arthurtuxedo
100 W
Max speed: 18 MPH
Range: 30 mi
Donor bike: Worksman Low-Gravity LGP
Rider weight: 150-250
Cargo weight: 200-300
Max grade: 20%+
I have started working for a company that hauls around small but heavy objects (6 objects weighing 35 lbs each, 8 or 9 of them would be ideal) to destinations all over the city, and I want to propose that we start using electric cargo bikes to do this. However, this is going to be a very specialized build given that our cargo will weigh around 200 lbs and we sometimes have no choice but to haul it up very steep hills. The only common motor that I can think of that can pull this off is the BBSHD, and I like the Worksman bikes because they are so heavily built and the LGP model has a steel box on the front that can fit our cargo and take a padlock for when we need to leave the bike for 5-15 minutes.
Worksman offers their bikes in either single-speed or 3-speed Sturmey Archer with either a 36 or 44 tooth front sprocket and 20t rear. According to Sheldon Brown, that gives 35-62 or 43-76 gear inches and a top speed of either 18.5 or 22.6 MPH @ 100 RPM. The low top speed is good because I am not confident in the ability of a Sturmey-Archer coaster brake and the Worksman front drum brake to stop ~500 lbs of gross weight at speeds higher than that. In fact, on a descent I'm not confident that they can stop the bike at all, which is one of my concerns and a reason that I am posting. The drum brake is listed as C6LG, and a Google search doesn't reveal anything about what kind of stopping power it has. I would just throw on a front hydraulic disc but I don't know whether the fork can accept one or not, or whether it has clearance for rim brakes either.
My other concern is the amount of torque that would be applied to the drive system carrying a lot of weight up a steep hill. It seems like a BBSHD could glide right up at only 35 inches of gearing, but I wouldn't want to order everything and find that the motor is burning itself up in the attempt or the chain snaps in two or the torque grenades the gear hub.
I also looked at the eRad 1000w Yuba Mundo, which has a lot more gear range and the huge advantage of being a turn-key solution that I wouldn't have to wrench together, but accessing the cargo from panniers or Wald baskets would be less convenient than a front box and I can't think of any way for us to leave the bike while we go around the corner and not have our gear get stolen.
Please let me know if the Worksman LGP + BBSHD is a good idea or would require a lot of additional work to be made viable!
Range: 30 mi
Donor bike: Worksman Low-Gravity LGP
Rider weight: 150-250
Cargo weight: 200-300
Max grade: 20%+
I have started working for a company that hauls around small but heavy objects (6 objects weighing 35 lbs each, 8 or 9 of them would be ideal) to destinations all over the city, and I want to propose that we start using electric cargo bikes to do this. However, this is going to be a very specialized build given that our cargo will weigh around 200 lbs and we sometimes have no choice but to haul it up very steep hills. The only common motor that I can think of that can pull this off is the BBSHD, and I like the Worksman bikes because they are so heavily built and the LGP model has a steel box on the front that can fit our cargo and take a padlock for when we need to leave the bike for 5-15 minutes.
Worksman offers their bikes in either single-speed or 3-speed Sturmey Archer with either a 36 or 44 tooth front sprocket and 20t rear. According to Sheldon Brown, that gives 35-62 or 43-76 gear inches and a top speed of either 18.5 or 22.6 MPH @ 100 RPM. The low top speed is good because I am not confident in the ability of a Sturmey-Archer coaster brake and the Worksman front drum brake to stop ~500 lbs of gross weight at speeds higher than that. In fact, on a descent I'm not confident that they can stop the bike at all, which is one of my concerns and a reason that I am posting. The drum brake is listed as C6LG, and a Google search doesn't reveal anything about what kind of stopping power it has. I would just throw on a front hydraulic disc but I don't know whether the fork can accept one or not, or whether it has clearance for rim brakes either.
My other concern is the amount of torque that would be applied to the drive system carrying a lot of weight up a steep hill. It seems like a BBSHD could glide right up at only 35 inches of gearing, but I wouldn't want to order everything and find that the motor is burning itself up in the attempt or the chain snaps in two or the torque grenades the gear hub.
I also looked at the eRad 1000w Yuba Mundo, which has a lot more gear range and the huge advantage of being a turn-key solution that I wouldn't have to wrench together, but accessing the cargo from panniers or Wald baskets would be less convenient than a front box and I can't think of any way for us to leave the bike while we go around the corner and not have our gear get stolen.
Please let me know if the Worksman LGP + BBSHD is a good idea or would require a lot of additional work to be made viable!