There is all kind of weirdness with the LC tires. Bridgestone even Discontinued the tire It Made (with much fanfare) Specfically For The LC.
Bruce in Fl

 

I went with the Michelin pilot sport a/s 4 all season tires. They do not make a 245/40/21 in that tire but do have a 255/40/21. Rears are available in the 275/35/21 sizes. Can't fit a much larger tire on the rear wheels due to the 9.5" wide rear rims (such as a 285 or 295) as would bulge a bit. Unless you are doing a wheel and tire swap out, you are limited with tire choices, especially all seasons. You could get 20" rims and tires (readily available) and do a seasonal swap, but if you are like me, I prefer to just use the all seasons. I am not a high performance driver pushing the limits of the car, so don't care about the sacrifice in handling that might be noticeable to a fussy driver. I have put these tires on a Chevy Corvette, Audi RS5 and Porsche Boxster and loved them. I can drive anytime I want to when it is just cold and dry out. Living in Northeast, this extends your driving season. Considering the car has heated seats, neck heat, steering wheel heat, deicing wiper blades and winter mode, it is certainly prepared for it. I just would never use this kind of car if there is any salt/sand or chance of ice on the roads. Other than that, drive away (even with the top down and heat blasting)!

Regarding the Primacy all seasons, they may physically fit for both front and rears, but I did not feel they were appropriate for this kind of high performance vehicle (as heavy as this car is). Maybe fine for a Grand Touring sedan, but the speed rating on the primacy is way low compared to the A/S4's. Although you most likely won't be going over 149 MPH, I don't like under rating that metric that much. The Michelin non-run flats were notably less noisy, softer riding and I expect will last much longer than run flats as have a tread rating of 540, almost double the run flat rating. If you are getting a 2024, I have seen they have moved to non-run flats and have a pump and slime kit in the trunk. If you don't have that kit, you will need one. If you can't inflate the tire, using roadside assist is next best solution for a flat. This is just my humble opinion so I hope it helps your decision!

 

A/S 4's ride better and perform at least as well as the run flats that came stock. Obviously they don't perform as well as a good summer tire. They're a great compromise for year-round driving if you live where it gets cold. Hopefully I'll get more than 18k miles out of them too....

 

I took off my Bridgestone potenza’s with only 3000 mile on them and tread was at 7/32”. Started at 10/32”. Warning strips show at 2/32”. Used about 30% of the tread life already. At that pace I would be lucky to get 10k miles out of them. Bought car with 2k miles on it so can’t speak to how hard previous owner was on the tires. Maybe I might get 15k as I don’t drive hard, but likely not. The Bridgestone tire was rated a 300 tread wear vs 540 on the a/s4’s, so I expect will be much better. Not as soft a rubber compound.

 

My 22' with 21" rims came with the Michelin run flats. With that being said, there's something about the ride and feel of this car that just always feels off to me and I'm wondering if it's the tires. For those of you that switched from the Michelin run flats over to traditional tires, is the difference extremely noticeable?

 

Have you checked the alignment ?

Checked my 24 after 900 kms on Thursday, it had the toe off on opposite sides just over 1mm front & 2mm rear, so it was crabbing down the road a little

After going on a short 265km trip yesterday & it seems to feel a bit better now, it has Bridgestone run flats

 

I had the Bridgestone Potenza run flats. As I mentioned, I swapped them out for the Michelin sport a/s4 non run flat to get extended driving season. I noticed a quieter and smoother ride immediately. Particularly when driven on less than perfect surfaces. Small road shocks seemed to transmit harder too on the run flats. Probably due to the stiffness of the run flat sidewalls. Handling seemed a bit less crisp, but these are all high performance all season tires so expects some sacrifice. I suspect the summer tires would be better in that capacity.

 

In my experience, when inflated properly, a non-run-flat will handle a lot better than run-flats when pushed to the edge, so I’m not sure why you’re feeling them to be less crisp. The more flexible sidewall keeps a bigger contact patch between the rubber and street when under heavy load. There may be one, but I’m unaware of any racing series that uses run-flats for that very reason. If they could, they would, as a shredded tire carcass will often cause six to seven figures of damage on a carbon fiber F1 chassis after a puncture.

