Critique my brake build

64Chevy said:
Especially to USMC Wrangler, but to anyone else I may have rubbed the wrong way, I'm sorry. My brakes are worrying me, I am no expert, and I came here seeking advice. To all who have already respond, thank you. I asked for comments, meaning everything was fair game and my skin may have been too thin.

In my track days I changed more pads and rotors, and bled more brakes than I can even remember. Point being is that I am not an expert, but buying an upgrade that requires opening the brake system ain't no thang for me. And I have bought stuff for my Jeep without doing much research--bought it, installed it, and didn't think much about it. So I understand that view too. To me (and maybe to no one else but me)--I am willing to do a deep dive into the brakes, and I want to optimize the performance I get for my dollar.

Regarding Teraflex--I knew there was a general feeling here and I did try to do some background research and find out what the issues (other than price) were. I didn't find it, and was hoping someone could explain--but yep, I will just do more research and try to sort it out.

To any of you who have weighed in, if you are ever in the Pacific Northwest let me know and I will happily buy you a beer as a way of thanks.
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While I appreciate the apology, it’s not necessary. It just seems to me you don’t want a critique, you want people to agree that your plan is the best/correct one.

We all have different setups, things that work for us and things that don’t. It’s your Jeep. Do what you want with it.

Although maybe not as scientific as you’d prefer here’s a video...

https://youtu.be/BgD4G-rN51A

And then there’s Eddie and Cindy’s video where the founder of Dynatrac explains the system in great detail...

https://youtu.be/rKl1P2L2K00

Personally, this seems like the best of many worlds. I don’t expect anyone to agree with me simply because I recently bought the 4 wheel kit.

Good luck
 
USMC Wrangler said:
While I appreciate the apology, it’s not necessary. It just seems to me you don’t want a critique, you want people to agree that your plan is the best/correct one.

We all have different setups, things that work for us and things that don’t. It’s your Jeep. Do what you want with it.

Although maybe not as scientific as you’d prefer here’s a video...

https://youtu.be/BgD4G-rN51A

And then there’s Eddie and Cindy’s video where the founder of Dynatrac explains the system in great detail...

https://youtu.be/rKl1P2L2K00

Personally, this seems like the best of many worlds. I don’t expect anyone to agree with me simply because I recently bought the 4 wheel kit.

Good luck
Click to expand...

Wow, that first video is pretty impressive. The second video really highlights the work/thought put into the kit, and also one of the X factors with trying to sort all of this out, which is the friction material of the pads. Thanks for posting both.

I suspect one might be able to generate slightly shorter stopping distances using a different front caliper/bracket/rotor, but it is also going to be a crapshoot in several ways. I'm probably not thinking of all of them, but even if you get more force being applied to the pad (double piston caliper) and more leverage (bigger rotors) the pad friction material is really going to determine whether you beat, equal, or lose to the Dynatrac system. Plus, while bleeding brakes ain't hard, replacing the vacuum booster (at least on other vehicles) isn't the easiest thing in the world to do. And bench bleeding master cylinders is another step, and if you somehow get air into the antilocks its off to the deal to have a special bleed done.

I'm coming around to thinking that trying to beat the Dynatrac could get expensive quick. I'd like to not have proprietary pads, on the other hand good pads is good pads.
 
I have seen other Terra-Flex parts fail on the trail, metal should not be snapping like plastic. With that in mind, I rule out Terra-Flex for any component that is life or death. I'm running stock brakes, and 35s, just today antilock kicked in. I'm in the research phase, like the simplicity of the DynoTrack kit, but considering better/bigger calipers and upgraded master cylinder too.

But due to helping a buddy do a trial repair, no chance on Terra-Flex.

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I really wish we knew the pad compound used in all the available kits. We'd be able to do a much better on-paper comparison them all. Figuring out the braking mechanics (at least as far as clamping area and rotor diameter) isn't difficult.

Based on piston size, piston count, and rotor diameter we can compare them as if they had the same pad compound and hydraulic pressure.

The normal force, F, applied by the caliper will the piston area multiplied by the hydraulic pressure: F = A*P

The torque, call it tau, applied to the rotor is proportional to (not equal to because we don't know coefficient of friction of the pad) the caliper normal force multiplied by the distance from the center of rotation to the center of the piston (call it r): tau = F*r

Keep in mind that the distance from the center of the rotor to the center of the brake piston is not the diameter of the rotor. It's the radius of the rotor minus (roughly) the radius of the piston cylinder. The stock pistons are 66 mm in diameter (1.3 inch radius). The radius of the stock rotor is 5.95 inches; Dynatrac is 6.75 inches. The relative torque would be (6.75"-1.3")/(11.9"-1.3") = 1.17 or a 17% increase in stopping torque from the larger rotor. The rest of the gains come from the pad material.

