mojom3

Anyone try the 245/40-18 and 315/30-18 NT-01 tires? I remember previous threads on sizing, but these tires are 25.55 and 25.35 in diameter. Would this diameter be a problem for the ABS brain? I still have a few RA-1 s left but have a second set of wheels with old hoosiers to replace. Not looking forward to having to go to 19 or 20 inch wheels to be able to get decent drivable tires.

Land Jet

I drive those tires but as you can see I have a different car, but no problems with ABS on my car.

mdrums

Land Jet...just so you know a 996 based car was designed around a smaller diameter rear than the front. The cars ECU and ABS system are programed for the stock tires to be smaller diameter in rear. So yes the NT01's are perfect DE tire for your car.

A 997 based car was not designed for a smaller diameter rear....997 based cars use a larger diameter rear and the ABS system is NOT designed around this spec. I would NOT go out on the track and try this out as the ABS or PSM and so forth could misinterpret what the car is actually doing and cause serious problems when the car is driven near 9-10/10ths.

Erik

Worked fine on my car, no extra Icemode issues for me but I developed a split across the thread on the rear tires and thought it was because the rear 30's did not have enough sidewall so I went back to RA'1's. But now I'm 335/30 RA1's, and no issues with splitting the tires. Will use them again when the world/Randy/Peter run out of RA1's

mdrums

Erik....the fronts on my Toyo R888's would sometimes split across the front///looked like a ran over something sharp. I sent 1 tire back to Toyo and they never would tell me what the cause was. This only happened to me on R888...never on RA1 and so far not on MPSC.

On R888 I ran both 245/40/18 front and 255/35/18 front....both sizes did this many times. Sometimes 1 tire only would split across the tread and sometimes both would split across the tread. Unlike you I never had this issue on my 305/35/18 or 315/30/18 rears. I Did notice that when I ran the R888's at lower pressures hot 32/34 and did slower warm up laps I lessened this splitting issue.

In order to keep ABS, PSM and the cars computer happy...I ran either of these combo's

245/40/18
305/35/18

or

255/35/18
315/30/18

Renn 951

But not on the Turbos like Land Jet has. Same diameter front and back due to the AWD. A slight variation can be tolerated; IIRC it's not more than 2 percent difference.

mdrums

I understand that but he has a 996 Turbo.....still different than 997 Turbo or any 997 car as far as what Porsche designed for the front to rear overall tire diameter.

deputydog95

I'm going to NT01's when I run out of hoosiers. I know several people at this point that have run the combo on their 997's with no issues. With that being said, I had a 30 min conversation with a tech at nitto two weeks ago. He said he receives no less than 2-5 inquiries per day regarding our sizing via email. They are giving it serious consideration at this point, but have no guarantees to either if or when.