Originally Posted by
ancker
Yes, but on the trainer there isn't much opportunity for coasting or tailwind. I find it much easier to maintain a faster speed on the road because I can cheat on the downhill side to recover from the uphill. On the trainer to maintain speed it requires consistant and constant power.
No, "speed" on a trainer has no inherent meaning, especially compared to riding on the road. The nature of the resistance is completely different.
You can use speed as a rough proxy for effort, but only in comparison to other sessions on the same trainer. Some trainers (such as KK) have known resistance curve such that you can approximate power from the speed using formulas, but there is really no way to know how well your resistance is calibrated without actually comparing the results to a power meter (some people report theirs is accurate, others report that it is not).
Finally, assuming that speed on a trainer was comparable to the road, you should be getting faster speeds for the same effort compared to going up a hill and coasting down the other side. Take the trainer out of the question and compare going at a steady effort on flat ground to doing that effort uphill and coasting back down. The flat ground effort will be faster.