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Wilwwod Brake larger rotor fit 15" Rally Wheels?

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: Suspension, Steering, Brakes & Wheels
Forum Description: What makes it stop, turn, and smooths the ride
URL: https://theamcforum.com/forum/forum_posts.asp?TID=90865
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Topic: Wilwwod Brake larger rotor fit 15" Rally Wheels?
Posted By: amxess
Subject: Wilwwod Brake larger rotor fit 15" Rally Wheels?
Date Posted: Nov/15/2017 at 7:13pm
Anyone know if the 4-piston caliper kit with the larger 12.19" rotors fit in the AMC 15" rally wheels? Any help appreciated.



Replies:
Posted By: LakesideRamblin
Date Posted: Nov/15/2017 at 11:43pm
May be tight. I put the 11" Wilwood brake kit on my 15" slotted wheels on my 69 Rambler. They fit perfectly. But I took a ton of time and research on the subject. A Wilwood tech rep probably can give you the straight scoop for your application.

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LakesideRamblin
69 Rambler 360
73 Javelin 360
"If you could kick the person in the pants responsible for most of your trouble, you wouldn't sit for a month." T. Roosevelt


Posted By: Red Devil
Date Posted: Nov/16/2017 at 9:35am
Wilwood has template drawings on their website that show required clearance. I made one for the 12.19" Dynapro6 kit and seemed to clear ok on a '74 Javelin 15" rally ... but after research, decided to stick with the stock KH disks with upgraded pads as a better option. Sorry, don't have direct installation experience with the Wilwood kit.

If wanting a kit, suggest the Dynapro6 instead of the Dynalite if wanting something close to stock disc capabilities ... but the rotors in the kits aren't intended for much more than general cruising, so may want to look for other options if planning hard driving needing more brake capacity.

12.19" Forged Dynalite kit clearance drawing:
http://www.wilwood.com/Images/BrakeKits/WCD_Drawings/WCD_dwg-Large/ds1025_wcd-lg.jpg" rel="nofollow - http://www.wilwood.com/Images/BrakeKits/WCD_Drawings/WCD_dwg-Large/ds1025_wcd-lg.jpg

12.19" Dynapro6 clearance drawing:
http://www.wilwood.com/Images/BrakeKits/WCD_Drawings/WCD_dwg-Large/ds1036_wcd-lg.jpg" rel="nofollow - http://www.wilwood.com/Images/BrakeKits/WCD_Drawings/WCD_dwg-Large/ds1036_wcd-lg.jpg

Hope this helps,RD


Posted By: 304-dude
Date Posted: Nov/16/2017 at 9:37am
Back in 2000 or so, Mopar guys were doing some 12" rotors on 15" rims. When I looked into reasons why, I found more bad than good.

One, improper cooling for any performance usage. Another you want better braking, have your pads relined with carbon metallic friction material, grade 90 (for street and performance use).

Cost and weight does equate for such an upgrade. What is already available in kit or OEM, is pretty good on it's own. Until you get into 17" and larger wheel and tires, then you must upgrade.

-------------
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker


Posted By: Red Devil
Date Posted: Nov/16/2017 at 10:00am
Nascar runs 12.9" rotors in a 15" wheel ... with some rotors 1.65" wide and over 20lbs for short track/road course applications ... albeit with cooling ducts. Corvettes ran 11.75" x 1.25" in 15" wheels for years. 12.19" are common for 15" wheels of lower levels of stock car racing.

Main reason most street guys go with 13" or larger rotors when fitting 17", 18" or bigger diameter wheels is the small rotors don't look right.

The Wilwood AMC kits are meant for typical street cruiser and are perfectly fine for that ... as are stock brakes ... but stock don't have much show appeal. Wilwood and others have lots of options for more brake capacity, but not in standard kits for AMC as few AMCs are raced, so likely need to piece something together to suit.


Posted By: einbier
Date Posted: Nov/16/2017 at 4:23pm
I just put the 6 piston 12" on my 70 Javelin and they fit with a very small shim behind the wheel, I believe the shim is like .095. I am running machine wheels.

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1970 Javelin Mark Donohue
1970 Hornet Shirley Shahan
(Tribute)







Posted By: amxess
Date Posted: Nov/16/2017 at 11:46pm
Thanks all, and thanks Embier. I think the Machine wheels and the 15" rally wheels are basically the same size from what I remember so that is good news. I saw the wheel specs on the Wilwood site, but wanted first hand knowledge as you never know.  

The stock Bendix 4 piston were Ok for the time, but the solid rotors just don't cut it for any track days etc. I used Porterfield racing pads with the Bendix calipers for Autox events years back which worked fine, but at a track day, really had to lay off braking as those solid rotors heated up way too fast and not good for any track events. 

Keeping the 15" rally wheels for now, but eventually going to 17" wheels, so wanted the larger rotors as the 11" wouldn't look very good in a 17" wheel. And yes, definitely better off going with the 6 piston, though budget is slim right now. 


