Matt Lane

I am trying my first set of 305's, and will be doing an alignment in any case. Previously ran 315/30.

Had a bit of rubbing with the tall 305 - even at 140mm rear height (which is pretty much the expected 13mm higher than I want to be based on my previous 'Kussmaul' setup). Small protrusion in the rear fenderwell had to be banged out to accommodate.

So now, I am still too high in the rear (rake), and not sure how much room I have to lower.

I guess the question is - do I even bother? I can't tell yet personally whether I prefer the feel of the 305 to warrant messing with ride height. They are still new, thus don't know if faster (with me driving).

I know some guys like > rake, which this will provide, but I am basically on the fence.

Powdrhound, I know you have had GREAT experience with the 305 setup - but your car is not on the stock end of the spectrum in terms of chassis or power.

So... long winded question: who has personally compared the 305/35 vs. the usual 315/30?

Thanks in advance for sharing actual experience. Do I stay the course here, or burn through these and go back to the 315/30?

Cheers

Matt

Matt Lane

Crickets - does anyone else here run the tall 305?

Spyerx

On the 997.... 996 the 315 is better

AudiOn19s

I wish I could help you here as I've been trying to score a used set of 305's to try out with my nitto setup, but I've had such the stockpile of 315's sitting around and they last forever so I've just never done it.

I can tell you that a good friend of mine ran the 315 rears on his 997 before the 305's ever came out. His feedback was very much that he liked the 305's better and felt they offered better grip.

To initially try them out...i'd leave the alignment and height pretty much as-is and see how you feel about them and then possibly change car setup from there.

Matt Lane

Thanks - yeah, that's what I am going to do. Will leave ride height as is for now (with the greater rake) and see if I can tell a positive difference. If I decide to keep these, I'd look to drop rear height a bit (but not so much to compromise driving on other wheels with the proper OD. My gut is telling me this experiment is not worth the aggravation - not because the 305 isn't better - but because I may not be able to appreciably tell the difference and warrant ride height, gearing, speedo and other issues.

For some reason, I believed that more people had tried the Nitto 305, so if you are out there, chime in!

Cheers

Matt

Matt Lane

When you say 315 is better - did you try the 305?

powdrhound

All the fast 6GT3 guys in my area have migrated to the 305. None post here however.... In my opinion the 305s really shine on the 6GT3 with the shorter R&P as the taller tire makes your gearing slightly taller naturally.

Matt Lane

Thanks for chiming in - your posts were the reason I've tried the 305 in the first place. I was able to buy them second hand, so no harm in trying.

Speaking of R&P, are you referring to one different than stock? Other than the Guard plates, my transmission is stock and the 305's have made the gearing noticeably taller. I was aware of this going in, but like I said earlier above, there are so many variables...

Cheers

Matt

powdrhound

I've tracked the 6GT3 and I'm of the opinion that the stock gearing is too tall. The gearing on my car is similar to the 6GT3 as I have similar speed in gears even though my redline is slightly less at 7500, however I have much higher rear wheel torque of 720 ft.lbs at 4000rpm along with 620+whp. In other words, tall gearing works for me. The 6GT3 in my opinion would benefit from a 4.0 R&P or a stock R&P combined with a shorter 1-4 to keep the engine in its sweet spot. The later 7GT3s have shorter gearing and to me they feel much better at the track. One of out local 6GT3 guys runs the tall 305s along with a 4.0 R&P and his car is noticeably guicker that other gt3s. Just my $0.02..

Backmarker

I tracked on nt01 305s for years, passed a lot of other GT3s, only passed by a few (997 rs, including one driven by jvob

Matt Lane

Thanks for filling in this info. I totally get the shorter gearing advantages - I had Copans build my short geared 993 box and it was a big improvement (if also adding a few extra shifts per lap, depending on track). Just more fun to drive all around.

For the time being, I am not planning any transmission work on the GT3, and the tall 305 (all things equal) has lengthened gearing.

As I mentioned above, no harm no foul, but I will probably revert back to 315's in this more 'stock' configuration.

Again, appreciate your insight and sharing all the parameters in your experience.

Cheers

Matt

Antonov

I went from a 315 NT01 to 305 (245 front) .

Def prefer the 305, they seem to be a bit more consistent through out a long session/handle heat a bit better.
I think the 26" 305's are a better match to the 245/40 fronts in terms of rake as well.

I haven't changed the ride/rake since I moved to the 305's, I may next time I throw the car on the rack, but I don't think its a pressing issue.

Martin S.

Dominant rear size it seems. Assuming the 315/30 will fit, I am ordering a set of 245s and 315s NT-01 tires on March 3rd...2018. Getting them from Discount Tires Direct. I will report back on my experiences.

997rs4.0

powdrhound

Pretty much all the fast guys from my area have switched from the 315 to the 305 on their 6GT3s. They just don't post on here. If you're an aggressive driver and have the ability to drive the car at 9/10s or beyond, you'll appreciate the benefits the 305 provides. At a more sedate pace, I doubt it will make any discernible difference. I would not try to score a used set of 305s to try as mixing in used tires of unknown past can lead to disappointment. Start with a fresh set all the way around. I don't believe the taller gearing is a show stopper. One of the fastest 996GT3 guys at my track runs the 305 with the stock gearing and he outruns the shorter geared cars. He says he makes up of the shorter gearing by being able to skip a few shifts. Obviously track dependent.

I no longer run the 245/305s as I switched to the 275/335s but the 245/305 was a great combo for sure.