2 wheel drive DH bike build (Delta/Wye Upgrade)

[GrayKard]

Ordered tires and tubes from Specialized.

Specialized Compound Control Tire.jpg (14.53 KiB) Viewed 1184 times

These will go up to 100 psi, so if I want to minimize rolling resistance I can air them way up, or keep them soft to absorb small bumps.

I also took the rims and motors to be laced up. He had a few jobs ahead of me so he will let me know when they are done. By the time they are ready my other stuff should be here and I can finally start assembling this beast.

I didn't know it would take this long but I think it will be worth the wait. Plus it's given me lots of time to tweak components.

While I was typing this post some stuff showed up.

Torque arms and lights.jpg (60.22 KiB) Viewed 547 times

Yeah buddy! Torque arms, lights and connectors.

Gary

[GrayKard]

It Lives! Well sorta...

I ran into a problem with the front motor. With washers installed inside the dropouts it caused some binding of the shocks. I'm not going to risk riding it like that so I only put the rear motor in place.

Now the rear went in great. I've got my 8 speed freewheel on and disc rotor installed and they both line up and function great. I did use a wider than supplied washer on the rotor side to get more clearance and a better fit.

I like the clean sweep rotors. They don't have the pulsing of the ones that came from the factory. And they just look way cooler too.

Rear wheel.jpg (44.6 KiB) Viewed 547 times

The wiring is a mess right now and will get worse until I finalize the controller mounting. As of now I only installed one controller and it's held on with a screw in the water bottle mount and some electrical tape.

Controller.jpg (42.76 KiB) Viewed 1145 times

Lots of extra wire up on the handle bar too. Some of it is from the second throttle wire not routed yet and the rest is the slack from the new headlight.

Throttle wires.jpg (37.56 KiB) Viewed 1146 times

I did a little riding last night but didn't bother recording any data. When I got to work I checked and the peak amps was 20.8 the minimum volts were 48.8 and that occurred at the same time as it matched the peak watts of 1015.

Sorry but I couldn't read the meter while riding as it had to be mounted near the controller due to short wires. I will change that later.

With one motor no peddling it did 16.5 to 17mph on the flats but I need to do runs in both directions later to confirm true speed. The no load speed of the front motor when testing earlier was 21mph but I did not test the rear. I'm thinking it will do about 18mph unassisted with both motors running. Not quite as fast as I was shooting for but pretty close.

I just can't wait to ride home now. No more tired legs if I don't want 'em. And I look forward to blowing past a few lycras on the weekend.

[Mark_A_W]

Are you sure you have the right winding motor?

With 48v I would be hoping for a no load speed of about 45kmh, which is closer to 30mph.


But glad to hear it is running and keen to hear how it goes with two motors, should climb straight up the walls!

[The Stig]

Nice, when are we gonna see some vids? I didn't quite understand the problem with the front motor, did you not have enough washers or does the axle need some filing or something?

They only thing I want to find out with these little motors before I do my dual 108 motor build is how little drag they have when freewheeling. Did you observe anything in that respect? If you've owned any other geared hub motors a comparison would be great.

[torker]

That's a good speed for offroading. Might get a little tedious for commuting. Or not. How fast did you travel on legs alone? How does that little motor pull from a stop? Get to speed pretty quick?

[torker]

Also wondering. BMSBattery is not showing any ebike batts on their site ????

[GrayKard]

Are you sure you have the right winding motor?

With 48v I would be hoping for a no load speed of about 45kmh, which is closer to 30mph.


But glad to hear it is running and keen to hear how it goes with two motors, should climb straight up the walls!

From what I've heard the Cute motors are wound for Euro standards so about 15mph on the road speed. If you want more speed I guess you need to get motors wound for 24 or 20 inch wheels and put them in 26 or 700c rims.

I think I'm getting a bit more speed because it's a very light build and I've gotten quite skinny since I started biking. I'm at 135 pounds plus 15 for backpack with battery. The bike with motor and stuff is around 45 pounds at a guess. I need to weigh it tonight.

[GrayKard]

Nice, when are we gonna see some vids? I didn't quite understand the problem with the front motor, did you not have enough washers or does the axle need some filing or something?

