Need Help With Front Brake Selection, 3,300# Street/Track Javelin

[Bulletpruf]

Fellas -

Could use some input on front brakes for my 71 Javelin. It's built with NASA American Iron in mind, but intend for it to be street legal as well. It has a 500 flywheel hp 401, T10, full floater 9". Race weight should be about 3,350. Rear brakes are Wilwood 4 piston FSL, .810 x 11.75" rotors, 1 3/8" pistons. Running 275/40/17 tires on 17 x 9 wheels.

Problem with the front brakes is the lack of aftermarket support. Wilwood offers a kit with 11" rotors, but methinks that's too small of a rotor up front. There is one guy who does a kit for the fronts using Wilwood 4 piston FSL calipers, 1.25" x 12.19" rotors, 1.75" pistons. It's $1,900 for the complete kit. Is this enough brake for the front on a 3,350 pound car?

My other options are using pieces/parts from the Wilwood 11" kit to put 13" rotors on the front (that's as big as I can go with 17" wheels, right?). Other folks have used Aerospace brakes, but I think they are more of a pro-touring brake than a serious race brake, but could be wrong here.

Thanks in advance for any info.

Scott

[Apogee]

With the right temperature range pad, you could probably make the 12.19 x 1.25 rotors and 4-piston Wilwood FSL calipers work (are you sure they're 1.75 pistons and not staggered 1.88/1.75?), but it seems somewhat counterintuitive to not take full advantage of the fact that you're running 17" diameter wheels. Given the weight and HP of your ride, a 12.88 x 1.25 rotor sure would fit the bill nice given your setup IMHO, but it all depends on how hard you push things and the tracks you run.

I'm not personally familiar with the '71 Javelin spindle/knuckle...do you have any links with pictures of your build that you can share?

Tobin
KORE3

[Bulletpruf]

With the right temperature range pad, you could probably make the 12.19 x 1.25 rotors and 4-piston Wilwood FSL calipers work (are you sure they're 1.75 pistons and not staggered 1.88/1.75?), but it seems somewhat counterintuitive to not take full advantage of the fact that you're running 17" diameter wheels. Given the weight and HP of your ride, a 12.88 x 1.25 rotor sure would fit the bill nice given your setup IMHO, but it all depends on how hard you push things and the tracks you run.

I'm not personally familiar with the '71 Javelin spindle/knuckle...do you have any links with pictures of your build that you can share?

Tobin
KORE3

Tobin -

I was looking at the 1.75" x 2, but no objections to the staggered 1.75/1.88.

I'll get some pics posted of the spindles; they are bolt on. You can also see several pics of them posted here - http://theamcforum.com/forum/help-calling-all-spindles_topic17645_page1.html?KW=drum+brake+spind le

Here's a link to the Wilwood 11" kit that is a bolt on - http://www.wilwood.com/BrakeKits/BrakeKitListFront.aspx?year=1972&make=American Motors&model=AMX&modoption=Disc Brake Spindle.

Ran across another kit - it's $1,500, but 13" rotors are an option. It's made by ASC; I have no experience with them -
http://performanceamstyle.com/Cart/description.php?II=41&sessid=d51e070a5a70407a2df7b95b1d4e2e0b&divi=amc

Thanks

Scott

[Apogee]

Interesting. I think the best image I found of the spindle is in Wilwood's installation instructions here, http://www.wilwood.com/BrakeKits/BrakeKitsProdFront.aspx?itemno=140-11940. The bolt-on spindle pins are pretty cool, but there certainly are plenty of variations to deal with between bearing size, spread and inner oil seal diameters. The Wilwood kit is definitely undersized for your application IMO and the ASC kit isn't much better as it still uses a .81" thick rotor, albeit a larger diameter one. What are guys who are road racing their AMC's running?

Tobin
KORE3

[jtomas801]

The ASC I believe is aerospace components. The 13" rotor seems under sized to me because it is only .810" wide.

