Wheel set up swap

So I’m going from the stock 20 inch chrome rims that came, I believe they did anyway, stock on 2015 Tundras, to the newer 18 inch TRD off-road wheels.
In order to not have to reprogram so that the speedometer is accurate, what tire size should I get?

 

Just the stock 18" tire size that came on the Tundras from the factory. Not sure the exact size since I have the 20's on my TRD Sport

 

google search will prob tell ya quick. but look at your spare. thats prob on an 18" wheel

 

Here's a good start

https://www.tundras.com/threads/official-tundra-wheel-and-tire-setups-pics-and-info.95/

 

Actually the speedometer was off on my with OEM tires. I switched to 33’s and now it’s even with my gps.

 

so if you change from a 275/55R20 to 255/70R18 your speed will be off by .1 to .6 mph over 20 to 90 mph. So at 70 you will be going 70.4.
Don't think Id worry with the speedo.

I'm thinking about the same swap when I need tires for my 2016

 

I moved from the stock 32 inch tires, on factory 18s to 33s, 275/70-18 and my speedo is more accurate with 33s than it was with the factory tires. Factory tires always had it 2 or so MPH slower than actual. Run whatever tire size you like, speedo will not be off by enough to really worry about unless you are installing 35/37 inch tires. Any tire in the 32-34 inch range will be close or correct MPH.

 

Following as I am thinking of doing the same once my tires wear down. The 18’ look and ride better.

 

How do you calculate inches in tire to the first number of the tire size (2hundred-something e.g)? What would a 265 be in inches?

 

Thanks man

 

Divide by 25.4 to convert from mm to in.

265 / 25.4 = 10.4” wide

 

Fwiw, from there the second number is your sidewall height, and is a percentage of the first number (width).

so 255/75-18

255 / 25.4 = 10” wide

10 x 0.75 (or 75% of 10) is 7.5”.

7.5” of sidewall

The last number being obviously the wheel height, 18.

Keep in mind when doing the height of the tire you have the sidewall Above AND Below the wheel.

So 7.5 (x2) + 18 = 33”

or 7.5 + 18 + 7.5 = 33”


33 x 10