Author Topic: various brake rotors compared  (Read 1386 times)

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kitno455

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various brake rotors compared
« on: February 06, 2006, 12:17:17 AM »



went to local u-pull-it, and measured all the slip-off solid (non-vented) brake rotors i could reach. all measurements rough at best, expect up to 1/10 inch error in some places, more on the larger dimensions, as the rotors were all on the cars with calipers and dust shields still installed. measurements in decimal inches, just to confuse everyone, metric and cavemen alike.


i bet this will look bad, but lets try:




car                           A     B    C    D    E   Comments



  1. ? BMW 735i (sedan)       0.5  11.5  7.0  2.3  3.0  biggest, tall hat, screwed on
  2. Olds Aurora/Caddy Dvil  0.45 10.8  6.5  1.0  2.8  short hat, second biggest
  3. MB 380E (sedan)         0.4  10.5  6.6  2.3  2.5  thin, tall hat, screwed on
  4. -2001 Chrys Concord/NY'r 0.5  10.3  7.3  1.3  2.8  bolt-on hub, drum brake in hat
  5. VW Cabbie (pickup)      0.5   9.0  5.4  0.9  2.5  front, 4lug, small



we are looking at the rear rotors on all of these except the VW.


japanese/korean cars tend to be drum or vented disks, and usually small.


i saw one volvo like the dans used to use, but it had a vented rotor on one front side, and a solid on the other! the hat was very tall, and the hub integral. i think the dans have covered those well.


in the case of the 3 german cars, you would have to do some cutting to use the original hub, as it is also integral with the upright. the vw is a solid beam rear axle, so it might be easiest to move disk to rear. the MB and BMW are IRS, so you have to worry about the hubs coming apart if you take out the axle CV. perhaps their front hubs can be used instead, though they are also integral. those two also have really tall hats, so you cant get two of them close together.


for the american cars, recent ford taurus/merc sable have rear rotors similar to the olds/caddy, but the hubs are integral.


so that leaves us with two brands with larger, solid rotors and removable hubs. slight difference in thickness and diameter. olds/caddy = $15 autozone/$19 advance, chrysler is $25/$19 respectively. gm looks easier to remove in salvage yard, but chrysler has neat integrated parking brake inside the hat. both are 5 bolt, and the bolt patterns look very close. close enough that you could touch one with a dremel and make it fit with the other. i cant tell from the autoparts websites just how much of the hub you get, but it looks like the gm hub is avail. complete from advance. the chrysler hub seems to only be the outer part. in either case, i would use a used hub. less expense, less friction.


both of these cars have slightly larger (11.0/11.5 inch) front rotors, but they are vented. the metal behind the mags will be 0.1-0.2 inches thinner. the hats look the same. so if you need that extra inch, and have thin mags, that might work.


i think the short hat on the gm rotors should make it possible to stack two of these and get a < 1 inch airgap between the plates (without mags). the gm rotor might fit inside the chrysler one, getting you down as low as you want to go.


allan

« Last Edit: February 06, 2006, 12:17:17 AM by (unknown) »

kitno455

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Re: various brake rotors compared
« Reply #1 on: February 05, 2006, 05:21:43 PM »
arg. scoop...


car                            A     B    C    D    E   Comments

1990? BMW 735i (sedan)        0.5  11.5  7.0  2.3  3.0  biggest, tall hat

1995 Olds Aurora/Caddy Dvil   0.45 10.8  6.5  1.0  2.8  short hat

1985 MB 380E (sedan)          0.4  10.5  6.6  2.3  2.5  thin, tall hat

1993-2004 Chrys Concord/NY'r  0.5  10.3  7.3  1.3  2.8  bolt-on hub

1981 VW Cabbie (pickup)       0.5   9.0  5.4  0.9  2.5  front, 4lug


allan

« Last Edit: February 05, 2006, 05:21:43 PM by kitno455 »

Jerry

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Re: various brake rotors compared
« Reply #2 on: February 05, 2006, 08:05:48 PM »
Hi Allan.


