All Weather Fat Tire eBike

[SaabGuy]

Hi all, new to the forum and this is my first ebike build. It's still in progress

Specs:
Dynacraft Krusher 26X4 Fat Tire bike
-Steel Frame
-36 spoke 80mm rims
-165mm rear dropout
-Upgraded to M445 Shimano hydraulic brakes from stock mechanical
-5" riser bar for more comfort
-Slightly modified Rad Rover full fender kit

Powertrain
-QS205 50H V3 150mm axle 8.33kv (About 45 mph max)
--Sabvoton SVMC72150 (hopefully this lasts)
--Pit bike style twist throttle w/remote encoder
-Custom LiPo pack: 10x Multistar 4s 10Ah packs for (4x5)s2p? 74v nominal 20Ah=1500Wh

Misc
-4x6 LED Headlight
-Two custom 3d printed control boxes on bars:
--Left: 3pos switch for headlight, 3pos for turn signals,
--Right: two momentary for enable/disable
-RFID Ignition

Im working on all the little stuff till the motor and controller come in from aliexpress sometime soon hopefully.

 

[SaabGuy]

I have pretty much everything i need to finish the bike except for the last few custom bits: torque arms, sabvoton mounts, cover panels etc.

got the rear wheel laced up with Sapim strong spokes, brass spoke washers, and SS spoke nipple washers



Also designed up these torque arms and even did a stress analysis on them for 200Nm on the shaft


Safety Factor

 

[SaabGuy]

Made up the torque mounts like a month ago and then plated them yesterday:


Installed on the bike:



Last thing to do was to bleed the brakes because i switched the front/rear brakes between the left and right bars as i ride motorcycles as well. Problem is that the check valve in my vacuum bleeder apparently doesn't work anymore LBS is bleeding them for me today. Will do test ride after work !

Still need to solder together my 20S battery charger https://endless-sphere.com/forums/viewtopic.php?f=14&t=102280

I'm using a throttle i got from qcnsmotor store on aliexpress because the idiots over at East Gem never shipped a remote potentiometer for the pitbike throttle i bought. finally gave me a paypal refund two days before the claim though

 

[pwd]

Nice build. The QS205 50H looks small on compared to those tires and wide dropout. That rig is going to be a crazy horse.

 

[SaabGuy]

Nice build. The QS205 50H looks small on compared to those tires and wide dropout. That rig is going to be a crazy horse.

Thanks, I had no idea. By the calculations it was 0-30mph in 6seconds w/ a 45mph top speed. Thank god i was cautious when i was trying this out cause it pops wheelies. Insta torque is quite dangerous even compared to a 650cc motorcycle!



Now it needs:
-Head stem re-tightened: probably wasn't tightened enough in the first place? Might have been the accidental whoolies? I need a front shock!

-rear pads cleaned, got a bit of mineral oil on them.

-stability addressed. I do not feel comfortable at speed with this thing. could be the tires, sharp throttle response and loose head though. lots of weight up top too. Need to fab a drop bar for the rear luggage thing so i can lower the seat.

 

[Balmorhea]

-rear pads cleaned, got a bit of mineral oil on them.

Disc pads are porous. If you get oil on them, they're wrecked. You can clean them and sand them all you like, but as soon as they get hot, they'll wick out some more oil and become weak and noisy again.

That's one of the reasons I prefer cable discs. The pads don't get ruined if a cable touches them.