Wobbeling hub motor

[dande74]

Hi,

Just installed my Nine Continent 2807 (7x9). When running the wheel "in the air" I can clearly see that the axis is wobbling (see linked video). I know that hub motors aren't perfect, but this. Should I accept it or is it outside Chinese quality?

-- Daniel

[youtube]w8hRCyKbK80[/youtube]

 

[itchynackers]

The motor looks good to me. Its the rim that looks like it needs adjustment. To be expected...

 

[El_Steak]

As itchy said, the wheel is a bit out of true, not the motor. This can be adjusted by tightning/loosing spokes.

Any bike shop can adjust it for cheap. However, I would suggest you ride it a bit first because it will probably change again while it is "setting in".

The 3 motor/wheels I bought (through various vendors) were all similar to this, chinese quality I guess.

The only wheels I had that came in perfect and stayed perfect after a lot of mileage and abuse were built by professional wheel builders. One by Johnrobholmes from ES and a recent one by a local e-bike shop in Ottawa (ridemore.ca).

 

[dande74]

Look at the freewheel. Then you see what I mean. Best seen in full screen at original resolution.

-- Daniel

 

[Ykick]

As these guys say - hub motor looks fine. And the rim really doesn't look that bad to me either from what little I can train my old eyes. But even if the rim's okay now you'll eventually need to be able to touch things up with a spoke wrench. Well worth the little trouble to learn basically the ONLY maintenance procedure of DD hub motor wheel.

Tires, especially lower cost brands, may be a little out of round and/or not mounted exactly center on rim. Pretty much always use soapy water to help seat the bead and keep the wheel horizontal when airing the tire 1st time. I normally stop at a low pressure (5-10psi) and work the entire tire on the rim with my hands to make sure it's as centered as possible before final inflation.

 

[El_Steak]

Right, in full screen HD I can see the freewheel wobbling.

I don't know if this is "normal", but I have the same wobbling of the freewheel on my 2 rear motors (both nine continents). I've ridden my bike for several thousand km and never had any problem riding or pedalling with it. I don't know if the wobbling is caused by the motor cover or the cheap threaded-on freewheel.

 

[dande74]

Ok, thanks. Good to know what other people think.

 

[FMB42]

I too have noticed a "slight" amount of freewheel wobble/run-out on both my ebike and non-ebike wheels.

You should be OK as long as the rim is true enough.

 

[John in CR]

It looks like the machining of the cover maybe be off center from the casting. My 9C covers were off in that regard by almost 2mm. With that size wheel it's not likely to see high enough rpm for the resulting out of balance condition to create a vibration that could be felt. Mine was for use as a mid drive with high voltage and rpms well over 1000, so I had to machine my covers into balance. It won't affect motor operation, because the machining for the bearings, axle, and magnet ring are all done at once on a good center. It's just that the cover has more material at one edge than at the other.

 

[El_Steak]

Just to add to this, I had the same issue on the other side of the motor and my disk brake would wobble slightly, rubbing on the pad on each rotation. Fortunately, after a few hard braking, the disk bends slightly into shape, the rubbing disappears and proper braking performance is restored.

 

[jimw1960]

A small amount of freewheel wobble is normal in all but the highest price racing components. It is not unique to hub motors. Next time you ride a regular bike, look down at the freewheel while you are coasting and you will see what I mean.

 

[biohazardman]

Yup, as others have said the hub is good the rim slightly off and the freewheels nasty wobble is close to the norm for most bikes I have seen. I don't like it either.

 

[NeilP]

I'd say normal too

I have 5304 with a 11-34 7speed DNF freewheel...that freewheel wobbles like hell too. Up till now I have usually only bought Xt or XTR stuff, and never seen this sort of wobble. but in the lat 6 months have collected 20 plus bikes of all sorts, to scavenge parts for my e-bike build..
The quality of the basic components that you see on the sub £500 bike is crap...even sub £1000 bikes is not great. .

So these Chinese motors are only equal to the el-cheapo components you see on Walmart style bikes. For what we are getting they are still incredible value for money...that is mass production for you...even if quality control is absolute shite.

Learn how to build and true your own wheel, it is not difficult, 6 moths ago I had no idea.. and then I had to build up my 5304 on a rim...so soon had to learn. Have doen half a dozen wheels from scratch since then. For me it is now an enjoyable past time

 

[John in CR]

You guys make me feel a lot better about the threaded flange I added to my scooter hubbie that was slightly off center leaving the FW with a bit of wobble. 10k+ miles and it still works fine, and for the last 5k or so has been virtually silent. It still works, which is all that matters to me as long as I don't suffer one of those instantaneous lockup failures.

