chappyja

So, I have a 2019 Tech that I have chrome deleted using A-spec parts. I'm getting ready to throw new tires on some A-spec OEM rims, which call for 255/40-20. Since I'm in NC, I've decided on Michelin PS 4S Summer tires. I can use them probably March-November. For the colder months, I'll put the factory A/S rims/tires back on. I drive a lot of very windy/curvy mountain roads about 50% of the time. The other 50% is HWY and urban but not quite city.

The question that I have is I have seen some people going one size up on their tires, so instead of 255/40-20, they are getting 265/40-20. Other than the slight difference in the speedometer being off a little, what else would the advantage be?

justnspace

iTrader: (1)

the first number is the width...255mm wide. the second number is the profile in relation to the width, or aspect ratio of 40%.. the last number is the diameter.
255mm/40/20.

so, when you move to a 265mm tire, you're widening the tire by 10mm.

however, the profile ratio will be wrong...
when changing tires, you want to remain as close as stock as possible.

https://www.1010tires.com/Tools/Tire...ismetric=False

the tire calculator says the 265/40 tire will be a little taller.

catbert430

The stock 20” tires are 225/45/20. 40s would be too small.
This is the size I went with on my Tech with BBS SX 20 x 9 wheels.
Several members are running 265/45/20 successfully.
I wish I had gone with the 265 to get a slightly taller circumference with minimal speedometer error.

chappyja

Oh yeah, good catch. They ARE 225/45/20's - I was incorrect. Thanks for catching that!

chappyja

Great tool. Thanks for that... Makes more sense!

Leaf 68

I have an A-Spec and the OEM tire size for the rim is 255/45/20. Some people on this forum have put 265/45/20 tires on these rims and if you search the forum you can read their posts on the results. The A-Spec rim is 8 Inches wide and most tire manufactures state that 255 mm is the maximum width for an 8 inch wide rim. I say this because I looked into putting 265/45/20 tires on my rims but decided against it.

supafamous

There's no advantage in the case of the RDX of going to a wider tire on the OEM rim - there's mostly disadvantages if anything. A wider tire will decrease fuel economy (see the difference between the A-Spec and other trims which demonstrate the disadvantage between the 19" wheel/tire combo versus the A-Spec's heavier and wider 20" setup). The OEM wheel is also only 8" wide which, for this sidewall height, usually means a maximum tire wide of 255 (or less). For a 265 wide tire like the Pilot Sport 4S the minimum wheel width is 9". If you run too narrow a rim you'll lose handling and be sub-optimal for performance.The RDX also doesn't generate enough power to overwhelm the tires (well, good tires, the Eagle RS-As are total shit tires).

FWIW, the A-Spec tire and wheel setup is not a very good setup for performance - the wheel weighs about 37lbs which is very heavy for a 20" wheel and the OEM tires are horrible (they are from the early 2000's). Unless you're really attached to the looks of the A-Spec wheel I'd opt for something a lot lighter - an Enkei TSR-X is about 23lbs in the 20x8.5 size which better matches the requirements of a 255 wide tire. Your suspension and your back side will thank you for choosing a light wheel and tire combo.

Leaf 68

^^^^I haven’t heard of too many A-Spec owners that have switched out their rims for aftermarket ones...🥱

chappyja

Ended up ordering the Pilot Sport A/S +3 in the 265/45/20 to be mounted next week. Since I'm in the Western NC mountains quite a bit, where the temps can drop/vary....decided against the Summer tires. Last thing I need is to get caught on back roads where the temp drops and it starts to rain and my tires become slick. I spoke to my local (trusted) tire place and we are going to do a test mount of the 265's on one of the A-spec rims and check it out on the RDX. I don't drive my RDX aggressive....but some of the back roads in Pisgah Forest have curves that can sneak up on you at times going in too hot and need to have braking recovery on a turn more than punching it through. I can't imagine the AS +3's running 265's on A-Spec rims will provide worse traction or control than my stock Tech rims running the OEM Continental Crosscontact tires.

Padre Dave

As stated elsewhere here, I did the Michelin PS3 as+ in 265/40/20 I love ‘em

chappyja

Here are the new Michelin AS 3+ in 265/45ZR20 on my A-Spec rims.....

SpaceBot

How do you like them? Looks better in the wheel well?

chappyja

Love them. Look good in the wheel well, no doubt. But man...what a massive improvement to the OEM Continentals in every way. Way quieter, smoother and handle so much better. Very very grippy. Highway driving is quieter and I feel way less road feedback on cracks, bumps, etc and back road driving is much more controlled. The RDX doesn't feel drifty at all. I'm super happy with these and glad I went up one size for sure!

SpaceBot

Great to hear. I'm considering replacing my advanced rims because they are horrifying to look at. But I can't decide on 255/50r19 or 265/45r20 like you. Personally, I think going with more tire with a 19 inch rim could work. I could also do 265/50r19 as well I suppose...but the 265/45r20 would fill up the wheel well nicely, like yours. Hard to decide. Plus offset for an aftermarket wheel, I have no idea what I should be considering.

supafamous

re: offset - stock is +50 and I've got winters that are +40 and are 8.5" wide so they poke out a touch more (about 15mm) which isn't noticeable at all. I'd guess that you could go down to +30 on a 8.5" wheel before it become visible.

FWIW, keep an eye on wheel weight - there are lots of light wheels out there which will really make the RDX feel light footed. Many don't cost extra either.

SpaceBot

Thank you for the input. This massively helps me out in understanding what wheels to consider.

For looks...a 20 inch rim is nice. But for actual performance, driving, and comfort, a 19inch rim with a bigger tire and side wall would help more so than with a 20 inch setup. Is my thinking correct on that?

supafamous

Generally speaking, a 19 inch setup will ride more comfortably because of the taller sidewall and depending on your specific tire/wheel combination it can even yield better straight-line performance (due to lighter weight - eg. The A-Spec is likely the slowest of all the trims) and possibly handling performance (using a wide tire). I like the looks of the 20 inch rim as well and, if and when lowering is an option, I'd likely go to 21 inch rims but I'd keep a very close eye on wheel weight which can dramatically affect ride and handling. My 19" winter set up weights 15lbs less per corner and ride dramatically better and the car feels like it has lost a couple hundred pounds.

chappyja

Just thought about this and want to fix it before I'm in a jam. My 2019 RDX has a factory spare tire under it that I assume was sized for the OEM Tech tires, not my new 265/45ZR20's. Especially since it is AWD, won't running my current spare if I get a flat be really bad? Do I need to get a different sized tire put on the spare rim or something?

MrmissmyTLX

Any pics of the entire vehicle?

SamuelJosiasFlores

Your 265 45 20 tires were on the stock rims with a plus 50 offset correct? Did they have good enough clearance in the back? No rubbing? I'm thinking of putting 265/50 19s on my 19x8.5 rims with a plus 45 offset. That should give me almost the same setup as you as far as width goes