Rear hub motor disc brake dilemma

[methods]

I would look into it. . . I just put my order on hold.
He said that he could machine the bearing hole to any size.
Find out what size yours is.
If it was easy. . . Everybody would be doing it right?
The covers he is getting are right off the shelf from Crystalyte and he told me that he uses all 12mm axles so . . . 2 + 2 is adding up.

I trust him too. Just make sure you are on the same page

-methods

EDIT: He was pretty clear: If the bearing is the right size it will fit. If it is the wrong size he can machine it. So you will be fine.

[64ragtop]

He said that he could machine the bearing hole to any size.
Find out what size yours is.
If it was easy. . . Everybody would be doing it right?
The covers he is getting are right off the shelf from Crystalyte and he told me that he uses all 12mm axles so . . . 2 + 2 is adding up.

I trust him too. Just make sure you are on the same page

And, I think that is the key! The Australian gent is doing the machining, but if I recall correctly when I suggested to
e-bikes.ca that they could do or have done the necessary machine work, they were not disposed to do it. I kinda got
the idea from the Australian site that their bikes require machine work anyway, so having the tools and talent on hand anyway,
machining the side covers is no problem. No dis to the Canadians, if it doesn't fit their business model - then so be it. And they
might change that policy if it looks to be profitable.

ATB

BC

[getadirtbike]

G'day all,

I'm not sure what all the fuss is about with these covers. All I need to know is the bearing size and I can mod the covers to suit. Up until now I haven't had a problem with any of the motors. I've taken off plenty of covers in my time... lets say at least 30... so I know my way around the mechanics of an X5.

I have a BIG engineering factory full of mills, lathes CNC's etc so if any of you do have the different sized bearings then I can make the necessary mods to the covers in a few minutes.

By the way, the axle size (at the thread) doesn't really make any difference to the size of the bearing. The axle steps up to 20mm on any of the X5's that I've worked on once it gets in behind the cover.

My guess is that they all use the 6004 sized bearing... I just want to make sure of it before I send anything to anyone and then they have to send it back to me.

[methods]

No fuss for sure.
Just making sure that we get it right the first time

Here is a data point that rings true on all accounts:

"Just for info. there are two different bearings 6005 left and 6004 right."
viewtopic.php?f=2&t=5067&st=0&sk=t&sd=a&hilit=6004&start=15#p76558

I will measure mine before I actually order but there is an example of different size bearing sizes for the record.

So what is the deal with Crystalyte? Everybody who sources from them has to wait 2 - 3 weeks for just about anything.
Why are they shipping via the slow boat? These days it seems like everybody in China/Taiwan can get stuff out to the US in 5 -7 days
Are they building to order? If so, what are the minimum quantities to start a build?

I am considering just picking up 10 or 20 of these to distribute to my local army of space monkeys. ElectricRider has a damn monopoly any anyone else who is cool (like eBike.ca or E-MTN) are cost prohibitly far away in another country. . .

-methods

[voicecoils]

"Just for info. there are two different bearings 6005 left and 6004 right."
viewtopic.php?f=2&t=5067&st=0&sk=t&sd=a&hilit=6004&start=15#p76558
...
I am considering just picking up 10 or 20 of these to distribute to my local army of space monkeys. ElectricRider has a damn monopoly any anyone else who is cool (like eBike.ca or E-MTN) are cost prohibitly far away in another country. . .

Good detective work
Looks like I've got the 14mm axle motor that should have different bearings. getadirtbike and I will try to work something out.

As for you and Crystalyte. If you're going to order 20 of them, perhaps try getting them to make them for you with useful sidecovers. ie a 6 hole ISO bolt pattern on one sidecover, and a standard shimano freehub body on the other so a modern 9 or 10 speed cassette could be used. Hub motors need to get with the times IMO.

[methods]

I just found out that Electric Rider will be putting a new version of the X5 into production in about 2 months. This disk'ed X5 will still fit in the 135mm dropout (as opposed to the 150mm required for the current disk version). I suspect we will start seeing these in more like 4 months but we will see.

