makio

My 18" A-Spec's will be here shortly and I want to get my tires ordered. I know Acura recommends 235 / 40 / 18 for them but it sounds like that leaves the wheels very susceptable to curb (or car wash track) damage. Thus right now I'm leaning towards 245 / 40 / 18.

So is that an acceptable decision? What would be considered to be the negatives of going with 245 over 235?

dcarlinf1

No negatives except for price. Get at least 245's. Maybe even 255's. The 235's are waaaayy too narrow for these rims.

Lore

Your speedometer would be slightly off. There's a tire calculator available for that sort of thing, to figure out the deviation from your OEM setup - I just can't remember the website off the top of my head.

dcarlinf1

http://www.net-comber.com/tirecalc.html

noleaf74

don't take ur car through car washes, and be more careful of curbs....problem solved. those things come along w/ getting rims u have to be more careful

sepatel

I was told by the dealer to stick with the recommended 235s for the A-Spec wheels and I did. Like noleaf said, just gotta be careful. IMHO don't think that the 245s are going to be much wider and provide that much more protection.

vclune

I have the 255/40-18's and have driven past some of those radar speed signs that the police put out to remind you of your speed and mine still comes out perfectly accurate.

999999

If the stock 17" tires would register 80 miles per hour, then:

235 40 18 = 80.2
245 40 18 = 81.2
255 40 18 = 82.2

Not a big difference.

I'm putting 245 40 18s on 18x8s for rim protection from both curbs and potholes and for comfort.

Sonic

I have 245/40/18 on my A-spec rims and I am happy with it. They fit perfectly and look very good. I have gone through the same thoughts and finally chose 245 because I want better rim protection. I did not want 255 because the tire too big and may produce more tramlining effects.

makio

Thanks for the help all, I'm going to go 245 / 40 / 18. Obviously you have to be more careful with a bigger wheel, but it sounds like the 235 offers zero margin for error whereas the 245 gives just a little more protection.

noleaf74

if u do something to screw up ur wheel w/ a 235 then its still gonna screw up ur wheel w/ a 245, thats the long and short of it man

timnguyen9

Sonic,

Have you taken your car with the 245s through a car was and if so, did it damage the wheels?

Sonic

Tim,

I have not taken my car through a car wash. I probably will hand wash it only.

If you already see my rim pics from my site, the surface of the rim is same level with the sidewall of the tire so it's probably not a good idea to drive into the rail inside the automatic carwash. Also, the tires are low profile tires so the rail could easily damages the rim surface as well as the rim protector.

cvajs

it depends on tire vendor. the new falken st115's in 245/45/17 are about 1inch wider in tread width, which does not follow the logic that a 245 is only 10mm (~half inch) wider than a 235 tire.

when it comes down to perfect fitment/look, always try the tire 1st at a local dealer, or find someine with same tire/size and check it out....

criss

The Falken 512's in a 245 on an 18" rim cover it pretty good and with the rim protector lip on them it should protect against minor scrapes. If you hit a curb hard then nothing is going to help.

When I told my wife that I bought the tires a little bigger to protect the new rims and her response "use your eyes and don't hit the curb dumbass"

AcuraTL2004

How do you get different speeds on tires that have the same profile height?

jjsC5

The height of the tire is the width (245mm) times the "aspect ratio". That would be 245X.4 for intance. To get the overall diameter of the tire, take this result and multiply X 2 (side wall on top and bottom!). Then, multiply the wheel diameter X 25.5 (number of mm per inch). On an 18" wheel with a 245/40 tire, here are the calculations:

18 X 25.5 = 459 mm
245 X .4 = 98 mm
98mm X 2 = 196 mm

459 + 196 = 655 mm
Divide 655mm by 25.5 = 25.7 inches O.D.