Why does the Rad City ship with a direct drive motor. Most every other eBike I have checked out uses a geared motor. This is more fully loaded bike with fenders, etc; perhaps this is a way to keep the cost down? Would this be an issue for the long term? Are there better alternatives?
RadCity direct drive motor
- Thread starter wiz302pa
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mrgold35
Well-Known Member
Maybe it is because of the regen braking with direct drive motors? My wife's RadCity has a much greater range compared to my Radrover with geared hub motor. I have 2X the torque and can coast downhill faster on my rover. She can get 40-50 miles from a charge; while, I need a spare battery to get that range (older rover with 11.6Ah battery).
smorgasbord
Well-Known Member
- Region
- USA
Here's Rad's take on why some of their bikes have geared motors while others have direct drive motors:
https://radpowerbikes.zendesk.com/hc/en-us/articles/115000749154
and here's a more in-depth blog article from them on the same subject:
www.radpowerbikes.com
https://radpowerbikes.zendesk.com/hc/en-us/articles/115000749154
and here's a more in-depth blog article from them on the same subject:
Guide to Electric Bike Motors
The motor, arguably one of the most integral components on any ebike, has seen many variations over the years. A motor needs to be designed correctly in order to propel an electric bicycle efficiently. Similar to a car, an ebike motor can be mounted at the front, middle, or the rear of the bike...
www.radpowerbikes.com
MechaNut
Active Member
In addition to regenerative braking direct drive motors have no moving parts inside to wear out and make no noise (again, no moving parts). They are pretty much a completely "bullet proof" electric motor. The down sides of direct drives is the tend to be physically larger (the distance between the coils and magnets plays into motor efficiency), heavier (because they are basically magnets and copper wire coils), and typically produce less torque than geared hub motor. Motor choices for bikes take into account more than just watts and torque.
mrgold35
Well-Known Member
I'm 2X heavier and almost 1 1/2 feet taller (extra weight and more wind resistance). We both have Topeak rack bags and I usually put all the heavy stuff on her ebike when we ride together. When we both ride the rovers, I switch the 11.6ah batteries between the ebikes about 12-15 miles in because she usually has 1-2 bars more than me.
The Radcity and rover weight about the same. Having Direct Drive, regen braking, 14ah battery, and probably thinner tires has greatly increased the ebike range compared when she was just on the rover. Never tested the full range; but, I think she could get +55 miles with her Radcity DD at PAS 2 at 12-15 mph. My max range with blinking LED battery indicator showing was about 37 miles at PAS 2/3 at 12-15 mph on the rover.
AHicks
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- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Direct drive vs. gear drive, and which one is "better" is going to come down to how an individual rider plans on using the bike. There is no one easy answer "fits all/universal" drive that's going to suit everyone. Gear drive may work out better in the hills and stop and go traffic, and while the direct drive works fine in that environment, it really starts coming onto it's own at higher speeds, say in excess of 15mph. This makes the direct drive (DD) appealing for people that commute to work for instance.
Re: direct drive motor diameter, all else being equal, the bigger the motor the more torque it has. Simple matter of leverage. A larger diameter motor has more leverage on the load/wheel than a smaller one would.
Direct drive is less expensive to manf, is able to shed built up heat faster, and is more efficient at higher speeds.
Gear drive, all else being equal, is peppier in stop and go situations, and stronger wile climbing small hills. I find I can keep mine at a lower PAS level more often than I could with the direct drive. On paper, there is potential for more noise do to the gears, but not noticeable in my experience. I can barely hear either one.
If given the choice between one or the other, again all else being equal and based on my usage (I have no use for speeds over 20 mph, I'm a big guy (300+), and I spend half of my time in a coastal area where a direct drive, even a big one (1500w) struggles with some hills I frequent), my vote would be for the gear drive. I've gone with a good one, the MAC 12t, that's designed to do what I need done, and I'm loving it.
Re: direct drive motor diameter, all else being equal, the bigger the motor the more torque it has. Simple matter of leverage. A larger diameter motor has more leverage on the load/wheel than a smaller one would.
Direct drive is less expensive to manf, is able to shed built up heat faster, and is more efficient at higher speeds.
Gear drive, all else being equal, is peppier in stop and go situations, and stronger wile climbing small hills. I find I can keep mine at a lower PAS level more often than I could with the direct drive. On paper, there is potential for more noise do to the gears, but not noticeable in my experience. I can barely hear either one.
If given the choice between one or the other, again all else being equal and based on my usage (I have no use for speeds over 20 mph, I'm a big guy (300+), and I spend half of my time in a coastal area where a direct drive, even a big one (1500w) struggles with some hills I frequent), my vote would be for the gear drive. I've gone with a good one, the MAC 12t, that's designed to do what I need done, and I'm loving it.
I didn't spend a lot of time reviewing specs before purchasing my Radcity. This is unusual since I normally research to death. My wife thought it would be best to get the bikes before it got too cold for this year. I'm glad I didn't wait and am very happy with the Radcity for performance and price. There are many specs to compare and most won't make much of a difference for everyday users.
