I do have trouble hearing my wife sometimes...
Check My Math Please
Thread Starter
Burning Brakes
Joined: Jul 2010
Posts: 959
Likes: 50
From: Peters Colony Republic of Texas
Check My Math Please
Thinking about going from bone stock wheels on a 2002 C5 to plus one wheels and wider tires. The stock front tires are 245x45 17s, and the backs are 275x40 18s. The replacements would be 275x40 18s up front and 305x30 19s in the back.
I want to insure the outside diameters ("OD") of the replacement wheel/tire combos will approximate the stock wheel/tire ODs.
I think the math equation I would use to calculate the outside diameters of the various wheel/tire configurations requires me to:
(a) multiply the tread width times the aspect ratio, (b) convert millimeters to inches (25.4 mm per inch), (c) multiply the resulting sidewall heighth by 2, and then (d) add that sum to the wheel diameter.
Doing that math, I calculate that the stock fronts have outside diameters of 25.68"; the stock backs - 26.66".
Outside diameters on the plus ones would be 25.58" (front) and 26.20 (back).
Did I get that right?
If yes, are the replacement wheel/tire combos close enough to the stock combos that my electronic nanny won't call me bad names, tell me my feet stink, etc.?
I want to insure the outside diameters ("OD") of the replacement wheel/tire combos will approximate the stock wheel/tire ODs.
I think the math equation I would use to calculate the outside diameters of the various wheel/tire configurations requires me to:
(a) multiply the tread width times the aspect ratio, (b) convert millimeters to inches (25.4 mm per inch), (c) multiply the resulting sidewall heighth by 2, and then (d) add that sum to the wheel diameter.
Doing that math, I calculate that the stock fronts have outside diameters of 25.68"; the stock backs - 26.66".
Outside diameters on the plus ones would be 25.58" (front) and 26.20 (back).
Did I get that right?
If yes, are the replacement wheel/tire combos close enough to the stock combos that my electronic nanny won't call me bad names, tell me my feet stink, etc.?
Thread Starter
Burning Brakes
Joined: Jul 2010
Posts: 959
Likes: 50
From: Peters Colony Republic of Texas
Drifting
Joined: May 2005
Posts: 1,564
Likes: 19
From: Driftwood PA
Instructor
Joined: Aug 2010
Posts: 175
Likes: 0
From: San Angelo TX
Thinking about going from bone stock wheels on a 2002 C5 to plus one wheels and wider tires. The stock front tires are 245x45 17s, and the backs are 275x40 18s. The replacements would be 275x40 18s up front and 305x30 19s in the back.
I want to insure the outside diameters ("OD") of the replacement wheel/tire combos will approximate the stock wheel/tire ODs.
I think the math equation I would use to calculate the outside diameters of the various wheel/tire configurations requires me to:
(a) multiply the tread width times the aspect ratio, (b) convert millimeters to inches (25.4 mm per inch), (c) multiply the resulting sidewall heighth by 2, and then (d) add that sum to the wheel diameter.
Doing that math, I calculate that the stock fronts have outside diameters of 25.68"; the stock backs - 26.66".
Outside diameters on the plus ones would be 25.58" (front) and 26.20 (back).
Did I get that right?
If yes, are the replacement wheel/tire combos close enough to the stock combos that my electronic nanny won't call me bad names, tell me my feet stink, etc.?
I want to insure the outside diameters ("OD") of the replacement wheel/tire combos will approximate the stock wheel/tire ODs.
I think the math equation I would use to calculate the outside diameters of the various wheel/tire configurations requires me to:
(a) multiply the tread width times the aspect ratio, (b) convert millimeters to inches (25.4 mm per inch), (c) multiply the resulting sidewall heighth by 2, and then (d) add that sum to the wheel diameter.
Doing that math, I calculate that the stock fronts have outside diameters of 25.68"; the stock backs - 26.66".
Outside diameters on the plus ones would be 25.58" (front) and 26.20 (back).
Did I get that right?
If yes, are the replacement wheel/tire combos close enough to the stock combos that my electronic nanny won't call me bad names, tell me my feet stink, etc.?
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Drifting
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From: ZHills Florida
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If you go to TireRack and pick the tires you are thinking of running it will have the diameter right there.
For instance, a Pilot Sport PS2 in 275 35 18 is listed as 25.7 inches in diameter. BF Goodrich is 25.8 inches.
http://www.tirerack.com/tires/tires....S2V3&tab=Sizes
For instance, a Pilot Sport PS2 in 275 35 18 is listed as 25.7 inches in diameter. BF Goodrich is 25.8 inches.
http://www.tirerack.com/tires/tires....S2V3&tab=Sizes
Last edited by burbleflyer; Oct 1, 2010 at 10:47 PM.
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If you go to TireRack and pick the tires you are thinking of running it will have the diameter right there.
For instance, a Pilot Sport PS2 in 275 35 18 is listed as 25.7 inches in diameter. BF Goodrich is 25.8 inches.
http://www.tirerack.com/tires/tires....S2V3&tab=Sizes
For instance, a Pilot Sport PS2 in 275 35 18 is listed as 25.7 inches in diameter. BF Goodrich is 25.8 inches.
http://www.tirerack.com/tires/tires....S2V3&tab=Sizes
That's the way I check the numbers for tires I buy.
Thread Starter
Burning Brakes
Joined: Jul 2010
Posts: 959
Likes: 50
From: Peters Colony Republic of Texas
Thanks to all who contributed to my knowledge. Faster-Than-Jeff's sold me his Weld wheels/tires (thanks Doc), I picked them up, had them balanced and mounted on my C5 this afternoon. Now, all's right with the world.
Pictures will come, but only after I take the Wiffe and my grandkids to Denny's in Dallas tomorrow AM where we will meet my son (home to watch the Zero Ewes play the (now short) Horns) for breakfast before he heads back to Austintatious.
The Liz
At least I had a good day!
Pictures will come, but only after I take the Wiffe and my grandkids to Denny's in Dallas tomorrow AM where we will meet my son (home to watch the Zero Ewes play the (now short) Horns) for breakfast before he heads back to Austintatious.
The Liz
At least I had a good day!