Lacing your own motor?

[Sunder]

As I get closer to my weight loss goals (70.7kg @ 16.6% body fat), I'm looking more and more at lighter bikes to replace mine.

One thing I have noticed though, is that the good, light bikes, always come with good, light wheels, usually with a fairly deep rim to reduce wind resistance. They also have very light rear cassettes. It would seem a shame to replace them with a huge heavy wheel with a shallow rim and a heavy cassette.

I'm wondering if anyone has ever laced their own wheel out of a motor? Where would you get such a motor? Or shortened spokes? Is it hard?

Just a thought at the moment, and not committed to doing, it, but just considering how hard and expensive it would be to do.

 

[ohzee]

I moved a wheel from a broke rim to a good rim by taping the rims together and moving spokes one by one.

The hard part and where skill is required seems to be making the rim true. When I had the spokes mostly tight I
took it to a local bike shop and for 30 bux they trued the wheel.

It's not impossible , but it does take some skill.

 

[MadRhino]

I laced them all 5 hub motors that I have. 2 of them have been purchased laced, but had to be re-laced soon cause I ride offroad fast and rough. Lacing a wheel is not a complicated task, but one need patience to true the first ones. The more you do, the better you become, like anything else.

Lacing a hub motor doesn't let you the choice of pattern, short spokes and wide flange require single cross. One could also lace radial, but not for offroad and high power. You may be lucky and find a local shop that is equipped to cut and thread custom spokes, else you will have to order online. Ebike.ca and Johnrobholmes can provide.

If you want lightweight and like to exercise, you're likely to prefer a geared hub motor. Look for Cellman who sell Puma, Ebike.ca has the Ezee, Ebike SF has BMC, all very similar motors with various kit quality. Lace one with butted spokes on the lightweight rim of your preference, then bring it to the local bike shop for fine trueing if you lose patience.

 

[RallySTX]

Welcome to The Sphere. It's nearly impossible to true a rim once it has been warped. It's much easier to pay a shop or person with a proven track record to do it right the first time. So, unless you are interested in learning a new skill, just send your work to JohnRobHolmes. He does the best work I have seen on this site. Holmes Hobbies is his store. Congrats on the weight loss. Best of luck with your build.
Brian L.

 

[Sunder]

So sounds like it's possible, but not easy...

Wonder if it's worth it to save 2kg and lower wind resistance.

May have to buy some junk wheels to give it a shot before I try it on a good rim.

 

[john7700]

So sounds like it's possible, but not easy...

No one here is saying it is hard. I personally never found it that difficult, particularly if it is already laced and you just transfer the pattern. As said, a shop can finish it up for you. Some one said $30.00 but I would be really upset if my shop charged me that much for 15 minutes work. I have heard JRH work is excellent but really any shop can do this for you.

Wonder if it's worth it to save 2kg and lower wind resistance.

The better reason would be that any pre-built hub wheel that I have seen so far is complete rubbish and you would benefit from a good rim. Rolling weight is the best way to lighten your bike but I don't really see that as to important on a powered bike,


May have to buy some junk wheels to give it a shot before I try it on a good rim.

Just google wheel truing/building to learn how. Chances are junk wheels will have siezed nipples.

J

 

[dogman dan]

Hmm, it's easy and hard at the same time. The thing to do is practice first on junk. Get two nearly identical or identical crap wheels from the bike shop dumpster. Prefrably front wheels, so you don't have to remove the freewheels first.

Then take one apart, and looking at the other, figure out how to put the spokes back in right. Always start with the one at the valve hole, so you don't have a cross on top of it. then count how many holes to skip in the rim to put in the next spoke on the hub in place. Work both sides of the hub at once, working around the hub. Pay attention to which way the butt end faces, and which spoke crosses over the other.

Actually pretty easy, once you grok it. If you don't snap in your mind as to how it works, you'll struggle. Think in terms of the two pairs of spokes in each group. You should be able to see that pattern in single cross pretty easy.

Goes without saying, it's over your head if you can't even true a wheel yet. Once laced, get all the egg shape out first, then go after the side to side wobble.

Edit, yeah, do look for junk wheels not completely corroded up. And shoot a bit of wd on the nips if they are pretty stuck. I forget, many of you don't live in the desert like I do. A beach bikes junk wheels would be a waste of time.

 

[john7700]

Edit, yeah, do look for junk wheels not completely corroded up. And shoot a bit of wd on the nips if they are pretty stuck. I forget, many of you don't live in the desert like I do. A beach bikes junk wheels would be a waste of time.

Or have a foot of snow in the front yard right now

Edit: People really should fill out location in their profile. Helps a lot some times.

 

[Drunkskunk]

http://sheldonbrown.com/wheelbuild.html
A good palce to start getting info.

Its worth it to build your own, Even if you don't save an ounce. You'll likely have something far better than you could have bought tailored to your specific needs and style.
And you'll also have no anxiety about fixing it when stuff goes wrong, and Murphy's law says stuff will eventually go wrong.

Easy is relative. Its not hard work, but its a process with many many steps and takes time.

