Well, it's almost time to purchase my new wheels. I'm getting 18"x8" Mille Miglia Evo5 Wheels. I just can't decide what tire size to get. I've been doing a lot of searching and reading lately, but I'm still stuck. I've found out that the recommended tire size for an 18"x8" wheel is 235/40-18, but I also found out that many people are running 245/40-18 tires.

Are there any benefits to running 245/40-18 instead of 235/40-18? I'm assuming that the 245/40-18 would ride a little smoother since it has more sidewall. Can someone verify this for me?

The reason I'm asking because the roads around me are fair. There aren't very many potholes at all, but there are some bumps around. I don't want to bend one of my new 18s and I want the smoothest ride possible with the bigger wheels.

Thanks,
-Nick

 

I have the 245/40-18 and have had the smaller one also, and I must say that it is smoother. Have you gotten a price on the wheels and tires? I might have mine for sale soon, like within 3 weeks if you are interested. I know this is a bit early, and I am planning on posting it in the for sale forum closer toward the date.

C.

 

I don't think that small difference would be noticable. I have the 235/40-WR18 setup btw on 18x8's. Since people are running 245/40's I guess there is no problem rubbing etc. I think the 245 is the correct set-up for the Maxs that come with the 225/50-17, not our 4th gens. You may get some speedo error to the minus side. You'd be riding higher by .5", so at 60 mph you'd be really going 61.2 mph. At 80 mph you'd be going 82 mph, so not a big difference. But 235's are the true match for the 215/55-16.

Do you like the Evo 5? I used to think they're hot but now since the trend is 6-7 spokes, if it were me, I'd pay a little more for something different. Interesting that the BMW 3-series has a "finned" wheel now, so styles come full-circle. Volvo introduced the finned aluminum rim on the 240 back in 1979 and I think they used it until 1993. Now they're back in style!

 

How come i have never seen a pic of your car?


in any light.. for the correct speedo adjustment go with 235/40 .. that and the fact that 245/40 make your 18's look like 17's.. so whats the use in paying for 18's when they look like 17's i mean .. just look at emax and dmbmaxima's wheels.. they look like 17's

 

most ppl that run 245/40/18 have 8.5" wheels. i would tell you to go with the 235/40/18 because your wheel is 8" wide.

i also agree with SprintMax, my 19's look small too and will try to get 20's next spring.

 

Do my 18s look like 17's too? my 18x8 did look a bit beefy now the 18x8.5 look just about right? I still say go w/ the 245

 

miata calc is your friend

http://www.miata.net/garage/tirecalc.html

 

Your 19's do look like 19's! I also remember seeing your car at the jersey meet!

What about 225/40/18 size tires?

 

but he is going with 18x8

Speedo is off.. and not enough rubber.. geomax had these with GC Coilovers.. lets just say his struts didn't last very long

 

I don't know, I still think my wheels look like 18"s. i think for the people who are saying there wheels look small, its because we are iused to the big wheels. I tell everyone that I want to go 19" and they are like why? I tell them my wheels look small, and they stqart on "OMG they look like 18"s... are you blind?" Who knows... here is link to my 18"s

http://images.cardomain.com/installs...48_49_full.jpg

 

go with the 245's every1 that says their rims looks small. they dont look small, trust me. i had 16" chrome on my old car, and i was running 225/60/16's and people thought i had 17's or 18's so dont fret over using 245's.

 

I had 225s on my evos when I first got them. It handled very well, but it was a harsh ride and they didnt look that good. now I have the 245s and it doesnt handle all that well but it looks a lot better. the 235s are prolly a good choice, a lil bit of both worlds i guess.

 

Geez you had 225, you was rolling on rims. But good thing you upped 2 sizes. What size rims you have?

 

i have 235/40/ZR18's on my 18x8 i highly recommend that tire size for any 18x8 rim.

 

18x8

 

I have and I think JAY25 has also...245/40 18 is the right size.
Regardless of 8 or 8.5 width.

225/40 18...Painful ride, wreck rims in a week. feels like you are walking barefooted on concrete.

235/40 18...Decent ride, but still will look thin on 18's, also it will look like 215s or 225s from the rear and side.

245/40 18...Plush ride! Hug the offramps like VELCRO. They will look fat and right in the MAXIMA wheel wells. The only drawback will be that you will be a little slower and speedo will be off.

