rcf8000

I'll ask the same question about the Dunlop SP 2030s. (the OE non-run-flat tire for the SC430) Any reason not to use them? The Tire Rack has no test or survey data on them. It appears that the SC430 may be the only car that uses that tire. Very strange if true. Those tires were on the SC430 that Road and Track tested for their Sept. 03 comparison test article. They measured much lower highway noise levels on the SC430 than the other cars tested. Of course, I don't know whether this was due to the tires or not.

LexPro

Harsh ride compared to what?

rcf8000

How about harsh ride compared to an SC430 without run flat tires.

LexPro

Yes the new runflats make a an improvement compared to the older hard sidewall tires. However this car with any of the available tires is still smoother than any car with a 40 series sidewall tire factory installed.

JCtx

I still argue a PROPERLY INFLATED RF (33 psi) or non-RF (36 psi) in 245/40, with <3" from floor to wheel, is not going to absorb crap from the road, and the difference in RIDE (not noise, handling, or anything else) should be, for practical purposes, almost nill.
I could be wrong, and would welcome a 'back to back' comparison, but I just don't expect a cushy ride from a 40-series tire; that's all.
If a RF car bothers any potential buyer out there (check tire pressures; 33 psi), I'd definitely ride one without them before buying, even as a passenger (you could ask one of the many folks here to drive you around a little bit). At least one owner here claims he sold the car because of the ride (traded it in for a GS3, I think), and it might not be what you're looking for.
My opinion is Lexus should have fitted this car with 17" wheels (maybe chromed?) and 50-series non-RF tires standard, to improve ride for folks so inclined, with the current 18" RFs as an option.

Good evening.

Doc C

JC,

I didn't have the new run flats, but will tell you my new 35 series, 19 inch non run-flat tires ride better than the stock 18 inch run flats. Way better. I'm sure the new ones you have are much better, but I won't get the run flats again because of the difference. It's too expensive of a gamble. Besides, the performance is better too. And, I know this sounds corny, but the tread design and appearance of the Michelins or the Goodyears looks better to me. More aggressive and sporty. Just my two cents.

Doc C

1NICESC430

John ...

I replaced my RFs with the Goodyears that you're considering. I have only one complaint about them - after the car sits for a day or so, the car rides as if the tires are severely unbalanced, ie, the steering wheel shimmies like crazy. This behavior disappears after about 4-5 miles. A Tirerack spokesman said that high-performance tires do that, but after I told him I had had high-performance tires that didn't do that, he then said some high-performance tires do that.

I was pleased that those tires got such a good review from Tirerack. I no longer "buy French", so for me, the Michelins were out of the picture right from the giddyup.I also happened to hit Tirerack at just the right time - the tires were going for about $150. A week later they were about $200.

I'm quite pleased and satisfied with them. What a relief to be rid of those horrid RFs!

rcf8000

Ah, yes; the dreaded flat spotting. I thought that phenomenon had been designed out of tires by now. Is it worse when the temperatures are lower? (Maybe it wouldn't be such a problem here in Tucson.) I'm looking at the Goodyears for my wife's SC430. But most of her trips are pretty short, so I wouldn't want a tire that has a serious flat spotting problem. I don't recall anyone mentioning the problem in the Tire Rack survey.

JCtx

Modern low-profile tires shouldn't flat-spot if inflated properly; what pressure are you running?
And don't go overboard like Lexus does, recommending 40 psi just to avoid the problem. I ran my GS4 with 17" wheels at 34 psi (manual said 33), and sometimes it sat for weeks, and never had a flat spot.
If you put 40, it won't flat spot, but will ride like a RF, defeating the purpose. I'd put 34/35 psi if used infrequently.
If it flat-spots with the right pressure, it's a crappy tire IMHO.

JC

jlinjpn

I am certainly no expert on the dynamics of flat spots on tires, but I do know that there is a significant amount of information on the Internet about the subject. Goodyear has posted extensive information about flat spots as applied to aircraft tires; some of that should apply to car tires too. There's even a company that produces a $300 product that claims to elminate the problem entirely (see: http://www.tirecradle.com/tcradle.htm). Whatever the case may be, thanks to the heads up on the forum I'll be aware of the possibility that hot tires parked on a cold surface could cause the development of flat spots.

1NICESC430

I keep the tires at 33PSI.

Yes, I think the problem is worse the colder it gets. The shimmy occurs only at around 55 MPH and then for only about 4-5 miles. It's not much of a problem for me because 99% of the time I have to drive 10 miles on a two-lane 45MPH road to get to any place that resembles civilization. And I invariably get behind some doof who thinks that (s)he must drive the speed limit ... or even lower!

dsimo

For those who believe in Consumer Reports, they rank the Goodyear Eagle F1 GSD3, Toyo Proxes T-1S, and Conti ContiSportContact 2 all higher than the Pilot Sport.

I just swapped out my Bridgestone RFs with Pilot A/Ss, and I have to admit that I'm a little disappointed by the noise level of the Pilots. They're certainly louder than the Bridgestones, and they are even louder than the some Bridgestone A/T tires I just put on my SUV.

rcf8000

It's hard to know what to think after reading a lot of Tire Rack survey comments about noise levels, and comparing test results.. If you can believe Consumer Reports, the Goodyear F1 GS-D3s are a lot quieter than Pilot Sports. Survey results say the same thing. But the Tire Rack tests reported that the noise levels of the two tires are essentially identical. Michelin's own web site says the A/Ss are quieter than the Pilot Sports, as does the user survey. But user survey comments on the A/Ss run all the way from very quiet to very noisy, and rate them as MUCH quieter than the RE 040s. Now we have a report that the RE 040s are quieter than the A/Ss! What am I to conclude from this?! I was considering replacing my run-flats with the A/Ss, but now I'm thinking maybe Lexus knows what they're doing, and that I should use Dunlop SP 2030s, the SC430 OE non-run-flat tire. But it's really a mystery tire; there seems to be no qualitative info available on it anywhere. Dunlop's own web site doesn't even acknowledge that the tire exists, except in the OE tire chart, but the Tire Rack shows them to be in stock. If you do a search on the Dunlop web site for tires for an SC430 it recommends SP Sport FM901s. The Tire Rack surveys give these a pretty poor rating (but better than the RE 040 gets).

dsimo

With the Pilot A/Ss that I just installed, I can literally hear them whine when I open my windows (too cold for top down here). I never noticed this with my Bridgestone RFs. I'm not complaining, but I hadn't seen anyone mention this to date. The ride is still firm, but noticeably better than the Bridgestone RFs--it's not nearly as harsh. Let me also make note that my replacements are 45-series which certainly positively impacts the ride.

Michelins in general are great tires, but you pay a premium. Being price sensitive myself, rather than the Sports I'd be leaning towards the GYs, Contis, or even the Bridgestone Pole Position S-03s.

Personally, given my need for an all-season tire, I'd probably consider the run-flat SP5000s in the future. I've been running non-runflat SP5000s on my BMW for many miles without problems. However, by the time my new Michelins wear out I'm sure RF technology will come a long way.

rcf8000

I notice that, in SC430 comparison tests reported in Road and Track, Car and Driver, and Motor Trend since 4/02, all of the cars tested had the SP Sport 2030 tires. Presumably, this is because Lexus USA wanted this configuration to be tested, but it is very curious because, presumably, very few cars have been delivered with these tires. I wonder if the handling is better with the run flat tires, but cars with the 2030s were offerred up because they give a smoother ride, which might be perceived as a more important factor to potential Lexus buyers than handling. All of the magazines condemned the SC430s handling but praised the "boulevard ride".