will a pair of 2.35" nokian dh tubes be ok with my 2.5" panaracer megablaster tyres?

yeah, no problem,
well, to a point anyway.
I run 1.9/2.1 XC tubes in 2.7" tires for downhill, and they are fine, and lighter.
nokians are pretty thick, so should have enough rubber to expand safely.

thanks mate. ive bought some nokians and they are now running smooth as a baby behind

I run these tubes in a Panaracer fire 2.1 rear and 2.4 (nearly 2.6!) front, it is better not to run too small a tube in a big tyre - they will snakebite easier. The Nokian tubes are rated 2.3-3.0! but will fit smaller tyres too, who would run bigger than 3.0 anyway!!!