 

Wonder how that could possibly be true? The way that Plus 1 and Plus 2 work is that the overall diameter does not change. Since the diameter of the 215/55-16 and the 235/40-18 are identical, that means you got 2" more rim and 2" less rubber. If you've ever done any handyman work 2" is something that the eyeball can see. 10mm would be harder.

That's totally bizarre that you think a 235 looks like a 215 from the rear and yet a 245 doesn't. 245 is definitely an incorrect size for a 4th gen if you want to preserve the overall diamter. It is the right size for 5th gens with 17" rims from the factory. But as your car shows the 245 will work fine. Take it to a tire shop and if the guy is good he will point out it's the wrong size under +2.

 

Well, I have a 5th gen, and i'm on 245/40/18s, but I still managed to bend the rim.
It's ok guys, it's all fixed now.. hehe

 

He is right. It is the same even for 17" rims. I'm running 17x8 with 235 wide tire. 245 is not recommended for 4th gens...

 

I guess I'll just stick with the 235/40-18 rubber than. I thought it would be OK to run the 245/40-18, but I don't want to run it if it isn't the correct tire size for my car.

Thanks,
-Nick

 

You dont have to listen to peeps you can do what ever you want. You can run 245 on your ride regardless if the **** makes your odometer off by 2miles who gives a f!ck if it does, is your car man. You asked for size vs size peeps gave you the facts. If you want 245 then go for it, on pic it may not look right but in person is totally different. Thats my opinion. No one said stop don t do that. I did have the 18x8 set up w/245's. I liked it and kept the setup. I am still on 245, and can careless what peeps say. How ever I went up .5 on width.

You want 245s get them.

 

Well, I was just seeing if the 245/40 would ride smoother than the 235/40 since there would be a little more sidewall. I also thought this would also be a little added tire so it might help prevent a bent rim better than a 235/40 tire would.

Now I'm all confused!
-Nick

 

I don't understand this...

235/40/18 is just not as wide as 245/40/18.. The 40 is the thickness of the tire.. in other words, how tall the sidewall is... if you had a 45 sidewall, it would be more beefy and give a more comfortable ride...

the 1st # is only width of the flat part of the tire which touches the actual surface of the road. I don't see how a wider tire would make the ride quality more comfortable..



The "correct size" that makes the most difference is the middle #... usually everyone runs 40 profile tires on 18s.. that is the correct size.
the width is subjective.. and depends on the width of the rim..

I think either one is fine.. 245s would be a little wider and maybe buldge from the lip of the rim instead of staying "flush" with it. but they should not matter as far as ride quality goes, i think.. because the tires still stay the same height..

 

Since I had the set up listen to me, yes 245 is the width 40 is the height, how ever you will gain .2 MM in sidewall height not just width. Thats the reason why Sprint said it will make your wheels look like a 17. If you want to see what a 245/40 looks like a 18x8 go to my homepage page 2. Page one is w/ 18x8.5. Next time just PM somebody about doing some set up like this.

 

18"x8" w/ 235/40-18 >>>



18"x8" w/ 245/40-18 >>>



Opinions on which looks better? The 235/40 just seems thin. It could just be the picture though. I mean I have 235/45-17 tires on my 17"x8" wheels and they look fine, so I dunno. I really don't want my speedo to be too far off. It's only like .2% off with the 235/40 and like 2% off with the 245/40.

As of right now, I'm probably just gonna get the 235/40, but I'm still not 100% decided. Just wanted to get some opinions on which looks better.

Thanks,
-Nick

 

235/40


245/40 same wheels pic is too big
http://images.cardomain.com/installs...48_43_full.jpg
http://images.cardomain.com/installs...48_49_full.jpg

 

It just baffles me how math is such an obscure concept. 40 means 40% of the tread, ie 235 mm.* 0.4 35 means 35% of the sidwall, ie 35% times 275 mm on the back of a 745Li. 235/40 and 245/40 are both 40% of different tread widths. The 245 is gonna be taller. When you go with bigger rims you attempt to leave the diameter the same, ie rubber gets replaced by rim. If a person can't do math it'd be senseless to use words like rev/mi or circumference.

I guess whether a window is plum or a foundation is level is simply subjective too....just look at the middle

 

235/40 18 do not look like 215s from any angle.

how is the speedo off on a 245, its the same hieght as a 225 or 235.

 

See above post.