I made a spreadsheet some time ago when I was deciding on my brakes. The spreadsheet did the above calculations and compared to the stock arrangement for many aftermarket kits. I found that the Dynatrac didn't fare well at all in the comparisons, even bearing in mind that Dynatrac also upgraded the rear brakes (KEEP IN MIND THAT THIS DOESN'T INCLUDE PAD MATERIAL). This is probably similar to what the OP and his friend did. The Teraflex kit had the best numbers of anything below $1500, while the Dynatrac kit had the worst numbers of anything over $1000.

To put numbers on it, I found that the Teraflex kit had a total mechanical advantage (torque and normal force combined) that was 70% greater than stock (assuming same pad material and fluid pressure). Consider that in a 60/40 front/rear braking scheme, that comes to about 40% increase for the total system just by upgrading the front brakes.
The Mopar kit (and the Crown/RT kit) ended up with about 55% increase in the front stopping torque, or 33% for the total system.
The Dynatrac kit ended up in the ballpark of 20% improvement for the total system.
The SSBC Tri-Power Caliper-only kit had about 20% improvement for the total system just by changing the front calipers (the exact opposite philosophy from Dynatrac but the same mechanical increase and can fit in smaller wheels).

The pad material and the pedal stroke required to get the same fluid pressure are the elephants in the room, obviously. A pad made with unobtainium is how Dynatrac gets such a good product using relatively modest geometry changes. More piston area means squishier pedal if you keep the same booster/master cylinder, which is a strike against the Teraflex and similar kits.

Mostly because of their reputation and cost, I couldn't bring myself to buy Terror-flex kit. However I also couldn't convince myself that Dynatrac was the best bang for the buck if so much of the performance comes from proprietary pads.

Obviously this is all on paper and I only write this up to show a quantitative approach to some of the options. Seemingly everyone who has the Dynatrac kit has been happy with it, so it's clearly great. I only offer this a way to compare what we do know about the specifications of each system.
 
FenderBender said:
I really wish we knew the pad compound used in all the available kits. We'd be able to do a much better on-paper comparison them all. Figuring out the braking mechanics (at least as far as clamping area and rotor diameter) isn't difficult.

Based on piston size, piston count, and rotor diameter we can compare them as if they had the same pad compound and hydraulic pressure.

The normal force, F, applied by the caliper will the piston area multiplied by the hydraulic pressure: F = A*P

The torque, call it tau, applied to the rotor is proportional to (not equal to because we don't know coefficient of friction of the pad) the caliper normal force multiplied by the distance from the center of rotation to the center of the piston (call it r): tau = F*r

Keep in mind that the distance from the center of the rotor to the center of the brake piston is not the diameter of the rotor. It's the radius of the rotor minus (roughly) the radius of the piston cylinder. The stock pistons are 66 mm in diameter (1.3 inch radius). The radius of the stock rotor is 5.95 inches; Dynatrac is 6.75 inches. The relative torque would be (6.75"-1.3")/(11.9"-1.3") = 1.17 or a 17% increase in stopping torque from the larger rotor. The rest of the gains come from the pad material.

I made a spreadsheet some time ago when I was deciding on my brakes. The spreadsheet did the above calculations and compared to the stock arrangement for many aftermarket kits. I found that the Dynatrac didn't fare well at all in the comparisons, even bearing in mind that Dynatrac also upgraded the rear brakes (KEEP IN MIND THAT THIS DOESN'T INCLUDE PAD MATERIAL). This is probably similar to what the OP and his friend did. The Teraflex kit had the best numbers of anything below $1500, while the Dynatrac kit had the worst numbers of anything over $1000.

To put numbers on it, I found that the Teraflex kit had a total mechanical advantage (torque and normal force combined) that was 70% greater than stock (assuming same pad material and fluid pressure). Consider that in a 60/40 front/rear braking scheme, that comes to about 40% increase for the total system just by upgrading the front brakes.
The Mopar kit (and the Crown/RT kit) ended up with about 55% increase in the front stopping torque, or 33% for the total system.
The Dynatrac kit ended up in the ballpark of 20% improvement for the total system.
The SSBC Tri-Power Caliper-only kit had about 20% improvement for the total system just by changing the front calipers (the exact opposite philosophy from Dynatrac but the same mechanical increase and can fit in smaller wheels).

