This is my very first post and I am in need of some serious help. I just purchased a set of Work Emotion CR-Kai 18" 18x8.5/9.5 wheels (BTW I got an excellent deal through fssport.com and their customer service is on point!). Also purchased a set of Falken tires (discounttire) with the original OEM specs being 225/45/18 front and 245/45/18 rear. Now my question is should I spend the extra $80 dollar freight cost to get the recommended 245/40-275/40 tire/wheel setup, which is only a few extra dollars or could wheel spacers, if recommended, do the job? If so what MM? I am somewhat of a newbie and have an 06 Z base 6sp MT 29k miles...Current mods are Borla Cat-back and JWT intake..mods coming up soon: plenum spacers, berk hfc, seibon CF hood...please help !!

 

45 is going to be way to tall of a tire
245 is going to be way to thin of a tire

I'd rock the 245/40 & 275/40...that's a very very common tire set up.

Spacers all depend on you're offset. Did you go w/ the +12 or the higher ones? Can't remember off the top of my head what they are...

 

The wheel offsets are +25 in the front and +20 in the rear..Thanks for the quick response BTW...I guess shelling out an extra $80 bucks will be worth it! suks but it's my mistake...

 

Spend the $80 and get the recommended tire size for your new wheels, the ones you ordered are for OEM wheels. If they let you exchange them thats great!

 

Thanks for the advise...hoping to get the wheel by next week to take pics..I am also going to drop the car by 1 inch at the same time.dude since your from nearby--I grew up in Clifton --is there a shop you would recommend?..thx

 

No prob on the response. Post pics when you have em...

Great wheel choice btw!

 

Will do...silverstone Z on bronze wheels.

 

stock pic...

 

No sure what "recommended set up means." Like there is only one possible way to go?

 

Nice choice in wheels though.

 

I have the same wheel same spec as you do
I bet you wont be happy about the offset since I want to add spacer too...
oh, and I have 275/40, 245/40 combo...

Still havent decide which spacer to go with

 

Do you have any pics? I'm still waiting for the wheels which should be shipped by next tuesday..sux because the tires are coming in tomorrow and I will need to refuse the tires and then order the correct set/size because of my mistake..about to order a set of springs. Was going the coilover route but damn they are expensive..I'm only a daily driver so its not on my top mod list..not just yet..anyone have pics with those work tires..I've seen only a handful..will post pics once setup is complete..hopefully i will be happy

 

Your new wheels and the sizes and offset (front and rear) are good.

For sure you want front 245/40-18” and rear 275/40-18” tires.

--Spike

 

You do realize the a 45 series is what's stock on the car, as are the 245s? Not that I recommend them for aftermarket wheels, but you can't say they are "too tall" or "too thin" with much justification. He mentioned nothing about lowering springs.

 

^^ Thanks for posting the correction. As you point out, the second measurement (i.e., 245/45-18) in the metric tire sizing system is the aspect ratio and it is not a measurement. So “45” in this system is meaningless as the sidewall height unless you know the tire’s width.

I’m surprised how often our members get this wrong. For example:
I’ve posted the following several times, but it obviously is worth repeating since at least a few member here are not getting this. Hope I’m not boring people.

The metric tire sizing system represents a tire size as: [section width (mm)] / [aspect ratio] - [rim diameter (inches)]

For example: a tire size 225/45-18 is 225mm wide, has an aspect ratio of 45 and fits an 18" rim (wheel).

The aspect ratio (the second number) is not a measurement. The aspect ratio represents the tire's sidewall height as a percentage of the tires width (section height divided by section width). In the example above, the sidewall height is 101mm (101/225=45).

The aspect ratio is important since that (along with the wheel size) determines the overall diameter of the tire allowing you to match your stock overall tire height (diameter). Using the Z’s front tire size as an example, a 225/45-18 tire's sidewall height is 101mm, and a 245/40-18 tire's sidewall height is 98mm.

So, both tires have nearly the same overall diameter.

 

Thanks to all for the feedback. I spoke with an associate from discouttire and changed my order after refusing the tires...245/40-275/40 it is after shelling out for the freight cost. Tires and wheels should be in by Tuesday. Also purchased a set of H-TECH springs. Will be posting pics soon..