I have noticed all the Japanese manufacturers have a J or JJ notation after the wheels diameter. Is this some sort of load rating or manufacturing process?

And I dont believe the Jamba Juice thing Max.....

 

"JJ" refers to the shape of the wheel's flange (lip which holds the bead of the tire).

JJ = 18.0mm high x 13.0mm wide, with a 13.0mm radius
J = 17.5mm high x 13.0mm wide, with a 9.0mm radius

 

The letters should be self-explanatory...

 

Damn, Jim. Always wondered that myself. Thanks for clarifying! So JJ has a more reinforced rim lip, eh?

 

Damn; you learn something new everyday.

 

I was wondering the same thing last week. It looks like a weird "Pi" symbol...

 

is there a real advantage to one over the other?

 

Not really. There is also a rarer "JK" (I don't have the dimensions for that one), but most P-Metric tires will fit a J, JJ, or JK rim, so it makes little difference.

Manny, by my math, the J flange has more material because of the smaller radius on the inside edge, 9.0mm vs. 13.0mm. Barely. Again, it makes little difference.

 

Thanks Jim! IS this a worldwide spec , or foreign only. I havent seen it referred to on any of the HREs or Kinesis we have gotten, nor the other US based wheels..

 

You'll probably only find the flange codes on imported cast and forged wheels, but I can't verify that. Also, it's often included in their wheel sizing information, as shown on the boxes my Volk TE37s came in...



Kinesis, HRE, Fikse and other CNC/machined wheel manufacturers probably wouldn't have this information on their wheels, especially since most of them machine wheel centers to combine with pre-formed "hoops" (which include the flanges, obviously), and many don't manufacture those hoops themselves. I didn't think to check my Kinesis wheels when I had them because obviously it wasn't that important. Maybe someone who has a set of this type of wheel can comment.

Considering that many of the major manufacturers of P-Metric tires are domestic, I would assume that it is a worldwide "spec", but that domestic wheels don't include this information unless they're manufactured outside the United States.