The pad material and the pedal stroke required to get the same fluid pressure are the elephants in the room, obviously. A pad made with unobtainium is how Dynatrac gets such a good product using relatively modest geometry changes. More piston area means squishier pedal if you keep the same booster/master cylinder, which is a strike against the Teraflex and similar kits.

Mostly because of their reputation and cost, I couldn't bring myself to buy Terror-flex kit. However I also couldn't convince myself that Dynatrac was the best bang for the buck if so much of the performance comes from proprietary pads.

Obviously this is all on paper and I only write this up to show a quantitative approach to some of the options. Seemingly everyone who has the Dynatrac kit has been happy with it, so it's clearly great. I only offer this a way to compare what we do know about the specifications of each system.
Click to expand...

Holy shit! I can’t read all of that! [emoji33][emoji23]
 
64Chevy said:
Okay, let me try to respond. First of all, every modern car (and even older ones) can lock their brakes (or activate the antilocks). I think you have something wrong here--I've run slicks on incredibly capable cars on the track--so maximum traction, big power, and 150 mph+ speeds, and the antilock function still worked fine. Me thinks you have some mis-understanding of the antilock brake system, friction physics, traction contact patches on tires, etc. And no disrespect to you (or others) but I want my rig to be able to brake the best that it can, given the tires and weight of the vehicle. If I cannot activate the antilocks (in your terms "lock them"), then my Jeep is not braking to the standard of almost every modern road-going vehicle. Which you (or others) may decide you are okay with--I am not. It is hardly pointless--we are talking emergency braking stopping distances. If you don't care about that I respect your choice, but I do not feel the same.

One direct question. You say the Dynatrac kit is a proven better option. It clearly is not on paper (larger rotor diameter is a plus, different pad compound is an unknown, but no increase in piston surface area is a minus versus other options). Link me ONE head to head comparison. -same vehicle, same day, same road surface, etc and I will throw you total respect. But otherwise you are screaming into the wind.

And as regards Teraflex--I am not a fan boy at all. Just trying to understand if the shade cast here is a price based thing, a price + quality base thing (which is hard to analyze--crappy finish machining is disappointing, but only if you are an form over function dude), or a price + performance thing (which I care greatly about, but so far haven't read, for example, that the Teraflex brake kit has poorly machined caliper piston bores that stick, and therefore decrease braking force). However I am happy to hear that other products suffered from failure or poor performance--I'd actually like some reason to take the Teraflex kit out of contention other than price (and the price bums me out, but my crap brakes bum me out more).
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Change your pads. Low friction pads won’t help you lock up/activate anti-lock. If you’re not racing, or running with super deep gears in 4-lo then heat build up isn’t a big problem and you can overcome the applied torque. Otherwise get a BB kit from someone other that TerrorFlex, (still change your pads to a high friction set), and tailgate away


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Zstairlessone said:
Change your pads. Low friction pads won’t help you lock up/activate anti-lock. If you’re not racing, or running with super deep gears in 4-lo then heat build up isn’t a big problem and you can overcome the applied torque. Otherwise get a BB kit from someone other that TerrorFlex, (still change your pads to a high friction set), and tailgate away


Sent from my iPhone using WAYALIFE mobile app
Click to expand...

I have Hawk HPS pads--should have more friction than stock. The problem that I am finding is that there are not a huge number of choices for the stock calipers, and comparing the compounds from different manufacturers is tough. I love Cobalt Friction pads in my track cars, but my shop says that, even if I had them make custom pads, in the Jeep they would last for maybe 500-1000 miles--that's not ideal.

You are spot on--got any suggestions for high friction pads?
 
FenderBender said:
I really wish we knew the pad compound used in all the available kits. We'd be able to do a much better on-paper comparison them all. Figuring out the braking mechanics (at least as far as clamping area and rotor diameter) isn't difficult.

Based on piston size, piston count, and rotor diameter we can compare them as if they had the same pad compound and hydraulic pressure.

