I'm off to the Alps in a couple of weeks and I'll be doing a couple of big road rides whilst I'm out there. Will i notice much of a difference in venting between a cheap road-specific helmet and an MTB lid?
I would expect most low-end helmets to be similar.
Agreed, a more expensive helmet will be better vented, irrespective of who it's aimed at.
The exception would be if you have a piss-pot currently, when a cheap lid (road or MTB) will of course have better ventilation.
The Specialized MTB one I have was about £50, its decent enough. I'm just not great at dealing with loads of heat so I thought it might be a cheap way to keep cool. I could always just take the lid off on the climbs but that is a whole other can of worms...
I'd just take it off on the climbs, a £50 mtb helmet should be reasonably well vented.
Just take it off on the climbs. Or start wearing a roadie cap under it.