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

General Discussion about electric bicycles.

Re: 2 wheel drive DH bike build

Postby GrayKard » Tue Dec 15, 2009 6:48 pm

dogman wrote:longer seatpost would tend to reinforce that area. It looks to me like where the seatpost ends inside the tube. If further down, a second, cut off section of seatpost could reinforce the area from inside some.


Looking at it again it does appear that it cracked where the bottom of the seatpost would be. If the shock had done it I would think the crack would be on the other side of the down tube.

Maybe being aware of the problem and never doing drop offs without most my weight on the pedals will make this less likely to occur. I will be using a much lighter setup and I only weight 135 pounds so the stress should be a lot less on the frame.

I think I will also look around and see if I can find a seat tube that will almost bottom out in the down tube to reinforce this area. Couldn't hurt.
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Re: 2 wheel drive DH bike build

Postby TylerDurden » Tue Dec 15, 2009 8:45 pm

On retrospect, an internal post may not resolve the cracking. That is not a torque fracture. It appears to be pulling the bracket right out of the tube.
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Re: 2 wheel drive DH bike build

Postby Qwiksand » Wed Dec 16, 2009 10:51 am

TylerDurden wrote:On retrospect, an internal post may not resolve the cracking. That is not a torque fracture. It appears to be pulling the bracket right out of the tube.


I think you're on the mark here, TD. The crack is at a high-stress point just below the seat tube shock mount, a good 12" below where the seatpost ends.

It seems that most of these failures happen on large (20") frames with riders in the over 200# category, so even fully built with a crap-ton of batts, GK should still be under that weight load. With camelback and gear, I weigh in around 210-215- I put alot of miles on this frame at that weight with rear shock pressure set around 110-120 psi. I think my increasing the rear shock psi to 160 coupled with the increased weight on both sides of the shock assembly fulcrum (heavier rear wheel and heavier triangle/rider) caused my failure.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Wed Dec 16, 2009 1:23 pm

Qwiksand wrote:
TylerDurden wrote:On retrospect, an internal post may not resolve the cracking. That is not a torque fracture. It appears to be pulling the bracket right out of the tube.


I think you're on the mark here, TD. The crack is at a high-stress point just below the seat tube shock mount, a good 12" below where the seatpost ends.

It seems that most of these failures happen on large (20") frames with riders in the over 200# category, so even fully built with a crap-ton of batts, GK should still be under that weight load. With camelback and gear, I weigh in around 210-215- I put alot of miles on this frame at that weight with rear shock pressure set around 110-120 psi. I think my increasing the rear shock psi to 160 coupled with the increased weight on both sides of the shock assembly fulcrum (heavier rear wheel and heavier triangle/rider) caused my failure.


Is it possible that the rear suspension also bottomed out at some point causing a huge spike in the pressure on that area? Or did the higher air pressure you put in the shock prevent that?

The fact that you put a lot of miles at a bit over 200 pounds with no problem does encourage me as even with my batteries and my usual gear I will be at about 170 pounds. The bike should come it at about 45 as I dumped the rear rack which was nothing but a headache.

Gary
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Re: 2 wheel drive DH bike build

Postby GrayKard » Wed Dec 16, 2009 10:22 pm

The test fitting of the motors looks good. Here's the front motor in:

Front motor fit.jpg
Front motor fit.jpg (140.6 KiB) Viewed 669 times

Had to remove the paint inside the dropouts for it to slip in. I will also have to file a little to get the curve to match the axle and go all the way down.

Width was a perfect except the inside washers aren't on yet. I will have to spread the dropouts to get those in. I will be adding torque arms once the fit is right.

Now the rear motor:

Rear motor fit.jpg
Rear motor fit.jpg (163.34 KiB) Viewed 607 times

This one dropped in without any tweaking. Yes that's an 8 speed freewheel in there. It will have the same spacing as the freehub once the washers are on. Same as the front the width was right on without washers. Very little spreading will be necessary to make it work.

I will need to radius the drop out to get it seat all the way but it's a much better fit than the front so won't need much persuasion. Torque arms here too.

Brake rotor fit is not bad. The front appears to line up but the rear will need some work. I will need to take off a bit of material from the rear bracket to move it out of the path of the rotor. But overall a pretty darn good fit.

