# 225 40 18 vs 225 50 18



## Chunki84 (Dec 18, 2008)

I need tires.

My original tires are 225 40 18.

Wheels are 18x9

I know my original tires are kinda narrow for the wheels but they could be mounted.

I noticed speedo meter is always show 6~9% slower than my navigation speed gauge, so 

I decided to buy little larger tires, so

I ordered 225 50 18 micheline tires online.

Today, I went a shop to mount my new tires but they couldn't mount because


"the tires I brought have larger inner diameter than my original tires have" 

Is it possible?

What you guys think? 

Do I need to try another shop? or Just return the tire? Returning tires will cost 150 bucks.


----------



## audia4NY (Oct 13, 2014)

Chunki84 said:


> I need tires.
> 
> My original tires are 225 40 18.
> 
> ...


They do have a larger diameter, circum and sidewall height 

25.09 v 26.86 dia 7.1%
78.81 v 84.38 circum 7.1%
3.54 v 4.43 sidewall height 25%
803.94 v 750.91 rpm -6.6%

where did you get the tires from? did you tell them you make model and wheel specs. if so they should have not sold you a tire that isnt useable. that why i like tirerack so much

prob should have gotten 245/45/18


----------



## [email protected] (Nov 26, 2014)

I don't see how they could have a larger INNER diameter (so they're certainly mountable), but yes the overall diameter is pretty big jump from 225/40. The tire shop once mounted 235/45's on my rear rather than 235/40's and even that was a big difference. I would try 225/45 though if you're looking for a more accurate speedo.


----------



## rodhot (Jan 4, 2012)

*something is wrong*

an 18" tire fits an 18" rim, its the width that varies. tires get mounted on incorrect wheel widths-read stretched. incorrect tires for said wheels changes how a tire works. some shops won't mount an incorrectly sized setup. tire rack has lots of specs for correct fitment, if unsure of sizing always consult a pro before buying


----------