When I still had the stock front end on my Javelin I got the wilwood 12.19" x 1.25 GT rotors and the forged super lite 4 piston calipers with the 1.88"/1.75" bore. The original goal was to use a stock car GN hub with custom spindles pins (I got the idea from Adam Tarr, he had a set made that bolted to the stock amc knuckle.) And make my own caliper brackets. If you could get a 13" rotor in there, that would be the ticket.

Also, are you running the stock pedal set up with a single master? or running a wilwood/tilton pedals with the 3 masters on it?


If you decide to piece together something I have a set of new 12.19" x 1.25" rotors and a pair of 1.88"/1.75" bore calipers I can sell.

Thanks,
Jon



Here is a picture of the spindle pins Adam had made, hopefully he doesn't mind me using his pictures.
https://static1.pt-content.com/images/pt/2011/12/IMG_0588-2.jpg

[Bulletpruf]

Interesting. I think the best image I found of the spindle is in Wilwood's installation instructions here, http://www.wilwood.com/BrakeKits/BrakeKitsProdFront.aspx?itemno=140-11940. The bolt-on spindle pins are pretty cool, but there certainly are plenty of variations to deal with between bearing size, spread and inner oil seal diameters. The Wilwood kit is definitely undersized for your application IMO and the ASC kit isn't much better as it still uses a .81" thick rotor, albeit a larger diameter one. What are guys who are road racing their AMC's running?

Tobin
KORE3

The AMC guys are running a little bit of everything; the ones running stock type front suspensions are probably using factory AMC drum brake spindles and hubs with a good 4 piston caliper on a fabbed up mount. A few guys are running an aftermarket front suspension made by Control Freak/Freakride that uses a Mustang II spindle.

As for the spindles, some folks prefer the 75-78 spindle because it's a bit beefier than what the early cars came with.

Thanks

Scott

[Bulletpruf]

[QUOTE=jtomas801;861537]The ASC I believe is aerospace components. The 13" rotor seems under sized to me because it is only .810" wide.

When I still had the stock front end on my Javelin I got the wilwood 12.19" x 1.25 GT rotors and the forged super lite 4 piston calipers with the 1.88"/1.75" bore. The original goal was to use a stock car GN hub with custom spindles pins (I got the idea from Adam Tarr, he had a set made that bolted to the stock amc knuckle.) And make my own caliper brackets. If you could get a 13" rotor in there, that would be the ticket.

Also, are you running the stock pedal set up with a single master? or running a wilwood/tilton pedals with the 3 masters on it?


If you decide to piece together something I have a set of new 12.19" x 1.25" rotors and a pair of 1.88"/1.75" bore calipers I can sell.

Thanks,
Jon


Jon -

Adam is a friend of mine; some of the parts on my car came from him. He lived a few miles away from me before I moved to GA in June.

Did you get your 12.19 x 1.25 kit from Ken McIntire?

I'll be going with a tilton or wilwood pedal and 3x master cylinders.

Thanks

Scott

[Bulletpruf]

Interesting. I think the best image I found of the spindle is in Wilwood's installation instructions here, http://www.wilwood.com/BrakeKits/BrakeKitsProdFront.aspx?itemno=140-11940. The bolt-on spindle pins are pretty cool, but there certainly are plenty of variations to deal with between bearing size, spread and inner oil seal diameters. The Wilwood kit is definitely undersized for your application IMO and the ASC kit isn't much better as it still uses a .81" thick rotor, albeit a larger diameter one. What are guys who are road racing their AMC's running?

Tobin
KORE3

Tobin -

Does KORE3 have anything that might work for front brakes?

Thanks

Scott

[Apogee]

Tobin -

Does KORE3 have anything that might work for front brakes?

Thanks

Scott

Not sitting on the shelf...but it looks like a cool project. We seem to be good at the niche markets, and I'm not sure it gets any more "niche" than this. I'd be more than willing to discuss options with you if you'd like, just give me a call or shoot me an email or PM.

