I have a trekking bike (similar to this one : http://www.hervis.at/products/product?code=BASE:1842986&referer=at-bike-cross ) and I plan to join some triathlon events in the future. I try to do some long runs (sorry if that is not that long for you) around 70-80 km, but I cannot be faster than 21 km/h. I see the others with road bikes are much quicker than me(but I don't know whether this is because of me or the bike).
My first point is that I dont want to spend money now and I am really undecided whether this is a good strategy to train for later. Do you think there is room for big speed improvement with the road bikes? Is it similar to train with the trekking bike and then change it or does it change the style a lot?