Billy Johnson Service Announcement, PS4S

[sigintel]

Cool thread. Great enthusiasm!

Now who has actual track pics or hot garage pics of Stang GT4 w tire details?
Last I heard it was 18x11 square.

Keep in mind that you can change front end balance w camber n swaybar. There is dynamic camber with suspension travel (due to geometry) and you can also get into height changes to change where you are in the dynamic gain of the geometry.

Balance and optimizing for learning is highly desired and less stressful. OS at limit is way more work load on driver. I could see staggered making perfect sense to limit trail brake OS.

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[CSL]

The difference in the staggered fitment on the 350 is so negligible most won't notice a difference squared or staggered. I think Ford went with the difference for a bit more sidewall in the rear. The extent the car understeers is much more dependent on whether someone knows how to drive. With the proper steering input the car won't understeer with the factory stagger.

I'm sticking with the stagger because it performs really well, and I don't think Ford went this route for aesthetics. You can't really notice a visual difference front to rear anyway, especially how low the rear valence sits and covers up the rear width. Also, I prefer not to run a spacer. As far as tire longevity goes, it hasn't worked out too bad just cross rotating. I'm getting 5-6 days on the fronts and twice that on the rears. I think the overall life of a set is turning out to be comparable, especially with buying fewer 315s which are more expensive. So I see the setup as a wash while still being able to keep the correct wheel offset and factory spec tires.

Another thing to remember in going with the factory spec Cup 2s is the significant weight savings you get by running that tire. And if it matters, as an instructor and racer I have a lot of experience running square fitment on various Mustangs and staggered fitment in other vehicles. The factory setup on the 350 is remarkably good.

 

[bellwilliam]

with most cars with staggered tire, they really ARE staggered. with GT350, it is 295/305. that's barely 3%........ why bother ? most cars are 10-25 %
wouldn't it be so much easier for inventory, to just go with 305 all around.

 

[Stuntman]

with most cars with staggered tire, they really ARE staggered. with GT350, it is 295/305. that's barely 3%........ why bother ? most cars are 10-25 %
wouldn't it be so much easier for inventory, to just go with 305 all around.

The car has custom tires specially designed for the needs of the GT350. Front and rear tires have different types of forces and loads, plus the geometry differences of the rear integral link and front strut are quite different. I imagine if you had 305s front and rear, it would be easy to confuse and mix a 305 front vs a 305 rear.

 

[Zitrosounds]

The car has custom tires specially designed for the needs of the GT350. Front and rear tires have different types of forces and loads, plus the geometry differences of the rear integral link and front strut are quite different. I imagine if you had 305s front and rear, it would be easy to confuse and mix a 305 front vs a 305 rear.

Its funny that this the argument is smaller tires up front vs rear. The 305 sec width on the R is one of 3 production cars that run such a wide tire in the front. Front is wide to reduce under steer as is. The rear are wider for acceleration, grip, "putting the power down." Speaking to Billy more on the topic, it is clear that the fastest way around the track (in GT350's), with pro drivers of course, is the staggered setup. I have only heard a few mention under-steer on this platform and it was not from pro drivers. Any car can be made to under-steer. I am no pro and I know the few times I have hit under-steer in my car is from over cooking the corner. A square setup is most definitely more cost effective but that is pretty much negated when you have to purchase wheels with different offsets and are non rotatable or having to use spacers, IMO.

 

[Stuntman]

I'm not sure that I agree with staggered being inherently faster than square tires. You CAN make any setup staggered or square under or oversteer by adjusting the suspension springs and bars to make it. I just don't see how you would differentiate a bespoke front 305 from a rear 305 and would imagine they could easily be mixed up.

 

[snaproll]

Exactly the GT3 and GT4 as well as numerous other race classes run staggered. Staggered setups in the hands of a pro driver are faster. As far as most on this forum, it won't matter either way in terms of speed, so as a practical matter running squared is simpler/cheaper.

Ok, let's try this another way, not that Z cars or P cars are the focus here, but the staggered setups are generally run because the rules specify not because it's faster. Race on Sunday, sell on Monday. Then they adjust the rules to make them roughly equal. But even the 50/50 weight distribution BMW's will stuff as much front tire in the hole as they can get away with. Trouble is, it's a PITA sometimes. Or the rules have it spec'd.

