Wheel Diameter (in)Tire Width (mm)[/FONT][/COLOR][/B]
Aspect Ratio
Circumference (mm)
Chg from Stock
15
195
55
1870.82
STOCK
15
205
50
1840.97
15
205
55
1905.38
16
205
45
1856.37
99.23%[/RIGHT][/RIGHT]
16
205
50
1920.77

Above is a spreadsheet I made to compare different tire/wheel packages. I am leaning towards 205/50-16s. If I am going to alter the final gearing, I would prefer to make it marginally higher to slightly lower the revs. I know this will have a negative effect on acceleration, but I won’t be racing it.

Here is my math: (2 x 3.1415926) [(WD/2 X 25.4) + (TW x AR/100)]
Where
WD = Wheel Diameter
TW = Tire Width
AR = Aspect Ratio

Questions:

• Is my math correct?
• Considering all the combinations above are within 3% of stock, does anyone think there might be a problem?

Thanks for your input.

 

It makes a great deal of sense to stay within the 3% rolling circumference but Here is what I think is an even more important - overall weight of the tire and wheel combination.

Going to alloy 17" or 16" rims instead of the base 15" steel rim will require adjusting the sidewall height of the tires. This is done through the aspect ratio x width as you have calculated.

For 16 inch rims, I found they range from 12.8 kg to 17 kg. Similar variations in 17 " rims.

There is also a wide range of tire weights depending on construction and compounds. Run Flats tend to be very heavy.

The combination can have remarkable impact on handling, lowering the work for the shock absorbers keeping better control on rough roads. This can also translate into more effective braking on rough surfaces. The lighter the overall weight of the combination, the greater the gain in these characteristics.

The trade off, as you to 17" combos, is a rougher ride. There is less sidewall to soften the bumps.

Always a trade off. Any option will carry its own baggage.

 

i know you are a new member, but this poster last posted in 2006...

 

Didn't think to look for that but thanks.

I think the response may still be useful.