They only thing I want to find out with these little motors before I do my dual 108 motor build is how little drag they have when freewheeling. Did you observe anything in that respect? If you've owned any other geared hub motors a comparison would be great.

I bought a new video camera for Christmas so I plan on getting some vids hopefully on my next day off.

OK, let me see if I can describe the problem a little better. The flats on the axle at 1.5cm are too small around IMO to have them directly against the dropouts. In comparison the flats on my QR hubs are 2cm. So I put in the supplied washers. It required me to spread the dropouts by the width of the washers which is causing the shocks to bind.

My solution will be to grind down the flats so that with the washers installed there will be no spreading. I will actually only grind on one side as the other has a nut on it and is shorter already. There is plenty of extra flat width for me to easily take off the width of two washers.

These are the first motors I've owned or ridden on so no comparisons possible. I did ride the bike around with the rear motor installed but no controller hooked up. It didn't seem to have any drag at all. But with it hooked up to a controller I can notice some drag I assume from it acting like a generator? It felt about like having knobbie tires as opposed to slicks.

It's also pretty quiet at speed with just a low growl as it winds up from a stop.

[GrayKard]

That's a good speed for offroading. Might get a little tedious for commuting. Or not. How fast did you travel on legs alone? How does that little motor pull from a stop? Get to speed pretty quick?

Yeah it should be great offroad. I was riding in the grass along an access road to stay out of traffic yesterday and it was plenty fast and fun.

My normal peddling speed was only about 12mph average so if it goes up close to 16mph that's a big boost. I may want more speed later but for now even the one motor is nice. I think with both running I will be happy.

It won't break traction on dry pavement from a stop so not a huge amount of torque but adequate. Not sure how long it takes for top speed so I'll check on that next time I'm on the bike.

So far it hasn't stalled out on any hills. 10mph without peddling is the slowest it's gone on some pretty steep ones. I need to get an inclinometer to get an accurate reading though.

Also wondering. BMSBattery is not showing any ebike batts on their site ????

That's weird. I wonder if they are consolidating websites over to ecitypower.com. That's their other site btw.

[torker]

I just read on the CUTE hub thread that it is the Chinese new year till march. That may be why the BMS site seems empty of stock. Or maybe you have to be logged in to see it. Plus on ecitypower do you have to contact them for prices? Sorry to get off topic.

[GrayKard]

I just read on the CUTE hub thread that it is the Chinese new year till march. That may be why the BMS site seems empty of stock. Or maybe you have to be logged in to see it. Plus on ecitypower do you have to contact them for prices? Sorry to get off topic.

Not off topic at all since that's where I got some of the major parts for the build.

Yep you email them with specs of what you need and they will tell you if it's possible and I would think they would do some quotes for different setups. How I did it was I contacted BMSbattery and the people who responded were from ecitypower and we did the old email tag. Actually the battery purchase went fast. It was buying the motors that was slow as they had just started selling them and didn't really know the specs.

I really haven't used the batteries enough to say much about them. I've maybe used 1.5 ah out of each a few times. Work has just been nuts lately but as soon as it settles down I will do some serious testing.

I should probably start a separate thread for the test data though and leave this one for finishing up the build.

Gary

[full-throttle]

I ran into a problem with the front motor. With washers installed inside the dropouts it caused some binding of the shocks.

Is there a way of installing the washers on the outside of the dropouts? Looking at the pics here http://endless-sphere.com/forums/viewtopic.php?f=3&t=14109&start=30#p221058 the axle is def long enough.

Great build BTW!

[torker]

On most hubs there is a very small flat area to rest against the forks if you don't have the washers in place. The axle would probably try to pull through the fork when you tightened it. That washer pretty much has to be there.

[Mark_A_W]

I've never used a washer like that, haven't had any issues.

[dogman]

Depends on the motor, some have larger diameter bearings, allowing a decent shoulder on the axle. Others have smaller axles with tiny shoulders, and need the washer or the motor will start spreading the dropouts. I had a similar problem with the washer and the suspension fork. One fork fits fine with the washer and the other binds like hell. I was able to just switch forks rather than grind the flats a bit deeper.

[GrayKard]

I ran into a problem with the front motor. With washers installed inside the dropouts it caused some binding of the shocks.

