Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum - View Single Post

Rich260z · 08-05-2013, 10:40 AM

Stock diamter size is 24.7" which is what most all nissans from this era run. Just fyi.

In regards to that I run at 245/40/17 which is a fraction of a percent bigger than 24.7" and I still don't get accurate speedo readings (compared to my gps speed and phone gps speed). At 60mph I'm at 60mph, but at 80mph speedo I'm at 77mph gps.

As per the original statement of if it will help your 0-30, smaller tires will. Miata guys run undersized tires when they show up to autox events all the time. Will it work in a road race track? maybe if you don't mind running out of gearing on a long straight. Undersized tires for a autocross is the easiest way of making your car "faster" around the cones since its more 1st and 2nd gear stuff

08-05-2013, 10:40 AM	#3
Rich260z Zilvia Addict Join Date: Apr 2011 Location: Burbank, CA Posts: 621 Trader Rating: (8)	Stock diamter size is 24.7" which is what most all nissans from this era run. Just fyi. In regards to that I run at 245/40/17 which is a fraction of a percent bigger than 24.7" and I still don't get accurate speedo readings (compared to my gps speed and phone gps speed). At 60mph I'm at 60mph, but at 80mph speedo I'm at 77mph gps. As per the original statement of if it will help your 0-30, smaller tires will. Miata guys run undersized tires when they show up to autox events all the time. Will it work in a road race track? maybe if you don't mind running out of gearing on a long straight. Undersized tires for a autocross is the easiest way of making your car "faster" around the cones since its more 1st and 2nd gear stuff Last edited by Rich260z; 08-05-2013 at 12:20 PM..