The normal force, F, applied by the caliper will the piston area multiplied by the hydraulic pressure: F = A*P

The torque, call it tau, applied to the rotor is proportional to (not equal to because we don't know coefficient of friction of the pad) the caliper normal force multiplied by the distance from the center of rotation to the center of the piston (call it r): tau = F*r

Keep in mind that the distance from the center of the rotor to the center of the brake piston is not the diameter of the rotor. It's the radius of the rotor minus (roughly) the radius of the piston cylinder. The stock pistons are 66 mm in diameter (1.3 inch radius). The radius of the stock rotor is 5.95 inches; Dynatrac is 6.75 inches. The relative torque would be (6.75"-1.3")/(11.9"-1.3") = 1.17 or a 17% increase in stopping torque from the larger rotor. The rest of the gains come from the pad material.

I made a spreadsheet some time ago when I was deciding on my brakes. The spreadsheet did the above calculations and compared to the stock arrangement for many aftermarket kits. I found that the Dynatrac didn't fare well at all in the comparisons, even bearing in mind that Dynatrac also upgraded the rear brakes (KEEP IN MIND THAT THIS DOESN'T INCLUDE PAD MATERIAL). This is probably similar to what the OP and his friend did. The Teraflex kit had the best numbers of anything below $1500, while the Dynatrac kit had the worst numbers of anything over $1000.

To put numbers on it, I found that the Teraflex kit had a total mechanical advantage (torque and normal force combined) that was 70% greater than stock (assuming same pad material and fluid pressure). Consider that in a 60/40 front/rear braking scheme, that comes to about 40% increase for the total system just by upgrading the front brakes.
The Mopar kit (and the Crown/RT kit) ended up with about 55% increase in the front stopping torque, or 33% for the total system.
The Dynatrac kit ended up in the ballpark of 20% improvement for the total system.
The SSBC Tri-Power Caliper-only kit had about 20% improvement for the total system just by changing the front calipers (the exact opposite philosophy from Dynatrac but the same mechanical increase and can fit in smaller wheels).

The pad material and the pedal stroke required to get the same fluid pressure are the elephants in the room, obviously. A pad made with unobtainium is how Dynatrac gets such a good product using relatively modest geometry changes. More piston area means squishier pedal if you keep the same booster/master cylinder, which is a strike against the Teraflex and similar kits.

Mostly because of their reputation and cost, I couldn't bring myself to buy Terror-flex kit. However I also couldn't convince myself that Dynatrac was the best bang for the buck if so much of the performance comes from proprietary pads.

Obviously this is all on paper and I only write this up to show a quantitative approach to some of the options. Seemingly everyone who has the Dynatrac kit has been happy with it, so it's clearly great. I only offer this a way to compare what we do know about the specifications of each system.
Click to expand...

This! My race shop buddy thought the Dynatrac system would increase torque about 17%, ignoring the effect of a better pad material. I gotta say based on my track experience that amazing pad material could make everything happy. Having said that, your analysis is why I am thinking Dynatracs rear, but something else in the front--understanding that any other solution will be much more of a pain in the ass than just doing Dynatracs all around.
 
64Chevy said:
This! My race shop buddy thought the Dynatrac system would increase torque about 17%, ignoring the effect of a better pad material. I gotta say based on my track experience that amazing pad material could make everything happy. Having said that, your analysis is why I am thinking Dynatracs rear, but something else in the front--understanding that any other solution will be much more of a pain in the ass than just doing Dynatracs all around.
Click to expand...

You must be an engineer.


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Holy fuck.... I just read the last few posts. I suck at math but I've had 3 beers and a glass of wine so that equals 4 drinks. Here's the easy version for you people: The Dynatrac brakes fucking work like no other. The stopping power can be compared to lifting up a chick's skirt at the bar and finding out she has a dick! No forward motion from then on. It's really that simple and I'm not even an engineer. I can honestly account for three episodes in traffic where the Dynatrac progrips saved me from hitting a car or bike way better than stock brakes.

And no I don't have a bikini nor blonde hair nor an annoying voice. I'm not a whore and I'm not sponsored by Dynatrac. I'm just a regular Joe who paid for my own fucking Dynatrac brakes, and yes they work.
 
Ruvicon said:
The stock brakes with stock tires is marginal at best. Even worse when adding weight to the vehicle as you have done. The Dynatrac Progrips have proven to work great. I also hated my stock brakes w35s, but when I added the Progrips it stops excellently now. I have much more confidence out on a trail with even larger tires now.

Theoretically, everything you suggested should work better, but I’d recommend sticking with something that’s proven to work for our application. It’s your Jeep, do what you see fit.


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Click to expand...

