Doohickey said:The screws are M4 * 12. I replaced them with Torx ones from Aliexpress - the heads were a bit too wide (meaning I could not get the cover on), so I spun the screws in a drill, holding the edge of the screwhead against a piece of sandpaper to get them down to the correct size. The head diameter of the original ones is 6.7mm.
I also replaced the hex screws holding the cover on, since those stripped for me too. They are M4 * 14.
I don't think you'd get any voltage on the battery connectors when spinning the motor due to the mosfets and electronics inside. It should not have a noticable amount of drag, certainly not so much to make it hard to keep up speed.
Great info, thanks for that! Do you also happen to know what size the ones holding the drive-side cover are? Without being able to get at them, they seem to measure 7mm with the threaded hole depth being 8mm but open on the end.
Did you choose stainless screws or zinc plated? I've checked the cover bolts and they are stainless but 14mm is a difficult length to find online here in button head. The front hole measures 20mm deep and I expect the others are similar. I'm uncertain as to how deep the thread goes but I'll give M4 x 16mm a try.
There might be risk of galvanic corrosion between the aluminium case and stainless, but in reality I've never had an issue in other applications. Anti-seize or grease on the threads would reduce that risk too. However zinc usually holds up pretty good in the weather, and if I recall correctly can be rated to a higher tensile strength than stainless.. not that it matters here.
Andrew707 said:However, when I was adjusting them on my handlebar they suddenly turned off. Then I noticed a very odd thing - one (or sometimes both) light are on (but very very weak) when the system is off.
The wiring in the speed sensor cabling is pretty thin so I'd be concerned about overheating and damaging it using higher output lights. Also the standalone battery pack powered versions of those lights I've seen all run off 7.2V. Eco Cycles has a good video on YouTube about installing a relay instead, then you can go nuts with the lighting.
https://www.youtube.com/watch?v=RuHUcbF1ClE