eric n

So I'm running 255 40 19's up front and I wanting to go with 305 30 19 in the rear.

Below are some specs for the two tires.
TOTALS ARE IN INCHES

Section Width: (tire 1)10.04 (tire 2)12.1 (difference)1.97
Overall Diameter: (tire 1) 27.02 (tire 2)26.2 (difference).83
Revs per mile: (tire 1)746.1 (tire 2)769.64 (difference)23.54

Ultimately the 305s are about 3 lbs heavier than the 255s. This should pretty much be a wash since I'm getting Charcoal AMR 19 x 10" wheels. These wheels run 27 lbs which is I believe is 3 lbs lighter than my current brembos. I could of course be wrong.

Now obviously I'm losing some diameter and that will mean more rotations per mile. But the significantly larger footprint should aid in launch. Another option is the 285 35 19 which which is about half way between each of the others.

Like many of you I like the look of more rubber filling out the wheel wells also I'm hoping for a more aggressive launch. I'm not tracking the car and am just looking for input from of you who are who have real objective wisdom in this area. I of course will listen to and appreciate everyone else as well.

TheDivaDanielle

Way too short. Those tires are a whole 1.1 inches shorter than the base wheel/tires which are 27.3" tall The Brembo cars have tires that are again shorter than base and visibly so @ 27.0

Most people go taller. In fact. I feel that I should find a TALLER tire for my 20's which the rears I have lined up are a 295/30 on a 20. you're going even shorter.

Don't do it.

USMC:302

hopefully this should help, i use it regularly and swear by it. check out the different views (front or side) by using the selections above the image of the wheel/tire.

http://www.miata.net/garage/tirecalc.html

Getportfolio

I thought smaller was better than taller because of the issue with the speedo???

AlsCobra

Go with the 295/35/19. Diameter right at 27 inches even. Or just get rid of those 19's and go with an 18 or 20.

USMC:302

You're going to have a reciprocal difference either way, smaller diameter will register on the speedo as going faster than you actually are, a larger diameter will register on the speedo as going slower than you actually are. if you play with the link that i put above it will read out the difference that you can expect to see in both mph and percentage difference directly below the image of the wheel.

TheDivaDanielle

I prefer them bigger if they are wearing a speedo.

Planeswalker

I don't like 19s because of the lack of tire options. What brand of tires are you going with, that can be more important than size for good traction.

jaywoo

I was going to post that same link! Awesome for figuring tire size and how far off your speedometer will be.

Getportfolio

My friend and I....,lol jk

PJRManagement

---
Eric - I, too, run 19 x 10 in the rear. Ford throws a 285/35 19 tire on the Boss LS (same 10" width wheel). I do the same. It's a pretty common size. I would like to step up to 295, but I will keep the 35 aspect ratio, like Danielle says, 30 is too short, your ride will suffer. The problem with 295/35 19 is lack of tire selection...UGH! Your idea of 305 might be just a bit too wide to fit on a 10" wheel, you may want to double check that it will not only fit, but work well for you.
USMC & Jay - thanks for that calculator link, very slick, and handy!

2k7gtcs

There is only one tire on the planet made in that size in a summer tire and I have it on Seven. I wouldn't recommend them at all. Find a different size.

eric n

Goodyear Eagle F1 Asymmetric 2, Michelin Pilot Super Sport, BFGoodrich g-Force T/A KDW 2

All feature 295 35 19...

I was planning on Hankook ventus v12 Which for my purposes have only
285 35 19 with a diameter of 26.9" if I want to stay at 27ish inches. These would be a solid increase of footprint over stock, but since I'm currently running 275's not much better.

The tires themselves did very well placing #2 in a car and driver performance tire test. http://www.caranddriver.com/comparis...12-evo-page-10. So I feel pretty good about deciding on them.

I do like the 295 35 19's as a size, but then I would have to pay significantly more for one of the sizes listed above. My fronts, which are 255's still have over 10,000 miles left on them, and they are ventus v12's so I was hoping not to replace them if possible and to run the same on the rear. That said, I would be open to the 295s if I thought I'd get similar or better miles out of them.

Thanks for the input everyone. I'll be ordering tomorrow, as my rears are in need of replacement, so let the advice come on in.

AlsCobra

I've posted this too many times but ill do it again. Stay away from Hankook, Khumo, and Falcon. Don't worry about what the magazines say. All three are inferior tire brands.

eric n

Interestingly Tire Rack shows the Eagle F1 Asymmetric 2 295/35/19 shows a 12" tread width while the Hankook Ventus v12 in 285/35/19 shows 9.8" tread width. that's a lot of difference for just 285's and 295's. I'm assuming some sort of typo.

AlsCobra

I'm guessing that you're looking for every day driving tires. Really would check into getting away from those 19's just too odd of a size.

Stormtrooper

Im looking to do the same thing you are.. After searching countless threads, im pretty convinced that im going to move up to a 20" rim to get what im looking for. The 18s are too small for the 10-12 fenders imo... the 19s are perfect, but as stated tires are harder to find and super expensive. So my solution is 20s. you can find near the same weight so rolling resistance would change much. Plus they will fill the wheel well perfect if sized right. I want to be over 27" in the rear anyways. Go bigger, not smaller.

jaywoo

The 295 equates to 11 39/64 inches. Pretty close to 12". The other has to be a typo.

To compensate for a 20" wheel vs a 19" wheel, just go with a shorter side wall to keep the overall tire height the same. I don't know why you would want to go taller, unless you are unhappy with the way the car is geared right now.

MustangGTPilot

I will need to get new tires soon but will not go back to the crappy Pirelli's. I am thinking the Conti Extreme Contacts DW (had nothing but good results with these in the past on other cars), but want to go 285/35/19. Question is will my BBP wheels take the 285? Don't want to have to go and get new rims just so I can have tires I feel comfortable with.

Mustang259

I will also be looking at the 285/35/19 size for my BBP wheels for summer, anyone out there tried that size on the Brembo wheels?