5mm height, and 22mm thick; all of which are matching very closely to the specs you got.

Hope this helps.... Let me know if you need anything else and I'll see what I can do / come up with....

[CJMR2T]

Oh BTW, that 6.5mm was measured directly for a OEM disc but it was on my car which is a 91 but the flange is sopposed to be the same thickness for all sw20 discs so the 93-00 should be the same.

[Oteck]

are you making your own rear rotors or trying to find one close to it? Most rear bbk for the mr2 req using rx8 sport front rotors and extending the 93 caliper. I don't really like this as it just exessive weight and pad coverage becomes limited.

My LS430 BBK using 12.6" front rotors and 12.2" rear rotors by retaining as much from factory possible so aside from the brackets all parts are oem and no hub ring adaper required. Though my setup suffers from loosing the hand brake (lack $$) but i will have one again when i can order some spot calipers

Fronts

Rears

[CJMR2T]

Oteck, I dont know how well you brakes compaired to what it should, but from the looks of your setup, the natural bias is off to the front too much (roughly 10% from quick calcs) your setup is somewere real close to 70/30 F/R where as a stock MR2 setup is right at 60/40 F/R....

If you are running more more tire (width wise) compaired to stock and its been lowered, then it would benifit from even more rear bias...... Remember, more tire mean more grip and lower Cg (center of Gravity) means less weight transfer and less weight trasfer mean less vertical load on the fronts and more on the rears during braking over the stock Cg.. Thus having too much front bias is only going cause the front tires to be over worked and locked up sooner then they should and the rears under worked.

Here is an example, My MKIII supra. In stock form, had a natural bias of 72/28 F/R

Stock with 225-50-16 (Falken FK-452) had a 60-0 of 128ft

Lowered (1.75") with 245-45-17 front and 285-35-18 rear and stock brakes had a 60-0 of 116ft (12ft drop)

Same as above (lowered and wheel / tire) but with a custom 13" 6pot front setup and a 13" 4pot rear set up sized to give a natural bias of 65/35 F/R that I built and this dropped my 60-0 down to 99ft (17ft drop over no BBK's and 29ft over stock setup and tire size)

As for the Mechanical Spot calipers. Unless you dont mind rattling sounds, I would stay away from them. The rattle like crazy and that is one of the main reasons why Wilwood stopped producing them and sold off the Rights to the design.

Im trying to work out some mounting detials to run a mini drum for parking similar to say the supra's, Lexus's, etc........ I was going to use a Brembo parking caliper, but they are way to expensive (more then the regular calipers im going to be using)...

[Oteck]

How did you calculate that? Doesn't the bore on the piston determin that? My system not final yet as the car running and I do plan to put an adj bias.

Also about drums, i've looked into it as i have all those parts and it means a new axle and spindle. Those will kick out your offset by +14mm
due to the massive size of the horse shoe needs

[CJMR2T]

Yes, bore diameter is sorta a determining factor. It not so much bore diameter but total piston area. Thats only one part of the overall factor that determins natual bias (uneffect by proportioning valve or base bias below the knee point of the valve). Effective rotor diameter is also a major factor in the natural bias.

MR2's have larger diameter rear rotors for the reason of increasing rear bias.

The third factor is the Pad Cf (coeficient of friction). This can also have a significant effect on the bias. One factor that has to be added in when dealing with pad Cf changes is the operation temps of that particular wheel / axle... Manufactures use differnent pad materials between the front and rear cause of temp differances. Fronts run hotter then the rears so they try to use a materials that have the same Cf at the different temps but with a linier change to each other cause all pad materials change with temp change. They also select materials that are best in the typical opperating range for the designed intended use.. That part is very improtant.... Try stopping a car with a Carbon / Carbon pad / rotor set up when its cold and your gonna hit what ever is infront of you. They dont work for sh!t below 500*... This is why you'll tend to notice some HIGH end (like GT1, LMP, and F1 cars) riding the brakes right before going green on a full coarse caution, its to get them heated up so they can slow down going into turn 1 etc.....

[hotsv1]

cheers for that

[CJMR2T]

Originally Posted by Oteck

Also about drums, i've looked into it as i have all those parts and it means a new axle and spindle. Those will kick out your offset by +14mm
due to the massive size of the horse shoe needs

Forgot to comment on this part....

I know using the toyota OEM stuff is pretty much not possible due to its size, but toyota is not the only company that uses this type of setup. GM has a very tight and conceled unit on the C5 and C6 Corvette's. The shoes are the same 190mm diameter as most all of the OEM toyota stuff but the they are only about 20 to 25mm wide... The C5 / C6 vette setup is very simple yet effective setup and was specifically designed to fit in a very tight spot. The GM shoes and actuators on a set of custom backing plates and I dont thing that it'll stick out past the face of the stock hub flange.

I need to get ahold of a set of the shoes to get some exact dimentions on them though to be sure. Also a similar setup was used on the GTO's but they are only 180mm diameter. I also think that they used a very similar setup on the new G6's and G8's too but Im not sure of this.