Lower my crappy MTBs rolling resistance on a budget.

[was8v]

Buy the narrowest, lightest, totally slick tyres you can find and pump them up really hard - 100 PSI.

Something like this: http://www.wiggle.co.uk/continental-grand-prix-roa...

You might even find a 1" tyre.

Use an appropriate lightweight inner tubes.

You will be flying!

[WinstonWolf]

You can quite happily run 26" slicks on an MTB, I got up to 48MPH down Ditchling Beacon on this



However if you go off road an 'urban' tyre is probably better. Whilst this looks bad I rode thirty miles home on it