Bridgestone RE-71r Tire Review
I tested a set of 205/50-15 RE-71r on a 1990 Spec Miata configured for AER endurance racing and a 2003 DE Miata. The AER Miata came with a set of used 205/50-15 Dunlop Star Specs, and in that configuration its performance was somewhere between AER class 1 and class 2. My primary goal with RE-71r testing was to determine if these tires would consistently put the car in class 2; my secondary goal was to evaluate RE-71r performance and wear in general.
I tested RE-71r at a number of tracks over the course of several months: NJMP Thunderbolt, Mid-Ohio, Summit Point Main, NCM Motorsports Park and Road Atlanta. Comparison tires were used 205/50-15 Dunlop Star Specs, used 225/45-15 Hankook RS3, used 225/45-15 Toyo RR, used 205/50-15 Nitto NT-01, used 225/50-15 Toyo RA-1 and brand new 205/50-15 Toyo R888R.
Dry Grip - Subjective Impressions
RE-71r, when new, subjectively slot in between other "non-cheater" 200 treadwear tires (i.e., not BFG Rival S) and R compound tires. Compared to "normal" 200 treadwear tires, RE-71r have the R compound feel of a lot more grip available everywhere. This is most pronounced under braking where RE-71r seem to be much closer to an R compound than they are to a street tire, but is also evident under cornering and acceleration.
As RE-71r wear down, and when driven on more slippery pavement like that at Mid-Ohio, RE-71r lose some of the R compound feel and drive more like a street tire, although they are remain distinguishable from street tires. Tire noise increases, especially in long sweepers.
In absolute terms, RE-71r offer very good response. They do not feel laggy or delayed at all. Responsiveness of RE-71r is very close to that of medium/hard R compound tires. When switching between RE-71r and R compound tires I found that I almost did not need to adjust my turn in points.
Steady state performance of RE-71r subjectively is not quite as good as that of an R compound tire with a similar heat cycle count. RE-71r break away a bit sooner than an R compound tire does; in case of a balanced car like a well set up Miata, this happens on both front and rear ends of the car, meaning the car can be balanced on R compounds and both understeer and understeer (in different corners) when switched to RE-71r. This quicker breakaway is probably a function of a more meaningful tread pattern as well as smaller tread area of RE-71r compared to even R888R/NT-01. Note that the earlier breakaway of RE-71r does not necessarily make them slower, but it does make them mildly harder to drive at maximum pace than an R compound tire.
RE-71r excel under braking. On a non-ABS car they are able to decelerate harder early in a braking zone, unlike most of the Hankook tires I drove on in particular (RS2/RS3/RS4/C30/C50). RE-71r are both stable under hard braking and tossable as well as predictable during trailbraking. The car was easy to rotate on RE-71r in both short and long braking zones. RE-71r provide ample auditory warning before lockup and reducing brake pressure slightly returns the tires to their happy place.
Laterally RE-71r were sensitive to where weight was in the car much more than R compounds usually are. The car exhibited light corner entry understeer at Thunderbolt turn 6 which is a full throttle, 80 mph corner in a Miata. Similarly the car exhibited light understeer in the middle of the Octopus once the car was accelerating. In both cases the lack of grip could be driven around - a partial lift in the middle of turn 6 rotated the car enough to finish the corner under throttle, and Octopus was fixable by rotating the car more at corner entry.
Additionally, RE-71r appear to be more sensitive to the car setup than R compound tires. In particular I had the car significantly toed in in the rear; while this no doubt made the car slower than it should have been, I could not feel the difference in how the car handled on RA-1 or RR/NT-01. I did however feel the understeer once I put RE-71r on, and zeroing rear toe dropped the lap time on RE-71r by a full second.
Compared to a medium/hard R compound tire (Toyo RR/Nitto NT-01 etc.) with many heat cycles, new to mid life RE-71r subjectively offer more grip. However, a new R compound does feel grippier than a RE-71r with several heat cycles on it, and in my estimation a new R compound will feel more planted than a new RE-71r. I wore out my set of RE-71r in terms of tread depth well before they heat cycled out, hence I cannot comment on how high heat cycle count RE-71r compare to high heat cycle count R compound tires.
Dry Grip - Data
I broke out the data analysis including graphs and commentary onto a separate page to keep this page at a reasonable size.
- NJMP Thunderbolt - Vs RA-1, RR, Star Specs: 205/50-15 RE-71r are a second quicker than full tread 205/50-15 RA-1, equal to a 225/45-15 RR / 205/50-15 NT-01 combo; RE-71r go another second quicker after tuning the car, though this gain may have also evidenced in RA-1/RR.
