what does "7.5J" refer to?

[c-square]

when it comes to describing the measurement of a particular rim, there are a few sets of numbers, one of those is eg. "7.5J x 17". Whilst I know that the "17" refers to a 17 inch diameter size rims, what does the "7.5J" refer to?

 

[V-Man]

the width of wheel which goes hand in hand with tyre width

 

[Member 33]

when it comes to describing the measurement of a particular rim, there are a few sets of numbers, one of those is eg. "7.5J x 17". Whilst I know that the "17" refers to a 17 inch diameter size rims, what does the "7.5J" refer to?

Means the width of the rim is 7.5"

 

[astroboy]

Rim width..

 

[astroboy]

Hope this help: http://customwheelsmarket.com/rimwheelwidth1.html

Aspect Ratio Metric Size Designations Approved Rim Width Ranges 35 Series 275/35R17 9.0-10.5 335/35R17 11.0-13.0 345/35R15 11.0-13.5 40 Series 285/40R15 11.0-13.5 215/40R15 7.0-8.5 245/40R17 8.0-9.5 255/40R17 8.5-10.0 265/40R17 8.5-10.0 235/40R18 8.0-9.5 45 Series 195/40R15 6.5-7.5 215/45R15 7.0-8.5 255/45R15 8.5-10.0 205/45R16 7.0 225/45R16 7.5-9.0 245/45R16 8.0-9.5 215/45R17 7.0-8.5 235/45R17 8.0-9.5 255/45R17 8.5-10.5 50 Series 175/50R13 5.0-6.0 195/50R14 5.5-7.0 205/50R15 5.5-7.5 215/50R15 6.0-7.5 225/50R15 6.0-8.0 195/50R16 5.5-7.0 205/50R16 5.5-7.5 225/50R16 6.0-8.0 235/50R16 6.5-8.5 215/50R17 6.5-7.5 55 Series 205/55R14 5.5-7.5 185/55R15 6.0-6.5 195/55R15 5.5-7.0 205/55R15 5.5-7.5 205/55R16 5.5-7.5 225/55R16 6.0-8.0

Aspect Ratio Metric Size Designations Approved Rim Width Ranges 60 Series 185/60R13 [td ] 5.0-6.5

	205/60R13	5.5-7.5
	185/60R14	5.0-6.5
	195/60R14	5.5-7.0
	205/60R14
	195/60R15
	205/60R15	5.5-7.5
	215/60R15	6.0-7.5
	225/60R15	6.0-8.0
	235/60R15	6.5-8.5
65 Series	185/65R15	5.0-6.5
	195/65R15	5.5-7.0
	205/65R15	5.5-7.5
	215/65R15	6.0-7.5
70 Series	165/70R10	4.5-5.5
	175/70R12	5.0-6.0
	175/70R13	5.0-6.0
	185/70R13	5.0-6.5
	185/70R14	5.0-6.5
	195/70R14	5.5-7.0
	205/70R14	5.5-7.5
	185/70R15	5.0-6.5
	205/70R15	5.5-7.5
	215/70R15	6.0-7.5
82 Series	155R12	4.0-5.0
	155R13	4.0-5.5
	165/70R13	4.0-5.5
	175R14	4.5-6.0
	185R14	4.5-6.0
	165R15	4.0-5.5

[td ]
5.5-7.0
[/td]

[/td]

 

[jarance]

So what does "J" in "7.5J" signify?

 

[V-Man]

Automotive Suspension & Steering Systems, Thrid Edition wrote:

Flanges are made with different heights and curvatures to match the tire bead configuration. Flange type is designated by a classification system using one or two letters. The most commonly used flange heights are J= .68"(17.3mm), JJ=.69"(17.5mm), JK=.71"(18mm), K =.77(19.5mm), and L = .85"(21.6mm).

 

[astroboy]

 

[mizhan]

Most educational. Thanks gentlemen.

 

[pussy]

So what does "J" in "7.5J" signify?

'J' is short form of the scientific name of 'radius'

 

[astroboy]

'J' is short form of the scientific name of 'radius'

"Radius" is represented by "r" lar!

http://en.wikipedia.org/wiki/Circle
As proved by Archimedes, the area enclosed by a circle is equal to that of a triangle whose base has the length of the circle's circumference and whose height equals the circle's radius,[3] which comes to π multiplied by the radius squared:

"J" however stands for "Joule"

http://en.wikipedia.org/wiki/Joule
The joule ( /ˈdʒuːl/ or sometimes /ˈdʒaʊl/); symbol J) is a derived unit of energy, work, or amount of heat in the International System of Units. It is equal to the energy expended (or work done) in applying a force of one newton through a distance of one meter (1 newton metre or N·m), or in passing an electric current of one ampere through a resistance of one ohm for one second.

... and it's totally irrelevant in this context. :thefinger:

 

[mizhan]

during my time in school, we were taught that a circle's circumference is calculated using the formula 2πj, and its area using πj squared.

of course those days the subject wasn't called maths, but ilmu hisab; and j therefore is 'jejari' or radius.

 

[astroboy]

during my time in school, we were taught that a circle's circumference is calculated using the formula 2πj, and its area using πj squared.

of course those days the subject wasn't called maths, but ilmu hisab; and j therefore is 'jejari' or radius.

Ops.. now I remember.. haha! Correct.. :top:

 

[mizhan]

it has been a long time since those days eh.. :wink:

 

[c-square]

Thank you, guys....truely educational.

 

[c-square]

Rim width..

Oh, one more thing....

Based on the image above, does it mean that with a tyre of say 225/50/17 on a 7.5J x 17 rims, the tyre will bulge out about 35mm (17.5mm on either side) since the rim width is only 17.5 inches (about 190mm) compared to the tyre which is 225mm?

 

[Maniac]

hello kawan-kawan. i wondered about this "j" question too when first coming across it a while ago.
here's an excerpt of an article i found which gave me a satisfying answer:

it is the letter that typically sits between the rim width and diameter figures stamped on the wheel, and indicates the physical shape of the wheel where the tyre bead meets it.

full article here, which a heck of a lot of other good information. http://www.carbibles.com/tyre_bible_pg4.html

key point to note - make sure your rims & tyres have the same profile stamp, otherwise they wont fit!

c-square. yup, a bigger tyre width will bulge out of your rims. check fitment to ensure that you are first able to put them onto the rims. if you can, you'll have added protection from kerbing your alloys

 

[naharnms]

radius = jejari !
yup, so long never heard the word jejari..but tapi takkanlah mat salleh pakai malay word jejari as the 'J' here..?