Pardon me if this as been asked before, but what trainers do you use with your 80s or 70s era bikes? My google fu wasn't good enough to turn up answers.

I think we are in for a short stretch of good weather but eventually it will be rain, rain, and more rain and I would like to get some exercise on account of I am overweight.

What I'm concerned about, though I don't know if it's a valid one, is the width of the rear. Do trainers generally only take wider rear ends like on newer bikes or are they capable of adjusting to narrower ones?

Thanks