A lot of your points are more for AWD vehicles. Changing the non-drive tires like I did will have a negligible impact, if any impact at all.

 

Actually none of those points are my mine. I was merely searching the internet, but specifically about any impact on the LC 500 which I mentioned in my query to be RWD. Those were the points that came up for the RWD LC500. I don't know the accuracy that's why I wanted to get a discussion going re if anybody knows if Lexus has ever commented in writing on how far one can go from OEM tire sizes and F->R ratios (so Lexus can't use it as an excuse to deny a warranty claim 20/30k miles down the road). (pun intended)

 

I didn't upsize the rear tires because of ignorance. I am supposed to change tomorrow so it is not too late to go with 285/35/21 rears. I appreciate your feedback and will check into that before proceeding.

 

The Michelin A/S 4 isn't offered in upsized 285/35/21 so stock 275/35/21 is the only option. Same with other all season tires available for the LC.

 

That's exactly what they told me at Discount Tire. They also mentioned that if I am not tracking the car that 275/35 and 285/35 would be a nominal difference that I wouldn't notice which I am sure is accurate.

 

what is wrong with Lexus enginered sizes,,,bigger is better?

 

Would this 285 work or would "40" make the sidewall too tall?

 

^^^^Yes, 285/40/21 is too big in outer diameter for the LC rear tire.

Lou

 

I was going to stay out of this thread - But here goes:

It is my opinion that the Wheels on the LC are at least ½" too narrow front and back. The wheels (though 19") on the Lexus GSF and the RCF are both ½" wider than the LC. The OEM front tires supplied with the GSF and RCF are one size larger in cross-section.

Also, again, IMHO, the offset on the LC is wrong, too far inset.

I have corrected these issues with after-market wheels and up-sized tires. The changes I have made make my LC more nimble, and handling is improved

 

to me it's not about track performance of 275 vs. 285 it's that the wider tire will fill out the fender well more in width and height (look better).

 

I think I'm going to email my Lexus Dealer Service Manager and let him tell me in writing what non-OEM size tires I should put on given the limited All Season size choices. Then it's on Lexus if a warranty item is ever a question for "wrong" tire sizes.

 

It has nothing to do with size other than trying to find an All Season tire. I had to go from 245/40/21 on the front to 255/40/21 to get an All Season tire to replace the OEM summer tires. The Lexus engineers put tires on my car that won't function as intended in temperatures under 45 degrees which makes them totally unsafe for me about 5 months of the year.

 

the dealer will not approve any other size than whats stated...too much liability.. UR whipping a dead horse,,,do what U want..

 

I have been looking to do the all season tire switch as well, since I am just a grand touring driver less concerned with super tight handing. Plus, living in a 4 season area, it still is fun to drive a convertible when roads are clear and it is just cold out (especially since my LC touring option included a winter heating package bundled in). I still wonder why they default add a winter driving package in the touring package, then they swap out the base 20" wheels and tires (that you can easily replace the summer tires with all season's if you wanted to), with 21" wheels and summer tires that have no all season equivalents. That is a conundrum I can't reconcile. I can't imagine that the engineers said: "Hmm, let's add a touring package option that makes this car really warm and comfortable for winter driving, and at the same time upgrade the wheels and tires to those that can't be driven if the temperatures are under 45 degrees."

It seems that only choice I can find with keeping the stock 21" wheels is to give up run flats, get an flat tire emergency kit for the trunk then go with upsized 255/40/21 all seasons on the on the front and keep the rear at 275/35/21. I would have preferred to go with 255/40/21 on the front and 285/35/21 on the rear, as it seems to be a better match to the ratios on the stock 21" factory configuration, but I can't find 285/35/21's all seasons. Moving to 255/40/21 on the front and 295/35/21 on the rear looks like a good combo too to keep similar to stock 21" ratios, but I think that the 295 tire width would be a bit too wide on the stock rims, so that option is out while keeping the stock rims on the car. If I wanted to replace stock rims and with a wider aftermarket 21" diameter rear wheel, then larger all seasons with a similar front to rear overall relationship seems possible

The only other option is to buy a set of 20" wheels for winter, and choose from a much larger selection of all season tire options in the stock factory sizes of 245/45/20 and 275/40/20. The lowest cost path (with a proper speed rated quality all season tire) seems to be to get the Michelin A/S4 non-run flats in the upsized front and stock sized rears for around $1700 or so. Buying new 20" rims, with TPMS sensors, and tires will run much more, plus probably not look a good in the wheel wells, and just be a pain in the neck to store and swap out every fall and spring. So 255/40/21 and 275/35/21 it will likely be (unless someone has figured out a better option on the stock 21" wheels).

 

This is my dilemma for my LC as well. I’m getting a headache looking and probably end up trickle charging it through the winter.
Im leaning toward a separate winter wheel package with the 20” rim but trying to confirm the wheels will be mounted okay using the lug bolts.