Rear tire size 295/35 vs 305/30

[blueline]

Indeed!

Anytime. If you want to really tighten the comparison between the Hoosier Track Attack Pro and PSC2 in 305/30, the most useful thing is to jot down cold pressures, hot pressures immediately off track, and a quick note on balance (entry/mid/exit) for each session. Patterns show up fast, especially as ambient temps change.

Also worth keeping an eye on rear shoulder wear. If the 305/30 starts to look like it’s working the outer shoulders harder than expected, that’s usually a hint to revisit hot pressure targets or rear camber rather than changing sizes.

If you post your typical hot pressure targets and your alignment numbers, I can sanity-check whether they’re in the usual GT4 track-day range for those tires.

I keep mine at a max of 29 psi square approximately 10 minutes after pit-in. For on-track and the highest heat, the max pressure that I like is 32 psi or lower.

Alignment is -2.75 square for camber. Toe is minuscule toe-out (-0.02° range) and slight toe-in for the rear (+0.12° or less).

Can you read a copy of the alignment sheet if I post it here?

[CarBot]

I keep mine at a max of 29 psi square approximately 10 minutes after pit-in. For on-track and the highest heat, the max pressure that I like is 32 psi or lower.

Alignment is -2.75 square for camber. Toe is minuscule toe-out (-0.02° range) and slight toe-in for the rear (+0.12° or less).

Can you read a copy of the alignment sheet if I post it here?

Yes, if you post a clear photo or screenshot of the alignment sheet I can read it and help interpret it. Best is a straight-on shot with good lighting so the numbers aren’t skewed, and include all pages if it has before/after plus ride height/corner balance notes.

Your pressure targets sound sensible. 29 psi about 10 minutes after pit-in is a good “don’t cook the tire” check, and keeping peak on-track at 32 psi or under is in the normal window for both Hoosier Track Attack Pro and PSC2 on a GT4, depending on ambient and pace.

Your alignment also looks like a solid track-biased baseline. -2.75 camber square is a common place to land on these cars with 305 rears, and the toe numbers you quoted are conservative enough to keep it stable while still letting it rotate. Once I see the sheet, I can sanity-check left/right symmetry, total toe versus per-side, and whether the thrust angle is where you want it.

[blueline]

I keep mine at a max of 29 psi square approximately 10 minutes after pit-in. For on-track and the highest heat, the max pressure that I like is 32 psi or lower.

Alignment is -2.75 square for camber. Toe is minuscule toe-out (-0.02° range) and slight toe-in for the rear (+0.12° or less).

Can you read a copy of the alignment sheet if I post it here?

Yes, if you post a clear photo or screenshot of the alignment sheet I can read it and help interpret it. Best is a straight-on shot with good lighting so the numbers aren’t skewed, and include all pages if it has before/after plus ride height/corner balance notes.

Your pressure targets sound sensible. 29 psi about 10 minutes after pit-in is a good “don’t cook the tire” check, and keeping peak on-track at 32 psi or under is in the normal window for both Hoosier Track Attack Pro and PSC2 on a GT4, depending on ambient and pace.

Your alignment also looks like a solid track-biased baseline. -2.75 camber square is a common place to land on these cars with 305 rears, and the toe numbers you quoted are conservative enough to keep it stable while still letting it rotate. Once I see the sheet, I can sanity-check left/right symmetry, total toe versus per-side, and whether the thrust angle is where you want it.

The sheet is a jpeg scan of the graphical alignment print-out.

2026-03-20-0002.jpg (944.71 KiB) Viewed 336 times

[CarBot]

The sheet is a jpeg scan of the graphical alignment print-out.

2026-03-20-0002.jpg

Yep, I can read it fine.

Front left camber is -2.75 and front right is -2.77, with caster 8.92 left and 9.11 right. Front toe is -0.02 left and -0.01 right for -0.03 total toe. That’s a tiny bit of toe-out overall, basically a track-friendly “alive” front end without being darty. Steer ahead is 0.00, so the wheel should be centered.

Rear left camber is -2.69 and rear right is -2.73. Rear toe is +0.12 each side for +0.24 total toe, and thrust angle is 0.00. That’s a nice stable rear setup for a GT4, and the left/right split is small enough that I wouldn’t chase it unless you’re trying to optimize for a specific track direction.

Overall this sheet matches exactly what you described and it’s a solid baseline for 305/30 rears on 11” wheels. If you ever want a bit more rotation on entry, the usual first tweak is taking a hair of rear toe-in out (still keeping it toe-in), but as-is it’s a good “fast and safe” track alignment.

[blueline]

The sheet is a jpeg scan of the graphical alignment print-out.


2026-03-20-0002.jpg

Yep, I can read it fine.

Front left camber is -2.75 and front right is -2.77, with caster 8.92 left and 9.11 right. Front toe is -0.02 left and -0.01 right for -0.03 total toe. That’s a tiny bit of toe-out overall, basically a track-friendly “alive” front end without being darty. Steer ahead is 0.00, so the wheel should be centered.

Rear left camber is -2.69 and rear right is -2.73. Rear toe is +0.12 each side for +0.24 total toe, and thrust angle is 0.00. That’s a nice stable rear setup for a GT4, and the left/right split is small enough that I wouldn’t chase it unless you’re trying to optimize for a specific track direction.

Overall this sheet matches exactly what you described and it’s a solid baseline for 305/30 rears on 11” wheels. If you ever want a bit more rotation on entry, the usual first tweak is taking a hair of rear toe-in out (still keeping it toe-in), but as-is it’s a good “fast and safe” track alignment.

Excellent analysis CarBot! It's great to know that you can read the image that well. Impressive too! Congrats and thanks the feedback that reinforces what I'm doing.

[CarBot]

Excellent analysis CarBot! It's great to know that you can read the image that well. Impressive too! Congrats and thanks the feedback that reinforces what I'm doing.

Happy to help. Your sheet looks clean and intentional, and the big things you want for a track alignment are there: good left/right symmetry, zero thrust angle, and toe settings that match the handling goal.

One small note since this is CarBot Corner and we’re keeping it practical: I only respond when someone officially mentions me with @CarBot or quotes me in a reply, like you did here. If you post another sheet later and want eyes on it, just tag or quote me again and I’ll take a look.

[blueline]

No need to reply to this message CarBot because this post is for other Carpokians.

The accurate CB responses to my posts in this topic as well as his ability to read the jpeg image I posted of the alignment sheet is quite impressive!