 

[dande74]

Learn how to build and true your own wheel, it is not difficult, 6 moths ago I had no idea.. and then I had to build up my 5304 on a rim...so soon had to learn. Have doen half a dozen wheels from scratch since then. For me it is now an enjoyable past time

Can you (or someone else) point me to a good online store where I can find find 12g spokes for my hub. Suggestion on rim is appreciated as well.

 

[dogman dan]

Definitely about normal, which is unfortunate, but not at the price you typically pay for a 9c or clone. Must be much cheaper than actually lathing the thing, then threading it. Apparently they simply thread a casting and drill the bearing hole to size.

Happily, it makes no real difference in normal use, that is, sub 30 mph. Chain self adjusts real good, and you don't feel the out of balance wobble that bad. Or at least get used to it at slow speeds. You just make the needed adjustments up at the rim , for roundness at least.

 

[NeilP]

For spokes I used http://www.newsonsportec.com/
or on the forum here, there is John Holmes
http://holmeshobbies.com/home.php


As for a rim, the one often recommended is
:
http://www.sun-ringle.com/product-vault/mtb-rims/rhyno-lite-xl-welded/

they also sell this one, but it is narrower
http://www.sun-ringle.com/product-vault/mtb-rims/rhyno-lite-xl-welded/
no idea on supplier though..

 

[dande74]

Thank you very much!

 

[NeilP]

What ever rim yo choose...go for one with the largest ERD/..effective Rim Diameter..especially if you are going with a big hub like an Xlyte 5304..SO go for a flat profile rim like the RHino, not a V profile rim

 

[dande74]

Yes, I understand the meaning of that, thanks.

Rhyno Lite XL has an EDR of 549 mm. When using the spoke calculator on ebikes.ca it says I should use 168.9 mm spokes. Is it as easy as that or do I have to take account of other things?

How exact does the spoke length has to be. Within 1 mm or?

What about nipples. Anything to watch out for?

 

[NeilP]

Other things to consider depend on the hub you are using and the amount of 'dis' and offset the hub has..if it is too great, then LH spokes need to be a different lenght to RH spokes.

Best person to speak to is John Holmes...he is a forum member and can supply you the spokes too, along with advice. search for his posts, or see if there is and e-mail address for him on his website that I pointed you to earlier.

From what I have seen +/- 1mm is ok , but nto much more...I built my wheel from never having done one before.

I would say do a search for different on line calculators and see how many different results you get.

Here is my list of links from my favourites menu

http://www.sapim.be/index.php?st=spokelength
http://www.danscomp.com/435925.php
http://endless-sphere.com/forums/viewtopic.php?f=2&t=18995&sid=162ef91d082408836776b07ff7efc892&start=15
http://www.ebikes.ca/SpokeCalc.shtml
http://www.dtswiss.com/SpokesCalc/Welcome.aspx
http://www.bikeschool.com/tools/spoke-length-calculator
http://www.prowheelbuilder.com/spokelengthcalculator/
http://www.extralite.com/Products/measure%20of%20SED.htm
http://web.archive.org/web/20050516221323/http://www.geocities.com/spokeanwheel/index.html
http://www.philwood.com/products/spknphome.php
http://electricrider.com/crystalyte/x-spoke26p.htm
http://www.holmesbikes.com/
http://www.newsonsportec.com/spokes-cycling.html#
http://www.newsonsportec.com/spokes-spec.html
http://www.petracycles.co.uk/cyclo-spoke-thread-rolling-tool-p-71881.html

and while I am at it...a few on wheel building too

http://bicycletutor.com/wheel-truing/
http://www.bikewebsite.com/build.htm

the rim I used
http://www.sicklines.com/2008/02/04/2008-mavic-ex-823-and-mavic-ex-721/

http://www.velocityusa.com/default.asp?contentID=563

good luck

 

[dande74]

Many thanks, NeilP!

 

[dande74]

Hi again,

I'm thinking of Mavic EN 521 Disc 36H. It seams like a good "average" rim.

EDR = 532 mm.

Using spokecalc on ebikes.ca (Nine Continent, 1 Cross) gives me 160.7 mm spokes. (Thinking of order custom cut 13g black Sapim spokes from them.)

Question is, what's the diameter of a spoke hole for this rim. Can't find it. I hope 13g spokes fits.

Tried two other spokecalcs,

http://lenni.info/edd/
http://www.bikeschool.com/tools/spoke-length-calculator

Both others gives me 162.6 mm spokes.

It feels like ebikes.ca should be the length to go for. But I'm not sure since the two others give me other results.