What I would really like to start seeing are rolled axle threads, larger gauge wire, cooling fins, integrated torque arms, etc. I disagree with anyone who says that cooling the case is pointless due to the air gap between the coils and the magnets. My case gets so hot that I can't touch it. Cooling that will definitely cool the coils and allow me to run a little more power.

-methods

[methods]

ONE MORE HITCH:

note: I am learning this as I go so I dont claim to be any sort of authority. . . This information is as correct as I know it to be right now.

After some discussion it appears that there are 2 reasons why you don't commonly see disks on X5's.

1) Bearing size does not match
2) Axle length is not long enough

The factory version of the X5 with disk uses a 150mm axle (that I believe is 12mm wide). This extra 15mm of axle allows your room to mount the disk and still space off the frame far enough fit the caliper.

It is my assumption that if you want to make a standard X5 take a disk, you will have to source the cover, machine it to a 6005 bearing, then space out the axle with washers to set the disk distance from the frame. As Fechter said, you may end up needing fancy U shaped washers because you still need to get the wires out. remember that the wires will now be exiting after the disk. Adding to this complication is that now you only have a tiny nub of threaded axle left on the outside of your frame to hold the nut. This should be fine, but many people like to run insane torque arms and there may not be room for this.

This is why I believe that E-MTN use the 12mm axle X5's with higher quality torque arms. Makes sense

So, to sum up my understanding:

- Source the cover
- Machine to bearing size
- U-shaped washers on the axle to space the disk-to-frame and allow the cable to route
- Spread the rear fork to 150mm
- Use minimal torque arm on the left side since there will not be much thread left

So it is definitely do-able.
I believe now that the reason that it is not "common" is because it takes some thinking to get right. Not a simple bolt-on affair. I imagine that it will work better for some bikes than others.

Aluminum frame downhill bikes already have very thick drops, like over 1cm in my case. I am already short on threads. A steel frame would give up another 4 or 5mm. My steel frame (which is stout!) was only 6mm wide. Every mm counts when bolting up to crappy cut threads. . . The more threads you can engage the more torque you can apply without worry of stripping.

And I stripped my threads so I am sensitive to this.

Again, this is a play-by-play of what I am learning and I am a nOOb compared to most of you moldy old dogs so I may be incorrect. Please no flaming if any of my info is wrong

-methods

[voicecoils]

Interesting stuff.

Since my X5 was free, I'm willing to put a bit of work into getting it right. Rear disc is essentially a necessity IMO. Maybe if Crystalyte doesn't do it, someone should create and offer a CNC machined side cover set that does have the good stuff on it ie standard disc mount and freewheel cassette body on the other side. Perhaps vents as you suggest too.

I already tried slotting my X5 (unlaced) into a hard tail dirt jumping frame with thick 6061 dropouts. They're exactly 135mm and it worked fine. Perhaps once the 7 or 8 speed cluster is on then it might be a problem?

Also, spreading your dropouts from 135mm to 150mm is NOT usually a good idea. Very risky with aluminium, can be tricky to do a proper cold set with steel. Cheap kmart frame = forget about it.

My DH Team dropouts are asymetrical and naturally sit 140mm apart, they're designed to then bolt up at 135mm.

I'll keep checking this thread for updates when I can.

[methods]

2 months, they are making them

I asked if they were going to do better rolled threads, a longer threaded axle, cooling fins, etc. but of course they said no. The average joe does not wan that crap and the average joe is who butters their bread. Fair enough.

I am sure that soon there will be some mega motors coming out. . . Maybe in the next 2 years when the EV's pick up.

-methods

[getadirtbike]

Ok,

I spoke to Kenny, took some measurements and remembered that most of you guys actually use a 135mm dropout.

Getting the disc brake cover to fit the X5 is doable. The standard bearing that is on the disc side of the 14mm axle type motors is a 25x47x12. The standard bearing that is used on the same side but on a 12mm axle is 20x42x12.

So to put the disc cover on to an X5 with a 14mm axle means that the 20x42x12mm bearing needs to be replaced with the 25x47x12mm bearing..... Simply machine the bearing bore in the cover to 47mm and the job is almost done.

