Ebike wheel wont stay on

[Cam3roon2k41999]

Hi.
I have a 3000w 48v setup at the moment and I've used it now for a couple of weeks no problems apart from yesterday I accelerated gently from a standstill and my rear wheel came completely out of the dropouts I have tried to fit the wheel again but it's just coming straight off without riding it.
Any ideas on why this is happening I also have a tourqe arm and the wheel is still coming off?

 

[Nealh]

The hub axle will be 14 x10, the bikes original drop outs will only be likely for 9mm QR. Currently the hub axle is simply rolling out of the shallow 9mm drop out.
The hub axle has a pair of flat sides and these need to sit fully in the drop out, you will have to file the drop out at least 2.5- 3 mm deeper, making sure the seat area isn't squared off and suits the axle semi round shape.

Show us some pics of the hub sitting in the drop out with no nuts or TA.

When fitting hubs often there is a bit more work to be done then simply to drop the hub in and tighten nuts, etc. Selecting the correct frame with decent drop outs to work with is the starting point as not all frames are suitable.

 

[Wicky]

You'll need more this kind of setup to stop the rear wheel flying off....

 

[vfr400]

3000w requires substantially reinforced drop-outs, not just a torque arm.

torque arm picture thread

Cross-posting these two threads so a search will turn up both: "Found an awesome torque arm" (3 pages) https://endless-sphere.com/forums/viewtopic.php?f=1&t=11570 xxxxxxxxxxxxxxxxxxxx Original thread died. Figured I'd help out and repost what I saved. Here is the album link...

endless-sphere.com

 

[Cam3roon2k41999]

Thanks for the replys I'll send some pics in a about 5 mins but I think the dropouts are damaged badly now I look closer lol

 

[Cam3roon2k41999]

Here you go

 

[Benjahmin]

You put what is basically a motor cycle motor into a bicycle frame and this is what happens. I don't know what current your battery is capable of delivering, but it is certain that the turning moment that the dropouts have been subject too are far higher than the frame was designed to stand up too. The non-drive dropout is broken, I can't see the drive side one.

 

[Nealh]

You will likely be better off with anew bike frame with suitable dropouts, as thought (pic #1) the axle nowhere sits deep enough for any decent purchase in the drop out. In pic two it looks like that the axle could have sat in a lot deeper with some careful filing (though could just be the pic angle and a shadow being cast) but as Ben has mentioned one of the D/O has snapped, it may be possible to still use the frame if diligently file the axle width for a snug deeper fit. However if the D/O has any fracture in it it won't last long also one is better with a stronger frame, a steel one with that heavy motor.

Why a 3kw hub in the first place ?

 

[vfr400]

Steel frames are better for those sort of motors, especially as you can weld on reinforcements.

 

[Cam3roon2k41999]

And I'm only running a 48v battery and it's max current is 30a ill probably just buy a new frame to be honest is there any decent steel ones? I'm in the UK. Thanks

 

[Nealh]

There is no gain in running a 3kw hub at 48v, one might as well use a lighter smaller hub instead at 48v .

One doesn't need to buy a new new frame, there are a few on ebay. Reynolds chomoly steel, Genesis frames , trek Mtb frame. The main detail is to closely look at the drop outs for a nice substantial strong flat area.

 

[Cam3roon2k41999]

I know pointless really but I ordered a 3kw motor kit and I ordered a stealth bomber frame also but it didn't turn up so I got the money back and spent it before I managed to get a decent frame because I thought the one I was using would last but obviously didn't

 

[Cam3roon2k41999]

Hi. I've decided to get a new frame but can only find aluminium ones for some reason is there anything i can do to stop this happening again lol
I'm not a professional at welding or anything that's all in fact I have never used a welder

 

[Wicky]

As has been mentioned when the motor in your bicycle is putting out moped/motorcycle level of power you'll need moped/motorcycle dropouts.

 

[Benjahmin]

Hi. I've decided to get a new frame but can only find aluminium ones for some reason is there anything i can do to stop this happening again lol

Yes:
1 get a 250w hub motor
2 Make sure the dropouts are filed deep enough to take the motor axle and anti rotation washers.
3 Fit a substantial torque bracket - if not two. Here's a good one I've used, fits to mudguard or rack mount holes.

Torque Arm for e-bike Heavy-Duty 3 or 5mm Stainless Steel,14x10mm, Electric Bike | eBay

Manufactured in the UK from 3mm or 5mm thick stainless steel.

www.ebay.co.uk

 

[Raboa]

I find using a round file is handy when filling the dropouts.
1. Make the file (not including handle) wider than the dropouts
2. Cut the handle off, this balances the weight better.
3. Put file in the dropouts and hold the middle of the file, file both dropouts at the same time.
It's also handy to out the anti rotation washers on the axle, measure the height of this (axle and washer), mark this on a piece of card. Use this a guide, it saves you lifting the wheel all the time.
Example of file, others are available.

Teng Tools FLRD10 10" Round Type Hand File

10" round type hand file, 2nd cut with a bi-material handle.

www.teng.co.uk

 

[Cam3roon2k41999]

I forgot to mention the bike I was using was a carrera crossfire ebike but the motor broke on me and the manufacturer wouldn't replace it so I just stripped it and installed a 1000w kit and worked perfect for about 1 year then my hall sensor wire got jammed in the spokes and ripped out so I went to a 3kw motor. I mainly ride on roads not restricted but I do stick to around 15mph I only use the extra power if it's needed. But also there's allot of potholes in the roads where i live, could that be part of the issue with the dropouts snapping? Thanks

 

[Nealh]

3kw hub just to go 15mph pull the other one, doesn't make no sense at all.

 

[Cam3roon2k41999]

I was going to use the 3kw motor on a farm path next to where I live in future with a few friends but meanwhile I just used it on the road as I don't want to get caught doing 40mph on the road so I try sticking to the 15.5mph..don't get me wrong tho I did get a bit carried away once when there was no traffic as I do

 

[soundwave]

you can go 80mph with one of those vroom