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Rear wheel wobbling

Go to solution Solved by Reddy Kilowatt,

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Hi everyone,

For about a day or two I have a quite big wobbling problem coming from my rear wheel. It was barely noticeable, but got worse to the point where my wheel is touching the frame when I'm turning left or right, and I can feel the bike wobbling when I'm riding. I should mention that I added an extra seat at the back, and I'm using it daily to bring my girlfriend and myself to work (which I'm not doing anymore since this issue obviously). So far, I have tried to tighten the wheel as much as I could with my 18mm wrench, but that didn't change anything really. 

Do you have any idea: 

- What the problem actually is ?

- What replacement parts will I need to fix that ?

Since the motor seems to be fairly well integrated to the wheel axis, does that mean I might have to buy a new motor if let's say the axis is bended or something like this ? Is it worth bringing the bike to a bike shop regarding how particular this one is ?

Thanks in advance for you answers !

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Having it looked at by a bike shop is a good idea.

If you've ruled the possibility that the hub is crooked in the frame, remaining possibilities could be that the wheel is bent or spoke tension could be way off. Bike shop should be able to diagnose and resolve either of those.

Edited by Hari Seldon
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Hi Yann, 

Actually if the hub was crooked in the frame’s  dropouts, as Hari suggests, the wheel wouldn’t wobble as it rotates but the whole tire would be rubbing in the same spot on the frame through out it’s rotation.  You didn’t say which Sondors Model you have but you’ve probably exceeded the weight limitation of your bike by carrying two.  Since you didn’t know what the problem is,  Hari and you are correct, that almost any quality bike shop can true your wheel, unless the rim is bent beyond truing, if that is the case you’ll need a new rim and probably new spokes and a complete rear wheel rebuild. Those two repairs,  are the least and most of an untrue wheel. If you intend to ride your girlfriend with you,  I’d suggest a rebuild with a double wall rim and quality 12 Gauge spokes,  to handle the weight, as I reported last week in the single or double wall rim thread. If you don’t, expect more rear wheel trouble. 

Going to a qualified bike shop is your only option.  Let them pick the brand of rim and spokes because their supplier may have specific brands they prefer.  



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Hi guys, 

Thank you very much for you answers, I have been to a bike shop and the guy thinks I need to rebuild the wheel. Problem is, he can't do it since he said that all the gear he has is for regular bikes, and I should contact the manufacturer. So I suppose my next move will be to order a new rim & spokes, as Reddy was advising. My bike is from 2016 (original fat one), does any one have any link for rim and/or spokes that I could use for reference ? Is there a particular thing to be careful with when ordering them ? I believe once I have the dimensions right, if I bring rim + spoke to a bike shop they might be able to fix it ? Thanks again for your help.


Edit: I had a look on the forum and saw another of you posts Reddy, I believe the dimensions I'm looking for are 26"x80mm. I came across this one on Ebay, would that fit ? (I live in Dublin, Ireland, so ebay.com will probably be too expensive in terms of shipping). I found this model, would that be alright ? 


Edit 2:

Or this one, way cheaper:


Also this model which is way cheaper but wider (96mm), so I guess that would require new tube and tire ?


Edited by Yann
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  • Solution

Hi Yann,

Any bike shop with a Parks Tool Profesional Truing Stand (the industry standard) and experience in building bicycle wheels ( but not the first shop you went to)  should be able to build your new wheel with the double wall (stronger / no holes, your second  rim choice not the first or third, which has holes, is weaker and the wrong spoke count 32) and only the bike shop can calculate the new spoke length.  I recommend 12 gauge spokes (the spokes that Bafang Specifies for all 8Fun geared hub motors) , for your extra weight application, Wheelsmith, Sapim or DT Swiss spokes and the matching companies brass HD long nipples. The shop will probably  have a brand they prefer and stock. All are top quality spokes. Let them specify the individual parts, they’ll have to warrant what they supply and won’t, what you supply. There are spoke length calculators online but let the shop do that also and supply the correct  spokes, it’s not for novice wheel builders. You can paint the rim before the build to match the Sondors Original color. 

 You’ll still be able to use the same tire but I couldn’t find which tube type (presta or shrader valve) in the eBay listing but either will be fine but if it’s presta you’ll need a new tube. The wider new rims spoke spacing,  should also help in building a more robust new wheel. I used a 100mm rear rim on my own new wheel build so it would be more robust. Contact the seller. https://www.ebay.ie/itm/Bike-Rim-559-80-Fat-Snowbike-36-hole-black/392007619296?hash=item5b457992e0:g:CA0AAOSwC-xay-V8 and ask them for the tube valve type  for that rim so you’ll know you have the right tube and if it’s presta you can get that from the shop that builds the wheel. 





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