The next step would be to machine the ID of the boss that the disc screws on to. This dimension ranges between 23mm and 24mm and the axle diameter at this part of the 14mm axle is about 24mm.... so the cover would then need 0.5-1.0mm taken out of the bore of the disc boss so that the axle will go through.

Here's where it might get a little tricky. The plastic sleeve that slides over the axle to stop the wires from rubbing on the cover has a wall thickness of 2mm. This means that a further 4mm needs to be machined out of the diameter of the bore of the disc boss bringing the ID of the disc boss up to 29mm.

The smallest diameter of the threaded disc boss is around 33mm (where the thread runs out).... 33mm-29mm leaves a minimum wall thickness of 2mm. Standard item has a 4.5mm wall thickness.

2mm is getting on the thin side in terms of strength, but the component is loaded torsionally so it's not as bad as it sounds. Personally I would like to see the wall thickness increased by another mm by making the ID of the boss 27mm instead of 29mm. This means that the plastic sleeve would need a wall thickness of 1.5mm... or better still 1mm thick sleeve would give you 3.5mm wallthickness on the disc boss.... surely this is possible.... it's only a sleeve and doesn't require any significant form of strength. The alternative is to toss the plastic sleeve and use a thicker covering on the wires.... and hope this doesn't wear through. I think the 1mm thick sleeve would be a better option and should still be strong enough... but I can't say for sure without testing it myself.

So to me this is how I would go about fitting the disc cover. 10 minutes on a lathe and it's good to go

The next problem is the spacing. The bikes I build all use a 150mm dropout, and so do a lot of DH bikes. I have seen the X5 with a disc brake fit into bikes with a 135mm dropout.... yes the frame needed to be stretched a little.... but the difference between 150mm and 135mm is 15mm.... divide that by 2 and it's only 7.5mm on each side.... I've stretched a few frames and it hasn't been a problem. Next time you take your rear wheel out grab hold of the dropouts and just watch how much you can stretch the frame using your hands.... you'll get pretty close to 7.5mm without too much effort.... Having said that I won't take responsibility for your frame breaking.... I haven't broken one doing that but an X5 in the rear of your bike puts all sorts of stresses on the bike that it wasn't designed for.

Someone said in this thread that a "U" shaped washer needs to be used to help the wires exit the motor. This is correct. Not a hard thing to make... it's just a spacer which is open and one end.

The torque arm/plates can be mounted on the inside of the dropout...they don't have to go on the outside.... somewhere around here I have a torque arm which incorporates the "U" shaped spacer and sits on the inside of the dropout. If I can find it I'll post a photo. Yes I have lots of machines but most of this can be made with basic tools such as a drill, a vice, and the right sized file... ok... and maybe an angle grinder too.

Having said that I have also come across 1 or 2 bikes where the disc simply wont fit. The problem can also depend on the taper of the chainstays. Some bikes taper in on a rather sharp angle so while the spacing back around the axle is fine, the disc rotor can rub on the chainstay. A smaller diameter disc can sometimes help, but you also need to keep an eye out for the spacing between the disc rotor and the motor cover because you still need to fit the caliper in behind there.... so the size of your disc caliper can also determine whether or not it'll fit.

Most of the chopper/cruiser style bikes have bucketloads of room back there and the chainstays are kept quite wide ... even parallel... so they generally always fit. A standard hardtail MTB is more of a try it and see scenario... they're all different.

As a last resort you could cut a small nic out of the chainstay where the disc rotor touches it and then weld a piece back in to maintain a closed cross section... and depending on the type of cut that you put into the chainstay you might need to reinforce it a little.

So back to the original question that I was asked.... Can I supply a side cover to fit a rear disc brake on an X5 with a 14mm axle??? .... yes.... but you'll have to work out an alternative for the plastic sleeve.

Will it fit your bike??? I have no idea. Getting the correct spacing is the key and every bike is different.

