Are all berg wheels interchangeable?

They are interchangeable with with all the 70deg (and newer Bergs) as well as KTM's from 04' and newer.
(I ran 2004 KTM sumo wheels/brakes on my 2010 FX450 for instance)

https://www.revzilla.com/common-tread/tech-ktm-wheel-swap

From article:
"If you followed this far, here is the takeaway: KTM hubs/rotor spacing/bearings interchange on all off-road models 125 cc to 520 cc from 2003 to 2017, front and rear. The only things needed to swap are the correct axle, spacers, rotor, and sprockets, confirmed by ZLA's media representative from KTM of North America. There are some other bikes outside those models that can work, but those are all a guaranteed fit."

KTM wheels.
'99 and older front axles were 17mm.

'00-'02 front axle-20mm.

('03 and LC4 fronts may be one or the other apparently depending on model)

'04-'15 front axle-26mm.

'15 front-22mm.

Rears axles were the same from 1990-2011. (Not sure about LC4's and big bikes)

According to the Revzilla article, 2000's bikes can use different spacers to accommodate axles. LC4's and big bikes might have different hubs and not work on smaller "off road" bikes.

https://motocrossactionmag.com/ask-the-mxperts-more-life-for-spare-ktm-wheels/

interesting, I have a 1999 FE 600 axle here that I'm resurecting (cleaning up damaged thraed and mushrooming. But its 15mm, I wonder if its not OEM ??

dustywheels said:

interesting, I have a 1999 FE 600 axle here that I'm resurecting (cleaning up damaged thraed and mushrooming. But its 15mm, I wonder if its not OEM ??

Click to expand...

Does it have the WP "Extreeme" RSU forks?

50309081000 KTM FRONT AXLE MEASUREMENTS AND PICS - KX Guru Racing