Is there a way of installing the washers on the outside of the dropouts? Looking at the pics here http://endless-sphere.com/forums/viewtopic.php?f=3&t=14109&start=30#p221058 the axle is def long enough.

I will have washers on the outside too. Just to confirm what the last few posters said about it: The flats are too small on this hub to install it without washers there. If the dropouts were steel and it looked like a good fit I would consider leaving the washers off. But since it's aluminum I'm going with overkill on the mating surfaces.

Great build BTW!

Thanks, I can't wait to get the other motor on!

[cell_man]

Hi Graycard,

Is your front motor the same QX85 motor that you have on the rear? I assume it is as that's all that will fit with disks on the front. I've got both versions and on 1 side of the axle there is a small nut that can easily be removed. If it were me I would start with that nut and take a little bit off of it. Just spending 10mins rubbing both sides down on a piece of sand paper would sort it. It's not doing so much there and doesn't need to be particularly strong. I'm sure you could lose maybe up to 2mm from that nut. If you can find some quite thin stainless steel washers that might be enough to stop the binding. I don't think the slotted washers that are included are necessary on the inside of the dropout and they are pretty thick too. If you need a bit more removed I'm sure you could carefully take a little material from the disk side of the axle. As long as you get it reasonably flat I'm sure it will be just fine. If you carefully took some material off with a handfile it would be fine. If you wanted a proper job take it apart and get it machined down on a lathe. The Axle is actually 2 pieces. It's not so difficult to take the motor apart once you've made a tool to take the side cover off (it's threaded on) but if the motor hasn't been run yet it shouldn't be so tight.

Best of luck
Paul

[GrayKard]

Hi Graycard,

Is your front motor the same QX85 motor that you have on the rear? I assume it is as that's all that will fit with disks on the front.

I measured them and they are 108mm from spoke hole to spoke hole so they are both QX100 models. I also checked my dropout widths. The front is right at 100mm and the rear is 135mm.

I've got both versions and on 1 side of the axle there is a small nut that can easily be removed. If it were me I would start with that nut and take a little bit off of it. Just spending 10mins rubbing both sides down on a piece of sand paper would sort it. It's not doing so much there and doesn't need to be particularly strong. I'm sure you could lose maybe up to 2mm from that nut.

Yeah, that is a good option, didn't even think of that.

If you can find some quite thin stainless steel washers that might be enough to stop the binding.

Another good idea that could be used with the first so less material would need to be removed from the nut.

I don't think the slotted washers that are included are necessary on the inside of the dropout and they are pretty thick too.

IMO the slotted washers are completely inappropriate for an install on aluminum dropouts. They don't transfer the torque to the frame they transfer it to the dropout slots which is what you want to avoid.

If you need a bit more removed I'm sure you could carefully take a little material from the disk side of the axle. As long as you get it reasonably flat I'm sure it will be just fine. If you carefully took some material off with a handfile it would be fine. If you wanted a proper job take it apart and get it machined down on a lathe. The Axle is actually 2 pieces. It's not so difficult to take the motor apart once you've made a tool to take the side cover off (it's threaded on) but if the motor hasn't been run yet it shouldn't be so tight.

Best of luck
Paul

I do have access to a metal lathe but I don't feel like doing all that work to get the axle out.
I'm going to use my dremel tool as I'm pretty good with it when I take my time.

[GrayKard]

Yesterday at work I noticed a puddle of oil under my bike right at the BB. I cleaned it up and found the source to be my rear shock. I guess I blew out a seal on the way to work.

Did the extra unsprung weight of the hub motor cause this? No idea.
Did the weight of two battery packs at about 25 pounds push it over the edge? Maybe.
Is this a good excuse to upgrade the rear shock? You betcha!

The one that came on it was kinda crappy but it did work pretty good while it lasted. Luckily it had a coil spring around it or I wouldn't be able it ride it now. I ordered a Rock Shox Ario 3.2 for a replacement.

I wonder if I'll damage the front shock with the extra weight too.

[cell_man]

Agreed the slotted washers that most ship with their motor are not great. The best 1s I've seen are those that ship with the Bafang motors. They are a proper machined part and can be used indide or outside the dropout.

