Changing Wheel Size Effects

[rncordy]

I have a set of winter tires (studded) on 18" wheels. What would be the adverse consequences of replacing my factory original 20" wheels/tires with the 18" wheels for the winter? We will not be making any long trips until after we change back to factory wheels. At a minimum, can the speedometer be temporarily reprogrammed? Is there anything else that might get screwed up?

Thanks.

 

[dieselshadow]

The overall diameter is the biggest factor. If you keep that relatively the same, no worries.

If you go bigger or larger than the OEM tire diameter, that’s when you get side effects like decreased power or less mileage.

Wheel size is a factor, just not as big as overall tire diameter or rotations per mile.

 

[lpennock]

As dieselshadow said, as long as overall diameter is same, rim diameter isn't much different. The 18 will ride slightly smoother due to more sidewall but will have a bit more sway for same reason. For a winter tire choose tall and narrow over short and fat. I.e. a 75 or 70 series over a 65 or 60 series.

 

[rncordy]

Thanks guys. Tomorrow I will measure overall diameters. I do know that my current 2018 "sits" 1.5" higher than the 2010, as measured at threshold floor level. I'll report back tomorrow.

 

[lpennock]

You don't need to measure tire size. You just get the sidewall tire size (LT295/55r20) and you can look height up on any of a couple manufacture websites. You can then find matching heights. For instance, a Toyo RT in LT295/55r20 is a 32.8" tire and a LT285/65R18 is also a 32.8" tire. No change in the speedometer then.

 

[HPSimpson]

The overall diameter is the best clue keep fairly close and no changes to speed-meter.

 

[Ozymandias]

https://tiresize.com/comparison/

Best site I know for comparing sizes.

 

[rncordy]

https://tiresize.com/comparison/

Best site I know for comparing sizes.

Outstanding! Thanks! Turns out my studded tires/wheels are 17"! And per your website, the diameter of my old tires are 1.9" less than my new ones. That's a good cross check with my "threshold" measurement!

But, everybody, is there anything in the computer systems on my 2018 truck that might get confused, other than the speedometer, with this tire/wheel change?

 

[Ozymandias]

Nope, no problems to be expected by doin so.

As long as you have TPMS units in the winter tires/wheels to.

 

[TRAMPLINEMAN]

https://www.tacomaworld.com/tirecalc?tires=
Here’s another one.

 

[AH64ID]

Dad ran 17” tires on his 18 for 2 hunting seasons without an issue.

I’d personally recalibrate the speedo for that much error.

 

[Ltngdrvr]

Sell the 17's and get some properly sized tires/wheels, that'll be the best bet.

 

[rncordy]

Nope, no problems to be expected by doin so.

As long as you have TPMS units in the winter tires/wheels to.

Ah ha! No TPMS in old tires! Shucks. I bet it will cost an arm and a leg to get them for the old tires! Damn!

Thanks!

 

[Ltngdrvr]

TPMS won't make any difference, you'd just have the warning light on and a message each start.

 

[Ozymandias]

Ah ha! No TPMS in old tires! Shucks. I bet it will cost an arm and a leg to get them for the old tires! Damn!

Thanks!

Not sooo expensive if you buy them aftermarket, but the install into the tires comes in top.

 

[Grimm_Reaper19']

I have a question, i need to recalibrate my Tire size on my 2019 is there a tool out there specifically for this or would i need to take into dealer and have them do it. i do not want to run any risk of connecting something that will mess with or question warranties at all. Any input is appreciated.

So far i went from Stock LT285/60R20 (approx. 33") to 35x12.50, i will most likely be going up to a 37" in the next year or so, but i want to correct the speedo for that drastic of a jump.

 

[EDankievitch]

Look on Amazon. I bought a speedometer calibration tool from pro comp for my 2013, my friend has one from a different company. You just need one for your year truck. It’s a simple setup using ways you can get the speedometer dialed in if you take your time.

 

[AH64ID]

AlfaOBD can also calibrate true size.

 

[Jim W]

If you do not have the AlfaOBD tool you should purchase one., as this is the go to tool now for issues on the RAM. This will provided a read out of codes and will allow you to clear them.

 

[Ozymandias]

And it costs less then the "tools".