Bridgestone Potenza RE-71RZ vs. RE-71RS Comparison Test How much better is the RE-71RZ? We found out on the M2 and BRZ!

Introduction

Everything to know about the Potenza RE-Z1RZ

This is a companion piece of sorts to the first preview drive we conducted for the Bridgestone Potenza RE-71RZ, so we'll skip a bit of the history and background for the tire (see that report if you'd like the additional flavor) and jump into what's different here.

The first, and most obvious change is that this time we're testing on a brand new set of RE-71RZ tires as opposed to the used tires Bridgestone made available early in its press cycle that we had tested previously. On top of not being in our usual test size, the exact amount of use, heat cycles, etc., was unknown to us. Good enough for a first impression, but hardly up to our usual tire testing. The current tires are all taken out of inventory to ensure they're the same that anyone picking up a set would get from our warehouses. All tires were heat cycled and allowed to rest for well over the 24~48 hour minimum and set at 32psi hot during testing.

We're also employing not one, but two separate test vehicles this time. Naturally, we have our trusty BMW M2 test car, but we're also bringing our old Subaru BRZ out of retirement. The M2 runs 275/35R19 tires with 10.5 inch wide wheels, and we keep it stock in every respect, including factory alignment, with approximately 1.5 degrees of negative camber on the front axle. The BRZ has been modified since its retirement into our test driver's personal limited-prep time trial car, with aftermarket dampers, springs, sway bars, front camber plates with 2.5 degrees of negative camber, running a square setup with 245/40R17 tires on 9 inch wide wheels.

Like most of our tests and previews, we'll share the on-road experience (albeit briefly), and then dive into the specifics on our track in both dry and wet conditions. We'll also be sharing the data we've gathered from conducting braking tests from 60 MPH and measuring lateral gs, again in both the wet and dry.

RE-71RZ on the Road Again

It was little surprise that the experience in the BRZ was the harsher of the two vehicles. Even back when it was stock the vehicle communicated a great deal of the texture of the road, which neither the Potenza RE-71RS or its successor helped much in masking. Every bump, tar strip and pothole was being sent directly into the backsides of our testers. Each hit was brief and never really upset the car, but this was not a soft and cozy drive. Noise was intrusive, and varied quite a bit based on the surface: from coarse, grindy concrete, ringing over asphalt or growling over chip-and-seal roads.

The Potenza RE-71RZ didn't have the same asphalt ring as its predecessor, but made up for it with a repetitive staccato tone instead. Obviously neither tire was quiet, but not really any better or worse than the other - just different flavors of noise. As performance products, it should come as little surprise that steering was extremely responsive on both, to the point where we needed to be particularly gentle with the Potenza RE-71RS, as it would respond to every twitch of the wheel, intentional or not. The Potenza RE-71RZ was slightly more tame in a good way; while not quite as immediate, it was also less twitchy, building effort the further into the wheel we reached.

On our stock M2, the suspension was a large boon to both tires, eliminating much of the harsh ride on the BRZ. Not entirely, of course, these were still performance tires and felt like them, but the vehicle smoothed out a lot of the smaller impacts so the road wasn't quite as annoyingly intrusive. Just like the BRZ, the auditory journey was simply different flavors of consistent noise between both tires. More interestingly perhaps was the similarity in steering feel between both. The Potenza RE-71RS didn't feel quite as overeager on the M2 as it had on the BRZ, which brought both tires much more in-line with one another, enough that any differences were too minor to note or score.

	Ride Quality	Noise Comfort	On-Road Handling	Overall Road Rating
Bridgestone Potenza RE-71RS BRZ	4.00	4.50	8.00	5.50
Bridgestone Potenza RE-71RZ BRZ	4.00	4.25	8.50	5.58
Bridgestone Potenza RE-71RS M2	6.50	5.00	8.50	6.67
Bridgestone Potenza RE-71RZ M2	6.50	5.00	8.50	6.67

RE-71RZ Rain/Wet Performance Comparison

64 degree temperatures. Partly cloudy sky. A perfectly representative day for the kind of spring showers we're experiencing in the Midwest when this report was written. With the track covered in water, we could put both sets of tires through their paces.

Once again, comparing the BRZ and the Potenza RE-71RS first: braking felt strong, grip felt strong, but in terms of balance, there was much more bite from the front end; enough that if we trailed the brakes, we could swing the rear end around. Hitting the slalom felt more like a test of bravery than a test of the tire's limits. Outside of specific instances where the front was loaded just right to push, it was responsive, precise, everything we could ask for out of a tire.

The Potenza RE-71RZ was its equal in nearly every respect, with the differences once again coming down to subtle changes rather than sweeping ones. At the absolute limit of grip, we noticed a bit less edginess, maybe a touch higher absolute traction, but it also tended to hydroplane slightly more easily.

	Wet Braking Behavior	Wet Steering Characteristics	Wet Cornering Traction	Wet Handling & Balance	Overall Wet Track Rating
Bridgestone Potenza RE-71RS BRZ	8.00	8.75	8.00	8.50	8.31
Bridgestone Potenza RE-71RZ BRZ	8.00	8.75	8.00	8.50	8.31
Bridgestone Potenza RE-71RS M2	8.00	8.75	8.00	8.50	8.31
Bridgestone Potenza RE-71RZ M2	7.75	8.75	7.50	8.25	8.06

The objective numbers buoy both the improvement of the newer tire, as well as the subtlety of that improvement on the BRZ. The Potenza RE-71RZ was on average a tenth of a second slower around the lap, four hundredths of a second quicker through the slalom, two feet shorter in braking from 60 MPH.

