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13th July 2010, 07:46 PM
#1
Advanced
New Tyre Sizing
Well It's not new but for me It's new and I'll be honest, I'm confused.
We used to always state our tyre sizes as 33" x 10 1/2" x 15"
Now I'm seeing 285/65/r16 (assuming r16 = Rim size 16") (285mm is tyre width???) Whats the 65 for???
So we are now mixing imperial with metric are we?
Sorry for the basic question for most of you but for an old bloke It's confusing as hell. haha
Thanks for your replies, just curious?
Muzza
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13th July 2010 07:46 PM
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13th July 2010, 07:56 PM
#2
SUCH IS LIFE
Size Coding - this might help
A tyre is referenced as "185/60R/15H", here is an explanation.
185=A, 60=B, 15=C
A = Width of Tyre (mm)
In this example it shows that the tyre is 185mm wide.
B = Profile as a % of width.
(i.e. profile is 60% of width)
In this example the ratio is 60%. This works out as 111mm.
C = Diameter of inner rim.
In this example it shows that the rim is 15" in diameter.
From this you can also work out your rolling circumference.
e.g. (2 x B) + C = diameter = d
therefore (2 x 111 = 222) + (15" x 25.4 = 381) = 603mm
circumference = pi x d = 3.142 x 603 = 1895mm
________________________
______ 2017 D-Max _______
I don't have a short temper. I just have a quick reaction to bullshit
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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Finly Owner (11th September 2010), my third 256 (17th December 2010), nedoleboy (1st February 2011)
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13th July 2010, 07:57 PM
#3
65 (or the number that appears between the tread width and the rim diameter) refers to the side wall height as a percentage of the tread width. So using your example, the side wall height would be 65 percent of 285mm, what ever that works out to be.
Tony
Edit; beaten by 1 minute!
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13th July 2010, 08:15 PM
#4
SUCH IS LIFE
And yes, some smartarse thought it would be good to mix metric and imperial. I think just to confuse everyone.
Or maybe the tyre manufactures have moved on in time and rim makers are still stuck in the dark ages. GO FIGURE
________________________
______ 2017 D-Max _______
I don't have a short temper. I just have a quick reaction to bullshit
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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13th July 2010, 08:18 PM
#5
Advanced
I know, thats just confusing.
mixing inches/mm as well as needing to calculate the percentage of width to work out your profile is just mad.
Is there any logic behind all this?
Cheers.
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13th July 2010, 08:46 PM
#6
SUCH IS LIFE
Not wrong about confusing.
Used to be easy. 33x12.5x16 where 33 is your diameter, 12.5 is width and 16 is rim
Now you have to calculate percentages, add, subtract and work out square root of pie to the power of 6 just to get the diameter.
________________________
______ 2017 D-Max _______
I don't have a short temper. I just have a quick reaction to bullshit
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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13th July 2010, 10:43 PM
#7
Expert
Don't worry Muzza, I'm with you and to this day I still talk old school,
Old dog new tricks kind...lol
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10th September 2010, 10:56 PM
#8
Patrol God
Originally Posted by
NissPat
Size Coding - this might help
A tyre is referenced as "185/60R/15H", here is an explanation.
185=A, 60=B, 15=C
A = Width of Tyre (mm)
In this example it shows that the tyre is 185mm wide.
B = Profile as a % of width.
(i.e. profile is 60% of width)
In this example the ratio is 60%. This works out as 111mm.
C = Diameter of inner rim.
In this example it shows that the rim is 15" in diameter.
From this you can also work out your rolling circumference.
e.g. (2 x B) + C = diameter = d
therefore (2 x 111 = 222) + (15" x 25.4 = 381) = 603mm
circumference = pi x d = 3.142 x 603 = 1895mm
another one for the index file
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16th December 2010, 03:00 PM
#9
Expert
Just found a useful write up on Tyre sizes, Load ratings, Speed ratings, and more.
http://www.carbonblack.com.au/car-ty...formation.aspx
This could help too.
http://www.1010tires.com/tiresizecalculator.asp
Last edited by ripper; 16th December 2010 at 03:14 PM.
1989 GQ LWB Wagon, TB42 Petrol/LPG Auto. Bought Dec 2010
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16th December 2010, 03:25 PM
#10
Moderator
Here guys, here is a very good resource for instant conversions.
Plug in what you want and it will tell you what to order or the equivalent is
http://www.dakota-truck.net/TIRECALC/tirecalc.html
Its a Nissan! =====> Its a Keeper!! ....... Got a TD42 in it BONUS!!
....... I'm a lucky bugger! I've got 2 of em!
Check out my Toy -->
MudRunnerTD's GQ From the Ground Up
Originally Posted by
Rogue Dung Beetle
Wish it was Nissan though, Toyotas just can't keep up with the Pootrol pace.
The only good thing about an 80 series is..... the front end?? Wrong!!, the Engine?? Wrong!! the Full Time 4WD system?? Wrong!! Its the NissanPatrol.com.au stubby holder fitted over the transfer lever.
WARNING: Towballs used for recoveries can, and do kill people and damage property.
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