Can not take rear wheel off, stuck in dropouts

[oded]

Need to change a flat tire on my rear wheel (which include the hub motor).

Released the bolts, but the wheel is stuck in the dropouts and will not budge. Tried to force it with no success.

When I originally fitted the wheel, it wasn't a real problem and slided in nicely.

Any ideas?

 

[MadRhino]

Twisted the axle ?
Bent the chainstay ?
...or just rusted tight
Use penetrating oil, play it back and forth with a 10mm wrench

Put the nuts on and hammer it off, then buy new nuts :wink:

 

[Ykick]

What he said plus use a strong light to get a good view of where/how the axle meets the dropouts.

My guess is that the axle may have twisted? Do you use torque arms? How much power do you run?

 

[oded]

It's a 36v 250w and was fitted 4 weeks ago, so no time for rust to accumulate.
No torque arms. ..

 

[Ykick]

Low speed/power geared hub motors can still generate serious torque. Have you mentioned installation details. Front/rear? Aluminum/steel forks?

Please let us know what you discover?

 

[MadRhino]

Without a torque arm, one doesn't need much power to spin the axle in the drop outs and it is likely to be your problem actually. The axle flat moved out of the drop out axis, starting to distort the metal and that is why it is hard to slide off. Use a 10mm wrench to turn it in line with the drop out axis and hammer it down on the nuts, alternate both sides until it slides out. After it's out you may have to file a slight correction to one or both of the drop outs, then I strongly suggest that you install a standard fit-all torque arm or fabricate a custom through axle torque plate out of 1/4 thick steel.

 

[teklektik]

Aluminum drops with no torque arm?

Axle may have turned slightly and wedged into dropouts.

• Try a large adjustable wrench on the axle flats (make sure it's a tight fit) and rotate the axle slightly to re-align the flats with the slot.
• If axle is aligned but stuck, you may be able to loosen the axle by gently rocking it slightly with the wrench.

EDIT: Ha - simul-post with MadRhino. Ya - what he said....

 

[Ykick]

I dug into your post history - this is an aluminum Schwinn geared rear hub motor.

Did you use washers on the interior of the axle so that the axle shoulder doesn't dig into the softer dropouts? TA would be a good idea but inside washers would be even more important IMO.

 

[Ypedal]

A few good palm-thumps on the rim vertical to the dropouts, left / right / etc a few times usually does the trick.. :wink:

Picture ?

 

[John in CR]

Leave it stuck in there with a flat until you get a proper torque arm, or a pair of them. The torque of the axle trying to spin, which even with a low powered motor is commonly thousands of pounds at such a small radius, and that has deformed the metal of the dropout, or the axle, or more likely both since it's hard to remove. If the AL hasn't cracked already, it's the one warning sign you will get, so take advantage before catastrophic failure to remedy the issue with a good torque arm(s). Bear in mind that aluminum fails differently than steel. Where steel will bend and twist and give you warnings ahead of time in the form of new squeaking noises, aluminum will suddenly snap right off. The largest forces are when you are taking off, so imagine if the failure occurs when you're taking off to cross a street to beat oncoming traffic.

 

[oded]

First of all, thanks for the warnings. I take it very seriously, and searching for a torque arm as I write. Any recommended links?

Your suggestions were spot on. A slight twist with a wranch and the axle slided easily out... Yeah, it's the torque.

I already have a front wheel TA lying around, but rear wheel torque arms are a bit harder to find.

BTW, here is the bike (ykick already found it. (-: )

http://vimeo.com/107231886

 

[bowlofsalad]

First of all, thanks for the warnings. I take it very seriously, and searching for a torque arm as I write. Any recommended links?

Your suggestions were spot on. A slight twist with a wranch and the axle slided easily out... Yeah, it's the torque.

I already have a front wheel TA lying around, but rear wheel torque arms are a bit harder to find.

BTW, here is the bike (ykick already found it. (-: )

Getting the wheel off (such as for changing a flat) on and off with closed mouth torque arms are a pain in the ass. http://www.endless-sphere.com/forums/viewtopic.php?f=31&t=29129&start=300 These are open mouth torque arms designed and sold by a user on this forum, doctorbass. Once you get an open mouth torque arm setup, you can forget about messing with it. To me, it's a bit of effort to set it up, but it saves a bunch of trouble down the line, and really, it's a similar amount of effort setting up closed mouth torque arms. Many have used DP420 epoxy to fix the torque arms to a frame.

 

[teklektik]

I already have a front wheel TA lying around, but rear wheel torque arms are a bit harder to find.

You have a small motor and don't need much...

• Here's a bunch from Ebikes SF - different orientations and shaft sizes.
• For a 14mm shaft I like these from Amped Bikes (weird thing going on with their web site, but..) - any orientation and easy to line up. Flip over the center star to shift alignment by 1/2 tooth.
• From ES members (alternatives to Doc's famous TAs which are are pretty thick and overkill for your case - unless you really need the convenience...):
  • steel
  • stainless

Or get a piece of 1/4" flat stock from the hardware store, a hacksaw, a file, and pretty quick....

