Mazda really got it right in offering the Brembo brake package on the 2016 MX-5 Club. For track use, it’s perfect.
This setup can handle the heat of hard track lapping without fading, yet it’s docile enough to run every day on the street. Give some credit, though, to a high-performance Ferodo pad that’s more than twice the size of the standard piece.
After pushing the original pads more than 6500 miles–a large percentage of them racked up around a road course–the wear on the friction surface was quite even. That suggests optimal use of the available friction surface beneath those big four-piston fixed calipers.
More Stop
When it came time to replace the pads, we looked for additional performance. As we got faster in the car, and especially once we fitted stickier tires, we found that it took every bit of leg effort we could muster to generate braking forces hard enough to engage the antilock brake system. This was mostly an issue on the track, but it also showed up on autocross courses, where we’d have to bleed off 20 to 30 mph within a very short braking zone. Given that effort level, consistency often suffered. Can we do better? You betcha.
Pagid is a well-known name in Europe’s racing and high-performance circles. Recently they’ve been making inroads into North America at both the professional and amateur levels. Mazda even partnered with Pagid when developing brake pads for the latest Global MX-5 Cup cars, so using the brand’s brake products seemed a natural path for our own project. Further, we’ve had very positive experiences running Pagid pads on our McLaren 12C in the Tire Rack One Lap of America.
At big tracks with long straights, the heavier and faster the car, the more energy the brake pads must dissipate. A larger pad can absorb more heat from that dissipation than a smaller one, but ultimately the compound used must be able to tolerate that heat without fading. Such high-temperature friction materials typically have a more narrow operating range, and they don’t work well at the lower temps encountered during street use. Racing pads that do work at street temps often do so at the expense of rotor life.
Fortunately, our MX-5 is very light and the engine is not that powerful. Plus, the car handles so well that its corner-entry speeds are frequently higher than those of most other cars. As a result, the extra-large brakes can easily dissipate the typical braking zone energy using something short of a full-on racing pad. But the dizzying array of available compounds can be a challenge to navigate. So we asked for help.
Our MX-5 Club came standard with big Brembo brakes up front. Swapping to Pagid pads all around brought them to their full potential. Photography Credits: Andy Hollis
Pagid suggested that we use a split combination: their RSL29 on the front and the RS44 on the rear. The former is a track-day favorite for a variety of cars, as it features a strong initial bite, a wide operating temperature range and good modulation. It’s also easy on the rotors.
Pagid has found that MX-5 rear pads operate about 100 degrees cooler than the fronts, so the higher friction ramp-up of the RS44 balances it well with the RSL29 fronts. This was the setup used on the front-running Freedom Autosport MX-5s campaigned in the Continental Tire SportsCar Challenge in 2016.
Installation was straightforward and took only an hour. At the front, two pins plus a sprung retaining clip secure the pads. A punch and a piston clamp tool make this job easy.
The rear caliper is a standard MX-5 single-piston floating design–painted red to match the front Brembos–that is held together by two bolts. The only tricky part involves making room for the thick new pad: A caliper retraction socket is used to wind the self-adjusting piston back into the caliper. These sockets are commonly available at auto parts stores and fit a wide variety of applications.
Pagid’s website details a fairly involved bedding-in process for their pads. However, it’s mostly for their high-end, professional race products. which take quite a bit of temperature to bed. We were advised to simply do two or three laps at the track, steadily increasing the pressure applied during braking events. The final few braking zones should be at full race pace, they said.
We felt the pads come in fairly quickly, as pad material was transferred to our rotors. Then we experienced a slight pad fade after a few laps due to final outgassing. Cooling to ambient temps completed the process.
Results? We love these pads.
While our lap times did not drop appreciably–tire grip is our limiting factor–they have become much more consistent. Braking effort is now reduced substantially, so modulation over the bumpy surface of our usual haunt, Harris Hill Raceway, is easier. Specifically, we are now better able to trail-brake after long straights and carry speed through the early parts of those turns.
On the street, even in cooler temps, the pads work similar to an OE setup but deliver higher grip. While they’re not overly grabby, we have had to alter how hard we pressed the brake pedal so as not to stop short at traffic lights. We have not yet tried the pads around cones, but we’re confident that they will meet those needs as well. Our triple-threat MX-5 just got a whole lot more threatening.
More Go
Our SCCA Street class rules don’t allow much room for adding massive power, but they do contain one opportunity for increasing speed: a provision that allows the wheel diameter to go up or down by 1 inch.
The postscript to that statement is the fact that our MX-5’s short gearing required some shifting back and forth between second and third gears on many autocross courses. So, we wondered, would a shorter or taller tire allow us to shift into third and leave it there?
