Question about my spare tire...
Champion
Joined: May 2008
Posts: 4,839
Likes: 5
From: Apex, NC
Actually, the first number is the cross-sectional width of the widest part of the tire in mm. The second number is the height of the sidewall as a percentage of the width and the third number is the diameter of the rim in inches (also, the R means radial construction not "rim" like I've heard too many times before). It the stupidest measuring system ever IMO.
So in the case of your 18" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
60 means the height is 60% of 265 mm which is about 6.26 inch sidewall
18 means its on an 18 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.52 inch tire
In the case of the 17" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
65 means the height is 65% of 265 mm which is about 6.78 inch sidewall
17 means its on a 17 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.56 inch tire
So in the case of your 18" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
60 means the height is 60% of 265 mm which is about 6.26 inch sidewall
18 means its on an 18 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.52 inch tire
In the case of the 17" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
65 means the height is 65% of 265 mm which is about 6.78 inch sidewall
17 means its on a 17 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.56 inch tire
Last edited by 95_318SLT; Apr 9, 2009 at 09:24 PM.
Actually, the first number is the cross-sectional width of the widest part of the tire in mm. The second number is the height of the sidewall as a percentage of the width and the third number is the diameter of the rim in inches. It the stupidest measuring system ever IMO.
So in the case of your 18" wheel:
265 means it is a 265 mm (10.4 inch) wide tire
60 means the height is 60% of 265 mm which is about 6.26 inch sidewall
18 means its on an 18 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.5 inch tire
In the case of the 17" wheel:
265 means it is a 265 mm (10.4 inch) wide tire
65 means the height is 65% of 265 mm which is about 6.78 inch sidewall
17 means its on a 17 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.5 inch tire
So in the case of your 18" wheel:
265 means it is a 265 mm (10.4 inch) wide tire
60 means the height is 60% of 265 mm which is about 6.26 inch sidewall
18 means its on an 18 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.5 inch tire
In the case of the 17" wheel:
265 means it is a 265 mm (10.4 inch) wide tire
65 means the height is 65% of 265 mm which is about 6.78 inch sidewall
17 means its on a 17 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.5 inch tire
If anyone is still having trouble understanding it after reading that they have a diagram here: http://www.discounttire.com/dtcs/infoTireDimensions.dos
Captain
Joined: Jun 2006
Posts: 559
Likes: 0
From: Mississippi coast
The 265/65 is a taller sidewall by a half inch than the 265/60.
So the overall diameter will be almost the same. Actually, the 17" will be .2 inch taller.
OOOPS! Didn't see page 2!
So the overall diameter will be almost the same. Actually, the 17" will be .2 inch taller.
OOOPS! Didn't see page 2!
Last edited by V8MANual; Apr 9, 2009 at 09:18 PM.
Champion
Joined: May 2008
Posts: 4,839
Likes: 5
From: Apex, NC
Actually, the difference is .04 inches. Back when I was looking into get new tires I made an excel spreadsheet to calculate differences in tire sizes and speedometer changes, so all I have to do is put in the size and it will give me the measurements to a hundredth of an inch.
Last edited by 95_318SLT; Apr 9, 2009 at 09:52 PM.
Holy sheit you guys post to damn fast,lol 
Anyways my truck has the same setup, 18s with a 17 spare.
BTW for the unknowing http://auto.howstuffworks.com/tire.htm
Anyways my truck has the same setup, 18s with a 17 spare.
BTW for the unknowing http://auto.howstuffworks.com/tire.htm
Thread Starter
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Banned
Joined: Sep 2008
Posts: 150
Likes: 0
From: Michigan.
Actually, the first number is the cross-sectional width of the widest part of the tire in mm. The second number is the height of the sidewall as a percentage of the width and the third number is the diameter of the rim in inches (also, the R means radial construction not "rim" like I've heard too many times before). It the stupidest measuring system ever IMO.
So in the case of your 18" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
60 means the height is 60% of 265 mm which is about 6.26 inch sidewall
18 means its on an 18 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.52 inch tire
In the case of the 17" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
65 means the height is 65% of 265 mm which is about 6.78 inch sidewall
17 means its on a 17 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.56 inch tire
So in the case of your 18" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
60 means the height is 60% of 265 mm which is about 6.26 inch sidewall
18 means its on an 18 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.52 inch tire
In the case of the 17" wheel:
265 means it is a 265 mm (10.43 inch) wide tire
65 means the height is 65% of 265 mm which is about 6.78 inch sidewall
17 means its on a 17 inch wheel
... so if you take the wheel diameter and 2x the sidewall height you get a 30.56 inch tire
Nice explanation. I never knew that, so thank you. It definitely helps knowing that stuff when you're looking to upgrade the rims and tire size...or in this case, figure out what's up with yer spare tire! Haha.
Thanks!
Rookie
Joined: Dec 2007
Posts: 95
Likes: 0
From: Virginia
Correction to my post, where I have factory 18" Aluminum wheels and stated that my spare was a 265/65/17 on a steel wheel, it is a 245/70/17 spare, which is still 30.5" tall.
Here is the label on the door jam.
Here is the label on the door jam.
Last edited by VA Dakota; Aug 5, 2009 at 11:36 AM.
All Star
Joined: Nov 2007
Posts: 987
Likes: 0
From: Dirty Jerzey
I believe that all Dakota's that came from the factory with 18" Aluminum wheels (265/60/18) will have a 17" "STEEL" wheel spare (265/65/17). I have a 2008 Dakota with the Factory 18" Aluminum wheels (265/60/18) and I have a 17 steel wheel spare with (245/70/17). They (Dodge) do not give you a 18" Aluminum wheel for a spare.
I guess they do not make a 18" "Steel" wheel and so you get the 17" with a taller tire to be equal in size to the 18" wheels.
I guess they do not make a 18" "Steel" wheel and so you get the 17" with a taller tire to be equal in size to the 18" wheels.
Either way, yours is the first 08-10 Dakota I've seen with the silver grill and headlight trim that isn't a TRX. Was that stock or did you add them after?
