Haven't had any issues yet. I might have been a little paranoid a couple of weeks ago and thought I smelled plastic after going up several blocks of steep hills. I saw something like 1600w while going up. After that I dialed down C5 setting to 8. I think that might limit it to around 1400w. I don't think that hurts top speed, just keep a sane output on the hills. Btw, I changed the chainring to a 46T, on my 2016 it was a direct drop in replacement. I saw a 33 mph top speed one time on the flats.
Yeah, 1600W is a lot of power, thus a lot of heat generated. I've read some people caution about melting the nylon gears (remember those when replacing the motor?). That's why I was a little worried about smelling something. At least we have a spare set of nylon gears from the old motor.
When I first did the motor upgrade I was trying to hit 1600 as much as possible, I wanted to go as fast as possible all the time. I was probably hitting 1600 only on the hill climbs.But how long do you actually hit 1600W??
Like 1 or 2% of your riding time?
It's not like you're hitting 1600W all the time.
I've never found temperature to be a big issue, I have two mid drives I monitor and I've never seen the temperature over 40C running them mostly between 700 and 900 watts with periods up to 1500 for hills etc. I check my rear drive hub motors with a infra red thermometer and even my 500 watt Radrover using Bolton's kit running at 1500 watts I've never seen alarming temperatures. And no, I'm not really a temp freak I just got in the habit when I used to rebuild motorcycles and I would watch temps in the the air cooled bikes after a rebuild. Oh, I typically wouldn't go riding with temperatures much over 30C.........I'd rather drink beer.
I think the heat issue might be more likely to become obvious on your RAD gear drive if you could find an area that would let you run at a load of 1200+ watts for a while. Like 15 minutes or more?
My understanding is that the gear drives have a terrible time transferring heat to the outside case, where your temp gun can read it - which may be leading to a false sense of security. I'd sure like to be wrong here.
I have a 1500w direct drive now, and in a search for a better understanding of what's going on with the gear driven rear hubs (proably a MAC 12t) with similar (or hopefully much better) performance in the 7-15 mph range where I spend most of my time, been doing a bunch of research. From what I can find, the gear drive offers much better performance - BUT - you need to be careful comparing that performance to the direct drive, because the direct drive is MUCH better at getting rid of heat. So the gear drive has better performance, but it's about short sprints. The direct drive will carry higher wattage settings for a longer period. Another compromise situation..... -Al
Here the difference is some of us are running hotter motors (bigger magnet 750w) plus 52 volt batteries with our Bolton kits.