Is 325 squared worth the hassle over 305?

[whatisgrip]

Need some convincing to step up to 325 or stay 305 squared. For the ones who have run both did you notice any substantial benefits? Have all the necessary perquisites to make it fit with no problem.. MCS RR2, OP Mustang studs, spacers, tons of camber.

So far the only cons I see is: limited tire selection and more expensive. But I plan on running exclusively SC3R on them anyways.

My car for reference

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[RBELUN]

Need some convincing to step up to 325 or stay 305 squared. For the ones who have run both did you notice any substantial benefits? Have all the necessary perquisites to make it fit with no problem.. MCS RR2, OP Mustang studs, spacers, tons of camber.

So far the only cons I see is: limited tire selection and more expensive. But I plan on running exclusively SC3R on them anyways.

Like you I wondered as well and run same tires 305/325 stagger on my GT. Con: moved rear to front and slapped on 30mm spacer on apex 19x11 with -4 itand rubbed magnaride strut however (-3.3camber fixed) but in tight corners. Also rubber top fender liner over curbs and some course bumps. I felt turn in was less crisp. Also tramlined pretty bad over track seams. So went back to stagger as ol faithful.

 

[NightmareMoon]

I run 315/30/18 and 315/30R19 tires (on OPMustang studs and spacers). I don't actually know anybody who runs square 325s, but then the SC3R isn't allowed in my class. Are you running 12" wheels? I'd say for 325s you really should be, and that complicates the stud/spacer fit equation quite a bit, plus the clearance in the rear gets very tricky w/r/t upper shock mounts etc.

I wouldn't say its a big step up, no. A small one at best.

FWIW, I'm not planning on going back to 305s.

 

[mavisky]

I run 315/30/18 and 315/30R19 tires (on OPMustang studs and spacers). I don't actually know anybody who runs square 325s, but then the SC3R isn't allowed in my class. Are you running 12" wheels? I'd say for 325s you really should be, and that complicates the stud/spacer fit equation quite a bit, plus the clearance in the rear gets very tricky w/r/t upper shock mounts etc.

I wouldn't say its a big step up, no. A small one at best.

FWIW, I'm not planning on going back to 305s.

Which 315/30-19 are you running right now?

 

[NightmareMoon]

Which 315/30-19 are you running right now?

19s are Falken RT660 (18s are Yoke A052)

 

[mavisky]

19s are Falken RT660 (18s are Yoke A052)

That's what I assumed. Just wanted to make sure I wasn't missing any 315/30-19 options.

 

[whatisgrip]

Are you running 12" wheels?

Nope, currently running Apex 19x11" but planning on picking up another set of wheels soon. Would go 19x11.5" if running a bigger tire would be beneficial or if I could squeeze out another second or two vs 305.

 

[webspoke]

I run 325 square (CRS) on my car with 20x11.5 wheels. Have gone back and forth with 305 fronts.
The 325 front does not feel like a big improvement. There is a bit less nid to exit understeer, but it is a very small difference. Lap times have been a wash, even trying all different bar settings. (stiff front, soft rear, big rear etc).

A well driven lap I think is faster on the 305 fronts. But they are easier to lock in braking, and easier to overcook if you enter the turns too hot. Also they heat soak a bit quicker on long runs. You will lose top speed with the weight and drag.

325 rears work well, noticeably more cornering and power down vs 305s.

 

[NightmareMoon]

Most of these 315s seem to be fine on 11s, but the A052 is known to like the wider 12" wheels whenever possible.

For a 325, I'd really be looking at wider wheels (thinking 12s), but fitting that much rubber on the front... you're probably going to be getting creative.

Vorshlag did the GT350 (GT500?) fenders to get more clearance for the wide 315 Yoke tires on 12" wheels. My friend in Houston just cut his fenders to clear the same wheel/tire. I wasn't willing to do that so mine are pinched on 11" wheels.

 

[WildHorse]

Why ? Lol. The Dodge Viper ACR uses 'only' 295's up front. Highly doubt any mustang will out anything it.

 

[mavisky]

Why ? Lol. The Dodge Viper ACR uses 'only' 295's up front. Highly doubt any mustang will out anything it.

Are you familiar with weight balance?

 

[WildHorse]

Are you familiar with weight balance?

Very.

 

[mavisky]

Very.

Then you'd know that a Viper weighs about 400lbs less than an S550 and carries more of its weight on the rear axle than the front (48/52 weight balance) so of course it doesn't need as much front tire. A GT3RS runs a 245 up front. Should we all switch to a 245 because that's what a GT3RS runs?

 

[whatisgrip]

I run 325 square (CRS) on my car with 20x11.5 wheels. Have gone back and forth with 305 fronts.
The 325 front does not feel like a big improvement. There is a bit less nid to exit understeer, but it is a very small difference. Lap times have been a wash, even trying all different bar settings. (stiff front, soft rear, big rear etc).

Interesting. My car tends to understeer on corner exits and I've been playing around with suspension changes but haven't found the balance I'm looking for. For that reason alone it might be tempting.

Most of these 315s seem to be fine on 11s, but the A052 is known to like the wider 12" wheels whenever possible.

For a 325, I'd really be looking at wider wheels (thinking 12s), but fitting that much rubber on the front... you're probably going to be getting creative.

Vorshlag did the GT350 (GT500?) fenders to get more clearance for the wide 315 Yoke tires on 12" wheels. My friend in Houston just cut his fenders to clear the same wheel/tire. I wasn't willing to do that so mine are pinched on 11" wheels.

I believed they used a GT500 fender on their LS project car. Maybe I should reach out to Terry and see if they have recommendations.

I don't think fitment will be an issue I've seen a few post pictures of their 325 square setups but haven't seen any data comparing the two. Here's some images I found on TMO of 350s running this setup.

 

[WildHorse]

Then you'd know that a Viper weighs about 400lbs less than an S550 and carries more of its weight on the rear axle than the front (48/52 weight balance) so of course it doesn't need as much front tire. A GT3RS runs a 245 up front. Should we all switch to a 245 because that's what a GT3RS runs?

It's essentially 50/50. like 49.6 front, 50.4 rear. Most pre c8 vetts are also 50/50.
Me, I'd move the battery (2% of front total weight) to the trunk, lightest wheels possible up front. Keep 305 max fronts. Avoids the headaches of a front 325 tire.

But ok. I concede to your knowledge on the subject.

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