Need help with tire size decisions.
 

So I am 90% sure on the rims I am going with.

Option 1:

20x9 +23 in front and
20x11 +28 in the rear

I have been playing around with a tire calculator and came up with these number.

Please let me know if these sizes look OK. (I don't want the tires to stick out past the fenders, at least no more then a few mm.)

Front 235/35 (this will lower the front by 7 mm - not ideal)
Rear 295/30 (this will raise the back by 11mm)

Is it OK to lower the front and raise the back like that?
Or should I go with 235/40 up front (raising the front by 17mm)?

Option 2.

20x9 +32 in front and
20x10.5 +15 in the rear

Front 245/35 (this will raise the front by 1 mm)
Rear 275/30 (this will drop the back by 1 mm)

Option 3.


20x9 +32 in front and
20x10.5 +25 in the rear

Front 245/35 (this will raise the front by 1 mm)
Rear 285/30 (this will raise the back by 5 mm)

Any feedback on these set ups would be appreciated.



.

Option 2 is closest to what I have. Back is flush, front sticks out a hair. Tho my wheel up front is 20x9 +20. Rears are perfectly flush (no spacers)

20x9 +20
20x10.5 +27

245/35/20 Fronts
285/30/20 Rears

My measurements. Rear flush, front flush except a tiny little peek at the front.

use excel next time not a calculator, cooltoy. :icon17:

go with opt3 if you're not going to lower

Of course i am going to lower it via swifts

Thank you.

I guess I should add, that I will stay stock height most likely. to start with anyway.

When you say +20 sticks out are you talking about the wheel or the tire?

My calculations show that with +20 the wheel should stick out 3 mm and the tire 11 mm.

That would be the CV-2.

So running +40 up front is not advised?

The tire sticks out a few mm. Let me see if I have a picture of it

Best I got for now. Stock height.

One more

That looks about like what I figured (and ketchan told me about), that's why I think I will go with +32. Not as concave, but will be closer to the way the rear looks.

yah ET20 will stick out too much on a 9"

here's the profile. i just put it together just now. check the total diameter

http://www.the370z.com/members/kench...51-capture.jpg

so from the above your best choices are:

245/35/20 and 285/30/20

That kind of sucks that I will not be able to get the rims I want (option 1).

CV-2's it is then.

cv2's are great looking wheels. are you getting the dark ones?

Silver, not into dark rims.

I don't even like the way the stock ones look from a distance. Up close they are nice.

Plus 1
The rear tyre would be stretched if he put 285/30/20 on 20X11

cooltoy- check out this link. this guy has the 20x9 ET32 front like how you wanted and clearing the infiniti akebono. :D

http://www.the370z.com/parts-sale-pr...ossen-cv2.html

but the thing is, his rear cv2 is 10.5 ET25 and has almost no concavity or lip. :ugh2:


in comparison, this is my gnosis at 10.5 ET25. this is 19" on my G, but check out how much lip
the wheel has and the curve on the spoke. this day and age, you'll want lip or
concavity or both.

http://www.the370z.com/members/kench...0-5-gnosis.jpg

Ya I saw that. Thanks for looking out.

I could get the +15 offset in the rear instead, which is more concave, but I would have to get 275/30 .

That wasn't in your table, will it work?

275/30/20 will be 673mm total diameter only 2mm smaller than 275/35/19 (675.1mm)
so yah, it will work.

if that is a 10.5" width wheel, then i recommend you go with 285/30/20 instead.
If that is a 11" width, then it will be a tight fit.

So here is the dilemma (and maybe I just can't visualize it properly).

Let's start with the front.

We have already established that the best offset for CV2's in the front is +32, and the best tire is 245/35.

From my spreadsheet the tire edge will be flush (or 1mm in) to the outside edge of the front fender. Lip of the rim wil be 9 mm inside.

I assume I want the rear to be very similar for an even look.

If I go with +25 (10.5) in the rear and 285/30 tire, the tire edge will be 3 mm inside the edge of the rear fender. Lip of the rim wil be 6 mm inside. So maybe a 3 mm spacer to even it out. But I will loose some of the concavity.

