Question on 20's and sidewall
 

Hey guys,

I want to apologize in advance for not using the search button but as it stands right now I'm balls deep in setting up this saltwater tank. My question is for anyone running 20's. What was the biggest sidewall you were able to go with?

I'd love to go with 305/30/20 for the rear and 275/30/20 in the front?

Is this just wishful thinking?

Craig

It all depends. Are you dropped?

Check this link:
http://www.the370z.com/brakes-suspen...springs-2.html

Thanks man. Ideally I'd really like to go 35's. I'm not dropped, yet, but my springs will cater to my wheel/tire specs.


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Good thread! i was going to start one as well, but then saw this one. Im currently running 9.5 front and 11" in the rear. Running 245/35/20 front and 285/30/20s tires in the back. After 285 tires installation in the rear I realized that I should have gone with 295 instead.

If I decide to go with 295 in the rear should I keep the side wall of 30 or go down in 25 ??? Not sure when we need to switch to side wall size when going with wider and wider tires to keep the diameter as close as possible.

Any imput?

What was about 285 that did not suit you? Are you lowered? I think offsets of the wheels dictate tire width choice as well.

My next set will be 255/35 front, and 285/30 rear. I was on 255/30 Front and 295/25 rear and they were too thin.

What? How are the offsets effect the tires fitment? It's all about the rim width. I really doubt that offsets can effect the tires in any way.
Well Seems like with my 285 in the rear they are a bit too stretched. The stretch does not really needed, it clearly clears my quarters. That's why I said I think 295s would have worked perfectly.
And Im pretty low, lowered about 2" on coilovers.

My suggestion is to keep the original OEM OD (outside diameter) of the tire. I see a lot of guys going with a shorter tire than stock and it looks terrible and drives like crap. Having said that, it appears majority of that is seen on cars that have too much poke and run super stretched tires.

R.K.

You are correct. the offsets will have no effect on the how the tire sits on the rim. However, they will affect on how far the whole package sticks out past the fender, and if you have a low offset, you might have to go with a narrower tyre.

But you already know that I am sure.

If you can fit it, go wider.

OP to answer your original question I believe I am the only person who has dabbled with the largest tires to fit factory wells on a 20" rim here are some pictures of my car as it sits today on ZERO alterations to the factory suspension
http://www.the370z.com/members/rid3_...e80166-373.jpg
http://www.the370z.com/members/rid3_...e80163-374.jpg
http://www.the370z.com/members/rid3_...e80164-376.jpg

the car currently sits on 275/40/20 NT-05 fronts and 315-35-20 NT-05R drag radials on the rear. this is probably the ABSOLUTE biggest you can run in our wheel wells. I'm actually currently awaiting coils so I can tighten down the dampening to keep the car from squatting and bottoming into the fenders. There's not even a fingers width of room tire-fender on all four corners.

I stand corrected. Here's a perfect example of wrong offsets and the tires being too tall...The factory tires in the front are 26.8" tall and the rear's are 26.5" tall. The car above's tires are 28.7" tall!!!!!!!!!!!!!!!!!! That's 2" taller than factory. It makes the car look like its riding on balloons. The rears are again 28.7" tall. Same problem as the front. Do not repeat his mistake.

Here's pictures of proper fitting wide wheels and proper offsets:

http://i110.photobucket.com/albums/n...ps2f97336e.jpg
http://i110.photobucket.com/albums/n...ps84229b7d.jpg
http://i110.photobucket.com/albums/n...psac9de90d.jpg
http://i110.photobucket.com/albums/n...psf63c7bd2.jpg
http://i110.photobucket.com/albums/n...psacf575f5.jpg
http://i110.photobucket.com/albums/n...ps8680add3.jpg
http://i110.photobucket.com/albums/n...ps7be2e1fe.jpg
http://i110.photobucket.com/albums/n...psfadc72a9.jpg
http://i110.photobucket.com/albums/n...ps08d965af.jpg
http://i110.photobucket.com/albums/n...ps82a530af.jpg
http://i110.photobucket.com/albums/n...psd3aa3f41.jpg

That's my car. I'm running 265's on the front and 325's on the rear; lowered on Swift springs. That's how its done.

R.K.

Wow!!!! Tire augmentation surgery.
:eek:
http://smileys.emoticonsonly.com/emo...oppin-1340.gif

the OP asked a question I answered. where your car is meant to look good and move slow; my car is meant to look good and move fast. to each their own rad.