 

[dogman dan]

Yeah, easy is quite relative. Lacing a straight rim and truing it could be quick and easy, compared to trying to keep a wrecked rim even sort of straight. Either task requires the right state of mind or mood. Slowish and methodical. No 3 cups of java before you start, but not tired at the end of the day either.

 

[Sunder]

Okay. Have looked at what hub motors I could use.

My main goal is to create a stealth bike, so I'm sticking to fairly low powered mini-motors.

I'm thinking about a MBG36R Here: http://www.goldenmotor.com/hubmotors/hubmotorIndex.html

250W is probably great for the majority of my commute, since it's mostly flat, and I pedal most the way anyway. But there are a couple 500m hills that I think this won't cope with.

I've seen other posts saying that motors don't know or care about voltage, just total power delivered.

So what happens if I get a 36V model and use a 48V brushless controller? and a 56v battery? Will it survive a 500m climb, or will I burn it out?

 

[RallySTX]

A 48 volt controller might have a problem with over 50 volts coming at it. I would try the 48 volts first and see where it takes me, and go from there. But I'm a noob, haven't even finished my bike yet.
Brian L.

 

[DAND214]

Or have a foot of snow in the front yard right now

Edit: People really should fill out location in their profile. Helps a lot some times.

I had a good guess without the loaction.

I wish it was in all the profiles of where they are located.
It makes it easier to understand what they and we are dealing with.

On subject, I have done about 6 wheels. Tne first was just a wheel swap, so it wasn't tough at all. Others were fresh starts with differant hubs and wheels. I still struggle getting the 1st spoke in the correct hole and truing is getting better. So if you want to do it, just sit down and do it!

Dan

 

[amberwolf]

So what happens if I get a 36V model and use a 48V brushless controller? and a 56v battery?

Well, the voltage will rpobably be ok. Not sure about the 56V; depends on the caps and FETs and low-voltae regulator in the controller. 48V SLA fully charged is up to maybe 54.4V, so many 48V controllers should take at least that much. Not sure what headroom they have, though. My guess is 60V or so absolute max, possibly 63V (cuz of caps), but you'd have to either try it or check the part ratings.

Will it survive a 500m climb, or will I burn it out?

My guess is that it will operate, but it might not last long. If it is a geared motor, especially, because it takes so much longer to dissipate the heat that builds up inside.

See my DayGlo Avenger thread, somewhere in it's most recent pages, for my 500W 36V-wound Fusin geared motor's experiences at 48V pulling a heavy load for a distance, whcih is probably equivalent to your hill problem.

Thing is, these small motors (DD or geared) are rated lower not just because of their windings and such, but because they have less ability to dissipate the heat that builds up in them, vs a larger-surface-area motor, plus since they have less mass, they will heat up faster and more thoroughly than the larger motors, too.


If you can keep the motor cool (forced-air cooling via ventlation, etc) then you can run whatever you like thru it. But if it gets too hot too fast, either the windings or the halls are toast.

 

[dogman dan]

As soon as people say hill, it's all relative just like the word easy.

When I was test riding the fusins AW has now, I found they could climb 7% grade, but you had to be careful for how long you climbed that steep.

But 5-6% was really no problem if you helped the motor with pedaling briskly. The main thing was that 400w was never going to climb the hill as fast as anothe motor with 800w. But hills less than 1.5miles long can be climbed with the small motors. It just goes slower and slower as the grade increases, increasing the time period for the hard pedaling part of the ride.

If you have real hills, then you want more watts, like a larger dd motor.

 

[AussieJester]

All the information you need to learn to lace and true a wheel can be found here

http://www.sheldonbrown.com/

Its not difficult takes me under 20 minutes to lace a cros 2-3 pattern maybe another
15-20 to true it... Theres spoke calculators online to find the length of spoke required
put in the hub dimensions and rim size and it gives you the length of spoke needed.

Best of luck

KiM

 

[kmxtornado]

Hills are a different story (issue can be solved or improved at least with a Shimano Megarange cassette with a huge granny gear like 34T), but in regards to the cost of lacing a wheel? I had a Sturmey Archer IGH (internal gear hub) laced on a rim I provided and the total for truing, spokes and labor to lace came out to almost $200. It was btw $150-200. I don't recall, but to me that's not exactly cheap.

Although truing may be the tough part, calculating the correct spoke length is also maybe a bit of a task. Remember since there's a freewheel on one side, the spokes on the left and right are not the same length. Looking directly at the back of any rear wheel, you'll notice it's slightly off centered to accomodate the cassette/freewheel.

If you're only going to do this once, have no real interest in the DIY stuff, I'd recommend taking it to a shop. Push the economy. Let the pros do their thing. If you do it yourself, you'll need to buy a truing stand (or fabricate some sort of way to do it), plus a few other tools which you may not have. In the end, it may not really be worth doing it from a financial standpoint. If you're doing a bunch of these, then it probably is worth learning and buying the initial equipment for setup.

Good luck and let us know how it goes. We like to see pictures.

Oh and while you're at custom lacing a wheel (whether you do it yourself or at a LBS), this is your chance to choose your spoke and nipple colors! Take advantage of it if you want that cool custom look. Make sure you buy the appropriate rim type. You'll need a "machined" one (silver lip) if you don't have disk brakes.