X5404 noisy under load

Hi the motor has been making noises for a little while but only if Im going up a hill with a bit of speed and decide to apply extra throttle. If I back off a little bit the noise goes away again.

In all other cases the motor is very smooth and quiet even at high speed with normal load.

I estimate I'm running it at about 3kw.

Is there anything I can check ?

What kind of noise? Lots of things that could cause noise under load, from bearings to magnets to lose windings to controller issues.

You're only running 3K on a 5404?

Just running the 12fet controller at 84v, drops down to 74v by the time I'm going up that last hill
http://em3ev.com/store/index.php?route=product/product&path=41_38&product_id=82

I will try to record the sound if I can, it actually sounds like its rubbing or something.
There isn't much clearance from the hub to the disk brake caliper and there are rub marks where it has hit before..

May paint over it and try a few climbs to see if thats it ? Although if it is that not sure how to prevent it...

It is usually the obvious. You definitely have some rubbing going on there. Try shimming the disc out 2mm and then recenter the caliper. Use either washers or a disc spacer. I like the aluminum ones more than the plastic ones.

A sound recording will help, but brake rub is certainly a possibility. The bearings on hub motors are simple bi-directional ball bearings, not designed to be stable for side loads. They roll highly efficiently, but they let the motor drift a little from side to side. Crystalyte motors are some of the worst offenders in this regard. The motor can "walk" 2 or 3mm side to side. It may have moved to one side under a light load, but then get pulled to the other side under the sudden load of the magnets while under power.

Since the brake disk is attached to the hub, that causes the brake disk to walk side to side as well. On both of my Crystalyte motored bikes, that causes the disk to sometimes rub on the caliper, making a loud scraping noise. I cured it by replacing the bearings with a higher quality bearing, and modifying my caliper to open a little wider to allow the disk to float. It looks like your issue is the caliper it's self hitting the cover, but you might also check the disk. try removing the caliper temporarily, and see if that cures the problem.

Thanks guys, yeh I'm trying to work out why and how this thing moves, I think you may be onto something with the bearings.

If you still have a link to them then that would be great but it would be an easy test to take off the caliper for a quick test