I need input on 225/40R18 tires

[Lone Solara]

I need your inputs, opinions and experiences on 225/40R18 tires. The optimum size for an 18" wheel would be 225/45R18, but the selection is extremely limited for that size. So, especially for those who actually run this size I have a couple questions:

1) how did the tire impact your ride, if at all
2) how satisfied are you with your selection
3) (optional) - what tire you have - make, model

Thanks !

[indiglosolara]

225/40R18 doesn't impact the driving ability that much. Most 18 wheels use 225/40 since its the most common size. I've had 18" wheels with the same size tire you mentioned and ran fine and allot of members here are doing the same.

If you want a larger side wall to protect the rim a little more you can go with 225/45 but its a very uncommon tire size as you mentioned already.

If you want the optimal size closest to stock i would probably go with 235/40R18. Which is allot more common.

That would be 99.6% closer to stock then 225/40 which is around 98%.

Hope this helps. If you want a tire with good thread rating along with a quiet ride i would look into perilli's p-zero nero or Falken Ziex 512.

If you want longer thread life and dont mind some road noise then Kumho 712 are good or Hangkook H104 are also very good in thread wear..

I'm sure other members will have other tire suggestions..

[ChargedSolara]

i run toyo proxes t-1 ( i think?) in 225/40/18. the ride is bumpier, but that is to be expected. overall i am satisfied with the performance of this wheel/tire size. my previous setup was 235/35/18 on nitto 555's , and i was running different wheels. i bent the wheels twice, my suspicion is the wheels were lower quality than the racing harts i have now.

good luck

[theprodigy79]

I use Michelin Pilot Sport 225/45R18s and I've been very happy with them (although they are pricey)... The ride will definitely be harsher with the 40s than with the larger side walls of the 45s, as you would be riding on 11.25mm less on the radius, which is a pretty substantial difference (101.25mm vs 90mm side walls). You're going to have very little flex in that size tire (essentially riding on rubber), so you will break free from the pavement a bit easier in hard cornering (more aggressive treads will keep this predictable)... You will need to have your speedo recalibrated as well unless you are a "traffic follower"...

[WTF??]

why not go bigger??

[methyl mike]

Try a 245 40???

[Lone Solara]

Thanks guys. Great stuff so far, keep it coming. Let me address some questions here:

Why not 245/40 ? Because I'm thinking about dropping the car in the future (eventually), and 245 would probably be too wide. Even as it is, it would come pretty close to rubbing on the strut. 235/40 would be better, but still risky and somewhat dependant on the shape of the tire.

Why not bigger ? Because I'm trying to apply some "fiscal responsibility". Going to 19" would increase my cost by at least $500 and I'm trying to avoid that. I also want to prevent the ride from becoming too harsh, and that's why I won't go to 20" either (strangely enough, 20s would not be significantly more expensive).

James - I can't say I'm a traffic follower, more of a traffic followee. But wouldn't the car travel slower than stock with 225/40 because of the smaller diameter ?

[theprodigy79]

James - I can't say I'm a traffic follower, more of a traffic followee. But wouldn't the car travel slower than stock with 225/40 because of the smaller diameter ?

Lol I hear ya about being a "followee". You are correct in your assumption that the car would be a bit slower, by around 5% actually (with an increase in acceleration). But it may still be a concern if you are the followee type... Speaking from personal preference, I just like being ahead of other cars (I hate getting stuck behind them)... so if your speedo says you're going faster than you are and you're anything like me you will begin to just push the needle up further to get ahead of them (and you'll have to guestimate how high you can go before you are going faster than you usually go). Getting your speedo recallibrated is really not that big of a deal (take it to a place like Precision Tune), however it's just an annoyance (esp if you plan to switch to snow tires in the winter that may be a diff size).

[x0swtextacy0x]

u kno i LOVE the wide tires...for some reason i think theyre soo hot. but i personally wouldnt go w/ anything wider than what i have b/c i'm too broke now. =)

[Sap Z]

tht seems to happen to everyone on this site...^^

[theprodigy79]

watch out for going above 235s... as you WILL run into clearance issues when you are dropped (I ran into trouble with the Pilot Sport A/S 235s on my ride).

[SPF 0]

Is the harsher ride on plus+ wheel more from the tires' stiffer sidewalls or greater unsprung weight?

[theprodigy79]

Greater unsprung weight would make more of a difference in this case (less tire cushion for those who didn't catch that). The stiffer sidewall ratings definitely add to the harshness of the ride, however moving from a V to a Z rated tire without losing the side wall would still allow for some flex (and therefor some dampening factor). The situation of losing 10mm+ of sidewall (especially when beginning with an already fairly low profile tire) would definately make a greater impact as it's a direct loss of flexible material. The easiest way to observe this is to go into a tire store and find two Z rated tires of the same brand / series (just to ensure that external factors are minimal), but one with a larger side wall than the other. Squeeze the side walls to see how much flex they give. The one with more side wall, even though they are both Z rated tires, will be more malleable.

Tires are intended to compliment the suspension of a vehicle (they are actually part of the suspension)... Keep in mind that the harsher the ride of your car, the more quickly your other suspension components will wear out (along with other parts of the car as well)... Between my suspension and my system, I'm beginning to get all sorts of creaks and rattles... My rear, passenger side spring is also making some really nasty groaning that I gotta get checked out...

-James