# Smallest tire for Eco wheels



## Robby (Mar 1, 2013)

You cannot make a change in diameter of the tire without a resultant change in speedometer reading.
A lower profile tire will rotate more turns per mile, making your speedometer read high and the odometer readings will be higher than actual.

To achieve the 'rubber band' look you have to go to a larger diameter rim, with a lower cross section tire that has the same diameter as what you are removing.

Example: Your ECO has a 215/55 R17….this means, 215mm at the widest points of the tire body, the tire is 55% as tall as it is wide, R is radial construction, and 17 is the rim diameter in inches.
If you go to the Goodyear website you can find the actual diameter of the Assurance tire you have on the car.

Now, I'm not going to look it up but lets say the diameter is 30.0 inches…….that is the target you must hit for your speedo readings to not be altered.

You likely will find that to get a shorter tire (lower percentage of width) there may be something along the lines of a 215/50R 18 or a 215/45R 19.
This is called plus sizing…….you have to increase the diameter of the wheel in order to decrease the diameter of the tire to maintain speedo accuracy.

All that to say, you cannot change the tires height from rim to tread without changing the wheel size……if speedo accuracy is part of the plan.

Rob


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## obermd (Mar 3, 2012)

Tire Rack shows rotations per mile in their tire comparison charts. The closer this number remains to the OEM tires the more accurate your speedometer and odometer.


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## UlyssesSG (Apr 5, 2011)

`
*Tire Size Calculator*

There are several online tire size calculators that I've relied on for years to explore my options when selecting a new set of tires. Some require the Java plugin or Flash which may or may not be supported by your chosen browser. For example, Java is no longer supported in Chrome. One or more of the selection below should work in most popular browsers. HTH.

Tire Size Calculator @tacomaworld.com
Tire Size Calculator & Converter, Tire Size Conversion | Discount Tire
Tire Size Calculator No.1 @miata.net
Tire Size Calculator No.2 @miata.net


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## 170-3tree (Nov 4, 2014)

You could go 195/60/17. Too much narrower and you'll be well over the stretch allowed to seat the bead on the wheel.


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## TheKidJoey (Jul 27, 2013)

I was thinking 205/45r17 but I'm not trying to mess with the odometer.


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## pandrad61 (Jul 8, 2015)

if you don't me asking what are you trying to accomplish?


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## TheKidJoey (Jul 27, 2013)

pandrad61 said:


> if you don't me asking what are you trying to accomplish?


putting on my coils this weekend. Don't want meaty tires, and not ready to pull the trigger on aftermarket wheels, so figured I'd flirt with the idea of a thinner side wall tire.


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