The thing I was worried about the most, gearing, was no problem at all. But the dropout shape I thought looked to be easy will actually take a lot of precise filing to get the snug fit it needs. I'm a perfectionist with details like that though so it will get done right, just will take some time.

I also finally decided on and ordered batteries.

48 Volt 12 AH.jpg
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Two shrink tube 48 volt 12 amp hour packs from BMSbattery. Was more expensive than the bike due to the $156.00 shipping charge. :roll:
Last edited by GrayKard on Sun Sep 04, 2011 6:44 pm, edited 2 times in total.
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Re: 2 wheel drive DH bike build

Postby Russell » Wed Dec 16, 2009 10:55 pm

Very cool :)

So those are the largest and most powerful (48V/500W) versions of the Cute motors bmsbattery/ecitypower offer right? Any idea how fast they are supposed to spin at 48V?


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Re: 2 wheel drive DH bike build

Postby GrayKard » Thu Dec 17, 2009 2:32 pm

Russell wrote:Very cool :)

So those are the largest and most powerful (48V/500W) versions of the Cute motors bmsbattery/ecitypower offer right? Any idea how fast they are supposed to spin at 48V?


-R


Thanks for the reminder that I need to edit the first post in the thread.

No, these are the smaller 108mm diameter motors. 48 volt 350 watts. I had to switch to these because after exchanging lots of emails with Rainbow at ecitypower it turns out that the 128mm diameter motors won't even fit a 6 speed freewheel without spreading the dropouts according to them.

Sorry, I don't have the rpm info on either size motor, although I seem to remember lynchy posting something about rpm on the Ananda motors in the Cute motor thread you started. My memory might be faulty though.
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Re: 2 wheel drive DH bike build

Postby Qwiksand » Fri Dec 18, 2009 9:55 am

GrayKard wrote:
Is it possible that the rear suspension also bottomed out at some point causing a huge spike in the pressure on that area? Or did the higher air pressure you put in the shock prevent that?

The fact that you put a lot of miles at a bit over 200 pounds with no problem does encourage me as even with my batteries and my usual gear I will be at about 170 pounds. The bike should come it at about 45 as I dumped the rear rack which was nothing but a headache.

Gary


The rear did not bottom out during the ride of death- the rubber o-ring marker shows the lowest travel point in my other pictures. That's not to say I've never bottomed this frame/shock before (several times actually), but not on it's last ride.

I can't wait to see your Iggy built up, I think you've got the right idea with smaller/lighter dual motors for weight balance. I tried a couple iterations of rear rack battery set-ups on another rig and was never happy with the balance either. Where are your batts going?
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Re: 2 wheel drive DH bike build

Postby Mark_A_W » Fri Dec 18, 2009 5:20 pm

GrayKard wrote:The test fitting of the motors looks good. Here's the front motor in:

Front motor fit.jpg

Had to remove the paint inside the dropouts for it to slip in. I will also have to file a little to get the curve to match the axle and go all the way down.

Width was a perfect except the inside washers aren't on yet. I will have to spread the dropouts to get those in. I will be adding torque arms once the fit is right.

Now the rear motor:

Rear motor fit.jpg

This one dropped in without any tweaking. Yes that's an 8 speed freewheel in there. It will have the same spacing as the freehub once the washers are on. Same as the front the width was right on without washers. Very little spreading will be necessary to make it work.

I will need to radius the drop out to get it seat all the way but it's a much better fit than the front so won't need much persuasion. Torque arms here too.

Brake rotor fit is not bad. The front appears to line up but the rear will need some work. I will need to take off a bit of material from the rear bracket to move it out of the path of the rotor. But overall a pretty darn good fit.

The thing I was worried about the most, gearing, was no problem at all. But the dropout shape I thought looked to be easy will actually take a lot of precise filing to get the snug fit it needs. I'm a perfectionist with details like that though so it will get done right, just will take some time.

I also finally decided on and ordered batteries.

48 Volt 12 AH.jpg

Two shrink tube 48 volt 12 amp hour packs from BMSbattery. Was more expensive than the bike due to the $156.00 shipping charge. :roll:



Don't spread your dropouts for those washers, file the washers down.


