Lemmy,
It might be worthwhile fitting additional protection when you fit these tyres. I used
Slime 26" Bike Tyre Liner Single from Halfords Price £7.99 on my old Raleigh bike and they seemed to work.
Having read the reviews it appears that thorns may still present problems.
Apart from Mussels point which I agree with, I don't think it's a good idea to combine any liners with the Marathon Plus tyres. These tyres have a thick inner layer which reduces the space for the tube and reducing that still further is very likely to lead to even more tube problems:
Marathon Plus Construction
Having bought and tested the slime liners I can't see that they do much good. Kevlar liners make sense since they resist penetration, but when I tested the soft plastic Slime liner it gave near zero resistance to penetration by nails, drawing pins or even a blunt ended thick piece of galvanised wire. All of them went straight through with hardly any finger pressure, far, far less than the weight of a bike and rider would exert.
Since the great majority of members have also reported the Slime liquid ineffective in the threads about that, it seems this company is making a good living out of near useless products.
Theirs aren't the only poor puncture prevention products of course, it's the nature of this market that invites the tricksters. When someone uses a product and them doesn't get a puncture they tend to feel the product is successful and often say as much, though in fact nothing of the sort is proven. It often merely means they weren't exposed to the risk of puncture and wouldn't have got one anyway, such is the random and spasmodic nature of punctures.
My own experience combined with the collected experience of others tend to indicate there's only two effective anti-puncture measures. One is that used by the Marathon Plus and equivalent Continental tyres, a very thick inner layer which together with the tread and tyre carcase exceeds the length of most penetrating items. The other is the kevlar type layer either built into the tyre or as an inner liner, these giving extreme resistance to penetration. However, both ways have a penalty in slightly increased rolling resistance.
The sealing compounds by Slime and others have only a slim chance of working with tubed tyres since the attempts to seal are broken as the deflating tube and tyre shift in relation to each other. In addition any slime that seeps between the deflating tube and tyre makes a sticky mess that makes subsequent patching very difficult. None of this is suprising of course, since these liquid sealants were invented for tubeless tyres where they work well, but were never intended for tyres with tubes.
.