- Mid-Ohio - Vs Star Specs, RS3 - old 205/50-15 Star Specs / 225/45-15 RS3 combo is half a second faster than new 205/50-15 RE-71r.
- Summit Point Main, Repaved - Vs NT-01, RA-1 - dead 205/50-15 NT-01 / 225/50-15 RA-1 are a second faster than half tread 205/50-15 RE-71r, despite a gearing disadvantage.
- National Corvette Museum Motorsports Park - Vs Star Specs, RS3, R888R - 205/50-15 RE-71r match best lap performance of dead 205/50-15 Star Specs / 225/45-15 RS3 combo, though RE-71r are much easier to drive and put down a quicker average lap.
- Road Atlanta - Vs R888R - 205/50-15 RE-71r with about a quarter tread remaining are half a second quicker than new 205/50-15 R888R.
- Sebring - Vs R888R, NT-01 - 205/50-15 RE-71r with about a quarter tread remaining are about a second quicker than still fresh 205/50-15 R888R and 3/4 of a second quicker than brand new 225/45-15 NT-01.
- On some tracks RE-71r are marginally quicker than hard R compound tires like R888R of the same size.
- On some tracks RE-71r, lower grip street tires and hard R compound tires of the same size perform about the same.
- On some tracks RE-71r - with low heat cycle count - perform worse than even old, heat cycled out R compound tires of the same size.
What this means, unfortunately, is that it is impossible to make a general recommendation regarding performance of RE-71r vs other tires. Testing must be performed at each track to determine which tire is faster.
I drove RE-71r in wet conditions at Barber. There was little standing water but the track surface was still almost entirely wet from intermittent rain throughout the day. At this point the RE-71r had barely any tread left; I did not drive them when standing water was present, opting instead for 3/4 tread 205/50-15 RA-1.
Subjectively RE-71r felt quite similar to RA-1 in these conditions. RE-71r seemed to have more braking grip on level surface (early in the braking zone for turn 5, for example) but less grip in hard downhill braking (late in the same turn 5 braking zone). RE-71r took longer to recover from brake lock up in turn 5. In turn 16 when the car would lose the rear grip and go into a drift, on RE-71r it would slide almost to the left edge of the track between turns 16 and 17; on RA-1 the car would usually stay no further left than track center in the same spot. When RE-71r lost rear grip over water puddles, the breakaway was more sudden compared to RA-1 and the car took longer to recover.
Based on this I would say the tread compound of RE-71r has similar wet grip level to that of RA-1, although RA-1 is more predictable and easier to drive even when there is no standing water due to its tread pattern of independent blocks.
In standing water I expect RE-71r to do worse than RA-1 due to the tread pattern differences. Small independent tread blocks of full rain tires like full tread RA-1 and Hoosier H2O are superior at water evacuation compared to a ribbed/large block tread pattern of tires like RE-71r, NT-01, R888, R888R.
I imagine that a RE-71r would have similar standing water performance to R888/R888R, and likely NT-01 as well, with similar tread depth. This is to say, not amazing.
I expect RE-71r to do better than "normal" street tires over both wet surface and standing water, due to the softer compound. For rain race application in particular, RE-71r can be a good choice as long as the driver(s) are careful to avoid too much wheelspin, because RE-71r still wear quickly even in wet conditions.
As I've only driven the tires in the wet conditions for about 15 minutes, I can only estimate wet wear rate but I think it is still much higher than that of "normal" street tires. Driving style plays a big part too - it is easy to spin driven wheels in the rain, and doing so on RE-71r will make them wear even quicker.
One of my general concerns with street tires is their (lack of) heat resistance. I encountered this with Bridgestone RE-11 which was considered a high performance street tire back in its day. The short of it is a street tire would overheat if driven hard for 20 minutes, at which point its performance would diminish significantly and if continued to drive aggressively, the shoulders would generally wear rapidly reducing useful track life of the tire.
In terms of performance, I was pleasantly surprised by the heat resistance of RE-71r. They certainly can be overheated if driven at 10/10ths for 20 minutes, however their performance at sustained 9-9.5/10ths driving is much better than any street tire I have used up until now.
In terms of wear, I expect continuous hard driving to wear RE-71r quickly, although in absolute terms this is hard to quantify given that the tires are wearing at an extremely high rate even when not abused.
RE-71r have very quick warmup, at least when they are not heat cycled out. Once the track event is underway the tires need less than a lap to get into their temperature window, and are very capable of running their full pace on lap 2. Together with outstanding heat resistance this makes RE-71r a good choice for time trial-style driving - the tires are capable of setting a good lap time early in the session but can also run a full session if there is traffic.