Did you use washers on the interior of the axle so that the axle shoulder doesn't dig into the softer dropouts? TA would be a good idea but inside washers would be even more important IMO.

+1

 

[oded]

Thanks again. I am studing the subject (always thougt that rear hub motors do not need torque arms).
Links provided are extremely helpful.

 

[Ykick]

Better to find out now than later.

Often "need" is a relative thing. Some low power DD (direct drive) hub motors might get by sans TA's if the installation is tight. Obviously much more warnings about front hub motors so maybe people become complacent about the "need" for TA's with rear motors?

Sounds like your little motor began twisting enough to creat a "stuck" situation and TA's will better protect against full spin out.

There's 2 different axle sizes for most motors. 12mm & 14mm. Be sure which you have before ordering any TA's.

 

[bowlofsalad]

Doctorbass torque arm (pair): 198 grams

Ebikes.ca v4 torque arm (pair): 260 grams

http://www.ebikes.ca/shop/ebike-parts/torque-arms/torqarm-v4.html source for mentioned torque arms.

 

[wesnewell]

Thanks again. I am studing the subject (always thougt that rear hub motors do not need torque arms).
Links provided are extremely helpful.

If you've got steel dropouts and it's installed properly, you don't. I've got ~15K miles on my 1000W motor withe 4000W max controller without TA's using mostly regen braking from higher speeds. If you have aluminum dropouts, I'd use torque plates screwed/bolted to dropouts. They will provide much better protection than TA's.

 

[oded]

I am kind of lost with all the vast selection of torque arms.
Attached is a photo of my bike's rear dropouts, instalation a TA might be a bit difficult.

 

[Ykick]

Thanks again. I am studing the subject (always thougt that rear hub motors do not need torque arms).
Links provided are extremely helpful.

If you've got steel dropouts and it's installed properly, you don't. I've got ~15K miles on my 1000W motor withe 4000W max controller without TA's using mostly regen braking from higher speeds. If you have aluminum dropouts, I'd use torque plates screwed/bolted to dropouts. They will provide much better protection than TA's.

Please don't confuse the situation. OP runs geared motor and aluminum dropouts - not comparable to your steel dropouts and DD motor installation.

OP - I buy 12mm universal TA's from BMS Battery when I order small geared hub motors. If you can verify the 12mm axle nut size, I have 1qty extra that I can offer to you at cost, if you're in USA? PM me...

Here's BMS link - http://www.bmsbattery.com/36v/450-a-pair-of-ebike-torque-arm.html

 

[Ypedal]

for that 250w Rear motor, a TA is really not needed imo..

Proper hardware however, ditch those capped nuts, get a nice flat washer and proper nylock or flanged nut, crank it down tight and ride on.

https://www.google.ca/search?q=castellated+nut&espv=2&biw=1680&bih=989&source=lnms&tbm=isch&sa=X&ei=f1YxVOeEPMy1yAT9mIJo&ved=0CAYQ_AUoAQ#tbm=isch&q=flanged+nut

 

[Ykick]

I agree, properly fitted and tightened hardware it shouldn't "need" a TA but OP appears to have some installation issues. We've already mentioned inside washers and properly fitting and torqued nuts but if those things go unheeded and/or improperly implemented, TA might save wiring and frame damage anguish.

TA's should merely serve as fail safe IMO.

 

[oded]

I'll make an experiment, and use proper installed washers and nuts on the axle. I will use the bike for a few days, and than see if the axle need a wrench twist in order to come off. If it does not need a twist, than the experiment suceeded. If it did twist, than torque arm it is.

In order to properly install, I need to know where and which of the following washers and nuts I need to install. Already have them (bought some spares).

BTW, do all fancy ready made electric mountain bikes (KTM, NEO...) have TA for the hub motor's dropouts? didn't see any. looked for it in these excellent video reviews http://www.electricbikereview.com

Learned a lot from this thread, thanks.

 

[MadRhino]

If you ride again without any torque arm, you may end up with damages that will require much more work than a simple torque arm installation. Saving 10 minutes today, is often turning into working 5 hours tomorrow.

 

[teklektik]

I'll make an experiment, ... If it did twist, than torque arm it is.

If you ride again without any torque arm, you may end up with damages that will require much more work than a simple torque arm installation. Saving 10 minutes today, is often turning into working 5 hours tomorrow.

+1

Your proposed test is itself potentially damaging....
Or - if your regular maintenance lags then you will quite likely have a future failure.

If everything is done Just Right and all your ducks are in a row, then this approach can work - but if one duck steps out of line, ducks die.

Don't make your dropout a dead duck. Get a TA.