*HELP* Filing rear dropout

[Tabman55]

Hi I have recently learnt I need to file my rear dropout, I went and bought a round file that fits in since all my others didn’t, is there anything I should know before I start to file it down? I would like pictures of failed/perfect filed ones if u can (please list failed/perfect if u can show me)

ive found it only needs about 2mm off, is there anything I can do to make sure the round head will stay the same size as needed and have the wheel fit in perfect so it avoids problems?

 

[Scruffydroid]

Don't use a round file! Use a Flat file, since you do not want to round out the corners, other than to match the profile of your axle. The idea is to have as tight a fit as possible - you can take away material, but not add it back (easily...)

Cut a piece of 5mm aluminimum, and trace your current drop out shape onto it. Place it into a vice and practice on that you get your muscle memory going and to match the profile to the axle.

 

[Nealh]

I used a dremmel tool and a small chain saw 4 or 5mm round file for finsishing, the last thing you want is any squaring off of corners.

 

[Fordulike]

Add a torque arm for a bit of extra safety!

 

[Tabman55]

I was under the impression I am going to be extending the dropout to make it deeper so that the wheel fits in to the dropouts more? Can someone explain what to do when filing please

 

[Yak]

Is this the answer to the problem of the rear hub wheel not fitting centrally to the frame?? So no/less need to dish the wheel?

 

[Nealh]

Is this the answer to the problem of the rear hub wheel not fitting centrally to the frame?? So no/less need to dish the wheel?

No.

 

[Nealh]

I was under the impression I am going to be extending the dropout to make it deeper so that the wheel fits in to the dropouts more? Can someone explain what to do when filing please

All you need is to match the axle profile as best as you can to the drop out, often you can use the flat file to lose some of the round but do not end up right angle on the seat of the drop out.
Typically dropouts are for 9mm skewers, a geared hub motor is normally 12 x 10mm.
Sometimes the 10mm axle will slide in the drop out, if it doesn't then firstly one has to remove up to 1mm so the axle does slide in. Once it slides in then one has to set the axle deeper usually 1.5 - 2mmon both sides so that the wheel sits true side to side. The slightly rounded drop out seat, the shape needs to match the axle shape as near as possible so if filing or using a dremmel type tool keep checking and don't rush the job. It doesn't matter if you go 3 or 4mm deep but the opposite side needs to match as well.
Do the geared side first as the derailleur hanger is the bit that will need doing first, these can be removed to make filing easier and if you take too much out the hanger will be no good.

If unsure use the torque arm or the torque washers axle profile to mark it on the drop out and work to that marked shape.

 

[Raboa]

I have used this 10.2mm (diameter) round file, it is useful to gauge dropout width as well.

Teng Tools FLRD10 10" Round Type Hand File

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

www.teng.co.uk