I picked up an old steel Allez racing frame which my mechanic converted to a 45x17 single speed. As I've found that it fits me better than my "real" bike, I have been riding it more and the real bike less. I'm curious if there are any benefits to doing intervals on a SS rig. Obviously, unlike a geared bike all of the effort would have to be from spinning and not from mashing a tall gear.
A bit of background: I've been riding about a year and have logged about 1500 miles since I started. I rode some MTB before and have generally been active my whole life. I've tried almost every athletic sport, but I'm not really good at any. I seem to have a knack for climbing on the bike, which I guess comes from a hockey background, as I've played and weight-trained for that sport since before high school. When I was a bit younger I actually played an entire game once, just to see if I could do it. I used to be in stellar shape, but unfortunately I work in a job where I sit a lot and don't always have an opportunity to eat what I want to eat or be as active as I normally have been. As a consequence, though I've actually lost weight the last 2 years, it has been in a bad way and I'm less toned and more flab than I was before (I am 30 now, which I refuse to use as an excuse).
Anyway, the way the Allez is set up the bike cruises around 18mph on flat ground with a light wind with little (perceived) effort. In a flat out sprint I can get it up to 25 but I can't hold it long because of the cadence required. On my geared bike I can approach 29 but pushing a much taller gear, again, not for long.
Any thoughts? Should I just suck it up and ride my real bike to train on? Are there benefits to doing spinning intervals on one bike and then doing mashing intervals on another in the same week or am I training for two different things? I don't have time to ride as much as I want, so I want my training to be effective and not counterproductive. Should I just HTFU and STFU?