zarifian383

Let me start off by saying you get what you pay for.

I switched from my factory sawblades to c5 thin spokes. I remounted my front tires from my old rims onto the new rims.

They were Bridgetsone Potenzas 255 in the front 285 in the rear. The rears were done, and the rears on the thin spokes are 18s anyway.

To save money and after hearing a couple good things about the sumitomos htr z 2 I figured I'd give em a whirl as I have other things I could do with my money.

Rims were really straight, only one was a little off, and rear tires inflated to 35 psi.

Got on my favorite freeway after warming them up and breaking that factory cast, and pushed the car hard. 110 Freeway between Pasadena and Hill st LA.

Instantly I could feel my back end try and go all over the place. Every turn had counter movement. The sidewalls felt like mush. They made noise around every harder turn. There was no high speed stability. Going from my Potenzas to these significantly reduced the handling performance of my car. The car is more squirrelly now and follows ruts in the road.

On the other hand they do grip well in straight line performance. the 285s seem to plant very well in the back, and I can launch from about 2k and get just a little spin.

I plan on raising the rear psi to around 40 in hopes of helping the mushy feeling a little bit.

Overall with price factored in I would rate these tires a 6.75
I got them for a pretty good price 290 for both rears mounted.
They grip well, just way to soft for my taste.

I probably wont get them again, unless I come up with a second set of track tires.

coupeguy2001

I got a new pair of Sumitomo HRTZ II for the rear.
Some guy bought 18's and actually had 17's in the rear, so they were on Craigslist, and I got both for $175, and it cost $10 per tire for mount , balance, and stems. 285/35/18.
I too bought 2002 C5 thin spokes, and since I tied the rim and tire change with brakes, I was looking to cut corners on tires right off the bat.
You do get what you pay for.
The tires are not as wide as Goodyears, do not grip in the rain, and seem ok in the dry.
I can break them loose from a standing start very easy, but I put 30# in them. at 33#, they get really squirrely.
I can't imagine putting more in them and expecting any performance since only the center of the tire would touch the road.

JackDidley

I tried a couple sets. OK. Didnt last that well. I thaought maybe it was alignment problem. Not. Tried Falkens. Same story. Got some BFG KDs. Car hooks much better. They still look good after 12k miles and I do smokey burnouts before every run. Probably more answer than you wanted.

Trebor

Sorry to hear your bad experience wit the Sumis. I have had them on my '96 CE LT4 for 4 years without any problems. When I needed to replace the Goodyears quickly in 2007 Goodyear (the car had the original 13 year old tires on it 13,000 miles , but hard as rocks) was coming off a strike and NASCAR was sucking up all their scheduled tire/ship times. So I had to look for an alternative. I bought the Sumitomos and have been happy with them ever since.

Trebor

PLRX

You should never race on the street among handicapped people, children and pregnant women. Go to the track, its safer there.

Don't go to the track with those cheap tires, buy BFG, GY, Pirelli, Kuhmo etc.

cv67

Never had an issue with noise or anything else, hard canyon runs or top speed runs either. Good budget street tire not a race tire

For the money they are decent, what do you want for $100 a tire or so....

kimmer

I have the HRTZ, not the II series and I find them fine for the street. Front 275 & rear 315. I Use Kumho XS for racing, can't beat them for street class.

oldalaskaman

I switched from toyo proxy's to sumitomo's, lost the stickyness, but i dont have to worry bout hookin a nail and nobody wanting to patch them. They're a better ride than the toyo's or the runflats that were there when I bought it. I got mine used , from another member(thankyou racepro), When they wear out , and if there's no issues, I'll probably buy them again. They're not a 'race' tire, but they dont claim to be. Used to run BFG's on my tow truck, they would have almost new tread, but after 4or5 years they would start bubbling out from the inside. Dont figure you young folks will keep a set on that long, but for a few of the older folks, its something to think about.

LD85

I have 315's and not many people make 315's for a reasonable cost.

I buy the Sumi's because they are affordable. I have had 2 sets so far and they last OK, but for the price , you can afford to smoke'em up if you want.

I cant see buying $1200 worth of tires that last me a year 12-18 months.

VetteMed

I have a pair of 315 Sumitomos, and I can't complain about them, for the price. As with most things in life, you get what you pay for, but if your expectations are REALISTIC, you won't be disappointed -- it's a $150 tire, people... I guess you want to pay $1 a gallon for milk and then complain that it's sour.

