Tires: Sumitomo HTR Z

[cuisinartvette]

No, sorry i don't. When I get it out of the paint shop I can take some. If you are wondering if they have a funky looking design or ribbing on the sidewall they don't. Good "looking" sidewall, I'm happy with them. Next time I get a chance I'll get pics.

[stedi]

Hello Patton,

I have a 91 stock Z and I put on these tires about 5 months ago. Definitely the best bang for the buck but I do have a few issues. Before putting these on, I had Goodyear GSC. I noticed difference as soon as I changed.

First, ride is much smoother. To try to quantify the difference, it's as if the suspension setting was offset by one. The Sport ride setting with the Sumis became smoother, like the tour ride setting with the GSC on (not exactly but try to imterpolate). This however comes with a price. Sidewall is not as firm so it isn't as laterally stable. This means the car follows groves in roads much more and is not as stable in curves at high speeds.

Second, the imprint on the pavement is not as wide as the GSC. If you look closely at the picture posted above by Cuisinartvette, you'll see that the edge of the tire is not vert dirty. It does not contact pavement. You loose about ½ to ¾ inch on each side of the tire. This would be particularly noticeable after putting armor all on the tires and driving on a gravel road. Tire has that overinflated look. The 315 has about the same imprint as the GSC 275/40/17. I know you loose surface contact with pavement but tire stickiness makes up for that. Tire sticks like glue (160 threadwear) which is why they wear out faster than others. Did the 1/4 mile in low 13's with these babies. One thing that people should consider when talking about tire wear on these cars is that unless you pull smoke shows at every corner or drag once a week with it, odds are you will surpass the tire's recommended age before they wear out. Most people put very low miles annualy on these cars. Tires are typically good for about 5-7 years, then they start cracking inside the thread. As soon as they start cracking, tires loose their speed rating. ZR rated tires become NO rated tires and high speed driving may result in blowouts.

So in conclusion to my lengthy text: If you plan on slalom driving at high speeds, these are NOT the tires for you. But If you drive at speeds close to the speed limit, don't go crazy in curves and do a considerable amount of city driving on crack and pothole filled roads, these are A O.K. As far as thread life, a tire with a threadwear of 100 wears out twice as fast as one with a threadwear of 200. So if you compare it with a Goodyear Eagle F1 GS-D3 with a threadwear of 280 and a price tag of 271, the Goodyear will last 1.75 times longer but costs 2.46 times more. And if you do low mileage, odds are you'll have to replace the goodyears before they wear out which reduces the 1.75 factor.

If you decide to buy them, or any other tire on tirerack for that matter, let me know, I may be able to save you a couple of bucks.

Hope this helped.
Steve

[stedi]

Sorry but with everything I wrote above, I still managed to forget to mention something. The geometry of the tire may also be a cause of the lateral instability. In other words, the rounded outer edges of the thread section results in less lateral stability than a tire that sits perfectly square. I highly recommend the tire though based on its price points.

Steve

[phrogs]

I put the GSD3's on my 90 about 12,000 miles ago ahd the rears are already in need of replacment they wore down real fast towards the end They are pretty slick no on dry roads.

I have to admit I love them but I havent draged in them and this is just my daily driving and a few thousand highway miles to the museum everything else has been around town driving.

500 for a new rear set of the Goodyears or 500 for a good set of the sumitomo's??

tough decision they always say that you get what you pay for but hell I could always get some grag radials for the strip and use the front GSD3s they still have a bunch of tread.

Oh and I didnt burn out in these but twice? just a soft tire

[cuisinartvette]

I wasn't looking for top notch performance when I bought these: just an affordable middle of the road tire which suits me fine. For under 500 bucks out the door the Z sits on new Z rated shoes. Most of my driving is just the average cruise/get on it thing with an occasional trip to the track, works for me. If I was draggin or autocrossing it a lot I would have spent more on a topline tire. To each their own.

