Hub motor axle does not go into droupouts

[suddenurge]

I have a rear mac 10t hub motor that I want to fit to a GT transeo 2. The bike has a quick release system in the rear hub and maybe this is why the dropouts are not wide enough to accomodate the axle diameter of 10mm. In fact, I cannot get the axle into the dropout at all. I know I have no choice but to file the dropouts down to fit.

Could someone please give me some good tips on how to do it, what to keep in mind and what type of file to use. The bike is made of 7005-t6 aluminium if that matters.

Cheers!

 

[Alan Quay]

I've done it more than a few times. Normally a standard drop out needs a bit more depth, and a touch more width to fit a 12mm axle, which is flattened to 10mm at the sides.

Most round files are tapered from about 9mm to 12mm. Start with that, filing the dropout deeper. Then use a flat file to widen a bit. Keep offering up one end of the axle until the dropout is about right.

While you are filing, try to keep everything parallel. When you finally offer the entire assembly up to the bike you may need bit more filing to get it to fit, as it both won't be identical.

Take your time, keep checking, get comfortable. Takes about an hour the first time, twenty mins from there on.

 

[suddenurge]

Thanks. What is the benefit of filing the dropout deeper first? At the moment I cannot even get the axle into the dropout, so I would prefer to file it wider first.

 

[anotherkiwi]

Because most people just file wider and the axle isn't set deep enough. You can file wider first but you must promise us to file deeper too so that the axle is properly seated. If you don't and you come back saying your wheel fell out... well... no you just don't want to go there...

What torque arms have you chosen?

 

[suddenurge]

If I understand you correctly, it is paramount that the axle sits flush in the dropout or the wheel might spin out of the axle.

I would definitely appreciate some input on good torque arms. So far, i have only looked at this one

https://bmsbattery.com/ebike-parts/450-a-pair-of-ebike-torque-arm-parts.html?search_query=torque+&results=82

I do not know if it is sufficient.

This is what the rear dropouts looks like on my bike:

https://www.google.se/search?q=gt+transeo+2+2014&espv=2&biw=1280&bih=646&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjY7u_cs8jKAhXH8ywKHWXYABsQ_AUIBigB#imgrc=Ob6nW6ZcEssrcM:

https://www.google.se/search?q=gt+transeo+2+2014&espv=2&biw=1280&bih=646&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjY7u_cs8jKAhXH8ywKHWXYABsQ_AUIBigB#imgrc=YQAtutby8W1qJM:

So I just assumed the above torque arem is the only model that will fit.

 

[flecc]

Yes, that's an awkward frame for most anti-torque arms which expect a larger flat area to sit against, the one you've chosen is a good choice.
.

 

[suddenurge]

Should you have torque arms on each side of the wheel?

 

[flecc]

Should you have torque arms on each side of the wheel?

It's not necessary if you've got one soundly fixed in place. In any case I think a right hand one might be tricky on your bike, it's a bit crowded in that area.
.

 

[Fordulike]

Should you have torque arms on each side of the wheel?

I don't like going against flecc's advice, but I owned a MAC 10T bike a few years ago, and I fitted a torque arm on each side.
It was running a 30 amp controller at 48 volts, so not amazingly powerful, but these beast do produce a lot of torque from standstill, which is harsh on dropouts.

Anyway, I fitted a pair of (Cyclezee) torque arms, which are immensely strong and give good scope for adjustment:

http://cyclezee.com/cyclezee-torque-arms.html

The ones at the top are the ones I fitted, and it's possible to get the torque arm flat and aligned with the help of some extra small washers. I'll explain better if you decide to go for this type

 

[Alan Quay]

Thanks. What is the benefit of filing the dropout deeper first? At the moment I cannot even get the axle into the dropout, so I would prefer to file it wider first.

You need to make the dropout 2mm deeper to accommodate the 12mm of the new axle. It'll be 10mm across, which just means taking the paint off (perhaps a smidgen more).

You don't want any lateral slack, as that's where the torque is applied.

For what it's worth, a well fitted axle, 250w motor, in half decent dropouts does not need any torque arms.

 

[Deleted member 4366]

Isn't it a 14 x 10 mm axle on the MAC? That means about 2.5mm deeper to centralise the axle, though it depends on your brake how central it needs to be. Multiply your nominal voltage by the e controller's maximum current. If it's greater than 900, you need two torque arms.

I use a Dremmel with a burr to adjust the size of dropouts. The burrs can also be used in a normal power drill. Be aware that some of these Chinese ones are smaller than the 3mm Dremmel chuck size, but these ones look OK at 3mm:

http://www.ebay.co.uk/itm/20x-3-3mm-Tungsten-steel-Solid-Carbide-Burrs-For-Dremel-Rotary-Tool-Drill-Bit/360519211913?_trksid=p2141725.c100338.m3726&_trkparms=aid=222007&algo=SIC.MBE&ao=1&asc=20150313114020&meid=efc54aa2a7424cbe836cb47c6944bc02&pid=100338&rk=16&rkt=21&sd=171946314553

 

[Benjahmin]

I can confirm that the Cyclezee torque arms work well and are very adaptable. In fact the bike with the red forks, in the link above, is my original conversion. How about that? Fame at last