Removed the bonty xr4 and se5 2.6 tyres on the Marin to try some continental tyres in an atempt to get some needed speed out of the bike. Fitted a mountain King lll on the front and a cross King on the rear' again in 2.6" and the bike is much better, keeps rolling now when you stop peddling, where it did not with the bonties. Need to play about with pressures, but so far no lack of grip!