So getting wheels like that will make me faster? Or is there more involved?

these wheels are set up for my car to be putting 800whp down to the street. is that the answer you were looking for or did I miss something?

Cool.

Guys I don't know if you're aware of the fact that when the tires go wider the sidewall % gets taller. That's why if you look at our factory set up we have 245/45/19 front and 275/40/19 in the rear.

So my question was to people who understand tires very well, when I get to 295 width with 20" wheel, do i still go with 30mm sidewall or go down to 25mm?? At what point/width should the sidewall thickness should decrease???

Hope this makes sence.

Question on 20's and sidewall
 

Actually on the 19's the tires are 245/40 and 275/35 but your exactly right.

245/40-19 is 26.7" tall
275/35-19 is 26.6"
305/30-19 is 26.3"

But the same width going up in sidewall ie 275/40-19 is 27.7" tall





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You pretty much answered your own question bud. The % of sidewall is just telling you your tire side wall is X number at 40% of 295mm. Yes you will always want to drop the sidewall size(in a normal case). To answer your question more specifically you need to make sure your front and rear tires do not exceed a 3% height difference or it will throw your abs/wheel speed sensors crazy in turn disabling the VDC. So make sure that when your sizing your fronts size them accordingly to your rear.

The only reason I didn't drop down to a 265 ish tire in the front is because they don't offer it for the radial tires I have and I wanted matching front and rear treads(picky yes, but it is what it is.)

Those are drag radials? Look like S0-4s with those rain channels.

you have to calculate to get to the closest to stock total diameter.
ive noted several examples to cooltoy, check out the tread. :)

basically take the width (in mm) multiply by sidewall in percentage.
then take your wheel diameter multiply 25.4 to convert the diameter in mm.

then diameter + sidewall x2 = your total diameter. btw, use excel.

GL

Yes they are nitto drag radials.

Alright. So I ended up going with 20x9.5" (255/35/20) in the front & 20x11" (305/30/20) in the rear. I'll get the Swift springs and call it a day. I went with the F14's in the Red Velvet w/Silver Base-coat finish. The car is light silver. Thnx for all of your input.

Craig

I think you should have gone with 305/25/20 in the rear instead of 30 side wall. Might be a little too tall with 305s?

Did you calculate it???

You are correct. Picking tires isn't rocket science. Obviously no one paid attention to my post about OD of the tires. Then people wonder why they rub...

If in doubt, go onto tire rack and pick a tire by size and go under the specs. It will tell you the OD of the tire you chose....

R.K.

I had the guys at getyourwheels.com do that for me. I'm not saying they're right, but I hope so.

What do you think R.K.?

Will they rub? I can still change the order as they're not shipping for another month or so.

The tires are 27.2" OD opposed to the stock 26.5". That's seven tenths of an inch difference. Whereas the 305/25/20 are 26" OD which is half an inch short of stock.

Also, I'm throwing the Swift R-Spec's on it as well so that'll lower me 1".

Thnx.

When I search 305/25/30's they are exactly the same size as OEM at 26.5":

http://www.tirerack.com/tires/tires....omCompare1=yes

Anytime you go taller than stock, you risk rubbing. Will it rub...I don't know.

Also, you better be running at least a 10" wide front to run 275's on it. Other wise they will bulge over and again have a chance to rub. I would also need to know the sizes and offsets of the wheels that you are getting.

R.K.

Nah it's a 20x9.5 (255/35/20) in the front.


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Okay. Get the 265/30/20's that way the way the tire sits on the front wheel will be consistent with the rear wheel. Otherwise your front's will be slightly stretched but the rears will be square. Its up to you in the end.

R.K.

You're saying to get 265s for his 11" rims? That's gonna be too stretched and look funny. I'd get the 285/30 or 295/30 in the back and be done. I got 285/30 right now on my Z and they are a bit too stretched for what I wanted.

No. 265's on the front and 305's on the rear.

R.K.

Shurik, any pics of the 285/30 on your 11" rim?

Not the best pic of how 285/30 looks on a 11" rim but you can kinda see. Had more but deleted them from the phone. will need to take more soon. Im thinking on going with 295 tires. and Gonna sell my 285 Michelin SP2 tires which only have like 300 miles on them.

https://scontent-a-iad.xx.fbcdn.net/...66858332_o.jpg