370z MEATY TIRE THREAD

[daisuke149]

Originally Posted by cjr1881

You got the wrong size profile tires and screwed up your gearing and speedometer, you think lowering it will fix that? lol
ha

did he say lowering would fix that? he wants to lower it for the look..

good comment tho...

[Nissanboy]

Originally Posted by cjr1881

You got the wrong size profile tires and screwed up your gearing and speedometer, you think lowering it will fix that? lol
ha

wrong size? that's like a perfect combo, both side walls from front to back are about the same size.
and please enlighten me on how it will screw up the gearing, didn't know tires changed your gear ratio

[Boost_lee]

lol I think he meant effective gear ratio. Now that, tire size does come into play a bit. With the shorter tire on the 295/30, gears will be shorter, granted not by much.

Top of 4th on the 275/35 is 126.44mph
Top of 4th on the 295/30 is 123.53mph

[cjr1881]

Originally Posted by Nissanboy

wrong size? that's like a perfect combo, both side walls from front to back are about the same size.
and please enlighten me on how it will screw up the gearing, didn't know tires changed your gear ratio

You need to keep the total circumference of the tire the same or you will change your gearing. He has effectively shortened his gearing and will now take more rpms to achieve the same speed. The profiles for 19" tires on the 370Z should be front/40/19 rear/35/19. His are F/35/19 R/30/19 . When his speedometer says he is doing 60mph, he will actually be doing about 50mph. 17-18% off. I can't believe how many cars I see with the wrong profile tires. People are obviously oblivious to the fact that they are not just changing how the tire looks. If you plus size you need to change aspects accordingly, and if you keep same wheel size then you must keep same aspect or you will be changing gearing and your speedometer.

[FortuneLSX-TT]

Originally Posted by cjr1881

You need to keep the total circumference of the tire the same or you will change your gearing. He has effectively shortened his gearing and will now take more rpms to achieve the same speed. The profiles for 19" tires on the 370Z should be front/40/19 rear/35/19. His are F/35/19 R/30/19 . When his speedometer says he is doing 60mph, he will actually be doing about 50mph. 17-18% off. I can't believe how many cars I see with the wrong profile tires. People are obviously oblivious to the fact that they are not just changing how the tire looks. If you plus size you need to change aspects accordingly, and if you keep same wheel size then you must keep same aspect or you will be changing gearing and your speedometer.

Considering that the overall diameter of the 275/40/19 was 26.5 inches and the overall diameter of the 295/35/19 is 26 inches... not as noticeable as you're claiming

The front 245/40's was 26.7 and the 255/35's are 26.1, a bit more than the rears, but still not as noticeable as you claim.

Don't forget that while he did decrease the aspect ratio he also increased the width, which makes the change to overall diameter not as dramatic.

Also, just out of curiosity what size tire do you think he should have changed to? There aren't exactly a ton of options for changing tire size to a wider tire while maintaining the exact same overall diameter. It's only going to be "close".

And to keep the thread on track... here are some shots of my "meaty" tires
285/35/19's ... up FRONT and 305/30/19's in the rear

[Ron]

Originally Posted by cjr1881

You need to keep the total circumference of the tire the same or you will change your gearing. He has effectively shortened his gearing and will now take more rpms to achieve the same speed. The profiles for 19" tires on the 370Z should be front/40/19 rear/35/19. His are F/35/19 R/30/19 . When his speedometer says he is doing 60mph, he will actually be doing about 50mph. 17-18% off. I can't believe how many cars I see with the wrong profile tires. People are obviously oblivious to the fact that they are not just changing how the tire looks. If you plus size you need to change aspects accordingly, and if you keep same wheel size then you must keep same aspect or you will be changing gearing and your speedometer.

so u are saying that no matter how wide said 19'' tires are you should always go with 40 front and 35 rear for side profile?? You do know that those numbers are directly proportional to the tire's width, right?

305/30/19 means sidewall is 30% of 305mm.
285/35/19 means sidewall is 35% of 285mm... etc etc

[Nissanboy]

Originally Posted by cjr1881

You need to keep the total circumference of the tire the same or you will change your gearing. He has effectively shortened his gearing and will now take more rpms to achieve the same speed. The profiles for 19" tires on the 370Z should be front/40/19 rear/35/19. His are F/35/19 R/30/19 . When his speedometer says he is doing 60mph, he will actually be doing about 50mph. 17-18% off. I can't believe how many cars I see with the wrong profile tires. People are obviously oblivious to the fact that they are not just changing how the tire looks. If you plus size you need to change aspects accordingly, and if you keep same wheel size then you must keep same aspect or you will be changing gearing and your speedometer.

17-18%?!??! What are you smoking?
@ 60mphs, his speedometer will be off about 1 1/2 mph, resulting 61-62 mph

Do the math Tire size calculator

[KaienZ34]

^ looks good, spacers and a bit more drop and your done

[One_Quick_Z]

^I know!

I have already dropped the car a little more than an inch all around on my Stance GR+ coils and now it looks like a 4x4 again ha





DAN

[wheee!]

How much of it is still touching the ground too!?

[W.O.W. 370Z]

More than the setups with 305s in the rear with 3-4 degrees camber!!

I got less camber than that with 345s.

It's all about the offsets. I am just saying!

[wdkwang]

Originally Posted by W.O.W. 370Z

More than the setups with 305s in the rear with 3-4 degrees camber!!

I got less camber than that with 345s.

It's all about the offsets. I am just saying!

sh1t looks dope, and i know you got the tt power, but dont you think all that added unsprung weight is killing speed? stickier 305/315mm nitto nt05 or nt01 tires could easily outmatch the invo's and give better feel and response. it was quite a difference of weight feel, especially on roll off whenever i put on my winter wheels on that are 32lb less total in unsprung weight compared to stock. im not bashing, just saying

[wheee!]

^^

[Ron]

wow if you ever decide to change wheels (again) hit me up. I'll buy those.

[Rusty]

The rims came in last night just before I left for work. So I got the tires mounted on the rims this morning. The lug nuts just came. So I will put the rims and tires on the Z tomorrow morning.