Taller Tires
Introduction
This modification changes your final gearing through taller tires.
Also greater tire circumfrence results in less rolling resistance.
Contents
Instructions for mod
The best time to perform this mod is when you need new tires and your vehicle is at the tire shop.
I recommend ordering your tires from some where like tirerack.com, because local tire shops will almost always try to sell you what they have on hand or try talking you out of doing your ecomod.
There are a few different ways to do this mod.
You can play it safe and go with the next size taller aspect ratio which may even be recommended by the vehicle manufacture.
Or you can use this as a time to upgrade to a larger rim size and tire size if you are currently stuck on a "dead tire size" such as 245/45R16 or a "dead rim size", which is pretty much anything 13 inch.
Your best bet is to do this right is to look up your OE recommended tire size on your vehicle data sticker or go on tirerack.com and look it up.
Take your factory tire size and try to go about an inch taller.
If you have a truck, you can go 2 inches taller than the factory size most of the time.
You may have to go one size wider to be able to go taller, don't let this discourage you.
With 15 inch rimed tires going 1 aspect ratio size taller will give you a tire less than 1 inch taller.
Most 16 inch rims will give about a 1 inch taller tire with the next size higher aspect ratio.
What you are trying to do is get less tire rotations per mile.
For example a Yokohama AVID ENVigor in 195/60R15 Vs. 195/55R15 will be 3/4 inch taller and will about take about 26 less rotations to go each mile. That could drop your typical cruse RPM from 2225RPM at 65mph to 2161RPM at 65mph.
User experiences
Enter your tire change results
| User Name | Car Make, Model, Year | Cost of Mod | Time to Perform Mod | MPG Before Mod | MPG After Mod | MPG improvement guess | Before and After Tire Sizes |
|---|---|---|---|---|---|---|---|
| Oil pan 4 | 1984 Chevy Surban C10 | $748 for 5 tires | 1 Hour | 25.2 MPG | No change | Possible slight improvement | Old size: P235/75R15 New size: 31x10.5R15 |
Additional notes: When going from the Pmetric size small truck tire to a real load range C floatation sized truck tire each tire was about 20 pounds heavier and about 2 inches taller. I kept the same factory steel rims. The new tires are the yokohama AT-S
Enter your tire change results
| User Name | Car Make, Model, Year | Cost of Mod | Time to Perform Mod | MPG Before Mod | MPG After Mod | MPG improvement guess | Before and After Tire Sizes |
|---|---|---|---|---|---|---|---|
| Oil Pan 4 | 1985 camaro Z28 | $550 for 5 tires | 1 Hour | 25mpg | Untested | Untested | Old size: 215/55R16 New size: 225/60R16 |
Additional notes:
My factory size is 245/50R16 a dieing size, not much selection. The camaro had 215/55R16 tires for the last several years. I installed a very popular OE size, 225/60R16 (yokohama S4 ultrahigh performance all season), that size offers a wide selection and great prices.
The 215/55R16 tires were about the same as the OEM size, the 225/60R16 tires are about 1 inche taller. No rubbing, not problems, just lots of road grip.
Enter your tire change results
| User Name | Car Make, Model, Year | Cost of Mod | Time to Perform Mod | MPG Before Mod | MPG After Mod | MPG improvement guess | Before and After Tire Sizes |
|---|---|---|---|---|---|---|---|
| Who | what | how much | how long | a number | more numbers | your best guess | Old size: ???/??R?? New size: ???/??R?? |
Additional notes:
Problems / Consequences of mod
Your vehicle will ride higher. If you have a car and stayed in the guide lines above your ride hight will have increased about a half inch or less. A half inch or less change in ride hight will have minimal effect on vehicle handling.
Any time you go to a different tire size it will change the read out on your speedometer and odometer. Most newer vehicles just need to have parameters changed on the computer. Older vehicles will require the driver to remember the correction factor or install a different speedometer drive gear on the transmission tail shaft.
One good consequences of the mod will be you always see an increase in load rating with the increase in tire size.
For example a yokohama AVID ENVigor 195/60R15 will have a 100lb higher load rating when compared to the shorter AVID ENVigor in 195/55R15.
That is a higher saftey margin if nothing else. On a truck vehicle weight, load and tire capacity become much more important.
Going to a larger more popular tire size could give you the largest saftey factor of all:
Being able to avoid tires made in china.
In some countries it is against the law to alter vehicle tire size.
References
Forum thread links
Went from 15 to 18 inch rims, MPGs down Surprize, surprize...
Taller tire test
choosing a tire on 13 inch rims
What diameter tires are you using?
LLR tires
Lots of tire data, noise db, wet grip
Taller tire test 5.7mpg increase observed
External links
Tire size, gear ratio, RPM and speed calculator
Tirerack survey results
Tirerack tire tests
Tirerack.com tire specs
barrystiretech
barrystiretech
