Tire recommendations
 

The wife and I are planning a road trip (Dallas -> Las Vegas -> Dallas) in the spring. We're prepping the ZR-1 for the trip. One area I'd like to think about are the tires and wonder about recommendations from the group here. Here are my considerations:

• The GSC's on the car are older. They don't show any signs of rot, but I've been down the old tire blowout road before, and I'm not anxious to do it again. I'll be most comfortable with new shoes.
• Our Z will spend most of its time on the road. Maybe once or twice a year to a track event. So priority is overall comfort over max performance. These GSC's seem awfully noisy and if there's something quieter out there, it's worth a look.
• Money is an object.

I understand the Goodyear Eagle F1's are pretty popular, and Kumho seems to make a good ZR-1 tire.

Tire Rack is selling something called the Sumitomo HTR Z for $490/set (as in, all 4 tires). Being that's less than what I paid for new meats on my pickup truck, I'm both interested and skeptical, but it's almost worth it just as a test.

Thoughts and input welcome.

Re: Tire recommendations
 

Id sterr away from the Sumitumos...I had them on my Z28 years ago and they didn't grip at all. Try to find some Veredesteins or the Nitto NT05 (street track) or the Nitto 555 (street). I think most people are happy with those. If you have alot of $ the Goodyear GSD3 is a favorite of many.

Re: Tire recommendations
 

GS-D3's would be great for a road trip, because they are excellent in bad weather. They are back in production now in 315 sizes. They were quieter than the GS-C's I took off my car. But the car is hardly quiet.

Re: Tire recommendations
 

I put Sumitomo HTR Zs on my 90 a couple of months ago. The things said in other threads about these tires were very accurate. They don't grip as well as the factory tire, but they ride much better. As for driving in bad weather, I don't think either tire is all that great. But, we have terrible roads where I live (very uneven, lots of large puddles to hydroplane in...), so no tire does all that great here in heavy rain. All things considered, I feel like I made the right decision. But, if the price were closer or if I didn't have other projects demanding my $$$, I would have went with the factory replacement for the grip.

Re: Tire recommendations
 

well I guess you know where my vote is...:o....the GSC's may look okay & be safe but the tread rubber is past it's useful life. Save them for the NCRS thing if that's a consideration down the road. You need to think about what is important for you in a tire, and how do you use your car.

Where I live the roads are a bit beat up & not glass-level so if there is water the ponding is a real hazard so I use the D3. It also seems when ever I decide to attend the Gathering I have to drive thru rain for at least 4 hrs....so I like the D3. Oh, they are noisy on cement, and asphalt too, but really noisy on cement. I don't make it a habit to drive in the rain, but if I'm out and it rains we don't cut our cruise's short. We just roll with it, most of the 5's & 6's I cruise with are on PS2's or Nitto Invo's, and some were on the OEM run-flats. I'm the only 4 in the crowd usually so I'm the only one on G/Yr's. I have no trouble keeping up and feeling in control of the wheels. Oh, I should mention that even at 30,000 miles the wet grip was tremendous, the wear bars were about 1/8" shy of the tread block's surface. That ain't too shabby in my book.

In the dry, the D3 needs heat to work. They don't have that "instant" response to input either. They slide a bit at normal operating temps, the more they're worn the more heat you need to get velcro. However, if you get them past normal temps they have a very wide band of "Hot, but not greasy"....you can smell them inside the car, they're ready. At that point the initial input is still not instant, but the now velcro like behavior makes up for it. I've never ran thru the useful Hot band... I guess I'm just chicken. I stress that be careful at normal temps as any sudden input and / or pushing of the limits of the chassis can result in that sliding feeling. Again, I've never had them break loose when I have encountered the sliding feeling....I just roll out slooooowly or keep the same input if I didn't mess up too badly. They will warn you as you can feel the limit clearly thru the butt dyno in a turn, specially a down hill off camber one....it's a little unnerving the first time it happens, but you have plenty of warning as you can feel the chassis twist in a C4 and the back feels like it's unloading. I suppose at that point if you insist upon keeping / or applying more power the back will come around on you? Again, I'm chicken so I'm not sure....but if you hold power constant and or roll out a bit she will hold the line. On a flat corner, and or a correctly cambered one the slide is very gradual and you know & feel it and it's in enough time that you can have time to think about your reaction. They are not abrupt at either end of the spectrum. All of this in the wet will blow your socks off as they are truly excellent.....but pricey. It is almost as if you are on dry pavement. I got 5 yrs & 32k miles out of my first set and I'm on my second set and I will be a buyer as long as they are made.

