[BulkBen]

Hey Guys, after much playing around with wheels and tyres, I’m now quite sure a 305 will work on the front of a G80 for the track. See pics below.
This is great news for those of us keen to run a 305mm square setup - as I am.

This was always my plan for the track, made sense given a 275mm tyre with a 20mm spacer works fine, a 305mm shouldn’t be an issue.
I first tried with Supercar 3R’s which was never going to happen.
These 305’s measure out at 335mm - ridiculous.

I’ve since moved to Nankang AR-1’s and todays fitment looks very positive.
Like everything when you’re running tight tolerances, offset is critical.

My rims are 19x10.5 with an ET14.
With the Nankang I’d estimate I’ve got 3-4mm clearance from tyre to strut, so I may end is using a very thin spacer.
I’ll measure up properly snd let you know. At this stage I’d say an ET of 10-12 would be perfect for a 10.5 inch rim running this tyre.

Outter guard clearance does not look like an issue at all and that’s with only 2 degrees camber. Pushing this to 2.5 or 3 degrees (which is better for the track) will only make outter guard clearance easier.

Unfortunately I’ve now got to order 3 more tyres and next track day is a month away, will keep people updated though.

[flsupraguy]

Sweet let us know how it goes on track.

[sly1types]

Nice that should reduce understeer.

[GTS Daddy]

Money on the 305 square.

[m2michael23]

It probably will chew up tiny bit of the strut fin.

Let us know how that turn out.

[coldsteelrain]

Can’t wait to see how this turns out. Best of luck 🤞

[zero21]

Originally Posted by BulkBen

Hey Guys, after much playing around with wheels and tyres, I’m now quite sure a 305 will work on the front of a G80 for the track. See pics below.
This is great news for those of us keen to run a 305mm square setup - as I am.

This was always my plan for the track, made sense given a 275mm tyre with a 20mm spacer works fine, a 305mm shouldn’t be an issue.
I first tried with Supercar 3R’s which was never going to happen.
These 305’s measure out at 335mm - ridiculous.

I’ve since moved to Nankang AR-1’s and todays fitment looks very positive.
Like everything when you’re running tight tolerances, offset is critical.

My rims are 19x10.5 with an ET14.
With the Nankang I’d estimate I’ve got 3-4mm clearance from tyre to strut, so I may end is using a very thin spacer.
I’ll measure up properly snd let you know. At this stage I’d say an ET of 10-12 would be perfect for a 10.5 inch rim running this tyre.

Outter guard clearance does not look like an issue at all and that’s with only 2 degrees camber. Pushing this to 2.5 or 3 degrees (which is better for the track) will only make outter guard clearance easier.

Unfortunately I’ve now got to order 3 more tyres and next track day is a month away, will keep people updated though.

Is chassis stiff enough to run that much grip? Just asking...

[PLF69]

Originally Posted by zero21

Is chassis stiff enough to run that much grip? Just asking...

Only one way to find out 😏

[BulkBen]

Quick update.

I finally hit the track with this setup and all seems fine - certainly no clearance issues.
The AR-1’s are renowned for requiring bedding in, so after the morning on street tyres I only gave them two quick sessions before packing up.
In a few weeks I’ll be back out having fun them for a proper day.

Nothing really to report apart from the obvious that they’re much noisier and feel heavier in the steering vs the 4S, I consider the feel a good thing. Those who’ve driven with big, flat track tyres will know what I mean.

I do have sone other observations though, not tyre related.

On the track 4WD is much better than 4WD sport.
I tried this for the first time on the 4S’s and the car became much more taily, really lacked stability vs normal 4WD mode.

Secondly, for those trying to get away with the 4S on the track, be careful.
I thought mine looked relatively unscathed after my first putting a few months back, however they quickly disintegrated this time out with a front delaminating.

They absolutely won’t hold up for multiple track days unless you’re a novice. They’re a great street tyre but a big heavy car like the G80 driven in anger will shred them.

[Dragonperformance]

Hey BulkBen. If I wanted to run a 11j front with 305 30 20 tyres. What offset would u recommend. I like the aggressive sticking out a little look. But dont want to catch the front wings, or Fenders as I think you guys call them!
Also offset for rear with same wheel and tyre would be helpful, thanks.

[Juice ///M]

Did you have camber plates with this setup already? What's your aligmment spec?

[FSECorey]

good info. I'm looking for measurement for front rim and tire.
here we go.

[beamlord]

Originally Posted by BulkBen

Quick update.


Secondly, for those trying to get away with the 4S on the track, be careful.
I thought mine looked relatively unscathed after my first putting a few months back, however they quickly disintegrated this time out with a front delaminating.

They absolutely won’t hold up for multiple track days unless you’re a novice. They’re a great street tyre but a big heavy car like the G80 driven in anger will shred them.

100% confirmed, even after just 3 track days with mixed mode (warm up, push, cool down laps), I can see the stock PS4s took a beating that is beyond normal and this kind of use of these tires is definitely not sustainable.

Cup2's will probably do it for me.

[arulm3cx]

So I have the 2 GYSC3R sitting and I don't want run 305 in front (I guess we can't unless camber plates) so looking at the tire diameter 265/35/19 SC3R matches the 305. Can I run 265/35/19 on 10" wheel upfront and 305 in rear on 11" wheel to keep the xdrive happy. Please share your thoughts. Thank you.

[FSECorey]

305 will work in the front. 305 square will work alright.

[Sam111]

Hi BulkBen,
Great info, update would be appreciated .

Do you have stock suspension or any mods? What is the brand of your wheels?

[beachBmmr]

I wonder how positive your scrub radius is from adding 30mm of width presumably all outboard of the center line. Thats probably the heavy steering feel you are getting.

Did the car do anything weird under braking on corner entry? Scrub radius would improve (get back to negative) with camber plates and more inboard steering angle to compensate for the change of wheel center point.

[Blk5er33]

Originally Posted by BulkBen

Hey Guys, after much playing around with wheels and tyres, I’m now quite sure a 305 will work on the front of a G80 for the track. See pics below.
This is great news for those of us keen to run a 305mm square setup - as I am.
.

Do you think the 305 square setup will work with 11 inch wide wheels? I’m looking at the Apex VS-5RS either the 19x10.5 ET 18 or 19x11 ET 22. I’m thinking to go with the 11 inch wheels since it would fit a 305 better.

[Hit_Apex]

Originally Posted by Blk5er33

Do you think the 305 square setup will work with 11 inch wide wheels? I’m looking at the Apex VS-5RS either the 19x10.5 ET 18 or 19x11 ET 22. I’m thinking to go with the 11 inch wheels since it would fit a 305 better.

I am going to try the same but cannot find anything conclusive. I am several weeks away from getting my wheels. FSECorey seemed to have issues and went with 10.5" but not clear what the interference was and whether it can be resolved with camber and/or offset adjustment.

[TopJimmy]

BulkBen are you X-drive or RWD?

[Blk5er33]

Originally Posted by Hit_Apex

I am going to try the same but cannot find anything conclusive. I am several weeks away from getting my wheels. FSECorey seemed to have issues and went with 10.5" but not clear what the interference was and whether it can be resolved with camber and/or offset adjustment.

Let me know how it goes. I may not upgrade my wheels until next year. The 305 on 11 does make more sense to me tho.

[fl1by]

Originally Posted by Hit_Apex

I am going to try the same but cannot find anything conclusive. I am several weeks away from getting my wheels. FSECorey seemed to have issues and went with 10.5" but not clear what the interference was and whether it can be resolved with camber and/or offset adjustment.

Did you ever get to running the 305s? If not what are you running?