My 2008 fit came (used) with a different tire size than standard. The speedometer reads about 10% low. I would like to get the correct size, how do I know if the rims have been changed as well without taking the tires off?
Diameter of the outside of the rim is 17.25", is this the size of the original rims and does this help me much?
Current wheels: 185/55 R16
sticker on door: P175/65 R14

My mechanic doesn't carry tires in stock and has asked me to order them online and have them delivered to the shop for installation. Thank you.

 

Outside of the rim has little to do with the diameter because there is a large lip on the barrel. That lip is what holds the tire in place. The last digits in a tire size tell you the wheel diameter.

With the tire size of 185/55-16, you have 16" wheels. The factory size on your car was a 14" wheel. So, the wheels have been changed from factory.

Your current 185/55-16 is 24" tall. The factory 175/65-14 was 23" tall. This would make your speedometer read low, NOT high. It should be reading almost 4% lower than actual. At an actual 60mph, your speedometer should be reading about 58mph.

Honda offered 16" wheels as an option and they came with 205/45-16 tires. That size is the closest to the factory diameter tire, but with a 16" wheel. You will need to look on the back side of the wheel to see if they are wide enough to support a 205mm wide tire. If they are 6.5" or wider, you can run the 205/45-16.

Tire size breaks down like this.
Ex. 185/55-16 =
185mm wide
55% of the width is the sidewall height (185x.55=101.75mm)
16" diameter wheel

Total height is 101.75 x 2 = 203.5 + 406mm (16 inch converted to metric) = 609.5mm. Converted to SAE that is 24" tall.

 

Thank you this is helpful. Perhaps the previous owner replaced the wheels with the R16 wheels, and since the numbers were no longer correct on the door they put something on that fit.
any chance that they just put r16 tires on an r14 rim or is that too much of a difference for it to stay on? There is a lip / ridge on the tire which makes the tire look like it is too big for the rim.
The speedometer is reading low, my closest guess based on speed cameras is 7% lower than my actual speed.

 

The inner tire diameter is dead locked to the wheel diameter. The last two digits of the tire size has to match the wheel diameter exactly. So, you have 16" wheels.

The R in the tire size stands for Radial. P at the beginning stands for Passenger car tire. Neither of those are important for the discussion. Just letting you know that the wheel is not an "R16." It's just a 16" wheel. The R refers to the tire being a radial.

 

185/55/16 is the stock tire size for 2009-2019 Fits. The previous owner may have just bought wheels for a newer Fit mistakenly. If you want the proper size tire you should be looking at 205/45/16 as GAFIT says.

That is all dependent on keeping the wheels that are currently on the car of course.

 

I was just in the shower and this exact thing dawned on me. I bet he has GE Sport wheels. Pretty good upgrade vs base GD steelies. Since the current set up fits, I'd be tempted to just get the same tire size again.