PowerLabs

So I finished off a set of Nitto NT 555R2s on the back of my car, and installed Toyo R888s in their place. I got the Nittos used, just above their wear bars, and they lasted 9000 miles to the point where they were getting "tricky" to drive in the rain (but still some thread left). Got the Toyos in the same condition; just above the wear bars.
Both tires are sized 305/35R18.
Some thoughts and comparisons:

- Toyo owns Nitto. The R888 and the NT-555R2 have exactly the same rubber compound. They are both 100 Threadwear. Incidentally the NT555R, the NT01 and he Toyo RA1 use that same rubber too... They change the thread pattern and sidewall stiffness to achieve different handling traits (the 555R is a Drag Radial tire for example).

- The R888 is wider than the NT555R2 of the same size. Looks almost 1/2" wider in fact. This has not caused any fitment issues.

My Review:
On a dry road I can not tell the difference. In the wet the NT555R2 was noticeably better. The R888s may be a little bit louder too, but not enough where I can say this for sure.

Given that the 555R2s are cheaper and work better in the wet, I think they may be the better purchase between the two, but I will put some more miles and few driving events on this set and see how long they last.

Oh yeah, they already picked up a nail. That's the 2nd nail I get since I switched to R-Comps. They are decidedly more prone to this

NemesisC5

Not sure on Nittos' but the R888's are designed for higher "hot" pressures for HPDE's. Target 44-47 hot and you're good to go.

MrDrezzUp

I have been waiting for this exact comparison for some time. Thank you.

A drawback to the Nittos is I do not know if they have an applicable size for the front?

PowerLabs

True. That is the reason why I called up Nitto and Toyo tech support. Here is what the consensus is (as per an Engineer from Toyo and then a sales person from Nitto):

- It is "OK" to run an R-Compound on the back and regular street tires up front. It does not lead to unpredictable or dangerous handling traits, but it will net a car that corners no better than stock while understeering terminally at the limit; it won't be very competitive in any kind of handling event, but this is how most run their cars on the street.

- Running R-Compound tires up front will result in the best possible handling BUT the front R-Comps will get eaten up pretty quick; they can get up to operating temperature and then start to scrub away at every corner; since you turn a lot when street driving, they wear fast. Expect 12 - 17K miles out of a fresh set on the street, at bet.

- If you want to run R-Comps up front for maximum possible grip and handling, you can pair up NT555R2s with any other tire that uses the same rubber compound. Refer to my list in the first post.

That's how I ended up with R888 up front and NT-555R2 for my first try. It netted 1.24Gs on cornering, 1.2Gs in braking and 1G in acceleration. I don't know how that compares with other cars on R-Comps, but compared to street tires it is unreal. The car holds so hard around corners that I have to find something to brace myself against.

MrDrezzUp

I have TractionMonster modded rear wheels with Toyo R888s ready to be put on the car. Toyo R888 on the front is probably overkill as the car will probably not see any autocrossing. Nitto Rx in the rear, and something reasonable in the front may make for a less expensive next set of tires.

1.24Gs. That is crazy!

PowerLabs

I know! You know what though? Even with 265/35R18 up front, AND -1.5 degrees of negative camber + maximum caster, AND a C6 Z06 rear swaybar on the back, it will still lose traction up front before the back end comes around. Its nice, predictable and safe, but the understeer was actually limiting performance before the bigger swaybar and more agressive alignment, and I am pretty sure the car would perform even better if I was to run a set of 275/35R18 R-Comps up front.

HuskerBullet

Just curious, why didn't you get the R888 335/30-18's for the rear? Are they too wide for your wheels or you couldn't get used ones or what?

PowerLabs

1- I am not positive it will fit.

2- They are much smaller in diameter than stock tires. The 305s are around 1% smaller, but th 335s are over 3.6% smaller. That is more than the 3% the system is designed to accomodate, so I antecipate problems.