Our preliminary conclusion–detailed last issue–found that running the short 205/45R16 tire on super-light wheels was indeed effective in that regard, but only with the right course design. Further, shifting proficiency was a key ingredient in that mix.
Last month’s issue also contained a teaser. In the test of the new Continental ExtremeContact Sport, we used the Bridgestone Potenza RE-71R as a control tire during our autocross laps–in two sizes.
We again tested that tire in 225/45R17 and 205/45R16 sizes in order to get more data. This test, we reasoned, would be even more focused and controlled than our original shootout.
We did this second short-versus-tall comparison in two phases. The first was simply to see if the taller, 225mm tire provided any more pure grip than the shorter, 205mm tire when both were mounted on a 7-inch-wide rim, the max the rules allow.
The MX-5 Club also comes standard with 17-inch wheels but on the right course, shorter 16s can be an advantage. Photography Credit: Ann Hollis
For this test, we timed each combination around the skidpad–the same way we typically test for optimal inflation pressures. We also did sweeps on pressures to see if perhaps some speed was hiding somewhere. Would lower pressures help the 16’s short sidewalls? Did the taller 17-inch tires need more air?
What we found was that the 16s had a nice sweet spot right at 28 psi that was a touch faster than anything the 17s could muster. And while we could somewhat alter the feel of the 17s with more air, it made little difference in lap times.
For the second phase, we set out to dodge some cones using our standard test course: a five-cone slalom down one side and three offsets down the other, connected at each end by a pair of on/off-camber sweepers. The speeds on this layout are low enough to stay entirely within second gear on both setups. And since acceleration runs are few on this course, we’d be testing pure handling and responsiveness. Results would be measured in lap times, but we’d also collect subjective performance impressions.
A second driver–multi-time SCCA Solo National Champ David Whitener–took turns behind the wheel to add veracity to our data. Up until this test, David had little time behind the wheel of an ND-chassis MX-5 around pylons. As usual, though, he quickly adapted. As expected, his run times show a little more improvement throughout the course, so think of him as a guest driver who was there to confirm the easy time gains and differences in feel.
Our test format again used a pair of laps to total one run. It’s an easy way to quickly duplicate the typical 60-second autocross run using our limited space and easily driven course. Pressures were reset after each run.
Since we were piggybacking on our Michelin versus Continental test, there were actually five cycles driven in an A-B-C-D-A pattern, only three of which matter for this particular story. Given the extra time in between the back-to-back A-B and the final bracketing retest of A, some improvement simply due to driver learning and surface cleanup is to be expected.
The SCCA Street-class autocross rules allow a one-inch increase or decrease in wheel diameter. Since tire sizes are wide open, the change in overall diameter can be significant.
Conclusions
So what did we find? Both drivers reported similar subjective impressions. The taller, 17-inch combination was vague in feedback and less precise. The shorter 16s were much more willing to quickly change directions through the slaloms and could run at smaller slip angles. As a result, both pilots drove their best laps on the shorter tires. The time deltas were not huge, but they were consistent. Adding these new results to last month’s, we now know the following:
1) On a 7-inch rim, the 205/45R16 tire delivers slightly more grip than the 225/45R17.
2) When no shifting is involved, the short-sidewall combination is slightly quicker on a balanced handling course.
3) On courses featuring significant acceleration runs, the shorter combination is significantly quicker.
4) All of the above can be negated through too much sloppy shifting.
Bottom line: We’ll be carrying two sets of wheels and tires with us for competition events. Why? Two reasons: to build up our gear-changing proficiency and to improve our ability to predict course speeds and optimal shifting patterns. Stay tuned as we continue to squeeze more and more performance from our triple-threat MX-5.
Comments
Old article I know, but it seems relevant to ask here: How well does the rear brake system in general hold up to track use? There are some aftermarket BBKs for sale out there, most of which use the Wildwood 4-piston Powerlite caliper and 7912 pad shape. Has the Triple Threat Miata ever had issues with the rear brakes not holding up? Do you see value in a bigger rear caliper? I looked for info on whether the GMX5 Cup cars use the OEM setup or something else, but I couldn't find much information. I also couldn't find much in the way of feedback from anyone who had actually installed a BBK on the rear and what their conclusions were.
Thoughts anyone?
Factory rear brakes work great with the right pads. I’ve even downgraded to parts store rotors w/o any cracking/performance issues.
GMX5 Cup cars use factory rears. Original pad was Pagid RS44. With their new front setup, they have gone to RSL29 rear.
None of the Wilwood stuff is an upgrade over factory Brembos. If you want a real upgrade for the front, choose either AP Racing or the new GMX5 Brembo upgrade. Neither of those is necessary IMO, unless you are on slicks or have a big power bump like a supercharger.