Oh, another negative. When they are at normal temp they pick up everything so buy mud flaps...and when they're Hot it's worse! Also, mind what G/Yr says about the operating limits for ambient temperature! These are not cold weather tires. They take about 30 mins. to get to temp at say 45*- 50*. Below 40* they take forever & don't seem to be able to hold the heat? It's not that they're dangerous. It's just if you want to push you don't have grip for that kind of driving. I think that applies to all of the summer performance tires though?

long winded, I know!:redface:

:cheers:
Tom

Re: Tire recommendations
 

A lot of us run the GY Eagle F1 GS-D3.
Like Bob said they are a good all around tire in dry or wet conditions.
You can get a set at Tire Rack
http://www.tirerack.com/tires/tires....Model=Corvette ZR1&autoModClar=
I see GY is offering a $80 mail in rebate per set if purchased before February 5, 2011.

The Kumho Ecsta XS also come in 275/40ZR17 front and 315/35ZR17 rear ZR-1 stock sizes. These have not been around as long but I have not heard any negative reports about them as of yet. Maybe someone here who has experience with these tires can chime in.
http://www.tirerack.com/tires/tires....1&autoModClar=


On the high end you can also consider Michelin PS2s.
They come in same 275/40ZR17 front size and a bit wider 335/35ZR17 for the rear which are no problem to fit on ZR-1 11" rear wheels. These are one of the best performing tires around but not as affordable as the others.
http://www.tirerack.com/tires/TireSe...chelin&tab=All

Re: Tire recommendations
 

Just wanted to add, whatever tire you decide to go with be sure to have them road force balanced. A couple of years back I replaced the original GSCs that were on my 94 Z with a new set GY Eagle F1 GS-D3s and was never very happy with the way they road compared to a set of Michelin Pilots I had on a second set of chrome A-molds. In the meantime heard a lot of good things about road force balancing so I found a local shop with a Hunter GSP9700 balancing machine and the difference was night and day. Now the D3s ride as good as the Michelins ever did.
Here is a link to Hunter with further info about road force balancing and a list shops with thier GSP9700 machines:

http://www.gsp9700.com/

http://www.youtube.com/watch?v=efhgM2TcQpI

Re: Tire recommendations
 

Last fall I removed a set of Sumitomos that had been on the car for 2 1/2 years, but less than 1000 miles. They never felt like they were properly balanced. When I finally had them road force balanced, all four failed. Very, very poor quality.

I replaced them with Michelin PS2s. They look great, but feel very stiff, resulting in a pretty firm ride. However, they feel very well balanced and that is what I was after.

Like others have posted, go with a name brand tire that comes with high recommendations.

On the plus side of my story, Sumitomo did refund the full purchase price of my tires.

Re: Tire recommendations
 

Good input everybody.

One thing I've never even heard of is the force balancing. Interestingly enough, looks like the last couple sets of tires I've bought at my local Discount Tire have been done that way. I recognize the machine and they're listed on Hunter's site. I just never realized it was anything "special." Huh. Learned something new today.

I'll let you know which way I go. The GS3's seem a popular choice here. I've heard good things about the Nitto's elsewhere. Looks like I'll be wise to not save SO many pennies on the Sumitomos. Based on reviews here and elsewhere the experience is hit or miss. I'll pay a bit more for the "no miss insurance." :)

But first... tomorrow is new stereo day. Tunes before shoes just happened to work due to scheduling. Soon I'll have an Alpine XM radio and sub box up for sale...

Re: Tire recommendations
 

I had the Sumitomo tires on my 91 when I bought it a year ago. The tires were in very good shape but the traction was unpredictable and the seemed to wander all over the road. I recently had the Nitto 555 installed an so far love them. The are quiet, seem good in wet, and ride better than the sumitomo. No wandering and The are also a bit larger as the sumi tends to run small. $725 installed at Discount tire. It took less than a week to get them from another warehouse out of state . Sold the old ones on Craigslist the first day I had them listed.

Re: Tire recommendations
 

Good to know 4-Cam.

I've decideed to go with the Nitto as well. Was originally thinking of the Veredstein, but Nitto seems to receive consistently good feedback.

Did you go with 315 or 335 on the rear?

Re: Tire recommendations
 

I just went with the 315. I did not see a 335 available in the 555 on the Nitto website so I did not even ask.

Re: Tire recommendations
 

apparently D3 are available again

http://forums.*************.com/c4-z...ble-again.html

Re: Tire recommendations
 

Nitto 555R's only come in 315.

They are narrower but they grip great.

They are drag radials, I hear they are better then most in rain but I'm sure they are scary.

I don't drive my Z in the rain so its not an issue for me.

On my Vettes that see rain, I have GSD-3s.

Re: Tire recommendations
 

Really?

