Bafang G510 Ultra frame build

[anotherkiwi]

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?

Wood mold.

I would buy the bafang one to use as a model.

 

[tommie]

a very neat bit of fabrication!

Only thing that would concern me when it comes to ebikes in general would be the extra weight of the steel?

 

[mike425]

The weight issue is a bit of a myth really. Modern Butted tubing means the frames can weigh similar to alloy, it's just the tubing isn't cheap. Look at some of the high end road bikes being made with Reynolds tubing......

As this is a first attempt I've only used mild steel for the mount. If I do another I will use 4130 or T45 for it, I think I could nearly halve the weight of the bracket if I used those.

And talking of weight, the motor weighs 7kg, so it's all irrelevant haha

 

[soundwave]

puny motor lol get one of these
https://www.evwest.com/catalog/product_info.php?cPath=8&products_id=297&osCsid=5jm0tgda48mdc8ju77psj2u9b3

 

[mike425]

Lol, it's moved a bit beyond "pedal assist" then

 

[Laser Man]

The weight issue is a bit of a myth really. Modern Butted tubing means the frames can weigh similar to alloy, it's just the tubing isn't cheap. Look at some of the high end road bikes being made with Reynolds tubing......

My 25-year old double-butted steel frame mountain bike weighed almost exactly the same as my modern "light weight"* aluminium one (both were/are mid-range bikes - nothing special).
I think that part of the reason for this is the fashion for curved and fancy shaped tubing : a curved aluminium tube needs a lot more material (thickness) to match the strength of a straight steel one.

* It actually says "light weight" on the frame, but it is telling porkies.

 

[wheeliepete]

puny motor lol get one of these
https://www.evwest.com/catalog/prod...ucts_id=297&osCsid=5jm0tgda48mdc8ju77psj2u9b3

No excuse for being late for work with that bad boy on your commuter.

 

[Benjahmin]

This is the type of back shed/garage engineering the used to go on with British motorbikes, when fitting a Triumph 350 engine into a Royal Enfield 250 frame for instance. Always wished I'd got the skills and patience - well done you for keeping alive a kind of individual genius.

 

[mike425]

My 25-year old double-butted steel frame mountain bike weighed almost exactly the same as my modern "light weight"* aluminium one (both were/are mid-range bikes - nothing special).
I think that part of the reason for this is the fashion for curved and fancy shaped tubing : a curved aluminium tube needs a lot more material (thickness) to match the strength of a straight steel one.

* It actually says "light weight" on the frame, but it is telling porkies.

Exactly, I think a lot of the the people are comparing new alloy bikes with £100 quid full steel bikes from cheap stores, they are likely boat anchors yes

This is the type of back shed/garage engineering the used to go on with British motorbikes, when fitting a Triumph 350 engine into a Royal Enfield 250 frame for instance. Always wished I'd got the skills and patience - well done you for keeping alive a kind of individual genius.

Thanks, if I am honest I probably enjoy the tinkering and making things more than the "using" them. You learn something all the time.

 

[mike425]

Only a small bit of progress this week but I'm getting there. I have the plans drawn up of where to cut and the fitting position of the motor mount. Also started to jig the frame up to make sure it is straight when I reweld it

 

[wheeliepete]

Liking the jig Mike, self build? I'm sure you've noticed, but those chainstays look very wide at the front, you OK for crank wheel/arm clearance?

 

[mike425]

Yes it's home made, pretty basic but cheap and does the job. You made me second guess myself.....yes there's loads, the g510 I have had a 150mm bottom bracket in it. I didn't realise you had to specify BB when I ordered it, so they sent a mega wide one. Lesson learned when ordering from China ......

 

[wheeliepete]

Sorry mate, no intension of mis-guiding you, i had no idea of variable sizes on that drive, never seen it advertised as such, unlike the BBSHD. I've been looking at retrofitting a M600 into a bosch fat frame, but i'm doubtful that there's clearance with the bespoke chainring and inset carrier on that motor. Making me wonder now if there's variable option BB sizes on it. Are you planning a high front tilt, rather than horizontal mount for the motor?

 

[mike425]

No worries you didn't miss guide at all. I only found out myself that the g510 comes in 3 sizes when the seller I bought it from sent me an email saying they now had all 3 in stock! So I went and measured mine having just assumed it was 68mm, turns out it is 120mm.

Note to self, Chinese sellers only provide information if you ask for it, otherwise they guess/presume!

I have an m600 build lined up next if this goes well, I will definitely be looking at other width options for that myself

 

[mike425]

It's been a while since I updated this but I finally made some real progress.


The motor also seems to fit a treat, from eyeballing it the chain line looks good.


I had run out of argon when I went to weld it, so ended up brazing the mount into the frame.....not the tidiest but I was ready to get it done.

Now I need to go through the parts bin to build the thing!

 

[mike425]

It has been a while since I updated this thread. I managed to build the bike using old parts I had lying around the garage. Since the photo I have swapped the tyres for some commuter semi slicks as the old maxxis were just what I had to hand.

I haven't done many miles on the bike but first impressions are pretty impressive. The torque from the g510 motor is massive. You can basically leave the bike on the smallest cog on the back and it will accelerate up even the steepest hills with no issues (not sure this will be good for the hub though!).

With the pretty standard MTB gearing setup I have the bike will cruise along at 32mph with a reasonable cadence on the cranks.

I went with a 52v 30A continuous battery from EM3EV which I am really pleased with (although it was not cheap).

I am not sold personally on the throttle, it kind of turns it into a slow motorbike really as the acceleration is very steady, but to be honest I wanted a pedelec anyway so I will probably remove it.

 

[xander02]

Wood mold.

I would buy the bafang one to use as a model.

Interested to see how you got on with your build and motor mount modification?

I'm planning on fitting the bafang to an existing Bosch Active line plus. But, not sure how easy it will be to weld the mount to the existing frame...I imagine I will have to do a fair bit of cutting of the original frame in preparation.