Have trained and TT'd this summer/autumn on Ultremo's without any major problems...however now that the shite weather is here I'm in the process of trying to fit Continental Hardshell Gatorskins for the winter bike....or I would If I could get the buggers on
never encountered a harder tyre to fit.
Having said that they seem
pretty puncture proof...
Used Schwalbe Stelvios last winter which were pretty robust and with low rolling resistance.