[thintin]

i am trying to locate an over the counter rotor ....11.5......5 on 5.....2.878 center hole.....have found 5 on 4.50 and 5 on 4.75 but no 5 on 5........input appreciated

[powerrodsmike]

Are you looking for parts store rotors? The overall height is a critical dimension as well. ( lay a rotor flat on a table and measure from the table to the highest point) I have a Raybestos catalog with part numbers, OD, bolt circle, rotor thickness, and overall height, as well as whether or not it is rotor or hub integral with rotor and mounting style. It does not however list the center hole dimension.

Possibly you can find a parts store that has the paper master reference guide, or illustrated buyers guide for the brake rotors they sell. If you give me your overall height and mounting style I'll look in my catalog and try to come up with a part # you could cross reference at your local parts store.

There are companies that can put a hat and rotor assembly for you, and let you choose the dimensions, such as coleman racing or wilwood, but then it's not over the counter....
Are you building a disc brake swap?
Larger Ford such as LTDs and station wagons and some later full size GM cars have 5 on 5" patterns.

You might be able to redrill your bolt pattern in a rotor with a smaller pattern, if it will fit on your hub.

Later, mikey

[thintin]

rotor hght. is 2.875......need rotors only......application is discs on a ford 9.....actually a 9 3/8's.....out of a lincoln or t' bird or something....stout....with 2.70 ratio.......good for my project ...going behind 454 cubesthanks for the interest and help

[joe_padavano]

I'm afraid I can't speak to the height, but some 5 x 5" rotors to try are 1977-1979 Seville rear rotors (this was the RWD Seville) and the early 80s FWD Seville and Eldo rear rotors.

[powerrodsmike]

Well a Lincoln Town car and 75 mercury marquis have those rotors, with that bolt pattern...can't you just ask for that application?
2.875 height sounds a little big for the stock rotor on a big lincoln/mercury.I have a set here from a 75 towncar and they measure 2.375 height and 3.050 center hole..

Are you building your own caliper brackets and using some other calipers than stock?
Could you use the lincoln rotors and put some spacers behind the caliper to bring it out to the shallower rotor depth? Then make a spacer for the centerhole?

I just did a look through the dimensional characteristics of my Raybestos catalog and there is nothing that is a slip over the hub type with a 5 on 5 pattern with a overall height bigger than 3 1/2 or so.

I know I've made caliper brackets to put a set of Baer calipers and a set of PBR 6 piston calipers from a ZO6 vette on 2 different cars with big Lincoln rear ends, and wound up using spacers to get the caliper where I wanted it.

The big ford rear ends that originally had disc brake setups had tapered axle bearings and a different axle offset than drum brake rears...IIRC it was about .150" difference inboard for disc.

Later, mikey

[thintin]

error measuring hght. is actually 2.4375.big thumb got in the way......center hole in existing marginal rotor is 3.06....

[fast68]

thse big late 70s rear disk cars are the ones that have the rotors that the full size gm truck guys use for rear disk conversions i know, has been this way for well ever.

same bolt pattern as on station wagons and 9C1 and 9C6 packaged cars and many '70s big civilian cars like the Electras and such.


good luck!

[powerrodsmike]

Originally Posted by thintin

error measuring hght. is actually 2.4375.big thumb got in the way......center hole in existing marginal rotor is 3.06....

Check out the lincoln rotors, application is 75 Mercury Marquis or 75 Lincoln town car.

5 on 5'" bolt pattern, 11.5 x .955 thick vented rotor, 2.060" hat depth, 3.050 center hole, 2.43 overall height. It will slip right over your existing hub.

Later, mikey

[barnym17]

Or get on speedway motors website and you can order what you want in a 2 piece rotor for about $50.00 each. Just order the correct offset hat and rototr to match but Mikes lincoln idea will work as well.

[joe_padavano]

Originally Posted by barnym17

Or get on speedway motors website and you can order what you want in a 2 piece rotor for about $50.00 each. Just order the correct offset hat and rototr to match but Mikes lincoln idea will work as well.

I must admit that I've frequently looked at those rotors in the Speedway catalog. Any issues with using them on the street?

[powerrodsmike]

Originally Posted by joe_padavano

I must admit that I've frequently looked at those rotors in the Speedway catalog. Any issues with using them on the street?

The cast iron used in the iron disc brake rotors that Wilwood, Coleman racing and Speedway is supposedly all pretty much the same stuff. There are various metal treatment and coating differences as well, some have a zinc wash, some are ceramic coated, some are cyrogenically treated...those will cost more than 25.00 each though I think.... The casting and machining processes may differ, and I'm sure that Speedway buys stuff that is of the lowest price, but if they were truly problematic they would not sell them. A close inspection for porosity and casting flaws should be done on any rotor that is suspect.

When I called Coleman racing about rotors that were in their catalog, for a street application, the tech guy told me that the rotors are not an issue for street use, it's the calipers that need the scrutiny when using racing calipers on the street. (racing calipers typically have no dust/moisture seal on the piston(s), and calipers designed for street use have dust seals. Examination of any Wilwood caliper shows it has no dust seal..(maybe that's why every single part you buy from Wilwood has disclaimers on every level of the packaging, saying that the parts are for off road use only. )

I would think that the ability to dissapate heat would be greater on a rotor designed for racing use, than a street rotor, if there was such a difference.

That is just what I have learned in the conversations with numerous brake engineers and tech guys, and I have never seen or heard of any rotor failing because of the material. I have heard of problems with an inadequate size rotor improperly used, and example being solid rotors used on the fronts of heavy cars, but that is a design consideration, not a material flaw.

I have the opinion that most brake rotors are overengineered anyway, just because of the liability involved.

Any info that can add to this will be appreciated.

Later, mikey