Re: Tire recommendations
 

I wonder when they are going to stop making these? Seems like GY could charge about whatever they want for them. As soon as they become available they are bought up.

Heck I run 18's but I bought 4.

Re: Tire recommendations
 

Having run several of the mentioned tires at one time or another I'll chime in with a couple data points. Sorry if it's turned into a book!

Bear in mind I'm an autocrosser. I spend as much time as possible in slip angle. It's what weekends are for!

I had several sets of Sumi HTRZ-2's on my 99 Cobra, liked them a lot wet or dry. Very sensitive to air pressure - run recommended pressures and they're docile, cushy even. Not crisp turn in but quiet for 3/4 of their life and very good in the wet (these were 245s, the 275s seem similar but the 315s are different). Aired up and not-too-much heat they worked very nicely. For those that don't know the company (I didn't), at the time they owned Dunlop and cross licensed manufacturing with Goodyear (meaning most US Sumis were made by GY and most Euro/JP GYs were made by Sumi).

On the same Cobra I went through many sets of Kumho Ecsta MXs, which are the predecessor to the XS. This tire loved heat and all the abuse you can throw at them but would go square sitting overnight, and were very greasy for the first 500 miles until you wore off the mold release agents. Conclusion seems to hold true for the XS as well, again much air and almost as much heat as a race tire. OK in the wet down to about 1/2 tread, got noisy then too.

Ran a couple sets of Nitto 555R2 in drag radial and non-drag radial. Nice enough street tire with softer compound, worked reasonably cold to mild heat. In reality they're neither fish (street tire) nor fowl (race tire).. I kept them around for early spring/late fall events when you knew you weren't going to get enough heat in the slicks and/or you saw enough wet to be "beyond a sheen". Not sure about the non-R compound, guess I'd expect it to be slower and more forgiving than the XS. Note these turn square after sitting a few days too. 5 minutes (or more air) fixes that.

The GS-D3s were OEM on the 03/04 Cobras, many of the guys I ran with liked them well enough (and they got high marks for wet) but they pretty much all migrated to faster & cheaper tires after a set or two.

FWIW the new hotness in street tire autocrossing amounts to Toyo R1R and Dunlop Star Spec, I've not looked to see which are available in 275 & 315.

On our Z I really only run Hoosiers so can't say so much about c4 street manners, the rim protectors I use are just to get back/forth between shops/inspection and distant events ;). But I found with all the tires I've used "in anger" they all prefer different pressures, temperatures, and alignment tweaks to get the best out of them. For street with weather and novice event work I'd save the $ get the Sumis and remember a little cheapie compressor for track stuff. Next choice for the same duty would probably be the 555s, the later Nitto NTs don't have enough sipe for weather IMHO.

PS none of the above performance tires are worth a tinker's damn below about 50 degrees. Also it does not take much mileage with abuse or alignment issues to wear a tire into behaving badly - I had to get religion about rotation and flipping on the wheels. I'll guess that could have been a part of 4-cam's Sumi problems. And I should note that it's taken me 10 years of multiple sets a year and much experimentation to learn what the dynamics are telling me a tire needs in terms of alignment/pressure etc and even then it's successive approximation.

I should also throw in that the OEM alignment specs for C4 are hideous and the performance difference to be found in just that is profound. Of course I should add that if anyone tried to transport either of our c4s (88 z51, 91ZR-1) on a worn-in road with our event setups they would pronounce them undrivable in 1/2 mile or less - keeps you alert!

Thinking back to the 70s, all these tires are freaking amazing. YMMV!

Cheers,
- Jeff

Re: Tire recommendations
 

Neither are available in ZR-1 sizes. The Star Spec is only available in fairly narrow sizes, I think about 265 max.

The Toyo R888 is available in stock sizes, as is the Kumho Ecsta XS. It's hard to imagine either of those being very good in the rain, just from looking at them. But who knows.

Re: Tire recommendations
 

I've had the michelens and sumitomos on the car. Sumis are on there now. For what I do, weekend / date night driving in mostly good weather (though I'm not afraid to ride in the rain), they are great. I'm not engaged in "spirited" driving when doing so, but I'll punch the gas and ride the grin when I want. The tires are just fine. They need to warm up, but after driving the 1.5 miles from the back of the neighborhood to get to the main road, they're ready for highway driving. For $500, you can't beat them.

When I had mine road force balanced, they came out just fine.

I would totally buy again. For the money and what I do, the tires are going to dry rot before the tread goes bear.

Re: Tire recommendations
 

I currently have the Khumo tire on my '92 Z. I have found it to be good in the rain and better in the dry. As far as noise goes, well it's not as noisy as the Goodyears on my Z06! :cheers: