Nissan Titan Forum banner

Tire Size/Odometer/Speedo Correction...

74K views 50 replies 38 participants last post by  Rick Havern 
#1 ·
I see this being asked alot, so I thought I'd make a post that describes why changing to a larger size of tire also changes your speedometer and odometer readings. It also explains how to determine the "correction factor" which can be used to calculate how many miles you really did travel, or how fast you are really going.

I also showed the correct method for determining the circumference of a metric sized tire (ex. 245/75/17).

Maybe this could be made a sticky if you think it's helpful??

 
See less See more
1
  • Like
Reactions: CL 8 2WD
#43 ·
I check my speed with a GPS for fun some times.
My truck was reading 1mph fast, now is 1mph slow.

stock: 265/70r18 = 32.6" = spedo 1 mph faster than the gps
spedo reading 50 / gps reading 49

New : 305/65r18 = 33.6" = spedo 1 mph slower than the gps
spedo reading 50 / gps reading 51


This is a percentage of course....

85 on the spedo = 89 on the gps :bump:
 
#44 ·
On my 08 2wd I switched from the stock 2.94 to the 3.36 gears and I also went from stock 18s (265/70s) to now running KMC 20x10s with 305/50/20s.

My speedo reads exactly 2-mph higher than what i'm actually going. This was confirmed by GPS and interstate speed trap display. So for IE... Speedo reads 60mph, i'm really going 58mph.
 
#51 ·
Titan Tech 659,
I put new LT 8 ply tires on my 08 T, running 65 psi. My tpms dash light is always on. When I asked the tire dealer & the stealership if the sensors could be recalibrated/replaced I was told they can't. The sensors & bcm have a set pressure span & & I believe 40 psi was the upper limit. If you have different sensors that can be installed please let me know the specs on them.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top