Unfortunately, the price RE-71r pay for their R compound-like performance is astonishingly high wear. When other people remarked that RE-71r wear quicker than R compounds, they were not kidding: based on my testing, I would cord the outside front tire in about 4 hours of driving at maximum pace (aiming for 10/10ths) and about 6 hours driving at 9/10ths. This makes RE-71r unsuitable for endurance racing as the race lasts 8-9 hours per day - the outside front is not going to make it that long. With rotation I expect a set of RE-71r to last 6 hours at 10/10ths, 8-9 hours at 9/10ths and 10-12 hours at 8/10ths.
My set of RE-71r after about 1.5 hours of track time, on a track with predominantly right turns. Left front, outside on the bottom:
Left rear, outside on the bottom:
LR outside edge:
LR inside edge:
Right rear, outside on the bottom:
With about 3 hours of total track time on two tracks with primarily right hand turns, with tire rotation but before I flipped tires on wheels, tires that got more time on the left side of the car looked like this (outside on top):
And predominantly right side tires looked like this (outside on top again):
At least one AER team that is running RE-71r change outside front tire mid day. They are able to do this because the car has a fuel cell and is able to run for 2.5 hours between pit stops, thus they use one of the mandatory pit stops for a tire change. Such a strategy is not possible in a stock Miata - the car can only run 1.5 hours on fuel and requires fill up at each mandatory pit stop.
I found RE-71r to perform well with the standard Miata setup: zero toe front and rear and about -3 to -3.5 degrees of camber front and rear. All of my testing except early sessions at the very first Thunderbolt event were done with the car configured in this way.
To wear evenly however, RE-71r need more camber than R compounds. A fellow racer remarked that they run over -4.5 degrees of front camber with RE-71r, though on a heavier and more powerful car than a Miata. My experience matches this - I was wearing outside edges of outside front and outside rear tires even with camber in the -3° range.
I have also been reading topics on Spec Miata forums about racers running over -4 degrees of camber, though this was for the rear with Hoosier SM7 and for performance rather than wear. Regardless, it seems that camber values over -4 degrees negative are becoming somewhat accepted if not yet common in production cars.
In terms of air pressure, I found RE-71r to be greasy at 41 psi hot when driven hard and more planted at 38 psi hot for the outside front tire. For reference I aim for the standard 39 psi hot with Toyo RR, RA-1 and NT-01. I would say RE-71r like a bit less pressure than the medium/hard R compound tires.
First Heat Cycle
The very first heat cycle I put on the tires I drove the car at 8.5-9/10 tenths. Partially this was because I did not know the characteristics of the tires, and partially I wanted to put a gentle heat cycle on them as is recommended for R compound tires.
My best lap in this initial heat cycle was a 1:41.5. In the next session with me driving more aggressively but still not at the absolute limit I ran a 1:39.5. In the next session with zeroed rear toe and a more balanced car I turned out a 1:38.5.
My feeling is the tires are not as quick in their initial heat cycle as they would be later in their life, and would therefore benefit from a gentle, non-competitive first heat cycle prior to being used in a competitive environment. I let the tires rest for about an hour after the initial heat cycle; at this point I can't say whether a longer rest period (say, a week) would make any difference.
Unfortunately, the result of my testing of RE-71r is anything but a clear "yay" or "nay".
For an endurance racer, RE-71r may provide higher performance than other street tires, or may not - depends on the track. Testing must be done at every track to determine if RE-71r are faster.
Regardless of whether RE-71r are faster or slower than other tires at a given track, they still exhibit extremely rapid wear, compared to other street tires. On many, and possibly most, cars RE-71r will cord outside front tire in less than 8 hours at race pace. This means RE-71r are generally only a viable option for cars with large fuel cells that are able to use one of the mandatory pit stops for a tire change instead of refueling.
When not driven at their full pace, RE-71r will last longer but they are still more expensive than buying other street tires and running those tires hard. That said, RE-71r are easier to drive consistently at a slower pace than a harder tire is to drive at a higher pace. If the team can make RE-71r last an entire race day they can be a viable option for endurance racing.
RE-71r are a good time trial tire due to quick warmup, excellent heat resistance and the fact that time trialers generally do not drive much. A set of RE-71r, used conservatively, may last an entire time trial season.
I do not recommend RE-71r for DE/track days due to their rapid wear. Both harder compound street tires and hard R compound tires like NT-01/R888R are better options if driving 2-3 hours per day is on the cards.
As RE-71r requires significantly more camber than medium/hard R compound tires for even wear, running both RE-71r and R compound tires on the same car is suboptimal.