11" disc brake kit for 14" wheel?

[ChargerST]

I run factory 14" magnum wheels on my 70 Charger and wanted to convert to disc brakes up front. All the kits I found so far have 11" discs. As far as I understand the problem is not the disc itself but the calipers and the spindles. Grinding down the calipers a bit shouldn't be a big deal. If the kit comes with spindles I shouldn't have to worry about the A/B body spindle etc. 

I found quite a few complete kits with the 11" discs running from 350$ (everything included except brake booster) to 500$ (including brake booster). They all claim to use new parts and that they are mopar parts. These kits are all single piston kits - a good price or loss of money?

[bull]

Do a search on this site; you'll find a lot on this topic but the short version is that you can't run the 11+ inch discs with 14" rims. I don't know if you're saying the discs you saw are exactly 11" or if you're rounding off because I think the typical single-piston kit many people use comes with 11.75" rotors. So which kit are you referring to and are the rotors exactly 11"?

[ChargerST]

I've been going through some threads and it seems some people DO use kits for 14" wheels. I'm referring to the 11" (not the 11.75") kit - talked to one shop and they said the discs are 11" not 10.87" or so but I'm not sure the guy on the phone knew the difference.

Here's the kit I'm talking about: http://www.performancesuspension.com/product_info.php?cPath=1_4593_4695_4701_181440_45408&products_id=4895

[bull]

I know there's been lots of debate about whether 10.87"-11" rotor-style brake kits will work with 14" wheels but not sure if anyone has actually tried it. Seems like I recall someone doing it who had to grind on the calipers to make it fit.

[b5blue]

Refer to Mopar Action "Disco-Tech" (10.87 will be needed for 14 rims) 

[HPP]

I think it is all semantics. If you ever put a tape to the discs, you can find variations in disc size from 10.75  to 11 depending on manufacturer, age, usage, etc. Honestly, the difference from 10.87 to 11 is only .125 total, or .060 per side. Not a huge difference, even with 14" wheels. The brackets that hold the calipers, if factory, will be either for the smaller disc or the bigger disc. An eighth of an inch less or more on the disc will not impact the location of the caliper. The fixed position of the caliper is the interference issue for the wheels.

Another consideration that many have forgotten about in the three decades since these were all new is that way back when, there were disc brake and drum brake wheels. Since most cars had drums, wheel manufacturers made most wheels with a flat face in the back. The advent of discs required a radius in the space between the hub face of the wheel and the hoop. If you are using vintage 14" wheels, this could be a potential interference spot regardless of disc diameter.

[b5blue]

Well said. 

[stripedelete]

I think it is all semantics. If you ever put a tape to the discs, you can find variations in disc size from 10.75  to 11 depending on manufacturer, age, usage, etc. Honestly, the difference from 10.87 to 11 is only .125 total, or .060 per side. Not a huge difference, even with 14" wheels. The brackets that hold the calipers, if factory, will be either for the smaller disc or the bigger disc. An eighth of an inch less or more on the disc will not impact the location of the caliper. The fixed position of the caliper is the interference issue for the wheels.

Another consideration that many have forgotten about in the three decades since these were all new is that way back when, there were disc brake and drum brake wheels. Since most cars had drums, wheel manufacturers made most wheels with a flat face in the back. The advent of discs required a radius in the space between the hub face of the wheel and the hoop. If you are using vintage 14" wheels, this could be a potential interference spot regardless of disc diameter.

I'm in the same place as ST.  I would like the option to keep running 14" magnums.  I like the MP base kit.  But it states "Note: Not all 14" or 15" wheels will fit with this application. Wheel fitment is the customers responsibility."

So I called them and they said I need a 2 3/4 opening.  My opening/hole at the cap is 2'1/4.  The opening at the base is 2/3/4(base = same plane as bolt/lug holes).

HPP, is this the radius issue you are referring to? 

Finnally, are any members running 14" magnums on any bolt-up-and-go-kit?

[stripedelete]

Sorry, typo might be confusing.  It should read   "............is 2 3/4"(base = same plane as bolt/lug holes)."

[ChargerST]

Just looked at the 1970 Charger option list and it doesn't say that you were required to order 15" wheels when ordering the B41 disc brake option. It just says that a power booster is necessary.
There must be some Chargers with vintage 14" inch wheels (mags, road wheels) and disc brakes.

[Cooter]

I know the "A-body '73-76" Brakes will clear 14" wheels as that's what's on Christine and I wanted to keep my factory 14" wheel covers....You DO HOWEVER, have to run "Disc Brake" wheels as they are made on the backside different than the drum 14" wheels....

[ChargerST]

Never heard about special disc brake wheels. In my eyes it wouldn't make sense for Chrysler to produce 2 different kind of wheels if you could make one set that fits both types of brakes. But who knows 

[Cooter]

Never heard about special disc brake wheels. In my eyes it wouldn't make sense for Chrysler to produce 2 different kind of wheels if you could make one set that fits both types of brakes. But who knows  

Well, I guess I shoulda broke it down a little further in retro-spect..After a certain year, almost everything with Factory steel wheels, WAS disc brake and all you could get was "Disc Brake" wheels..In 1958- around 1966, all you could get was "Drum" brake wheels and they are made different...Not sure bout the later model wheels that came with drum brakes factory, as the FIRST thing I do is swap to disc's and they are long gone after that...I just simply try and get the steel wheels off of whatever I'm getting the conversion off of and run those.

[b5blue]

I believe the biggest concern was aftermarket rims like aluminum slots and stuff, there are tons of old wheels out there. 

[HPP]

I'm in the same place as ST.  I would like the option to keep running 14" magnums.  I like the MP base kit.  But it states "Note: Not all 14" or 15" wheels will fit with this application. Wheel fitment is the customers responsibility."

So I called them and they said I need a 2 3/4 opening.  My opening/hole at the cap is 2'1/4.  The opening at the base is 2/3/4(base = same plane as bolt/lug holes).

HPP, is this the radius issue you are referring to? 

Finnally, are any members running 14" magnums on any bolt-up-and-go-kit?

Well, this is another consideration with vintage wheels. The diameter of the bearing hub on some new discs is larger than some older rotor designs. Hence the 2.75 vs 2.25 opening for the cap you outlined above. The simple answer for this is to have the bearing housing of the disc turned down on a lathe to fit your old wheels. It is a simple machine shop procedure, but certainly a pain to have done to brand new discs

The radius I was referring to is the same one cooter is talking about when fitting discs. Some calipers are wider than the wheel mounting flange on the disc. If the back face of the wheel does not have the corresponding curve to allow caliper clearance, they will not fit. The easy way to see this is to lay a straight edge on the face of the wheel that sits on the disc/drum mounting face. Just out from the mounting flange diameter, the wheel should curve out with a slight radius to provide clearance.

Since discs became factory options on almost all cars by the mid sixties, fitting factory wheels should not be an issue as the factories typically only had two or three wheel offerings and they had to be able to fit any combination of brakes. The rub is that since drums were still available on cars until the late 1970s, a number of aftermarket wheel manufacturers had a distinction between drum and disc wheels. Many of these wheels are still out there and a cheap swap meet score can sometimes lead to a set of wheels that won't fit disc brakes. This is why you see disclaimers that the buyer is responsible for wheel fitment. If your using factory steel, magnum  or rallyes, it likely won't be an issue. If you have some old slots or spoked mags, it could be an issue.

[THERAMMAN]

50 % of my calls are people un happy with the choice of power unit
power unit   =  booster and master cylinder
you cannot beat factory set up..........wayne the ramman.com  the mopar brake answer man