Reading faster on the GPS than the speedo after I replaced the part.
So going 65 on the dash, 70 on the GPS?
If that’s the case, you need a 29 tooth gear.
65 * 31 / 70 = 28.8
I never recommend anybody buy their gear based on a chart or nominal tire size. Math is always the best way to get it accurate. Too many incorrect charts out there and too many fluctuations in real world tire diameters.