So I'm looking for new tyres for my bike. The ones I have at the moment are 18-month old Schwalbe Marathon Plus - they have a zigzag down the centre which gives an extremely low rolling resistance, knobbly bits down the sides which give grip in the mud and are lined with plastic to give nigh on ultimate puncture protection. At least that's the theory.
In practise they roll like a dream on the road, seem totally indestructible as far as punctures go (I've pulled an inch-long thorn out of one tyre, which failed to penetrate to the tube) but it doesn't take a lot of mud before they lose grip completely.
So I've been looking at tyres with more grip in the mud, but which also give me a low rolling resistance because so much cycling I do is on the road. I'm looking at Schwalbe Marathon Plus Tour and Marathon Extreme tyres. From what I can tell they are pretty much the same in terms of tread patterns, they both have good puncture protection etc. But the Plus Tour weighs 1100g per tyre and the Extreme more like 600g. The Extreme is more expensive but I can live with the extra cost if it's worth it.
The Plus Tour weighs about the same as what I have now, so I'd expect it to be harder to accelerate with a more mud-friendly tread pattern, even if not significantly so.
So the question - if I spend a little more and get the Extremes, is losing 500g on a wheel going to make a huge difference to acceleration? On the face of it I'm losing 50% of the wheel weight, but a total of 1kg on a bike/rider combo that's over 100kg seems trivial by comparison.