Folks sticking with the stock Brembo wheels (19x9) will often turn to 275/40/19s as the widest tire with a stock-like diameter...but the diamater is .6" larger than stock which in some cases looks a bit "4x4"

275/35s are .5" shorter than stock... so they have the advantage of raising your effective "final drive ratio. There are also quite a few more tire options in this size.

Most folks say not to run the shorter tire unless you've also lowered the car..which makes some sense.

What do you guys think?

 

Actually the 275/40 19 IMO do the opposite of the 4X4 look by filling in the wheel wells.
My V6 Performance Package with the stock height and 275/40 19 Continental DW's

 

I'm going to do exactly this. I wish I could go lower than my Steeda springs, but I have a super stiff driveway. The 275/40s will allow me to fill up that gap with tire and effectively make it look lower with less wheel well gap.

 

I'm going with 275/40/19, for 2 reasons.
Fills wheel wheel gap and I have 3.73 gears which are a little too step for me so the tall tire will help slightly!

 

I have 275/35R20's all around, which are basically the same height as the 275/40R19. Just yours would have more rubber and less wheel. Go with the 40's they are the perfect height. The 35's are about an inch shorter. The 40's will really fill the wheel wells nice and you can still lower if you want to. Mine has the Roush suspension which lowers about 1.5 inches off of stock. See my album for pics...

 

here is a side shot that might give you a better idea of the tire height...

 

Ok...so 275/40s look great on your cars, guys...but what's the argument against the 275/35s?

The extra tire options and shorter final drive are appealing no?

 

You are correct but the more stiff ride combined with the final drive increase is what did it for me since I have 3.73's. The broader range of tire choices are nice for the 35's though.

 

The 275/35/19s are .45" shorter versus 40s that are .63" taller than the stock 255/40s..

The 35s are closer!
They're also favoring the dimensions that would provide better acceleration in most circumstances.

 

The 275/40s are about the same height as the 245/45 and 235/55 that are stock too. Only the 255/40s are shorter. Everything else is taller. I'd like to take away some of my 3.73s. They're a bit much for a dd.

 

True. You have a good point, and I would say that for cars with 3.31 or 3.55 final drive, if you want more acceleration this size would be the way to go.

I'm with the other guys though on 275/40 band wagon since I also have 3.73s. With that final drive your 1-4th particularly are already short gears, and 275/35 makes them even shorter, and pretty useless for 1/4 (have to shift to 5th) or road curses (hits redline with few hundred yards left to brake zone).

 

I have an AED dyno tune so my rev limiter is now 7500, but still, I'll take the slightly taller gears. That and I'm sure it would ride a little smoother with the 40s.

 

Wow, nice Pat!
I'm always curious about that. What did AED say about the ability of our engines to handle 7500 rpm? I'm always curious since Ford set the rev limiter at a pretty low 6800 rpm, and most tuners go to at least 7200 or 7300. Is there any longevity issues?

When I take my car to the track I do 20 or 30 minute sessions, and the engine is between 4000 and 6800 rpm for the entire duration. I wonder how well a stock Coyote motor in our TP cars can handle sustained 7000-7500 rpm excursions.

I'd love to get an intake/tune combo, but I worry about hurting my motor at sustained rpm north of 7000.

Also good point about the ride with 40 sidewall. Deffinitely better. I do notice the sidewall in my 275/40 is not as stiff as 255/40. 275/35 has got to be really stiff.

 

Shaun raises the limiter to 7500 with all his tunes, but I didn't really ask about longevity, as 99.9% of the time I never take my car that high. I've only shifter at 7k once or twice when really pushing it to see what it could do, when I first got it. I have a Boss manifold and Steeda CAI that I was going to put on prior to the tune, but Shaun basically told me it was a waste if I wasn't going to be tracking the car. I'd pick up power up top, but lose a bit of midrange torque, and for my DD I didn't see that as a desirable outcome. I would like the wow factor of opening the hood to show off the Boss manifold, but I always had plans to do a Whipple or KB, so it really is pointless unless I was going to do the Procharger.

I'm picking up the parts this weekend, so I might just relist them for sale here. I got a Boss STB to go with it too.

 

When you want to sell the combo let me know.

As far as the high rpm, the engine can handle it but keep your fingers crossed on the oil pump.

 

I want to sell asap lol. I paid $650 for everything (the Boss manifold is lightly polished and ported), so since I never used it, I need to get that plus shipping. Also, the Boss letters are painted white, so it'll match your car perfectly! What do you think?

 

Pm sent.

 

Hey Tom, do you have any more information on this, or links? Any info here would be much appreciated. Now that you mention this I've seen oil pump/ gears and I was wondering what use case they were meant for... I know the Cobra Jet comes with some mods for high rpm:
1) M-6600-50CJ High Performance billet steel oil pump
2) M-12A227-CJ13 high RPM pulse ring

Cobra Jet motor is capable of 8000+ RPM. I wonder if you're limited at 7300-7500 if you need to upgrade the oil pump as well

 

I can't link using the app but check out s197forums.com in the 5.0 tech section there's an oil pump rebuild thread (great info) and various posts about how the higher rpm looks to be the main culprit in failures.

 

So the 275/40/19 with 3.55 is a no go?