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[grc]

the kids are just playing Jerry, I (we) really do appreciate your expertise.

OWL

I wasn't upset by the comment (see the little wink emoticon in my reply), just having some fun myself.  And if you were to talk to my wife you would find that she agrees with the "days with a D in them" comment.  She's been calling me a grouch a lot longer than the guys around here.

Jerry

[Akicita]

It's an SAE measuring definition/standard.  Force (either as horsepower or torque) could be measured many different ways taking the variables in to account even more different ways.  For some recognizable comparison a measuring standard is needed.  The standard may be no more right or wrong than some other measurement method and mechanism.  The important thing is that it's a fair and consistently applied measure from a recognized source (that's is the recognition given SAE). 

Ok, tried to key in the formula but couldn't keep the lines straight.  Saved it as an image.  Here is the latest revision of the J1349 standard that I'm aware of:

Well, to quote the Church Lady, "isn't that special".  I feel so much better now!

[Steve Cole]

What is it really?

It is a way to stop people from pumping out numbers that mean nothing and at least get them ALL playing from the same place. The advertising departments got so carried away with HP and Torque ratings SAE came up with a newer standard to try and limit the BS. Rest assured none of the current motorcycle chassis dyno's can meet the specification.

[deldago]

I thought Harley's numbers were off the crank,not off the rear tire accounting for driveline losses?If I am wrong please correct me.

[Midnight Rider]

I thought Harley's numbers were off the crank,not off the rear tire accounting for driveline losses?If I am wrong please correct me.

They are, but the methodology is what is being talked about.

[deldago]

Is there a formula to compare Harley's crank rating with a rating from a chassis dyno?i would imagine not too many people would want to remove the engine just to get an accurate crank reading like what Harley uses.

[Steve Cole]

No formula that is worth the paper it is written on. The problem is no two chassis dyno's read the same due to the cost involved in using proper measuring equipment. They are fine for doing a comparison from before to after as long as the run conditions are close to the same but that's about as good as they are.