Front hub spacing/fitting question

[kaltsoplyn]

Hi there

So I got this Cute 350W front hub motor from BMSbattery. Very happy with the service and the communication with Mr. Jack Xie. I'm building my wheel now and I'll be posting my impressions of the motor in due time.

However there are various issues with the hub itself:

For starters its 10mm axle would not fit into my 9mm dropouts (an Orange F8 fork); I had to grind it (the axle) with a dremel tool.

The fork also has non-dropout lips on its outer sides, so the non-turn washers had to be filed into the appropriate shape to fit in, too.

Then the disc brake fitting holes. Screwing the bolts all the way in locks the hub, as they end up pushing the inner body/rotor of the electromagnet.

Filing the bolds to circumvent this, fixes the rotor at a position outside the adjustment range of my brake caliper (aren't these standard distances?!?). [spacing the caliper is not an option as I plan to switch wheels frequently on this bike].

Putting a spacer between the rotor and the hub body fixes this issue, but then I noticed this:

The profile of the non-drive side end of the hub, which is supposed to press on the dropouts, seems to be quite narrow (see attached image). So, there is a regular washer supplied in the package and I'm thinking whether it is intended to be used there (it's somewhat visible in the image, too). If the spacer is used, however, then the rotor needs 3 spacers (in each of its 6 bolts) in order to achieve alignment with the caliper. I don't feel this is very safe.

So, you kind people, do you use spacers to fit your hubs?
do you think the hub end I show in the picture is too narrow or is it ok?

Any input will be highly appreciated.

 

[banbury frank]

Hi I have seen all these problems before Yes you can use 2 washers X 6 but it is fiddly to put the on .You need to put the first washer in your photo on the inside off the forks to stop the shaft puling through the forks also you need a torque arm or you will smash the end off the forks

Always remove the brake caliper and fit the wheel then offer up the caliper or you will bend the disc

I also found that you end up with all the spacers to line everything up it is 5 or 6 mm wider the the 100 mm inside the forks so you have to spring the out to fit the wheel

Don,t bother to use the washers with the lug on them as this will only put more pressure on the forks you could take them off and weld a arm on them and fit jubilee clips around them

look at the torque on this link


http://www.ebikes.ca/store/photos/TorqArmRev3.jpg

Hope this Helps

Frank

 

[kaltsoplyn]

Frank thanks for the reply. Using a torque arm is not a very viable option as the wheel will have to be exchanged with a regular wheel 2-3 times a week. A non-turn washer contraption of custom shape which will lock onto the fender mounts of the fork is more likely.

Removing the caliper is also something I don't like as is kind of a hassle and, quite frankly, I don't see the reason, too. It was quite easy to install the wheel with the caliper on when the rotor was spaced correctly. The actual question, though, was whether it is SAFE to run a rotor spaced that far out of the hub body in terms of the torque applied on the bolts under heavy braking.

But I'll figure these out. What matters for me is that you say that the "first spacer" has to be installed on the INSIDE of the forks. Are you sure that this spacer is absolutely necessary?

 

[banbury frank]

Hi yes you can use the mud Guard mount holes but need a good fit on the 2 flats if you don't fit the washers on the inside it will just pull through the forks
as they are only soft alloy as for changing the wheel I don't see why there is little drag on the motor so it will work with no power

I have spacer for disk 54 mm OD 34mm ID 1 mm thick or 2 mm thick with 6 holes laser cut in stainless steel please PM for more info

Frank