Hmm 275/35 still not so bad then but already pretty thin too (only 9.6cm sidewall height). Generally I would guess just a bit harsher than mine now on 245/40 (9.8cm sidewall) but maybe yours feels harder coz the Extreme Contact may have firmer construction than my F1.Noted on that, thanks for the useful info will read them at home later.
I just checked again, its actually 275/35/18 my bad!