Posted By: Red Devil
Date Posted: Nov/17/2017 at 9:50am
If planning track days, personally I'd suggest something more capable than the Dynalite or Dynapro kits. The kits use Wilwood's 12.19" x 0.81" thick x 32 straight vane Ultralite HP or SRP rotors. The Ultralite are for light braking on dirt tracks with cars < 2500 lbs or rear service in light braking applications on pavement. The SRP are drilled, slotted and coated to look pretty on your cruiser. The calipers likewise are meant for light braking applications in light cars or basic street use, occasional drag or light autocross (with appropriate pad change). Calipers are powder coated to look pretty.

I was excited about Wilwoods kits, but disappointed after researching what they include. The stock KH rotor is wider, has more vanes and more thermal mass. The caliper has more piston area. The pads have more area, thickness and volume. I saw little advantage to Wilwood's kits over stock with upgraded pads.

They do have lots of better options, just not in kit form. McIntire Machine used to offer a kit with the 12.19" x 1.25" thick GT series rotors with 1.88"/1.75" Superlite calipers. A more worthy option for track days. If you price out anodized calipers and GT rotors, you might be surprised that you can get a more capable caliper and rotor than the pretty powder-coated lower-end ones and the SRP rotors.

For a street, light autocross, occasional drag car that wants a nice looking option, the Wilwood kits are great. For something more track-capable, best to piece together your own kit. 12.19", 8 bolt x 7" track-capable rotors are available from many places with the price point $80 - $120. The AP Racing 60 vane seems to be one of the better options, but not sure if the J-hook grooves would be noisy or noticeable for street cruising more so than a traditional slotted rotor?
https://pitstopusa.com/i-5071302-ap-racing-60-vane-late-model-j-hook-brake-rotor-rh-1-25-rotor-thickness-12-19-diameter-8-bolt-x-7-bolt-circle.html" rel="nofollow - https://pitstopusa.com/i-5071302-ap-racing-60-vane-late-model-j-hook-brake-rotor-rh-1-25-rotor-thickness-12-19-diameter-8-bolt-x-7-bolt-circle.html

Compared to the SRP rotor in the kits:
https://www.summitracing.com/int/parts/wil-160-7103-bk/overview/" rel="nofollow - https://www.summitracing.com/int/parts/wil-160-7103-bk/overview/

... a much more capable AP racing rotor for less money than the pretty SRP rotor.

Likewise on calipers:

Dynalite Red caliper in 12.19" kit:
https://www.summitracing.com/int/parts/wil-120-6816rd" rel="nofollow - https://www.summitracing.com/int/parts/wil-120-6816rd

Superlite anodized caliper for 1.25" rotor with 1.88"/1.75" pistons:
https://www.summitracing.com/int/parts/wil-120-11330/overview/" rel="nofollow - https://www.summitracing.com/int/parts/wil-120-11330/overview/

A more capable caliper with a much larger and thicker pad for better thermal stability and longer life for about $10 more. Superlites are very popular so lots of pad options from street to full race.

Wilwood has lots of details on their site, so good to spend some time reviewing options and capabilities before buying a kit.

Hope this helps,RD


Posted By: amxess
Date Posted: Nov/17/2017 at 12:01pm
Good points RD. Definitely going to autox car again with an occasional track day. I actually have a set of NOS large HD Matador rotors and calipers which I thought about using and saving money, but putting Dairyland coil over kit on now and would like lighter and newer brake system. I'll look into the Superlight rotors. Really just wanted a bolt on option and Wilwood was the only one offering that I've found unless for drag racing.


Posted By: 343sharpstick
Date Posted: Nov/17/2017 at 3:46pm
Curious how many AMCr's would step up for a serious big brake kit with a 12-inch (or larger) disc and a AP race caliper or similar?
My guess would be very few.


Posted By: 304-dude
Date Posted: Nov/17/2017 at 4:51pm
Originally posted by 343sharpstick 343sharpstick wrote:

Curious how many AMCr's would step up for a serious big brake kit with a 12-inch (or larger) disc and a AP race caliper or similar?
My guess would be very few.


I chose the 13" Mustang GT in front and Explorer 4x4 12" in the rear. A bit big, but I intended for 17" wheels and street use. Though, I am going to 18 wheels for better tire choices.

One thing I am contemplating is dual Firebird T/A aluminum caliper setup, similar to Dononhue tests with the 71 T/A Javelin. Now these days, that we got some pad material that can handle heavy race conditions, no more brake fires.

Just an opinion, smaller pads (at a 180 spread) over a 6 or 8 piston race caliper pad, will allow more even cooling without a lot of duct and fan work.

Though many may say differently, but iron is iron. Bigger, thicker and heavier to compensate for high extremes takes a bit of cooling once they heat up.

For short durations the iron will take time to heat up, so brake pads may need to be selected properly for the heat range, if going with ceramics.

The key is not over heating 15" rims before any sign of brakes overheating. 12" brings the heat closer to the tire, thus changing tire pressure and possibly blowing out a tire bead.

Yep, I am the 1% that will over kill a street use car just to have something fun to take to the track when the itch happens.






Posted By: amxess
Date Posted: Nov/19/2017 at 9:05am
After looking at Wilwood's wheel specs diagram, I don't see the larger rotor kit being able to fit in the 15" AMC Rally Wheels. I guess the Machine Wheels are different inner dimension? From Wilwoods specs, the caliper would not fit in the rally wheel. Was hoping someone had tried it. 







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