WAFlowers wrote:
Speedometer would be all messed up because it is calibrated to the smaller wheel. You would be going faster than indicated. Much faster!
It’s the overall height of the tire that would make your speedometer read wrong, not the rim size.
On my Jeep, I was able to change the speedo gear to make it read the actual speed being driven. Confirmed it with gps.
My motorhome reads 4 mph slower than what the speedo says. GPS confirmed.
And that is with Factory OEM tires and rims.
There are numerous calculators online to determine rpm and speed with different size tires. I am sure you could figure it out mathematically, but that makes my head hurt.
https://tiresize.com/calculator/
Using this calculator puts you at 1/2 mile per hour faster at 60 mph with 19.5 tires.
The only question then becomes clearance issues as were previously mentioned.