Goldcylon

Worse pair I ever put on on car.... Also the cheapest so you get what you pay for. These are the tires you buy just before selling the car. SO you can say hey it has new tires.

bluepearl92

I went through 4 sets. Bad traction in wet/dry, noisy, horrible ride, and they wear uneven (every set). The alignmet shop used to HATE to see me come in....until I put Goodyears on it. This set of Goodyears has outlasted the 4 sets of those "things".

LD85

It a personal preference, I choose to save money on the tires, even Goodyear's wont last 1 year if I smoke them with my 458 RWTQ , but if I toddle about which I mostly do, then I could see them lasting my a couple of years. But then, the Sumitomo's last me 2-3 years as well.


Tire Rack prices
Good year $1306 a set of 4, 315 & 275

Sumitomo $530 a set of 4, 315 & 275

cv67

Not that it matters but once with another car I broke down and bought the super expensive tires of the day.

They didnt seem any better than the avg tire out there and god forbid I spin them and wear em out you start feeling guilty.

Different strokes..rather replace them and have fun or just buy a REAL sticky tire period.

Cant even buy a cheapo tire for my truck for what the Sumis cost for a Vette.
Stop bitching people lol.

proracr

My last C5 had Khumo's on it and I was very happy with them, but I don't do burnouts or competition type driving on public streets. I raced formula cars and Nissan's as an SCCA member up and down the Eastern Seaboard for four seasons in the mid-1990's and got all that dangerous driving out of my system. If you are going to drive like you're racing on public street's you should pay the high dollars for racing tires.

WW7

My turn... I have the Sumi HTR Z II tires and am very happy with them. Last tires I had were Cooper Zeons and didn't get many miles out of them.. The Sumis have almost as many miles as the Coopers did when I changed them over and they still look great with half the mileage left on them,plus I think they handle great for normal driving .This is the tire the OP asked about , there are half a dozen different Sumi tires to fit our cars and there not all the same...... Opinions do vary....WW

RetiredSFC 97

They are not made for racing. They are made for typical driving with occassional playing around and are fine for 75% of us. Rides good and very little to zero noise.

Putting these on a car and driving like you're on a race track is in the same category as those who spend 1500 bucks on tires to go to car shows.

C4Fanatic

Had Sumi's on the front of the Z when I bought it, seemed "twitchy". Probably didn't help that it had MT ET Street Drag Radials in back. Went with Nitto NT555's and haven't looked back, love'em. And not a bad price for a 315, even from a local dealer and not off the 'net.

zarifian383

Thanks for all the responses guys.

You seem to identify with what I feel about these tires.
We do get what we pay for, and these tires are definitely just street tires, and yea they are the cheapest, and I give them good value. That why I gave them a 6.75 out of 10 instead of like a 3 or 4.

I did expect more out of them from all the great reviews. I just had a higher expectation.

Like I said I may even buy them again, I don't push my car that hard on the street usually, I just wanted to test the new tires out in an area I am comfortable with. (The 110 freeway In my area, is a small 3 lane with major twisties, I hit it when there is little to no traffic, It isn't the safest freeway, kinda old and no pull off areas (no waiting police) but I've been hitting it since I got my license and with a few different cars, and I know every single turn by heart, and exactly what my limits are. Knock on wood I hope the day I make a mistake that I cant correct never comes. Or if it does at least I'd be on the track.

But these are not suitable for the track, I'd actually be embarrassed of my times up at my favorite track (Willow Springs, Horse Thief Mile) with these rubbers. I feel like I couldn't reach the vettes true potential. Personally I am proud to be a C4 owner. I want to show people what it can really do, and you guys better believe when I'm at the track I push this thing to the very limit.

It also feels like I may be pushing the upper 300s in power and tq, and the fact that I downgraded from my Potenzas, make me feel like these tires are inferior, but maybe thats just me. I'm almost done with my brake upgrade, and once I finish the body, and get the rest of my tuning equipment, I'll probably invest in a nice set of track tires, when the time comes, I'll do some research

Till then, these soft sidewall sumis must get me by.

LD85

BTW, After many trips down the quarter mile trying to flog my new 406ci engines,,,,

@ 30-45 days ago, I bought my 3rd set of rears, they told me that I bought my last rear tire set in 2007, the same time I bought my fronts, and my fronts are still in great shape

That is all