[voicecoils]

2 months, they are making them

I asked if they were going to do better rolled threads, a longer threaded axle, cooling fins, etc. but of course they said no. The average joe does not wan that crap and the average joe is who butters their bread. Fair enough.

I am sure that soon there will be some mega motors coming out. . . Maybe in the next 2 years when the EV's pick up.

-methods

I'd still like to see some super side covers in the future to pimp my existing X5 I can dream

Anyways, the attached mechanical drawings agree with our findings (from ebike.ca site)
John aka getadirtbike @ http://www.e-mtb.com.au clearly has the M12x1.25 sized axles and sidecovers with matching bearings. With the strong drop out and torque plates his bikes use, those motors actually seem like a better option.

"average joe" probably is better off with the version you and I have. Ah well...

Have a look at the PDF's they paint a clear picture and I should have realised this before. The different bearings are the last major piece of the puzzle I suppose. My own measurements match the X5_nodisc_... pdf very closely.

I'm not convinced that hubmotors are the best solution for a bike or electric moto that sees serious air time at BMX tracks or moto parks/tracks but they're still the best "drop in" option we currently have even if a bit of messing about is required.

That's it for me today, I've got an exam tomorrow.

[methods]

.... So back to the original question that I was asked.... Can I supply a side cover to fit a rear disc brake on an X5 with a 14mm axle??? .... yes.... but you'll have to work out an alternative for the plastic sleeve. . . . .

Good man!
That was some clear communicating. Others would do well to take notes
Thanks for taking the time to explain.

So there are two points that I would like to clarify in my mind:

1) How many mm will we need to spread the 135mm forks (7.5mm on each side?)

2) How many mm of threaded axle will this leave for fasteners (18mm - 8mm = 1cm of threads?)

It sounded like you were saying that we would need to space the left side 7.5mm to get the disk lined up with the caliper. I visualize this as a 7.5mm torque arm between the X5 and the inside of the drop. Is there some reason that we would also need to space the same 7.5mm on the other side other than to center the wheel? Assuming we do have to space 7.5mm on each side for a centered wheel:

Currently I have 19mm of available threaded axle extending past my drops. Take from this 1mm for the rounded tip of the axle and 8mm (rounded up for margin) of spacing and that only leave 10mm for an axle nut. That is doable but. . . I would want to have a ** REALLY ** good torque arm in that case. Currently I run 14x1.5 automotive lug nuts to engage as much thread as possible. Cutting that in half would be a hard concession.

The only real show stopper I see there is if someone then strips/scrubs/mars the last 1cm of threads they would be hosed. On my motor I have actually stripped out the threads from the drop out about 10mm so I only have the last 10mm of the axle as good thread.

As far as cutting down the plastic. . . I think I already took that off mine but I would have to check. I certainly have an angle grinder

-methods

[methods]

That's it for me today, I've got an exam tomorrow.

School? Nice!
I finally finished the longest Masters degree known to man just 3 months ago . . . It took me 5 years to finish my MSEE. To be fair it was Stanford (which was very, very demanding) and I was working full time so I could only handle 1 class at a time

What are you studying and how long till you are done?

Dude. . . I am SO glad to be done with my endless education.
I did not "get out of school" till I was 31 years old!
All that time my friends had all the fun, got all the tail, drank all the beer, while I did homework. . .

But now.... Now they can kiss my ass cuz I got my meal ticket

-Patrick

[voicecoils]

Check your PM's Methods.

Cheers!

[getadirtbike]

Methods,

You'll have to work out the remaining axle length for yourself.... your calculations sound right ..... just to make it all the more exciting some axles are longer than others.

You should space both sides evenly... or you'll have to dish the wheel accordingly... Like I said. All bikes are different and I can't give you answers unless I have the motor and the bike here in front of me. Dishing the wheel weakens it so try to avoid that.

6mm wide is enough for a strong torque arm.... (one on each side).... That's the maximum torque arm width that I use and I've never had one fail.

Think of the nuts being there purely to stop the wheel from falling out of the dropouts. A 10mm nut is all you need for this. The transmission of torque should be handled separately.