Tobin
KORE3

[jtomas801]

[QUOTE=jtomas801;861537]The ASC I believe is aerospace components. The 13" rotor seems under sized to me because it is only .810" wide.

When I still had the stock front end on my Javelin I got the wilwood 12.19" x 1.25 GT rotors and the forged super lite 4 piston calipers with the 1.88"/1.75" bore. The original goal was to use a stock car GN hub with custom spindles pins (I got the idea from Adam Tarr, he had a set made that bolted to the stock amc knuckle.) And make my own caliper brackets. If you could get a 13" rotor in there, that would be the ticket.

Also, are you running the stock pedal set up with a single master? or running a wilwood/tilton pedals with the 3 masters on it?


If you decide to piece together something I have a set of new 12.19" x 1.25" rotors and a pair of 1.88"/1.75" bore calipers I can sell.

Thanks,
Jon


Jon -

Adam is a friend of mine; some of the parts on my car came from him. He lived a few miles away from me before I moved to GA in June.

Did you get your 12.19 x 1.25 kit from Ken McIntire?

I'll be going with a tilton or wilwood pedal and 3x master cylinders.

Thanks

Scott

I just bought the calipers and rotors by themselves. I was going to mount the rotors to stock car hubs, having a spindle made up like Adam's and make my own caliper mount. I also thought about using nascar GN spindles/knuckles, I believe coleman racing will build them to your specs.

Thanks,
Jon

[Bulletpruf]

Not sitting on the shelf...but it looks like a cool project. We seem to be good at the niche markets, and I'm not sure it gets any more "niche" than this. I'd be more than willing to discuss options with you if you'd like, just give me a call or shoot me an email or PM.

Tobin
KORE3

PM sent.

Thanks

Scott

[Bulletpruf]

Here's Ken McIntire's custom kit with Wilwood FSL calipers and 12.19" x 1.25" rotors:

https://static1.pt-content.com/images/pt/2011/12/AMX27002-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX27001-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24004-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24003-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24003-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24002-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24001-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX27003-1.jpg

[Bulletpruf]

Here's Ken McIntire's custom kit with Wilwood FSL calipers and 12.19" x 1.25" rotors:

https://static1.pt-content.com/images/pt/2011/12/AMX27002-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX27001-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24004-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24003-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24003-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24002-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX24001-1.jpg

https://static1.pt-content.com/images/pt/2011/12/AMX27003-1.jpg

[amx2334]

The AMC guys are running a little bit of everything; the ones running stock type front suspensions are probably using factory AMC drum brake spindles and hubs with a good 4 piston caliper on a fabbed up mount. A few guys are running an aftermarket front suspension made by Control Freak/Freakride that uses a Mustang II spindle.

As for the spindles, some folks prefer the 75-78 spindle because it's a bit beefier than what the early cars came with.

Thanks

Scott

I fall into this category. I adapted cobra calipers to the drum hub setup. Rotor selection is 12.6x28mm or 13.6x28mm (pictured). I could go 14.2x32mm with the cobra R brembo caliper but I am running a much lighter AMX. The 14.2" rotor would require 18" rims also.
https://static1.pt-content.com/images/pt/2011/12/12710004-1.jpg
https://static1.pt-content.com/images/pt/2011/12/12710018-1.jpg
https://static1.pt-content.com/images/pt/2011/12/68102-1.jpg

[AMC Racer]

AMC spindle comparison. The big spindle was used on '75-'78 disc brake cars.

IIRC, specs are:

Small spindle uses 1.25" inner bearing, 0.75" outer bearing.
Big spindle uses 1.378" inner bearing, 0.866" outer bearing.

Wilwood hub for small spindle:
http://www.wilwood.com/Hubs/HubProd.aspx?itemno=270-11942


https://static1.pt-content.com/images/noimg.gif