[FriedPiston]

Originally Posted by Blk5er33

Isn't 305 too meaty for a 10.5 inch rim? Max recommended size for a 10.5 is 295, no? It would be nice to run 305 RS4's on a 19 X 10.5 square setup.

10.5" is the minimum for most 305/30/19 tires.

[TrackM4x]

Originally Posted by Blk5er33

Can you daily this setup? Or will the -3 camber cord the inner shoulder of the front tires? Can this be pulled off with 0 toe, daily driving during track season from March to October?

Even with -3 camber the outer edges of the tire wear much faster with track use. I would welcome wear on the inner side from street use but still wouldn’t get to that point because my tires wear out on the outer from track wear way sooner than the inner ever would from street use.

[Mapper]

Originally Posted by FriedPiston

Thank you for your contributions BulkBen and Hit_Apex

It looks like the sweet spot for this setup is 19x10.5" ET10, -3 front camber, along with your choice of 200TW (or less) 305/30/19 rubber.

To confirm, you are saying 19x10.5 ET10 all around wihtout spacers ?

[Mapper]

Hit_Apex huge shout out sharing details on the progress. Testing limits 👌

[BackOnBlack]

Thank you guys for trying this out and sharing your findings

The part I would like to seek your opinions on, or factual findings, is whether 305s on 10.5" wheels would actually provide improved grip.

Maybe the objective is different and it is more about going square setup with the largest possible tire, and not necessarily increased grip.

[Hit_Apex]

Originally Posted by BackOnBlack

Thank you guys for trying this out and sharing your findings

The part I would like to seek your opinions on, or factual findings, is whether 305s on 10.5" wheels would actually provide improved grip.

Maybe the objective is different and it is more about going square setup with the largest possible tire, and not necessarily increased grip.

I think 305 became the target partly because of the availability - particularly in the SC3R which are an absolute bargain for their performance. The other dynamic at play is the amount of room on this platform on 19" square. We're on this awkward cusp between 30 and 35 series tire where 305/30 is .5"ø smaller than stock, 295/30 is .7"ø smaller, and 295/35 is .4"ø larger thus more likely to rub.

285/35 on 10.5" is a great choice - especially for stock camber - and probably offers the best stock-bias compromise for a square setup.

305/30 on 11" is a mod-bias compromise in that it requires a setup that is much more aggressive than stock and not ideal on the street.

So, it's a mix of tire size availability/price/performance relative to the geometry of our platform and the owner's propensity to go all in on an aggressive suspension setup. With that said, I have no idea how 305 at the min limit of 10.5" compares to 305 on 11" and agree wider is not always better - but we are limited in our options. Reminds me of this video which helps sort out some of these details.

[BackOnBlack]

Hit_Apex Thank you for the explanation, I understand it better now. As I was suspecting, the opening of the video you posted says it for sure.

You are certainly right that there aren't good higher performance tire options specifically in appropriate sizes. CSL being 2WD might actually be an advantage in this case compared to 4WD G8x. Also, with SCR3 at 305/19" sizes the front weight will be higher by 5 lbs each and 2 lbs in the rear. Tough to make good choices here

Thank you again.

[somer]

Any difference in the steering feel with 28mm more of positive scrub?

[Hit_Apex]

Originally Posted by somer

Any difference in the steering feel with 28mm more of positive scrub?

It’s fair question but haven’t tried enough variations from stock to give to an answer. How did you calculate 28mm? The centerline of 19x11 ETA 11 wheels is 9mm positive from stock. Add a 3mm spacer it becomes 12mm.

[somer]

Originally Posted by Hit_Apex

It’s fair question but haven’t tried enough variations from stock to give to an answer. How did you calculate 28mm? The centerline of 19x11 ETA 11 wheels is 9mm positive from stock. Add a 3mm spacer it becomes 12mm.

Just a wheel offset calculator, 3mm spacer would mean 31mm scrub wouldn't it? I am no expert in this area in regards to suspension kinematics and what not, just figure there's a point where moving the wheel outboard enough will start to negatively affect the car in some way

[Mapper]

Originally Posted by somer

Just a wheel offset calculator, 3mm spacer would mean 31mm scrub wouldn't it? I am no expert in this area in regards to suspension kinematics and what not, just figure there's a point where moving the wheel outboard enough will start to negatively affect the car in some way

alternate online calculator.
https://www.wheel-size.com/calc/

[somer]

Originally Posted by Mapper

alternate online calculator.
https://www.wheel-size.com/calc/

This one is nicely detailed, it says 14mm of positive scrub, maybe I had to just divide the results I had by 2, who knows heh.

Cool website.

[BulkBen]

I must apologise from missing in action for so long.

To answer some questions, I believe an 11 inch rim would fit.
At a guess, you’d want to run an offset of ET10 or 11.
This would move it a touch closer to the strut, while reducing the extra width on the outside to 8-10mm.
Anymore than this and outter clearance isn’t going to work.

Re fitment of 305 SC3R’s I mentioned in my initial post this was never going to work.
The AR1 works as it’s virtually the narrowest tyre for its section width, whereas the SC3R’s is the absolute opposite, it’s incredibly wide.
There’s honestly 30-35mm difference between these tyres in the real world.

If you want to run a SC3R run their 285. That wasn’t available to me in Aus, but it would be a much better fit.

I didn’t try other tyres out but I suspect the Nankang CRS, Re71 and a few others would probably fit too.
As has been pointed out, the 305/30 19 works partly as it has a shorter diameter than the factory 275/35 19.