Back to mustangs, you want the tire where the weight is. Everyone runs the widest tire front and rear tires allowed in production based Pony car racing. End of story.

 

[Zitrosounds]

I'm not sure that I agree with staggered being inherently faster than square tires. You CAN make any setup staggered or square under or oversteer by adjusting the suspension springs and bars to make it. I just don't see how you would differentiate a bespoke front 305 from a rear 305 and would imagine they could easily be mixed up.

I did not mean to imply that staggered is inherently faster. I was trying to say that for the 350, specifically, and for a production car of its proportions, the fastest way around the track is what was produced. In other words, its not a full blown race car. race cars do not make good road cars. So the balance of tire, wheel, chassis and suspension is set so that it can be a good road car and a great weekend racer.

 

[Stuntman]

Ok, let's try this another way, not that Z cars or P cars are the focus here, but the staggered setups are generally run because the rules specify not because it's faster. Race on Sunday, sell on Monday. Then they adjust the rules to make them roughly equal. But even the 50/50 weight distribution BMW's will stuff as much front tire in the hole as they can get away with. Trouble is, it's a PITA sometimes. Or the rules have it spec'd.

Back to mustangs, you want the tire where the weight is. Everyone runs the widest tire front and rear tires allowed in production based Pony car racing. End of story.

Because they don't know how to move the weight or set cars up to be balanced with a stagger

 

[CSL]

Ok, let's try this another way, not that Z cars or P cars are the focus here, but the staggered setups are generally run because the rules specify not because it's faster. Race on Sunday, sell on Monday. Then they adjust the rules to make them roughly equal. But even the 50/50 weight distribution BMW's will stuff as much front tire in the hole as they can get away with. Trouble is, it's a PITA sometimes. Or the rules have it spec'd.

Back to mustangs, you want the tire where the weight is. Everyone runs the widest tire front and rear tires allowed in production based Pony car racing. End of story.

305 is a damn wide tire to run on a front. Anything more is not conducive to the design would probably numb the front a bit. There comes a point where there is a dimished return on going wider up front and sidewall is a big factor in this equation. Mission accomplished with a 305.

The bigger question is whether or not there is benefit to running a 315 in the rear. That's Negligible as the stock setup is nearly square anyway. It comes down to if you're willing to run a front spacer. Going stagger and cross rotating is comparable longevity wise to square since the rears get twice the life.

 

[snaproll]

Because they don't know how to move the weight or set cars up to be balanced with a stagger

Maybe if no one in AI or AS knows car setup. I don't think that's the case.

I was standing in the pits tonight and asked a bunch of racers why one would want to run a narrower front tire, you know, like that R sitting over there, and guys just laughed and said only if you want more understeer. Best answer was that the R was probably designed for 305's because that's what the Camaro had years ago and then the test drivers said the rear was a little loose and the engineering team threw a little more tire at it.

Or they just couldn't easily fit bigger ones up front. Or the marketing team spec'd it. Doesn't matter. The staggered tires and wheels are a PITA. Two wheel sizes, two tire sizes, etc.

 

[Stuntman]

Maybe if no one in AI or AS knows car setup. I don't think that's the case.

I was standing in the pits tonight and asked a bunch of racers why one would want to run a narrower front tire, you know, like that R sitting over there, and guys just laughed and said only if you want more understeer. Best answer was that the R was probably designed for 305's because that's what the Camaro had years ago and then the test drivers said the rear was a little loose and the engineering team threw a little more tire at it.

Or they just couldn't easily fit bigger ones up front. Or the marketing team spec'd it. Doesn't matter. The staggered tires and wheels are a PITA. Two wheel sizes, two tire sizes, etc.

My mistake for not knowing the only way to change a cars balance is by by changing the tire width and that springs and bars have far less effect on changing a cars balance. Sounds like the logic of amateurs :headbonk:

 

[BMR Tech]

This is great. Knowing who is behind some of these usernames in here, I gotta say - I am enjoying this thread; immensely!

 

[stanglife]

Lol this ^

 

[CSL]

Initial report from a friend who went with the "Billy setup" on his R wheels is....zero tramming.

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