Tire size adjustment

[BamaBoy]

I just got my diablo trinity and had the intune before I have 285/75 R18 Nitto Trail grapplers so what will be the proper height in inches it has an OD of 33" on the sidewall of the tire but when I put that in the trinity it has the speedo off by about 3mph on my Intune I entered 31" and it was right on but with the trinity its still off by 1mph any suggestions??? I am running the 87 octane tune with the tranny on modify stock and still have hard shifting during WOT anyone had this problem??

[mikel]

1 mph is more than acceptable, but you can tweak in in .5" increments until it is perfect

[rlkimmel]

I just got my diablo trinity and had the intune before I have 285/75 R18 Nitto Trail grapplers so what will be the proper height in inches it has an OD of 33" on the sidewall of the tire but when I put that in the trinity it has the speedo off by about 3mph on my Intune I entered 31" and it was right on but with the trinity its still off by 1mph any suggestions??? I am running the 87 octane tune with the tranny on modify stock and still have hard shifting during WOT anyone had this problem??

I entered the sidewall size (265 70 16) and played around with the ratio. I ended up with 265 "69" 16 and it's about as close as it can be according to my GPS.

[BamaBoy]

Thanks I just wanted to make sure I was in the safe zone. I don't know how much difference there are between the trinity and intune canned tunes but my mileage on the 87 ocatane tune went from 14.5 to 17 mpg's I was impressed!!