Bafang G510 Ultra frame build

[mike425]

Hi all, I had registered for an american forum as I hadn't realised there was a UK based one. I am based in Sheffield.

I am a long term MTB'r and have ridden most of my life.

I have been interested in ebikes for the last 6 months or so, a new born baby has mean't going out and buying one wasn't feasible so I decided to build my own.

Initially I was going to build an enduro hardtail out of a reynolds tubeset I have in my garage. However I decided that as this was a bit of an experiment I would be better of building something a bit more all round. As a result I am going to make a bit of a commuter/XC trail bike so that I can use it to get to work as well as on the trails.

Rather than waste a good tubeset I ended up buying a Genesis 29er hardtail frame which is reynolds anyway for peanuts. So the plan is to cut this up and fit the motor into this frame for the first build.

Progress so Far

29er Frame is here and I have started making drawing plans of where to cut etc
Bafang G510 1000w motor arrived the other day
Mounting plate / cradle for the motor is underway.

Initial Thoughts

I am really impressed with the build quality on the Bafang motor, it is definitely not the cheap chinese short term build quality I have seen from other things recently.

Weight - This thing is HEAVY, I have weighed it at 7.4Kg motor only, hopefully the power of it will compensate for the weight.

I am hoping to get the full build in under 22KG, will have to see, I will post pictures as I go along if anyone is interested.

Cheers

 

[wheeliepete]

Welcome to the forum, nice to see another builder on here, the more the merrier. Interesting project you've chosen to take on. What made you decide on that motor? Look forward to following your progress. Keep us all posted.

 

[mike425]

Hi, thanks. I chose the motor because I wanted something integrated. The choice for anything integrated seems to be very limited and the Bafang seemed to be good bridge between cost and performance.

A lot of the Chinese frames designed for the g510 also have the most random looking geometry numbers I have seen so I didn't really have a choice but to go custom for the frame.

I will post pictures once I start cutting and welding

 

[wheeliepete]

A lot of the Chinese frames designed for the g510 also have the most random looking geometry numbers I have seen so I didn't really have a choice but to go custom for the frame.

Yes, it's strange that they seem unable to look at other modern bike frames and copy them, I always thought they were good at that! This is a good example of this with the new M600 motor.

The G510 is quite a lump, but I don't think you'll be disappointed with the performance.

 

[mike425]

I did look at the M600 briefly but they are just a little out of budget at the minute. I did think if this works out and I decided to build a full sus frame that would be an ideal motor, I think the weight is well under 4KG on those.

 

[anotherkiwi]

I am interested in your motor mount technique. I really like the MM G360.250 - marked 250W, 48v, PAS not torque sensor...

My idea was to replicate their motor mount in CF and bond that to the cut alu frame or possibly build an interface between the original Bosch CX mounting points and the Bafang motor depending on which was easiest.

 

[mike425]

I can't really help you with the CF option as I have absolutely zero experience with it. I am going to make version 1 by hand, it will be made of 6 pieces all TIG welded together.

If this one is successful I would get it laser cut and machine bent out of 3 pieces and then TIG those

 

[mike425]

I've managed to make a decent start on this, I am not far off having finished the motor mount....just some more welding to do........

 

[lyme]

Looks good and a great bit of welding as well.

 

[mike425]

Thanks. I managed to get the whole mount welded up tonight and test fitted. Fits a treat, just a bit of tidying up to do!

 

[wheeliepete]

Very nice Mike, I wish my welding looked like that, top job!

 

[mike425]

Thanks, yes I'm pleased with it so far. Although can already see a MK2 with improvements ha, need to finish this one first!

 

[jarob10]

Is steel the only option?

 

[mike425]

Not sure what you mean? You could make it out of anything if you have the right tools.....

 

[wheeliepete]

Is steel the only option?

Needs to be the same metal as the frame you are welding it to.

 

[anotherkiwi]

I have been looking at epoxies for aluminium. My idea is a carbon fibre motor bracket (stronger than steel) which is bonded to the aluminium frame with epoxy.

 

[mike425]

If you have made parts out of carbon before I guess it's possible. The shape of the motor mount would need some kind of mould for carbon wouldn't it?

Bafang make an alloy mount themselves, I would have thought it would be neater + easier to use that and weld it to the alloy frame?

 

[wheeliepete]

use that and weld it to the alloy frame?

Aluminium needs to be heat treated after welding though, dosn't it?

 

[mike425]

Yep it should be, but depending how you use it the frames can last quite well if not.

I'd have it done, I think you could get it heat treated for around £150, so it's not a cheap option but would give you piece of mind

 

[wheeliepete]

I'd have it done,

Me too I think, esp. cutting and welding what is the bottom bracket of the bike.