The wet track in the M2 was less of a departure between vehicles than the road ride had been, but did expose some interesting nuance. Once again, the Potenza RE-71RS illustrated why it has long-enjoyed status as one of the top Extreme Performance tires. In the M2's slightly wider size, it felt like it wanted to hydroplane more than on the BRZ, which also made it harder to put down power. The dynamics felt different, we needed to be more judicious with the accelerator, though it was otherwise just as capable as its slimmer version.

The Potenza RE-71RZ on the other hand, felt even more prone to hydroplaning than its predecessor, even if it was nearly its equal in all other respects. Its lap times were marginally faster overall (30.60 seconds vs 31.00 seconds), likewise through the slalom (5.71 seconds vs 5.82 seconds) - the capability was there, but thanks to its hydroplaning, it just didn't feel quite as nice to drive.

Wet Track	Average Times			60-0mph
	Slalom	Total Lap	Lateral gs	ABS Stop
Bridgestone Potenza RE-71RS BRZ	5.84	30.92	0.84	162.2
Bridgestone Potenza RE-71RZ BRZ	5.80	31.01	0.85	160.6
Bridgestone Potenza RE-71RS M2	5.82	31.00	0.82	153.7
Bridgestone Potenza RE-71RZ M2	5.71	30.60	0.81	160.9

RE-71RZ Dry Performance Comparison

A cloud smattered sky, 69 degrees on the thermometer, and a nice, dry, open track to play with.

The Potenza RE-71RS was unquestionably in fine form on the BRZ. Immediate turn-in, strong grip from the front end that felt like more than we could even utilize most of the time. We could power through the slalom, swing through the 180, braking was consistent and powerful. Every part of the drive just felt magical. Not perfect, we did manage to find some understeer, and it can be argued there's such a thing as steering being too quick, at the cost of some cones... but the overall experience was glowing.

Conversely, while the Potenza RE-71RZ outpaced its older brother (more on that in a moment), it didn't feel quite as finely put together or composed in the process. It was easier to push with a little too much speed or big inputs, and we had to be a bit more conscious of keeping our inputs separate. The steering was one of the biggest changes: it didn't feel as instantaneously reactive as it did on the Potenza RE-71RS (though still very quick), which could be taken as boon or bane depending on the person, it was certainly noticeable.

	Dry Braking Behavior	Dry Steering Characteristics	Dry Cornering Traction	Dry Handling & Balance	Overall Dry Track Rating
Bridgestone Potenza RE-71RS BRZ	9.00	9.25	9.00	9.00	9.06
Bridgestone Potenza RE-71RZ BRZ	9.00	9.00	9.00	8.50	8.88
Bridgestone Potenza RE-71RS M2	9.00	9.00	9.00	9.00	9.00
Bridgestone Potenza RE-71RZ M2	9.00	9.50	9.00	9.25	9.19

When we get into the objective numbers though, for as adoringly positive as we felt about the Potenza RE-71RS on the BRZ, it was the slowest of all four permutations we tested in lap times (27.53 seconds), the slowest through the slalom (5.36 seconds), and the farthest to brake from 60 MPH (101.1 feet) during dry track testing. Granted, all of the numbers were very close, but it speaks to an interesting divergence, and calls to mind a consistent maxim: "What's fast doesn't always feel good, and what feels good isn't always fast."

The Potenza RE-71RZ's improvement over the Potenza RE-71RS on the BRZ was slight, but noticeable in each metric: 5.21 seconds through the slalom, a 27.41 second average lap, 99.7 feet to brake from 60 MPH.

When we switched over to the M2, the Potenza RE-71RS again showed us why we like it. It gave us a broad traction limit to work with, but also forgiveness at that limit, the ability to correct and recover when it does step out, to overspeed or be a little sloppy and count on the tire to handle the mess helpfully. The M2 wasn't as blisteringly immediate as the BRZ through the slalom, but that distinction didn't matter too much, it was still as twitch-reactive everywhere else on the Potenza RE-71RS. When we moved to the Potenza RE-71RZ though, this was where it really shone: less manic, more refined, more precise, easier to drive. Graceful, even. It felt very well mated to the M2's characteristics as a vehicle. The changes to steering felt much more appropriate and welcome here.

The objective numbers tell the story again here: slight improvement, but a consistent one. The Potenza RE-71RZ was better, faster, across the board on the M2. Lap times (26.96 vs 27.09 seconds), Slalom (5.12 vs 5.16 seconds), and braking distances (92.9 vs 95.3 feet) all fell in the Potenza RE-71RZ's favor.

Dry Track	Average Times			60-0mph
	Slalom	Total Lap	Lateral gs	ABS Stop
Bridgestone Potenza RE-71RS BRZ	5.36	27.53	1.09	101.1
Bridgestone Potenza RE-71RZ BRZ	5.21	27.41	1.10	99.7
Bridgestone Potenza RE-71RS M2	5.16	27.09	1.05	95.3
Bridgestone Potenza RE-71RZ M2	5.12	26.96	1.07	92.9