And I fear you will encounter severe wheel-dish issues with such a big cassette, and the motor is not well designed for a big cassette - the spoke rim is far away from the edge of the motor.
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Re: 2 wheel drive DH bike build

Postby voicecoils » Fri Dec 18, 2009 9:34 pm

Mark_A_W wrote:And I fear you will encounter severe wheel-dish issues with such a big cassette, and the motor is not well designed for a big cassette - the spoke rim is far away from the edge of the motor.


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Yeah, not looking good. I can't see the full swingarm from that photo but it looks like, at best, you'd end up with totally vertical drive side spokes and much longer non-driveside spokes.

Here's hoping you can figure out a solution!
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Re: 2 wheel drive DH bike build

Postby GrayKard » Sat Dec 19, 2009 11:13 pm

Mark_A_W wrote:

Don't spread your dropouts for those washers, file the washers down.


And I fear you will encounter severe wheel-dish issues with such a big cassette, and the motor is not well designed for a big cassette - the spoke rim is far away from the edge of the motor.


Well, the motor sits in the same place regardless of which freewheel is on it. The position is determined by the axle. I have not added any spacers to fit the 8 speed as opposed to a 6 speed so the dishing will be the same regardless.

What I need to do is measure the width and position of my current non motor hub and cassette and check that against the motor and freewheel setup. I suspect that they will be very similar as there is already some dishing on my non motor rim both front and rear.

The current dishing on the rear is due to the freehub, and the front is due to the disc brake rotor.

As to filing the washers: They are going to spread the dropouts regardless of their width as without them it's a perfect fit. But they have to be there as the shoulder on the axle is way too small to be the surface that contacts the dropouts.

One option would be to shave down the shoulder on the axle. But to do it right I would have to pull the axle and put it in a metal lathe I have access too. I'm not too thrilled about doing that though.

Another option I have considered it so machine a space inside the dropouts for the washer and then JB weld them in place and cut them so they are C washers. Not so happy with that option either.

Any suggestions regarding either issue are very welcome.

Gary
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Re: 2 wheel drive DH bike build

Postby biohazardman » Sun Dec 20, 2009 12:50 am

GrayKard wrote:
Mark_A_W wrote:

Don't spread your dropouts for those washers, file the washers down.


And I fear you will encounter severe wheel-dish issues with such a big cassette, and the motor is not well designed for a big cassette - the spoke rim is far away from the edge of the motor.


Well, the motor sits in the same place regardless of which freewheel is on it. The position is determined by the axle. I have not added any spacers to fit the 8 speed as opposed to a 6 speed so the dishing will be the same regardless.

What I need to do is measure the width and position of my current non motor hub and cassette and check that against the motor and freewheel setup. I suspect that they will be very similar as there is already some dishing on my non motor rim both front and rear.

The current dishing on the rear is due to the freehub, and the front is due to the disc brake rotor.

As to filing the washers: They are going to spread the dropouts regardless of their width as without them it's a perfect fit. But they have to be there as the shoulder on the axle is way too small to be the surface that contacts the dropouts.

One option would be to shave down the shoulder on the axle. But to do it right I would have to pull the axle and put it in a metal lathe I have access too. I'm not too thrilled about doing that though.

Another option I have considered it so machine a space inside the dropouts for the washer and then JB weld them in place and cut them so they are C washers. Not so happy with that option either.

Any suggestions regarding either issue are very welcome.

Gary



Well I spread the dropouts on my aluminum framed Schwinn about that much and 2K later even with a bit of trail riding I had no problems. It's just a little and you don't need it actually bent to set them. I would guess they will be fine. You could actually hit up a hardware store and get some slightly thinner washers to make it easier.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Tue Dec 29, 2009 6:43 pm

My 48 volt 12 ah batteries came in yesterday. They didn't even email me that they had shipped yet so I was quite happily surprised. The box was in great shape, no major dents or damage at all.

Box.jpg
Box.jpg (59.91 KiB) Viewed 591 times

Now all the goodies out of the box:

Batteries-and-Chargers.jpg
Batteries-and-Chargers.jpg (44.83 KiB) Viewed 591 times

One of the chargers failed the shake test. Something was rattling inside so I opened it up to see what it was. Turns out a screw that holds the board in place had come out so I just put it back in and all is well.

I checked the batteries and chargers as follows:

Charger output is stated on the bottom of each as 58.8 but one puts out 60.1 and the other puts out 60.2 volts.

I labeled them A and B battery.