When I say QX85 I just meant the width and that is the way Ecity described them. Basically the QX100 takes up the full width of 100mm forks and cannot accept a disk brake. The QX85 has fittings to bolt the disk directly to the side of the motor. The QX85 is a little lower powered though than the wider QX100. Both the QX100 and QX85 have 108mm spoke radius.

I reckon you'll be ok by just messing with that nut and changing the washers. Even modding the axle a little is no big deal with a steady hand and a dremmel

[GrayKard]

Agreed the slotted washers that most ship with their motor are not great. The best 1s I've seen are those that ship with the Bafang motors. They are a proper machined part and can be used indide or outside the dropout.

When I say QX85 I just meant the width and that is the way Ecity described them. Basically the QX100 takes up the full width of 100mm forks and cannot accept a disk brake. The QX85 has fittings to bolt the disk directly to the side of the motor. The QX85 is a little lower powered though than the wider QX100. Both the QX100 and QX85 have 108mm spoke radius.

I reckon you'll be ok by just messing with that nut and changing the washers. Even modding the axle a little is no big deal with a steady hand and a dremmel

Ahh, I thought the different motors had different diameters, now it makes sense. So I originally ordered the QX128's but they told me they wouldn't work. I switched to QX100's that they said would work. But they sent me QX85's which do fit with a little coaxing. Makes me a bit angry that they didn't consult me, or notify me about the changes, before sending them. Thanks for clearing that up.

Guess I'm doing a review of dual QX85's. Sorry for any confusion this may have caused anyone.

I took a closer look with the front installed and unmodified. The side with the nut is already very close to the leg of the fork so I'm not going to shave it down. The other side has plenty of extra shoulder so I'm taking all the width I need off that side.

Yeah, I'm good with a dremel so it should be a piece of cake, just need to do it.

[cell_man]

It shouldn't matter even if the nut is cut back as long as the washer you use has less than 20mm outside diameter. There is a recess on that side of the motor and if the washer fits in there it's all good. I would say that nut is very likely not required if it's replaced with a suitable spacer/washers. Try spinning the axle and looking at that side of the motor and you'll see what I mean.

[LI-ghtcycle]

Love the Idea!!

I have to ask, do you plan on just using it for a commuter, or will you be doing some trail riding too? I have skeptic shop owner who doesn't think DH and electric bike go together.

I'd love to show your build as an example to prove him wrong!

[GrayKard]

It shouldn't matter even if the nut is cut back as long as the washer you use has less than 20mm outside diameter. There is a recess on that side of the motor and if the washer fits in there it's all good. I would say that nut is very likely not required if it's replaced with a suitable spacer/washers. Try spinning the axle and looking at that side of the motor and you'll see what I mean.

That isn't the issue. It's the distance from the cover to the fork leg. If I remove the width equivalent to two washers from the nut, and only put one washer on this side, it will probably rub. But if I remove it from the other side and add a washer here I will gain a bit more clearance.

Very close.jpg (50.58 KiB) Viewed 457 times

Love the Idea!!

I have to ask, do you plan on just using it for a commuter, or will you be doing some trail riding too? I have skeptic shop owner who doesn't think DH and electric bike go together.

I'd love to show your build as an example to prove him wrong!

It's intended purpose is for commuting but... Shhh, don't tell anybody, I already tried it offroad with both motors temporarily installed. It was a blast! I had an EV grin on steroids.

I had to limit myself as the rear shock is still bad and the trails were messed up from rain and wind. But I got a taste of what it will be like and I can't wait to go out again.

[LI-ghtcycle]

Your proving the naysayers wrong already! Good work!

I'm going to do some off-roading myself tomorrow, nothing too technical (or so I hope! ) just some moderate trail riding, my brother trashed his mountain bike in this same place a few years back coming down the mountain in the dark I'll hope to avoid anything like he ran into, but anyway, I get to put on my best knobbies and take a shot at some trail riding myself.

I couldn't help but notice your build list as I was just today tallying the value of what I have into my E-Bike, and I got lots of deals and didn't have to pay retail, but all told I came up with $3087 so far, and I'm planning on eventually doubling the battery pack, maybe I should look into eventually running a second geared motor on the front wheel too ... that would be a beautiful thing!

You're living the dream, keep us posted!