Hello Greg, I think mine is the 275 lb Spring and I make it 2.65 ".
The total length of the unit, Eye to Eye is nearly the same as an old Koni, So I thought , Would it go on the front !!.
But the bottom of the unit, I think would be too fat ?.
I don't think at my time of life I want to change too much.
It is a smashing looking unit, And I think it would be a good man to not know it was a "D".
Can't wait to see if it will work for me, With the Norton forks being a bit stiff I have found with the "D" unit, If I unwound the spring too much it made the front forks move less ??, I don't know anything about all this preload stuff.
My bikes have always been a bit of a Bodge, But I like them. Cheers Bill.