front hub differences...

[800screws]

are 400ex and 250r front wheel hubs interchangeable? and are the stock 400ex's better for racing? i notice alot of hybrids run the stock front hubs...

[stocktires]

Yes, they are interchangeable.
The 400ex hubs are solid, I haven't seen any break and they are aluminum too.
Aftermarkets seem to break more than stockers, but any guy with aftermarket hubs generally is a hardcore MX'er so that may be the reason.
Aftermarket's are lighter. Less unsprung weight is key.

[800screws]

thanks, i thought maybe switching hubs was the reason my old spindles took a crap, guess it was because they were the old generation...

[stocktires]

If you have the old steel 250r hubs and spindles, swap them ASAP!
I had the steel set-up on my R, and on my hybrid I have all aluminum. SOOOO much lighter. Probably a good 8lbs less.

[800screws]

my old jrd spindles actually wore...the steel shaft wore in the aluminum and delevoped a wobble. i bought a new set from them and they were twice as thick....and i haven't had a problem since. i thought because i switched to baldwins 250r hubs maybe it was the cause.