I have two identically set 26 inch rigid fork bikes from early '90 for my city commuting , one is hi ten as in OP case, the other db tange cr- mo, both 7 speed 28mm road tires, 48t-12 rear. There is 1 kg difference between them, but when I check the same sigma comp on both bikes it appeares that the cheaper hi ten frame is faster on flat and mixed terrain, maybe because of the more compact frame, 2cm lower bb , narrower fork and rear drop out. The cr-mo feels a bit livelier and a bit more effortless to ride, but the only time I was faster on it on a same route ride was when I had 6 cups of coffee before the ride, so I think it was because I have 3 times as much as my normal coffee drinking habit on this ride. Incidentally it is still my fastest time on this route. I can find a nice used cr-mo frame and swap all the stuff from the hi ten frame, but having both current bikes to compare for 5 years now I'd rather go with something different for a change like Fuji touring bike or other similar 4130 28inch bike, but I am not expecting to be much faster or lighter than my current bikes. As for aluminium frame, I had a cheap one and get rid of it after one year didnt like the ride compared with my other bikes.