For greater concavity, if I go with +15 (10.5) in the rear and 285/30 tire, the tire edge will be 3mm outside the edge of the rear fender. Lip of the rim wil be 2 mm inside. So that would look uneven compared with the front.

If I go with +15 (10.5) in the rear and 275/30 tire, the tire edge will be 2 mm outside the edge of the rear fender. Would I even notice such a small difference?

Please comment on any of these set ups. I want to pull the trigger on this purchase pretty quick.

Thank you.

The impact to the height that you mentioned will be indistinguishable. I'm thinking you will be looking at suspension mods down the road. Based on the options you listed, I'd go for opt 3.

Option 3 in my fist post, or option 3 in my last post? I think you mean I should go with 275/30 and +15.

Not really concerned about the height difference between the tires, but rather how much the tire will stick out in the back.

And I wil be staying stock. I will not be able to get into the underground parade at work. The initial ramp down is sharp.

cooltoy- remember that camber plays a huge roll when the suspension compresses so
even with a ET15 on the rear, it's not going to rub with the 275/30/20.

but the issue is going back to the wheel gap vs sidewall height. running my 19's
the gap and sidewall are about even. running 20s will make the gap a tad more
pronounced.

if you want to take a look at wat ET15 looks like, check out my
WEDS wheel picture in my albums pages. the rear is running ET15 with 285/35/19 tires.

i have no rubbing.

Thank you.

I feel confident that the 285 on +15 will not rub. I am more concerned with how the front will look compared with rear, as the rear tire will be sticking out 7 mm past the fender, where as the front will be flush. That is why I was thinking the 275 in the back with +15 might look more balanced.

Regarding your comment about concavity. Here are pictures kindly provided by NoirG of the +25 rear wheel. Is this not concave enough?

http://www.the370z.com/attachment.ph...1&d=1404138997

http://www.the370z.com/attachment.ph...1&d=1404138997

http://www.the370z.com/attachment.ph...1&d=1404139007

^^ yah, that looks pretty good. :D

the ET15 will not be really 'sticking out' and your front will not be completely flush either at ET32. it's tucked in a bit, the way it should be, but not sunken in.

if you like the ET25 for the rear, go for that for sure. at 10.5" width, the fitment will
look nice. ET15 at stock height is pushing it kinda.

Thanks for helping me out.

Tried to rep, but I already gave you too many apparently. :-)

:icon17: haha, np.

Found this pic for reference. Good comparison of 10.5 ET25 and ET15.

ET25 is in the front. Not a huge difference between the two.

http://farm6.static.flickr.com/5024/...5d6e8186_z.jpg

yah, the cv2's look good. :tup:


but when i see accords like that i lol cause they appear to be RWD/AWD but they are WWD (wrong wheel drive). :icon17:

I apologize for the Honda, but it was a good visual comparison.

Cooltoy, if you take the +25 on the rears, they will be sunken in 18mm into the fender than my rear wheels:

http://i110.photobucket.com/albums/n...psc61fa127.jpg

You will have absolutely no problem with rubbing. I don't rub what so ever with my setup.

I personally would get option 1 and run 255/30/20 on the fronts and 305/25/20 on the rear. That will keep you at the same OD as the factory tires and will make the tires fit square on the wheels with no stretch. Option 1 sucks the wheels 15mm into the fender as compared to my fitment. Again, no issues with rubbing. If you need anymore fitment pics of my car, just let me know.
R.K.

Thanks for the advise.

Two things that are different between what you have and what I am looking to do.

1. I am not looking for an aggressive set up like you have (just want the tires to line up with the fender(15-20 mm) from stock).

2. You are lowered, and I am staying stock. So I wil not aver the advantage of the wheels tucking in a bit.

Lowered definitely looks better, but no can do.

I just measured my "poke" past the fender and its 13mm. So if you're staying stock height, I still suggest getting option one. They will be just shy of being flush and if in the future you do lower the car on Swifts, you won't need to buy new wheels because the fitment will still work.

R.K.

Different philosophies.

I'd cringe if I was had even 1 mm poke. Lowering will never be an option. Places where I need to get into (at an angle of course), I only have two fingers worth to spare.

I hear you. I can't believe how low the car is stock. Then I lowered it on Swifts and wow, its really low. I can't believe people go even lower...

R.K.