A out of the box: 54.5 volts
B out of the box: 54.5 volts
I like the consistency.

A after being on the charger until it went green: 59.8
B ditto: 59.8

A after sitting overnight: 57.1
B ditto: 57.1

Now I just need some connectors and wire to start hooking them up and do some testing.

Gary
Last edited by GrayKard on Sun Sep 04, 2011 6:57 pm, edited 2 times in total.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Sat Jan 09, 2010 6:32 pm

The Holidays really slowed the build down but I did get some work done.

I finished the fitting of both motors in the dropouts. They now go all the way to the bottom so there is no chance of the axle acting like a wedge and driving the dropout apart as its forced in further. I still need to order torque arms so rotation won't do the same thing but I'll do that later today.

I'm also going to order some new tires and tubes and keep the current ones on the other rims for backups in case I want to go back to non-electric for some reason.

I'm currently working on modding the throttle just like methods did here: http://endless-sphere.com/forums/viewtopic.php?f=2&t=12356&start=169 to solve the dual motor single throttle glitch.

I'm doing it a little differently in that I'm forcing both wires through the existing hole by stripping off the outer cover. I will then use some shrink tubing to seal it back up later.

Throttle-1.jpg
Throttle-1.jpg (34.16 KiB) Viewed 772 times

On the throttle body I removed some plastic, look in the red square in the photo, so that both sensors can stack up where one was. Then in the red circle you can see where I took a small amount out of the webbing so that the extra wires would fit easier. It should not affect the strength.

Throttle-2.jpg
Throttle-2.jpg (31.94 KiB) Viewed 1160 times

I will then pot the sensors with some hot glue so it's waterproof.

On my next day off I will try to get to the LBS and have the motors put in the rims!

Gary
Last edited by GrayKard on Mon Mar 07, 2011 9:09 pm, edited 2 times in total.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Sun Jan 17, 2010 4:44 pm

Just noticed they have a new version of their torque arms at Ebike.ca. Looks perfect for my build so I ordered a couple. It now is thicker and has multiple slots for fitting on the hose clamps. It also comes with two clamps and is more adjustable.

I also ordered a front and rear light set from them as my current setup will be under powered for the faster speeds I will be averaging.

Added a few 30 amp Anderson connectors to the order and I'm good to go. :wink:

BTW I didn't get to the LBS to have the hubs laced, was too dang tired, so hope to get that done tomorrow.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Tue Jan 19, 2010 12:47 pm

Ordered tires and tubes from Specialized.

Specialized Compound Control Tire.jpg
Specialized Compound Control Tire.jpg (14.53 KiB) Viewed 1290 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
Torque arms and lights.jpg (60.22 KiB) Viewed 653 times

Yeah buddy! Torque arms, lights and connectors.

Gary
Last edited by GrayKard on Sun Sep 04, 2011 7:28 pm, edited 2 times in total.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Tue Feb 09, 2010 5:34 pm

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. :twisted:

Rear wheel.jpg
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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
Controller.jpg (42.76 KiB) Viewed 1251 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
Throttle wires.jpg (37.56 KiB) Viewed 1252 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. :D
Last edited by GrayKard on Sun Sep 04, 2011 8:07 pm, edited 2 times in total.
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Re: 2 wheel drive DH bike build

Postby Mark_A_W » Wed Feb 10, 2010 8:26 am

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!
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Re: 2 wheel drive DH bike build

Postby The Stig » Wed Feb 10, 2010 9:03 am

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.
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Re: 2 wheel drive DH bike build

Postby torker » Wed Feb 10, 2010 6:21 pm

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?
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Re: 2 wheel drive DH bike build

Postby torker » Wed Feb 10, 2010 7:11 pm

Also wondering. BMSBattery is not showing any ebike batts on their site ????
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Re: 2 wheel drive DH bike build

Postby GrayKard » Wed Feb 10, 2010 7:12 pm

Mark_A_W wrote: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.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Wed Feb 10, 2010 7:39 pm

The Stig wrote: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.
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Re: 2 wheel drive DH bike build

Postby GrayKard » Wed Feb 10, 2010 8:29 pm

torker wrote: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.

torker wrote: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.
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Re: 2 wheel drive DH bike build

Postby torker » Thu Feb 11, 2010 12:25 pm

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.
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