[RedRiderZR1]

I had ZR1 wheels on my 87 coupe and also had Sumitomo HTRz Tires on it. For the money not a bad tire. I could take my favorite interchange home from work and have no problem taking that interchange. No over or understeer. When those wore out I bought a nice set of Falkens (HUGE MISTAKE). Supposedly a great tire, but the first time I took that interchange I about soiled myself. Severe understeer, with a higher cost than the Sumitomos. For the money they do OK. If you are AutoXing I would go with another tire. If you are looking for a daily driver tire with some fun times this could be the tire for you. Oh yeah If you drive in the rain often This is not a great tire. I was on the freeway when it was raining kind of hard, at 60 MPH the car lifted and moved over to the next lane. Luckily there was a next lane to move into. Wet traction is not that good with these tires. Just dont go over 55 MPH in the rain.

So good tire with great price, good performance dry traction and not so great wet traction.

[tomtom72]

Hi Patton, not to confuse the issue on tires but if wet performance is high on your list because of local weather then the GS-D3's are a good tire.

Okay I'll turn in my "Key" now. Yesterday afternoon and last night, sat., I drove up to hang with a group in the CF/NE section in CT. I got a first hand demo of G/Y's rain performance. The trip was about 180 miles round & it was in various wet conditions, from the just wet pavement to the steady rain that causes puddles on the interstate. Man were those tires great. Very stuck to the road & definately not afraid of puddles! I was moving at speeds that felt secure & found that upper 70's was almost like being in the dry! I was amazed how these tires part the water and the grip level was fantastic. No loss of steering feel thru puddles, you know they are there. The car didn't "skate" thru puddles & the steering didn't go "numb".

End of advertisement!


Tom

[Patton]

Wow, thanks guys for all the info! Very very informative!
UPDATE: The beast now wears four new paws, Out the door at America's Tire Co. (AKA Discount Tire Co.) Sumitomo HTRz's installed and taxes for $405!!! Amazing price. without taxes was like 380 something.

You guys were RIGHT on the money about this tire with Its high and low points! Steve, Everything you said about this tire is dead on. I thought EXACTLY the way you put it as "it's as if the suspension setting was offset by one" Very very good analogy. I was worried that I would be very dissapointed going from BFG geforce KD's in the back and GSC's up front, the slight increase in sidewall flex is made up in the fact that the tire is made of freakin silly puddy! I took a 270 degree freeway onramp at 45mph and it was nothing,... went back and tried it again at 60mph - a quick glance to my accelerometer showed .93Gs! I think i was at the G limit because i heard the ever so faint beginnings of a screech gently chriping from the fronts. To make a long story short this tire is in a class of its own solely because its nearest price competitor for all 4 tires is over 800 bucks. Add to that the fact that it is no slouch in the twisties or a straight line make this tire hard to pass up, especially when you are still saving money to FIX YOUR GODDAMN SECONDARIES!!

One more thing worth mentioning. After a lil' U turn tail slide, I pulled over to see the wear (which was VERY noticable,... SILLY PUDDY) and also noticed that the tire does not have a "rim protector rib" or whatever the hell you call it. So ya, If you are planning to do some quality offroading with your vette or frequently conduct "curb checks", or if you happen to be a woman... This tire is not for you. Even if you cannot avoid the afformentioned activities, after a couple sets of tires you can buy new, true OEM rims with the money you have saved.

-Patton

[sledutah]

Thanks for the update. Sounds like the obvious choice for me

Craig

[Patton]

Do these tire smell kinda funny/wierd right after you get on it a bit? After I did a little half donut I could smell it,... It didnt smell like normal burnt rubber,... It had a funny chemical smell to it, I thought I was burning something ealse but everything checked out. Then a day later I did a little 110mph freeway juant and after I parked it I could smell the same thing again. Not as strong though... Maybe it is that new tire crap and will wear off.

Just ranting.