Power on Road vs Trainer

I do quite a few hours on the trainer and this beats me. With the power being measured at the pedals it shouldn't make any difference.

I wouldn't take the HR as the benchmark but I'm sure you can feel the difference between 280 and 360 watts and if you couldn't get over 280 on the trainer that is very odd.

The only thing I can think of is that there is some slippage or something going on in the trainer which just isn't giving you enough resistance to reach your higher power levels. Although I would expect that you would feel that if it was causing such a huge problem.

I go inside and outside with big temperature differentials but still get pretty consistent figures from my Powertap wheels and also a Stages meter. The suggestion of trying a Powertap to see if there is any variation is a good one.

It may also be worth seeing if you can borrow a Powertap wheel, and do a comparison, as a PT is easy to just slot in and compare.

That way at least you know if it is an equipment based issue or not.

The power is measured at the pedal, so I can't see a situation where the type of resistance at the wheel could affect the amount of power being put through the pedal.

As a note though, even if the trainer is outside, you need a big fan, as you are in still air as opposed to a 20 mph wind blowing you cool on an actual ride. Your ability to create power and also your perceived exertion will be quite well skewed by being too hot.

I know quite a few riders who just cannot reach their power figures they are used to on he road when on their trainers. I am one of the odd ones it seems, who generally do better on a trainer, but I am odd in that I can spend hours on a turbo without wanting to kill myself!

Sounds like you are best finding a good stretch of road for your FTP tests, long steady hills often seem the best option as it is easier to settle in to a good hard rhythm.

I often do my FTP tests on rollers, and the gear I'm in is irrelevant. It certainly isn't going to equate to outdoor riding with the added rolling resistance, wind resistance and gradient variation.

I generally end up near the end of the block, and the key is just go as hard as you can for the time. HR can be affected by heat, so if you are indoors with insufficient cooling this could account for the (presumably) higher HR for the same effort. I have a massive industrial type fan when on the rollers, and even at FTP I rarely have any visible sweat as this thing blows hard!

I have a resistance unit on my rollers, and if I get to the point where I cannot hit the power required without spinning out in my biggest gear, I just up the resistance by one notch and that sorts it out.

Don't try to compare the indoor and outdoor efforts in particular gears, just ride as hard as you can in whatever gear gets you to exhaustion in 20 mins or an hour etc, but do pay attention to cooling when indoors.