Hey Andy,
Thanks for the reply. I've already dismissed Wilwoods for the front - I had in mind exactly what you suggested, either the AP or the GMX5 front kits. I haven't made any moves yet, but I'm on the stock non-Brembo front brakes which are on the small side, so I do have a plan in mind should the need arise.
I'll stick with the stock rear setup. If it's good enough for your purposes and the GMX5 guys, it's plenty good enough for me. Thanks!
eb59214 said:
Hey Andy,
Thanks for the reply. I've already dismissed Wilwoods for the front - I had in mind exactly what you suggested, either the AP or the GMX5 front kits. I haven't made any moves yet, but I'm on the stock non-Brembo front brakes which are on the small side, so I do have a plan in mind should the need arise.
Unless you are in a severe use case, go with factory Brembo front calipers —bolt on swap. They pop up regularly lightly used by people “upgrading” to aftermarket. I have two sets.
Worst case, buy new from Mazda Motorsport.
The real benefit is discounted Pagid pads from Mazda, always in stock. And “normal” rotors…not an expensive aftermarket two-piece.
I appreciate the advice. I'll keep an eye out for a used set.
I disagree about the efficacy of Wilwoods. We’ve run them on track in a 500 hp Miata, no concerns. We’ve used them for a 15 hour test with journalists at Laguna Seca. Better pad choices, better wheel clearance and lighter weight than the chonky factory Brembos. The Brembos were found wanting for GCC, thus the existence of the Mazda Motorsports kit.
Wheel brake clearance aside, the Wilwoods have less pad swept area than OEM Brembos....seems like on a given rotor size, that would impact stopping ability.
And while the interwebs is ALWAYS fully truthful and accurate, it does seem there have been many issues experienced with Dynapro calipers leaking or having sticky pistons.
If those leaks are happening to our customers, they’re keeping it a secret from us. We haven’t even had to stock rebuild kits for a long time despite selling them for the past couple of decades. Are you scouring the internet for all possible Wilwood Dynopro failures on all vehicles for all time versus Brembo problems on a relatively small sample size of ND Miatas?
By stopping ability, do you mean maximum brake torque or heat management? I suspect you’re thinking of the former, and the Wilwoods aren’t lacking there. Especially since they’re not being used on rotors of the same diameter. The Wilwood kits use significantly larger rotors, which means more heat capacity and more brake torque.
Car and Driver did instrumented tests of one of our cars. 70-0 dropped from 170’ to 148’ despite an increase in weight. Of course, there was a tire difference but obviously the Wilwoods were able to generate sufficient brake torque to take advantage. And when Road and Track tested two cars at Laguna Seca (one turbo, one V8) they did not have trouble with fade. Seems to me the performance is proven.
I’ll check actual pad dimensions and see if the Brembos really do have more swept area and total pad volume, but their primary advantages are that takeoffs are cheap (initial purchase price is painfully high) and they have a cool brand name.
This is partly why I tend to get analysis paralysis when it comes to deciding on upgrades - there's so many helpful, passionate people out there willing to share their opinions, and I very much appreciate having this resource where some very well-respected and experienced professionals in the community to speak with me directly. However, they don't always agree, so I end up torn.
My thought before posting this was "buy once, cry once". When I looked for the OEM Brembos for sale I was seeing them for $1500-1800. So I figured that isn't too far from the GMX5 kit for $2600, but it gets me larger, stiffer calipers, thicker pads with more surface area, a much bigger disc with curved vanes for better cooling, and discounted consumables and hardware from Mazda Motorsports. Seemed like a good deal, even if it is overkill for a beginner to track days. I figured I'd rather buy more than I need now and be able to grow into it, rather than having to buy twice.
But "buy once, cry once" may not be the best way to go in this situation, I admit. I'm very much not the expert, so I'll listen to any advice or feedback I get in order to make an informed decision.
Regardless, I appreciate everyone's input 
I’m not going to poo-poo either Flyin Miata or Wilwood, who are both GRM project car partners and advertisers…a mutually beneficial relationship.
I chose the factory Brembos, and continue to use them, because they are a proven OE-engineered combination with by far more track time than any other. This setup was used by the GMX5 Cup cars for seven seasons. On slicks. With the highest level of competition.
They only went to a larger setup two years ago because in the worst situations, they were at the limit of thermal capacity. Switching to the stickier Michelin slick made that a necessity.
And I recommend that setup to others because I personally have more track hours on my car than almost anyone not running Cup.
Running costs are key to me, so using stock rotor sizes helps immensely. As an example. I recently bought two pairs of front rotors for $28 each from Rockauto on a close-out. They were Carquest labeled. Working great. I usually use Centric at $40 each but those are going to dry up with the First Brands closure, so I am trying others.
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