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Discussion Starter · #1 · (Edited)
Playing around with doing a drag brake kit for the Focus ST/RS. This would allow for the use of 15” wheels, and shave approx 50lbs off the front end, a good chunk of which is rotational mass. Other benefits are low cost pad and disc replacements, a lighter scalloped rotor option, no need for wheel spacers with stock wheels, and did we mention like 50lbs of weight savings!?

We spec the caliper pistons sizing to retain a near OE level of brake basis, all while using a smaller and thinner rotor. Now we wouldn’t recommend this setup for road course use, but for drag, AutoX, street, and even rally, this kit is badass. We’ve had a similar kit out for awhile on the Mazdaspeed3 platform; tested on passes quicker/faster than an ST or RS has yet to run in the 1/4 mile. Cost would probably start at just over $1k, anyone out there making quick passes who would be interested in a kit like this?

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Here's a pic showing the lighter scalloped rotors:

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Link to our Mazdaspeed3 kit Mazdaspeed3 Drag Brake Kit
 

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'18 ST1+ Sync3 Euro Blue Recaros
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From their MazdaKit;
  • Optional Ultralite Scalloped Rotor, recommended only for drag use
  • Also, street versions available
 
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Guys, I read the points you call out. Am more interested in the vendor response as I have been looking at braking options recently. The scallops from all my reading=drag only and makes sense. Am not wanting to lose stopping/cooling power to save weight, really.

Also, what drives the "shave approx 50lbs off the front end"? I presume this is accounting for weight of the stock wheels/brakes then going to a smaller wheel+this brake kit. Would be more curious about the weight savings over stock components replaced since the stock wheels are long gone on my ride.
 

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Discussion Starter · #6 ·
*Mazda.

And this would be 100% daily driver friendly, or are we looking at 100% track duty?
Yes, this can be a DD friendly kit. That being said, it would require more maintenance in terms of pad & rotor replacements, as well as caliper rebuilds. The latter is mainly due to the standard calipers in the kit not having dust boots. However we intend to offer additional calipers with dust boots as well, for those who plan to street the brake kit more vs racing on it. It'll just cost more... but the calipers are prettier :D

Guys, I read the points you call out. Am more interested in the vendor response as I have been looking at braking options recently. The scallops from all my reading=drag only and makes sense. Am not wanting to lose stopping/cooling power to save weight, really.

Also, what drives the "shave approx 50lbs off the front end"? I presume this is accounting for weight of the stock wheels/brakes then going to a smaller wheel+this brake kit. Would be more curious about the weight savings over stock components replaced since the stock wheels are long gone on my ride.
The scalloped rotors are not recommended for street use. The standard rotors for the kit are fine for street use. We may also offer another rotor better suited for higher temps and venting.

On the Mazdaspeed3, this kit shaved 45lbs off the braking system alone. Just over 50lbs with the scalloped rotors. We expect this to be even more on the ST due to it's heavier calipers and rotors over the MS3.

This does not account for lesser weight of smaller diameter wheels over stock wheels. Also, if you're not wanting to lose stopping/cooling power to save weight, then for you there's no need for this kit. We're building this kit mainly for drag use, and those who want to go down to a wheel size with much more drag slick options, and not sacrifice much in braking performance.

The con to this kit will be the loss of thermal capacity, so if someone is doing multiple back-to-back braking applications from high speeds, then they're better off with larger braking components, like stock or a BBK.
 

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Thank you for the clarification and detail. Your last sentence is what I keep coming back to in my head over and over when I look at light weight brake options. The downside primary is the loss of overall brake performance when used heavily, the OE brakes are heavy but for a reason. BIG concern is getting caught up in the need to go lightweight and giving up braking performance. My car is a daily, but when I drive it hard, I drive it hard but it's also a car I drive my family in so safety first.
 

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What's the weight penalty for say switching to like a base model s focus front brake setup that runs an 278mm rotor vs these wildwoods? I know the focus parts will be all iron and obviously heavier.

Not that I have any interest in downsizing brakes, just thinking of the option of a readily available setup that should be dirt cheap to source
 

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Discussion Starter · #9 ·
What's the weight penalty for say switching to like a base model s focus front brake setup that runs an 278mm rotor vs these wildwoods? I know the focus parts will be all iron and obviously heavier.

Not that I have any interest in downsizing brakes, just thinking of the option of a readily available setup that should be dirt cheap to source
Compared to the bigger 335mm bois you'd be looking at like 9-10lbs a rotor, and about maybe a couple lbs per caliper. However, the the caliper piston size is the same between the ST and regular Focus calipers. The issue here is that, while clamp force is the same, since you've reduced the disc diameter you've effectively reduced the brake torque... and at the end of the day, that's what matters.

You can combat that a few ways going to the smaller Focus brakes.
  • Increasing the fluid pressure (the smaller brake Foci may have a higher pressure output master, idk), which will increase clamp load, and in turn brake torque.
  • Going to a higher coefficient of friction pad.
  • Reducing caliper flex (like with our brake bushings) which will improve clamp load.
  • More pedal effort
With this kit, we intend to keep or slightly better the stock brake torque, mainly by increasing the clamping force via piston area, as well as moving to a fixed multi-piston caliper with much less flex vs OE. The downside is thermal capacity, which for this kit's intended use, is NBD.

Side note. I actually have downsized the brakes on my Mazda5, mainly to fit smaller wheels and ALL THE SIDEWALL tires. I run some pretty aggressive pads and our caliper bushings to help restore the braking torque on the car, without having to stomp on the pedal every time I go to brake. Even then, it still feel like I'm putting in more pedal effort.
 

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.

Side note. I actually have downsized the brakes on my Mazda5, mainly to fit smaller wheels and ALL THE SIDEWALL tires. I run some pretty aggressive pads and our caliper bushings to help restore the braking torque on the car, without having to stomp on the pedal every time I go to brake. Even then, it still feel like I'm putting in more pedal effort.
yeah I remember posts on the other focus site with the mk1's where they were happy to down size to the brakes from whatever trim came with the 14" wheels. They were doing some sort of rally where they wanted all the sidewall they could get and didn't prioritize brake size
 
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