This is timely. Today I was playing around with some brake disc. I've collected a few over the last several years but never used them.


I've built 2 dual rotor disc alts now but I've just used cut steel.


So far my alts have been small. I'm rounding up parts for my 3rd disc machine.


It will be a 10". I mount my blades to a shaft so this requiered some form of adaptor to combine a car disc and a shaft.


Being in the car stereo biz I have many old junk speakers to use a doaners for parts.


Today I machined a speaker magnet end plate to fit a GM disc. I drilled hole through both and bolted them dogether. I chucked this combo in the lathe and it ran real smooth and true.


The disc is 10" dia. and has a D meassurement of only 3/8". I don't know what GM car it comes from but the GM# is 14087871. Its 7/16" thick. Most likley 1/2" or more new.


The area for magnets though is only 1.5" wide. It would be nice if they made a 12" version of this 1 with 2" or more available for magnets?


Here a few pix of what I did today.

















I was just checking room for the 1.5" magnets. They are not position correctly. I just stuck them on random to get a ballpark idea.


                              JK TAS Jerry

« Last Edit: February 05, 2006, 08:05:48 PM by Jerry »

kitno455

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Re: various brake rotors compared
« Reply #3 on: February 06, 2006, 07:25:04 AM »
so your prop is some sort of shaft mount? are you adding a set screw to the speaker cap, or did you put bearings in it? the outer part of the factory hub is basically just like that, but has a larger inner hole for bearings and shaft.


allan

« Last Edit: February 06, 2006, 07:25:04 AM by kitno455 »

Jerry

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Re: various brake rotors compared
« Reply #4 on: February 06, 2006, 10:52:37 AM »
Yes I've drilled holes through both the speaker end cap and the brake disc. The shaft is secured directly to the speaker end cap. I drill and tap the small potion of the end cap (magnetic pole pice) for a set screw.


I use bearings on the shaft as per Eds kit and my diary on my last dual rotor.


The shaft portion your refuring to on the stock hub is a spindel and does not turn its stationary.


                       JK TAS Jerry

« Last Edit: February 06, 2006, 10:52:37 AM by Jerry »

Jerry

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Re: various brake rotors compared
« Reply #5 on: February 06, 2006, 09:52:28 PM »
Hi Allan.


I picked up the other GM rotor today, new $11. That # I posted is a casting # but the auto parts guy was able to cross it.


I machined a few more speaker backing plates. So here goes another 1 month or more dual rotor project?


                        JK TAS Jerry

« Last Edit: February 06, 2006, 09:52:28 PM by Jerry »

kitno455

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Re: various brake rotors compared
« Reply #6 on: February 07, 2006, 07:40:35 AM »
yes, all cast parts have a casting number instead of a part number. this makes it possible for the oem to make running changes and not change the parts books.


were you able to determine what car it came from? (most gm cars have drum rear, so i may have missed it)


nice work on the bearing and pipe setup in your diary, looks neat.


allan

« Last Edit: February 07, 2006, 07:40:35 AM by kitno455 »

Jerry

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Re: various brake rotors compared
« Reply #7 on: February 07, 2006, 09:07:20 AM »
No the parts guy didn't tell me what car. I have a feeling GM uses this disc on several car models.


Now I'm trying to figure out coil size, shape, wire gage and all. I'm useing 1.5"X1/4" round NEOs on this 1.


I've machined the backing plates to fit the disc and bored a 1" hole for the  shaft.


I figure another month or so on this one to.


                        JK TAS Jerry

« Last Edit: February 07, 2006, 09:07:20 AM by Jerry »

kitno455

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Re: various brake rotors compared
« Reply #8 on: February 20, 2006, 01:41:15 PM »
i think at this point, my favorite setup would be the gm hub with gm rotor on it (maybe the one jerry found?), followed by the chrysler rotor on top. i think the larger hat on the chrysler will fit over the gm, making easy air-gap adjustments.


allan

« Last Edit: February 20, 2006, 01:41:15 PM by kitno455 »