dogman dan
1 PW
Bafang 750w would be better. On 48v, close to 1000w of assist.
Best motor for steep city hill low speed climbing?
- Thread starter naitsirk
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spinningmagnets
100 TW
The LightningRods kit will be shipping this week, and I can't think of a better hill-climber. One of the main benefits of a mid-drive is that you can swap-in a different chainring to suit your particular hills. Assuming that a simple set-up has a single chainring at the BB and 7 sprockets at the rear wheel...you can give the system a smaller chainring to get the climbing speed in the lowest gear down to 5-MPH, while the motor is happily spinning along at somewhere around 3,000-RPMs. You could make the lowest gear 7-MPH or 10-MPH...with a simple chainring swap.
A lot of the heat in a motor comes from the amps. So one way to get more power while keeping the amps low is to raise the voltage. The GNG motor in the LR kit has been verified to run well at 72V.
If you are mechanically handy, it is shockingly cheap and easy to make a longtail bike by combining a hardtail frame and a swingarm from a WalMart full-suspension MTB. The benefit with this is ending up with a 20-inch rear wheel to further improve hill-climbing.
A low-Kv hub will climb well, but will also have a low top speed. If the top gear in a non-hub 7-speed cluster is twice the speed of its lowest gear, then the motor will have twice the operational range as a hub that matches the low-gear performance of the LR kit.
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If you are more interested in a 2WD set-up, Ben Chiu's 2WD 60V bike struggled with one MAC on his steep hills, but when he doubled the copper mass with a second motor, it has now has no problems...even on very long uphills. Be aware he took the precaution of getting motors with built-in temp sensors, and he has a Cycle Analyst V3 with automatic amp-rollback if they get too warm (93C/200F).
A lot of the heat in a motor comes from the amps. So one way to get more power while keeping the amps low is to raise the voltage. The GNG motor in the LR kit has been verified to run well at 72V.
If you are mechanically handy, it is shockingly cheap and easy to make a longtail bike by combining a hardtail frame and a swingarm from a WalMart full-suspension MTB. The benefit with this is ending up with a 20-inch rear wheel to further improve hill-climbing.
A low-Kv hub will climb well, but will also have a low top speed. If the top gear in a non-hub 7-speed cluster is twice the speed of its lowest gear, then the motor will have twice the operational range as a hub that matches the low-gear performance of the LR kit.
_______________________________________
If you are more interested in a 2WD set-up, Ben Chiu's 2WD 60V bike struggled with one MAC on his steep hills, but when he doubled the copper mass with a second motor, it has now has no problems...even on very long uphills. Be aware he took the precaution of getting motors with built-in temp sensors, and he has a Cycle Analyst V3 with automatic amp-rollback if they get too warm (93C/200F).
even though their expensive- for SF mid-drive is the ticket
DD are nice on flat but any serious hill - you'll need a really powerful DD in a small wheel that will heat up and stress you batteries during heavy climbs - not to mention stress on wheels spokes etc- totally inefficient
perhaps a 2WD could work- but nothing will compare to gears there's reason all automotive use them
DD are nice on flat but any serious hill - you'll need a really powerful DD in a small wheel that will heat up and stress you batteries during heavy climbs - not to mention stress on wheels spokes etc- totally inefficient
perhaps a 2WD could work- but nothing will compare to gears there's reason all automotive use them
cwah
100 MW
For 20% grade mid drive is the only solution. 2WD will require an incredible amount of power just to keep the motors happy and spinning over 15mph to have decent efficiency.
1 BBS02 750 should be good enough!
1 BBS02 750 should be good enough!
TotalConfusion
100 W
After reading all these comments i still like Dogmans 1st suggestion i think it was,
The idea of a 750W mid drive Bafang with a 12T mac in the rear hub would also pull well up hills and as Spinningmagnets said you can change the chainring to suit.
Im still working on getting my 1st bike working as it doesnt want to go but im already considering a 12T Mac on the front for the steep hills in the snowy mountains when i go trout fishing to get me up the longer steeper hills and having the freewheel when not in use wouldnt affect my DD.
The idea of a 750W mid drive Bafang with a 12T mac in the rear hub would also pull well up hills and as Spinningmagnets said you can change the chainring to suit.
Im still working on getting my 1st bike working as it doesnt want to go but im already considering a 12T Mac on the front for the steep hills in the snowy mountains when i go trout fishing to get me up the longer steeper hills and having the freewheel when not in use wouldnt affect my DD.
dogman dan
1 PW
I haven't tried that, so I don't know if the bb drive would twist the freewheel off the cover of a Mac. But you could put a front motor on.
I haven't ridden a bb2 yet, but the first indications are very good. Right now, starting from scratch, I'd try the bb2 750w first. Then add more power later if needed.
Bear in mind, the original post spoke of not only climbing a steep hill, but with two people on the bike. But in the lowest gear, it's quite possible that 750w will do er. It's like having Sagan on the back of your tandem.
I haven't ridden a bb2 yet, but the first indications are very good. Right now, starting from scratch, I'd try the bb2 750w first. Then add more power later if needed.
Bear in mind, the original post spoke of not only climbing a steep hill, but with two people on the bike. But in the lowest gear, it's quite possible that 750w will do er. It's like having Sagan on the back of your tandem.
