My own JK 'Big Brake' research:

SDG said:
So this may be stupid, but what if you used the 2 sets of front brakes off or a ram, with a different master cylinder?
Not super familiar with dodge trucks, but all the fords I have had have rear drum brakes, would this account for the difference?
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I'm using late-model setups only - only those that came from the factory with disc/disc setups. If I understand your suggestion correctly, you are asking what if I used a matching set of calipers front and rear, correct? That would be simple, however, would cause rear wheel locking/skidding under even just moderate braking. Rear calipers are designed with less piston surface area intentionally, because as you depress the pedal, weight shifts forward, unloading the rear tires somewhat, and making a skid much easier. Surprisingly, there is a huge amount of research that goes into selecting the correct front-to-rear piston size differences to make your front and back wheels brake well. That's where my spreadsheet has come into play.... I can list a dozen different combinations, and see comparison ratios front and rear and compared with the master cylinder bore.

Right now, due to the large 4-piston calipers I'm leaning towards at the moment, to mantain a similar-to-stock (or slightly firmer) pedal feel, it looks as if we may need a master cylinder with a 1.25" bore. Problem there is finding a master cylinder with a large bore like that that also isn't too large externally to fit in the limited space in the front corner of a JK engine compartment.

If anyone knows of a custom master cylinder manufacturer or where I can get a very short MC with such a 1.25" bore, please let me know. Thanks!!!!
 
Majik said:
BTW, as a question to the crowd: If you were going to be able to order the calipers painted, what color would you pick if they were all to be ordered in the same color? Assuming standard colors (silver, red, black, blue...) - not body-matched colors.
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I vote for red or silver.

Majik said:
...Surprisingly, there is a huge amount of research that goes into selecting the correct front-to-rear piston size differences to make your front and back wheels brake well. That's where my spreadsheet has come into play.... I can list a dozen different combinations, and see comparison ratios front and rear and compared with the master cylinder bore.
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I know next to nothing about brakes, but what if you just reuse the factory front rotors and calipers in the back? Would that get you close to the right ratio with the new front setup?

Dave
 
Majik said:
Well now you guys are giving me alot to live up to! I sure as hell hope I don't fail! LOL! :thumb:

It's been quite fun and a great learning experience so far, so I don't see why I won't carry this through to the end. Putting together the Excel spreadsheet to do all of the calculations of piston area vs master cylinder bore, etc, was the best thing I could have done. It allows you to see visually what combination of front and rear calipers will give us a certain type of pedal feel. I think I'm gonna have to just buy the caliper tomorrow.... then I can move on to taking measurements for the caliper bracket/adapter. I noticed some online fab shops selling such adapters out of aluminum, and while good for heat dissipation, I feel more comfortable using thick plate steel. 120+lbs of spinning wheel/tire is a huge rotating mass, and I feel better with a big chunk of steel holding my caliper to my knuckle. My machinist is just itching to do the first one!!

BTW, as a question to the crowd: If you were going to be able to order the calipers painted, what color would you pick if they were all to be ordered in the same color? Assuming standard colors (silver, red, black, blue...) - not body-matched colors.

Thanks for following this fun project everyone!!! Even my boys are excited to see your questions and help with the research!!
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I wish I had a machinist...but then he may not get much sleep with the project list..
my vote is red
sounds like it's getting closer!
 
jeeeep said:
sounds like it's getting closer!
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Well, when you have a giant stack of tires (37s), axle upgrades, locking hubs, etc sitting in the garage and you make yourself a pact that you aren't installing them until the brakes are better, you have good motivation!! :thumb:
 
I hate to be the one to throw cold water on things, but I'd recommend against any logo or branding of the product unless you are prepared to purchase liability insurance for your brake mfg business. There's always a chance that someone comes back on you after an incident where their brakes "may have" contributed to vehicle damage or worse, an injury.

Sorry, as an insurance agent, it's just the kind of stuff I think about...
 
dgriz said:
I hate to be the one to throw cold water on things, but I'd recommend against any logo or branding of the product unless you are prepared to purchase liability insurance for your brake mfg business. There's always a chance that someone comes back on you after an incident where their brakes "may have" contributed to vehicle damage or worse, an injury.

Sorry, as an insurance agent, it's just the kind of stuff I think about...
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I don't think anyone was serious about sticking a logo on it...
 
No problem. Would just hate to see such a great project be rewarded with a lawsuit somewhere down the line. Please, keep up the great work. I'm anxious to see how this turns out. :)


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I knew the logo was a joke ...

Thanks though for the legal perspective, though. That is why a forum like this is such a great way to explore a project like this...to obtain unique perspectives and be sure I'm not missing anything.

I have thought about this in detail and will have my bases covered when it comes time to release. The only part that I might end up selling would be the caliper adapter [edit: and that would not be for a profit] I'm trying to make the rest just off the shelf stuff. But I will heed your warning. But........ No lawyer is gonna stop me from trying to make our rigs SAFER than stock....if they wanna try, well they can go for it. I'm gonna keep truckin along :)
 
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jacksup said:
update ? you are killing us lol
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Ha. Well, I just ordered my set of Hutchinson RockMonster wheels, so I was a tiny bit sidetracked the last few days. I actually obtained from Hutchinson a technical drawing for their wheels. I needed this so I could get exact clearances for this brake upgrade. I was worried that, after focusing on making this upgrade fit even with OEM wheels, that the beefy construction of popular aftermarket wheels, like the ATX slabs or RMs, would reduce the inner diameter of the back side of the rim, and thus reduce available clearance for my 'big brake' idea. So far, it doesn't look to be an issue. I just didn't want to get into a bind with providing a brake upgrade path that worked for OEM wheels, but not the beefier aftermarket wheels that alot of us will be running. So.... that's why I hadn't updated in a while.

Incidentally, Hutchinson has been awesome with their help! They sent me the detailed engineering schematics for their wheels within 2 hours of me contacting them with my request! Talk about service!!

More to come soon...
 
Update!

Test caliper is on the way! Will be here roughly next Friday! This is a reman, OEM part that can be ordered from any auto parts store. They are a little difficult to find in stock unless you are in a bigger city, however, they are available for order from any store for no additional cost. I needed to get my hands on one so that I could take some more detailed measurements... so I pulled the trigger! Will post pics the minute it arrives!!
 
Majik said:
Incidentally, Hutchinson has been awesome with their help! They sent me the detailed engineering schematics for their wheels within 2 hours of me contacting them with my request! Talk about service!!

More to come soon...
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I too found them to be very helpful on the phone. :thumb:

Dave
 
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