1996, light use, general touring car. 2000 mi/year and just 'regular' speeds (<90)
Specs say 255/45R17 and 285/40R17.
Last time I changed rear tires, I put on 275/40R17's. I recall someone telling me there would be no difference.
Now, all the tires are at th 10 year mark so I need to replace them. To keep the balance, it seems if I lowered the rear tires, I should lower the fronts to 245. There is a tiresize.com site that has great info.
It shouldn't make much of a difference but I'm curious if there is ANY difference - as long as I'm buying new ones, I might as well buy the 'more right' tire. Any real tire techies have any comment?

Also, I found a great price on Amazon for Sumitomo tires but there's now way to find out how old these are. I would hate to order them only to find out they are already 4 yrs old.
Anyone have any experience buying tires on Amazon tires? They will ship directly to a Mavis to install for a great price too.

 

There is difference in size: the 275 is 10mm narrower and about 1/3" shorter in diameter than the 285. However, it's a great fit on a C4 and for those with 17x9.5 wheels front and rear (88-92 C4s and 93-96 Z07/Z51 C4s) it's what GM put on them. The taller/wider tires don't handle better - they just ride cushier. The story is the same for 255 vs 245 up front. Functionally, both sizes work. In terms of performance, the smaller sizes will actually be slightly better and will give you a lot more buying options. If you do the 275/40 in back, then you should do the 245/45 up front so that you don't have taller front tires than rear.

I don't have any tire-buying experience on Amazon. In general, I don't think especially highly of Sumitomo tires. They aren't awful, but I think there is probably better value to be had. The best value tire for a C4 is the Riken Raptor. Riken is a subsidiary of Michelin these days. The Raptor got a new tread compound formulation about five years ago, and it has decent grip. They are actually good quality tires that stay true/round. They ride pretty well, too. They even look good. Best of all, you can get a full set from Tire Rack delivered to you for $452. They do not have razor-sharp steering response, so if you're looking for that you need a different option. You can cheaper no-name Chinesium tires, but these are actually good quality tires with decent performance at a bargain-basement price. I ran these as my "street tires" on my 96 and I have no hesitation recommending them.

 

I saw the Riken Raptors and they are of the coolest looking tires. But the Tirerack video review of them shows them to perform the significantly worse than the rest of the group in wet conditions. And one of the reviews said the same thing. Strange that this contrasts with their own write up. Sumitomo might be a bit stiffer but the one thing you want out of a tire is safety.

What do you think of Toyo's?

Thanks for the input.

 

I drove the Rikens in the rain quite a bit. They definitely weren't the best in the rain, but they weren't going to kill you. They just had lower grip limits on wet pavement. I thought they actually resisted hydroplaning (by far the most dangerous aspect of wet driving) quite well. Keep in mind that when Tire Rack says they have lower grip in the wet than some competitors, they are talking about how much grip the tires have on wet pavement: i.e. how fast a lap you can run on a track with sprinklers keeping the surface wet (that's literally how they test them). It's not how suddenly a driver loses all grip, like in a hydroplane situation. It's the latter that tends to lead to accidents. OTOH, the Riken still has more grip on a wet road than almost any tire did when the C4 was new. The Gatorbacks that GM put on most C4s were terrible in the rain. So perspective is important here.

I don't think very highly of Toyos. The one set I've had (still have) don't stay round - that's something they have in common with their brand cousin, Nitto. I also think they'll have pretty low grip in both the wet and dry. I'd stay away. If rain performance (i.e. the highest grip you can have on a wet road) is really your primary priority, then the Continental ExtremeContact Sport 02 is the tire for you in these sizes. It's so good in the rain that they often get used as rain tires for autocross and track events where true street tires are required. They are faster on a wet road than any all-season, for real. They will also be faster in the dry than Rikens, Sumitomos, or Toyos. They are "three-season" tires: they are fine down to freezing temps or a little below, but not great for temps in the teens or especially ice and snow. I'm guessing you aren't driving in that kind of weather, though? The downside is the Contis will cost $940 for a set of four. If you really need an all-season, the highest performing option in these sizes is the Michelin Pilot Sport All Season 4. They are similar in cost to the Conti EC Sport, though, and slower (i.e. have less grip) on both dry and wet roads. Their only advantage is on snow/ice.

Let me know if you absolutely require an all-season. If so, and you really aren't comfortable getting Rikens, we can explore a couple mid-priced sets that will perform well for you.

 

I downsized so I could get the Michelin All seasons and I love them. Perfect for weekend cruises, don’t get out of round being parked for a couple weeks and are very smooth and quiet. Visually you can’t tell a difference at a glance.

 

I put the raptors on my 96 front and rear. They are now owned by Michelin so I felt the quality should be high. They are rated lower in wet conditions but higher in all other areas. Since I rarely or never drive on wet roads I felt that was not a big issue. The price is great. I did upsize the width on my front wheels to match the rear wheels.

 

I just realized, my spare is probably older than 10 years. Do the same rules of safety apply to a spare? Or does it keep much better since it didn't have any pressure on it? Maybe still safe at lower speeds (say, <60) for a shorter distance?

 

I don't think it's about the pressure, but rather exposure to elements. So it's old in terms of useful life. That said, a spare doesn't usually have to get you very far, and it won't have seen any sun. Therefore, I wouldn't worry about it.

 

I got the Michelin All Season Pilots. I had to get 17-inch rims to do it. I wanted a high performance tire because I drive the occasional OTD, but otherwise I drive in all seasons.

 

So what do you think the max age of a spare should be?

 

If it's original to the car, the car sat outside all its life, and you can find a replacement, then it's probably reasonable to replace it soon. If it was garaged its whole life, it might be okay for another 20 years.