Hi all, could someone please let me know what the idler diameters are and where the diameter is measured. I have a pair of spoked idlers on my 5U and I also have a pair of solid idlers from d2gary. Both measure 23 inches at the OD of the center rim that rides between the rails. The parts catalog lists optional front idlers (solid and spoked) at 23 1/2 inches, but they don't list the diameter of the standard idler. 
Reason I ask is that currently, my 5U has 33 link D2 rails (standard is 32 links) and this appears to only match with 23 1/2 inch idlers but nothing on my idlers measures that - only 23 inches. The riding surface diameter for both my spoked and solid idlers is 22 inches
I'm ordering D3/B rails and I plan to order them at 33 links (same pitch of 6.125) but I'm having misgivings because I don't have 23 1/2 inch idlers, at least in terms of actual measurements. I don't want to have to add or remove a link because that's a pain and I'd rather just get it right the first time. I should also mention that my existing D2 rails are completely worn out so they're probably a foot longer than they should be but the idlers were certainly not all the way out. The new D3 rails will be shorter because they're new so the idlers will come back into the track frame so the other way it could go wrong for me is that I might not have enough rearward idler adjustment

Thanks that would be my expectation too since it would be a meaningful diameter change from 22" to 23 1/2" which seems to match how much the standard idler running surface is above the roller running plane