 

I had a set of Michelin PS4AS installed this weekend. Holy smokes what an improvement over the OEM Dunlop’s. Ready some 4-season enjoyment now.

 

What's in the slime kit for the 24MY? Do you get a valve stem removal tool and that green sealant? I've never used it; does it work?

 

I have experiences with roadside flats on motorcycle tires.
Slime is a Royal PIA to install and works maybe half the time. IMO, it is Half A Step UP from Lexus not doing Anything to address flats.
Your tire guy will cuss the Slime clean up. I would just guess it gets all over the TPMS. Operationally, you are better off with a gummy string flat repair kit. They work probably 85% of the time but are Twice the effort of the Slime to install.
Lexus would pull a BMW and say that flat is not the tire or Their problem. It is pilot error. They will point out that the Real Cause (probably 90%) of roadside flats are The Driver's Fault by failing to Properly, routinely, use Their Provided Finest TPMS made.
Most blowouts, sidewall flats excepted, Are Not from the actual puncture. They are from the tire being over heated from being driven With Low Pressure FROM the puncture. Checking your pressure within the First 5 minutes of Every drive will catch most potential blow outs before they occur. Pulling over and topping off the leak with your 12v air pump until you get to the tire shop will allow a cheapy tire plug repair to save you $600. PS Discount Tires usually does not charge me for a tire plugging.
Bruce in Fl

 

nice. what sizes did you get (OEM?) and how did you choose the PS4AS - there are other Michelin's as well (PS5?) i think.

how many miles did you have on the dunlops? i have dunlops with about 10k miles and they're noisy on less than smooth road surfaces.

i'd like to go a size up to fill the wheel wells a bit more though and add a bit more cushioning. (so 255/40, 285/35)

 

In all of my recent memories, I only recall having flats from sudden uncontrollable circumstances, not from picking up a nail that slowly dropped the air pressure to dangerous levels. TPMS provides a great advance warning from slow leaks, and should not be ignored for reasons previously mentioned. One tire incident I had was a catastrophic failure after hitting a pothole. It immediately set off the low pressure warning lights and the tire flattened immediately. The impact damaged the tire's bead, so even inflating the tire (with or without slime) would have been useless. Run flat tires might have helped in kind of situation, but it happened on a car that had a spare. The only other time I had to deal with a flat was after running over a piece of metal that caused the low pressure alerts to go off. Tire was not a blow out, but pressure was swiftly dropping. I had a pump, so I was able to get the pressure up to a safe level, but it only lasted a short while before I had to pull over and top off again. I limped this way for a short distance and fortunately found a nearby firestone shop that plugged the hole. I had a spare on that vehicle too and I just didn't feel like going through the effort of changing the tire as the leak was manageable with the pump.

I recently swapped out the run flats on my LC and love the difference in the drivability, plus went with non-run flat all seasons so I have a longer driving season in the northeast. I went overkill on flat tire backup plans though to cover the worst case scenario where I might get a flat in a remote area with no cell service. I have an emergency air pump, TPMS safe slime (that I think can go in without removing valve stem), a tire plug kit, plus I found a factory scissor jack and put it in the empty cutouts already in the trunk. Depending on where the puncture is, it can be easier to plug the tire if the wheel is off the car. These precautions should cover me against any likely situation other than a side wall puncture from a pothole. That might be the only situation where the run flats have the edge.

 

If you are upsizing on the stock 21" rims, check the tire widths you choose for compatibility with the stock width of the rims, as well as choose appropriate front/rear diameters. Front rims are 8.5" and the rears are 9.5" so oversizing the tires can cause a bit of sidewall bulge if you go to big. Upsizing the rims to wider widths, although expensive would give you a lot more options.

 

I see a lot of people talk about this, but I wanted to point something out. When you talk about upsizing the tires by 10mm (i.e. 245 to 255), remember that half of that goes on the inside of the wheel well, and the other half goes on the outside to visually fill in the well a bit more. So you are effectively eating up 5mm of visual space, which is just under 1/5th of an inch - probably a visually imperceptible difference. If you really want to fill the well out more, you are going to need to look at either spacers, or aftermarket wheels. Nothing wrong with getting the extra 10mm of extra width on the tires, just don't do it because you think it will fill out the wheel wells.