[Hit_Apex]

With 19x11 et+11 the 305 SCR3s just barely touch the OEM shock body so I added a 3MM spacer. However, this is on a CSL where additional camber is achieved via hubs thus reducing inner sidewall clearance further. You might not need a spacer on a non-CSL/CS car. Either way, the SC3Rs are very wide and this is pretty much the max fitment without further fender, control arm mods.

[Blk5er33]

Originally Posted by BulkBen

I must apologise from missing in action for so long.

To answer some questions, I believe an 11 inch rim would fit.
At a guess, you’d want to run an offset of ET10 or 11.
This would move it a touch closer to the strut, while reducing the extra width on the outside to 8-10mm.
Anymore than this and outter clearance isn’t going to work.

Re fitment of 305 SC3R’s I mentioned in my initial post this was never going to work.
The AR1 works as it’s virtually the narrowest tyre for its section width, whereas the SC3R’s is the absolute opposite, it’s incredibly wide.
There’s honestly 30-35mm difference between these tyres in the real world.

If you want to run a SC3R run their 285. That wasn’t available to me in Aus, but it would be a much better fit.

I didn’t try other tyres out but I suspect the Nankang CRS, Re71 and a few others would probably fit too.
As has been pointed out, the 305/30 19 works partly as it has a shorter diameter than the factory 275/35 19.

PhD racing now sells 19X11 ET 8 Titan 7 wheels (link below) that allow for 305 square without spacers. They require at least -3 camber and recommend fender liner trimming. I ordered myself a set, but wont fit them until Feb.

I'm considering getting the Hankook RS4's, do they run wide or not as much as the SC3R's? Other options are Kumho or Nankang.

https://phdracing.store/collections/...47658782982418

[shwayne5]

Originally Posted by Blk5er33

PhD racing now sells 19X11 ET 8 Titan 7 wheels (link below) that allow for 305 square without spacers. They require at least -3 camber and recommend fender liner trimming. I ordered myself a set, but wont fit them until Feb.

I'm considering getting the Hankook RS4's, do they run wide or not as much as the SC3R's? Other options are Kumho or Nankang.

https://phdracing.store/collections/...47658782982418

The RS4s aren’t as wide as the SC3R which measure closer to a 315. Apex offers similar offset/setup as Titan. And you can get same offsets etc from Forgeline and HRE. If you put the SC3R on and you track it, you won’t want to use any other tire. They’re the best tire I’ve ever run on track. Also USAA has a 25% discount on Goodyear. So they’re like $1400 for a set.

[Blk5er33]

Originally Posted by shwayne5

The RS4s aren’t as wide as the SC3R which measure closer to a 315. Apex offers similar offset/setup as Titan. And you can get same offsets etc from Forgeline and HRE. If you put the SC3R on and you track it, you won’t want to use any other tire. They’re the best tire I’ve ever run on track. Also USAA has a 25% discount on Goodyear. So they’re like $1400 for a set.

Thanks for tip. I have the Titan 7 19X11 ET 9 wheels fitted now with 305/30/19 square Kumho V730. The front end grip is tremendous. Stronger steering wheel inputs are needed.

I will consider the SC3Rs in the future with these wheels in a 285/305 stagger since they run wide.

[BrendanZ0402]

Originally Posted by Blk5er33

Thanks for tip. I have the Titan 7 19X11 ET 9 wheels fitted now with 305/30/19 square Kumho V730. The front end grip is tremendous. Stronger steering wheel inputs are needed.

I will consider the SC3Rs in the future with these wheels in a 285/305 stagger since they run wide.

Nice to see you here! Saw your pics in the FB group. For me SC3R with these wheels didn't work out, quite some rubbing in the rear. They run stupid wide, they were rubbing my rear bumper under big compression!

[Blk5er33]

Originally Posted by BrendanZ0402

Nice to see you here! Saw your pics in the FB group. For me SC3R with these wheels didn't work out, quite some rubbing in the rear. They run stupid wide, they were rubbing my rear bumper under big compression!

Nice you to see you here too! I'm surprised to hear that they rubbed in the rear too. I thought a 315 would fit back there with these rims.
Perhaps 285 square SC3R would work?

[BrendanZ0402]

Originally Posted by Blk5er33

Nice you to see you here too! I'm surprised to hear that they rubbed in the rear too. I thought a 315 would fit back there with these rims.
Perhaps 285 square SC3R would work?

A 285 should work! I think it’s because of the aggressive offset, and the G80 have a lot less clearance than the M2 and maybe G82. I sold my set off to a M2 guy and it fitted perfectly on his car. I’m running around -3deg rear camber and he’s running stock arms, maybe -2deg rear camber. The other person who I know is running a 305 SC3R square setup on a G80 has to run a more conservative offsets and resort to spacers in front. For me the main concern is that it rubbed my rear bumper under heavy compression on track. Pics attached. Jackie told me to run a higher ride height but I wanted to be hotboi lmao

[M4LAKA]

Tires arrived, just waiting on my wheels from Phd Racing.
I have ohlins, full spl, Millway chamber plates and fender mod. Hope they fit! They are extremely wide.

[Hit_Apex]

Originally Posted by M4LAKA

Tires arrived, just waiting on my wheels from Phd Racing.
I have ohlins, full spl, Millway chamber plates and fender mod. Hope they fit! They are extremely wide.

Welcome to the club! What is fender mod, did you roll them? Or maybe referring to liner mod?