Would love to try your brakes over the rubicon weekend . I’ve been meaning to save up and upgrade but honestly my stock brakes haven’t been an issue to date . Maybe trying the upgrade and feeling the difference would push me over the 1K upgrade edge


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WJCO said:
Holy fuck.... I just read the last few posts. I suck at math but I've had 3 beers and a glass of wine so that equals 4 drinks. Here's the easy version for you people: The Dynatrac brakes fucking work like no other. The stopping power can be compared to lifting up a chick's skirt at the bar and finding out she has a dick! No forward motion from then on. It's really that simple and I'm not even an engineer. I can honestly account for three episodes in traffic where the Dynatrac progrips saved me from hitting a car or bike way better than stock brakes.

And no I don't have a bikini nor blonde hair nor an annoying voice. I'm not a whore and I'm not sponsored by Dynatrac. I'm just a regular Joe who paid for my own fucking Dynatrac brakes, and yes they work.
Click to expand...

https://media3.giphy.com/media/x6s...fc3c8975d3a7f06344454476bd39148&rid=giphy.gif
 
WAY overthinking things. All I have is experience but I’d either do the Mopar big brake kit or Dynatrac or a combination of the two and move on. I had the Mopar big brake kit (my understanding is that it’s the same as the Crown kit) in the front and Dynatrac in the rear and it did a very good job stopping a JK that is much heavier than yours (6600 lbs). Others have said Dynatrac front and back is working well for them. Save the math for work or your track car and trust us on the recommendations.


Sent from my iPhone using WAYALIFE mobile app
 
FenderBender said:
I really wish we knew the pad compound used in all the available kits. We'd be able to do a much better on-paper comparison them all. Figuring out the braking mechanics (at least as far as clamping area and rotor diameter) isn't difficult.

Based on piston size, piston count, and rotor diameter we can compare them as if they had the same pad compound and hydraulic pressure.

The normal force, F, applied by the caliper will the piston area multiplied by the hydraulic pressure: F = A*P

The torque, call it tau, applied to the rotor is proportional to (not equal to because we don't know coefficient of friction of the pad) the caliper normal force multiplied by the distance from the center of rotation to the center of the piston (call it r): tau = F*r

Keep in mind that the distance from the center of the rotor to the center of the brake piston is not the diameter of the rotor. It's the radius of the rotor minus (roughly) the radius of the piston cylinder. The stock pistons are 66 mm in diameter (1.3 inch radius). The radius of the stock rotor is 5.95 inches; Dynatrac is 6.75 inches. The relative torque would be (6.75"-1.3")/(11.9"-1.3") = 1.17 or a 17% increase in stopping torque from the larger rotor. The rest of the gains come from the pad material.

I made a spreadsheet some time ago when I was deciding on my brakes. The spreadsheet did the above calculations and compared to the stock arrangement for many aftermarket kits. I found that the Dynatrac didn't fare well at all in the comparisons, even bearing in mind that Dynatrac also upgraded the rear brakes (KEEP IN MIND THAT THIS DOESN'T INCLUDE PAD MATERIAL). This is probably similar to what the OP and his friend did. The Teraflex kit had the best numbers of anything below $1500, while the Dynatrac kit had the worst numbers of anything over $1000.

To put numbers on it, I found that the Teraflex kit had a total mechanical advantage (torque and normal force combined) that was 70% greater than stock (assuming same pad material and fluid pressure). Consider that in a 60/40 front/rear braking scheme, that comes to about 40% increase for the total system just by upgrading the front brakes.
The Mopar kit (and the Crown/RT kit) ended up with about 55% increase in the front stopping torque, or 33% for the total system.
The Dynatrac kit ended up in the ballpark of 20% improvement for the total system.
The SSBC Tri-Power Caliper-only kit had about 20% improvement for the total system just by changing the front calipers (the exact opposite philosophy from Dynatrac but the same mechanical increase and can fit in smaller wheels).

The pad material and the pedal stroke required to get the same fluid pressure are the elephants in the room, obviously. A pad made with unobtainium is how Dynatrac gets such a good product using relatively modest geometry changes. More piston area means squishier pedal if you keep the same booster/master cylinder, which is a strike against the Teraflex and similar kits.

Mostly because of their reputation and cost, I couldn't bring myself to buy Terror-flex kit. However I also couldn't convince myself that Dynatrac was the best bang for the buck if so much of the performance comes from proprietary pads.

Obviously this is all on paper and I only write this up to show a quantitative approach to some of the options. Seemingly everyone who has the Dynatrac kit has been happy with it, so it's clearly great. I only offer this a way to compare what we do know about the specifications of each system.
Click to expand...

Please STOP... You get it?? No but really Stop!
 
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