I'd like to give them a try though, just not willing to spend the money until someone else pioneers this on stock fenders

MrDrezzUp

305/35/18 10.0 [11.0] 12.0 - 12.4" wide
335/30/18 11.5 [12.0] 12.5 - 13.3" wide

PowerLabs

That's not too important though; they fit 11" wide wheels like mine just fine.
In much the same way I mounted 265s on my stock 8.5" fronts

Its the overall diameter and wether it fits under the fender well that concerns me...

Ragtop 99

Can you expand upon the wet performance? Do you find the R888s force you slow down significantly in the rain? Do you find yourself in the right lane with the grandmas in the rain or are you just not hammering it?

PowerLabs

Of course.

When the road is just wet, I am comfortable driving up to 75, maybe 80 MPH, at which point I am passing all traffic anyways. The car stops VERY well on a wet road (probably close to 1G), but tends to understeer much sooner than it otherwise would, and traction is very limited, obviously. Limited as in EASY 3rd gear wheelspin. I get it moving in 1st, shortshift 2nd and make my way to 6th gear as quickly as possible, trying to keep revs below 3000RPM all the time.

On standing water it gets bad... I can cross small puddles and watnot just fine, but when it rains really hard and water begins to pool on the road, its off to the right lane, and 55MPH.

This is a product of the fact that the tires have very little thread to begin with, start out with only 6/32nds of thread depth, and I am getting them shaved, so I'm driving on the wear bars. A fresh set would probably allow 70MPH in standing water with relative safety (for comparison purposes I have driven in torrential downpours at 80MPH with a fresh set of Michelin Pilot Sport PS2s). The reason they are quite good when there is no standing water is that they are made of very soft rubber, so they bite down nicely on the road no matter what.

All in all I would say they are just as good, probably even better than any regular street tire on a wet road, while performing like a balding street tire on standing water.

Did that answer your question?

MrDrezzUp

Excellent explanation!

Ragtop 99

PL: Thanks for the write up. Very helpful.

IIRC, you have the R888s upfront too? Will you see 12k - 17k from your set or was that a general estimate.

PowerLabs

Yes, I am running R888s up front in 265/35R18. They are getting to the end of their life now, but I'm at 10K miles, and I got them shaved, close to their wearbars. That 12-17 thousand mile estimate was from a Toyo rep, regarding how long he thought a set of those tires would last up front. You will recall my rears lasted me 9000 miles, starting out near the wearbars also; I think it is a good estimate.

I am also not the best person to ask about tire life... I drive my car so hard its ridiculous; I purposely spin the tires from a roll any time I'm going slow enough to break traction, and if I don't put it sideways at least 3-4 times a day on my way to work at the spots I have scouted out because they are safe and have plenty of room, its because of traffic... Your "average" Corvette driver would probably get much better life from his tires

Ragtop 99

I have included a Powerlabs Driving Factor in evaluating your results and how many miles I might get.

PowerLabs

SpinMonster

I got caught in the rain on the way home from a car show. The road was comming to a high point and i was at 45mph and the back end just kicked out and I was sideways on the hiway. No standing water.....just raining. Luckily there were no cars behind me. I limped home at 30mph knowing the MT ET street of the same size is no tire for the rain.

I had the Nitto 555r2 for 1500 miles on the second set and they were fine in the rain on the hiway and I was in 65mph traffic.

I agree with the statements on using the r-compound in the rear as far as handling. I disagree with the statement for actual use though. The reason is: the vast majority of the time when I was driving my car the back end kicked out because I was accelerating out of a turn. The R-compounds end that forever. Its 100% true the front supercars wont keep up if you're driving in a circle at a constant speed but thats not how real life is.

In all the miles I used two sets of 555r2's, I never once saw the front tires lose traction before the rears. I had on countless times lost the back end with the supercars to accelerating out of a turn or even taking a hiway exit too fast. R-compounds in the rear fix the condition of the rear fishtailing and thats real life use that most experience. Accelerating out of corners will be vastly improved with the street tire up front and the r-compund in the rear.

I would bet in an auto cross setting the street tire up front/nitto rear will outperform a stock vette. When I see friends lose traction its always in the rear during the exit phase of the turn and its not doing a 1 g turn.