[Kurt]

When I first got my x5 I did I quick test fit of my disk brake to my x5 side cover it came with a 7" disk and a threaded aluminium adaptor.The x5 side cover boss was threaded both sides for the 7 speed cluster the other I screwed the disk to. Fitting it between the drop-outs wasn't a problem but the distance from the inside of the rotor to the hub wasn't enough to fit a calliper over. You can unscrew the rotor a bit and put a thick spacer there but even then it will be pushing it. The calliper I tested is about 15mm thick.

The other issue is when you lock the rotor down onto the x5s threaded boss there is a Sh** load of run-out. Putting the x5s axles between centres on a lathe and a drive dog/carrier you could face the surface true to the axle.

Perhaps the 8" rotor gives you a little more room between the inside of the rotor and the hub as it starts to tapper in a little a about 8"radius.Or there could be some callipers that are thinner than 15mm.

I haven't put any more time into it other than a quick look at first I am sure I could make it work but its not a bolt on job.

[getadirtbike]

OK.

I've decided that I'm going to make a batch of disc brake covers to fit the X5's withe the 14mm Axles. They'll have the correct 25x47x12mm bearing in them so they'll fit straight on to the existing motors and a Crystalyte screw on disc will fit them.

Whether you'll have enough spacing to fit the wheel between your dropouts is something that you'll have to work out yourself.

I'm only going to make these covers once so if anybody would like one they need to let me know in the next week so that I can order the parts that I need from Crystalyte.

I can be contacted through here or via http://www.emtb.com.au

I'll require payment before I order the parts to avoid tyre kickers.

The covers will cost $60 AUD each plus $10 AUD postage within Australia or $30 AUD postage to anywhere else in the world.

As I said. I'm only going to do this once so if you want one, now's the time to get one.



If

[64ragtop]

OK. I've decided that I'm going to make a batch of disc brake covers to fit the X5's withe the 14mm Axles.

The covers will cost $60 AUD each plus $10 AUD postage within Australia or $30 AUD postage to anywhere else in the world.

I'm only going to do this once so if you want one, now's the time to get one.If

Live rates currency converter at 2008.11.14 06:21:10 UTC

90.00 AUD = 58.8541 USD

So, can you take $59.00 US via PayPal? If not, what's the best payment method?

I knew we'd get this worked out sooner or later - probably sooner!

ATB

BC

[getadirtbike]

Anyone interested should email me at fivezip@optusnet.com.au

Yes, I can accept Paypal

[methods]

I will probably pick one up to.
I just know that Murphies Law will apply and as soon as I order one on the long lead I will find another local solution.

I have been eyeballing docs solution:

download/file.php?id=12993

from this thread:

viewtopic.php?f=2&t=4409&p=92875&hilit=+rack#p92875

Trouble is that Doc has very thin steel drops whereas I have big fat aluminum drops. My drops are as wide as his torque arms + drops.

-methods

[getadirtbike]

So far I'm only going to make 1 disc brake cover for voicecoils.

I haven't had any other emails frm anyone so I guess that's it.

Last chance because as I said I won't be making any more after this.

[64ragtop]

Whoa! I want one too! Didn't realize there was such a short time frame, but yeah, count me in, please!

$59.00 US sent via PayPal just now! Thanks for the reminder, as I'd wandered off on another project for a
couple of days.

Shipping info sent in separate email to fivezip!

ATB

BC

[methods]

Yea, I have been spacing out too.
You may want to repost a "last chance" in another thread as this one is in the "General" section. . . I dont normally even look here and only found it due to a specific search.

I will send you an email right now.

-Patrick

[methods]

Ok, I ordered 2 sets (2 cover & 2 disk)
I will be making a pair of plastic sleeves to match.
IIRC ebike.ca makes a converter that will allow you to run a normal disk if you prefer.

Anyhow, I dont need the second setup. I just bought it because I was sure someone would come along late looking for one.
If that is you, it will be in the Bay Area of California when you want it.

I will sell it to you at a criminal markup

-methods

[voicecoils]

Sweet, I'm glad to see this is moving along.