The geared hub will have an advantage on a hill but that does not mean a direct drive can't climb the hill. This weekend the ride included a steep hill with a switch back where about 25% of the acoustic bikes are walked up. The narrow path and switch back requires you to slow down to make the turn. I was worried since I was pulling a trailer with a 50 lbs dog. I started out on the lowest gear and that was too low. I ended up on 3rd gear and 5 PAS and climbed while seated.
I don't know how much the regen makes but after 20 miles I was still showing full charge.
If I was getting a fat tire for trail riding, I would get a geared hub. Mid drives have an advantage but to me there is too much stress on the drive train. For me the Radcity is perfect.
The geared hub will have an advantage on a hill but that does not mean a direct drive can't climb the hill. This weekend the ride included a steep hill with a switch back where about 25% of the acoustic bikes are walked up. The narrow path and switch back requires you to slow down to make the turn. I was worried since I was pulling a trailer with a 50 lbs dog. I started out on the lowest gear and that was too low. I ended up on 3rd gear and 5 PAS and climbed while seated.
I don't know how much the regen makes but after 20 miles I was still showing full charge.
If I was getting a fat tire for trail riding, I would get a geared hub. Mid drives have an advantage but to me there is too much stress on the drive train. For me the Radcity is perfect.
mrgold35
Well-Known Member
The extra tq with the geared rear hub+throttle comes in handy for trail riding if you hit a sandy spot and need a little extra power or a short incline to push you over. We have sections of single track near the Rio Grande river so over grown in the summer where I have sit on the downtube and duck head to handlebar height and use the throttle to ride (not easy at 6'3"). Hard to do that with a mid-drive without a throttle.
RadCity has a throttle and is not mid-drive (?)
Correct and that's where comparing direct drive to geared is not an easy answer.
The direct will be slower to react but you have the throttle to go from 0 to 750 watts with a simple twist.
mrgold35
Well-Known Member
I have two 2016 Radrovers and the wife has a RadCity Step-Thru. The rover's geared rear hub is perfect for trail riding. I even use my rover to work commute because of the comfy ride and extra tq when I need to get up to speed in a hurry when need to make a light or when I cross 4-6 lane intersections. The extra geared hub tq comes in handy during winter with winter gloves+bar mitts and I can't really change gears that easily. I just hit the throttle to make up for it to get up to my commuter cruising speed of 20 mph faster.
phoenixtoohot
Well-Known Member
Okay, I only have 1 hour on a rented RadRover and 1 hour on a rented RadCity. I found both about equal on the sidewalk/pavement wrt acceleration and hill climbs. I didn't test on trails, but I was quite worried about the 80 Nm on the Rover and 40 Nm on the City ... was okay with either from a torque/acceleration standpoint. I did like the "engine braking" down hill with the City.
mrgold35
Well-Known Member
The Radrover and Radcity weight about the same. The only issue I have with Radrover is it is so big and bulky. It takes up a lot of space and hard to maneuver if you have a tight spot to store at work or home. It is a real pain in the butt to stuff in the rear of my 7 passenger SUV and I usually ask for help putting it on my Saris superclamp 4 platform rack. The Radcity feels so much easier to live with in those situations. I had to call the wife a few times to pick me up because of flats or weather. I couldn't use public transport or Uber/Lyft because of fat tires on the rover if I needed.
My Radrover works best riding out my garage door and back. Radcity is the way to go if you travel out of town to ebike, store/lock up in different locations, and need to transport the ebike on a rack or rear hatch to riding spots.
My Radrover works best riding out my garage door and back. Radcity is the way to go if you travel out of town to ebike, store/lock up in different locations, and need to transport the ebike on a rack or rear hatch to riding spots.
phoenixtoohot
Well-Known Member
How difficult is the RadCity to pedal with no assist? Could you realistically go, say 10 miles on relatively flat road?
AHicks
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- Region
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- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
First, are we assuming you miscalculated the battery's available distance so badly you ran the battery dead 10 miles from home? If so, this isn't very likely going to happen unless you are really asking for it. The bike will give you plenty of warning the battery is getting low. They do not go at 100% until they shut off. There's a bar graph for instance, that will give you an idea of your charge level, and the controller will actually start tapering available power in case you don't notice the graph.
Or, are you wanting to ride it 10 miles for exercise reasons? I think that answer is going to depend on how good a shape you are in. Mine broke down one day (the only time it's done that, turned out to be the battery key switch) and I had to ride it home, a distance of maybe 3 miles. Hardly flat or ideal conditions (grass path and rolling hills), that was some excersize I'd rather not repeat. 'Bout killed me - but - I'm hardly the picture of health or fitness (6'2/315 68 years young).
As mentioned in another note already, when pedaling with the assist turned off (PAS=0) there is little doubt you are riding on a direct drive bike. If you are in decent shape though, and willing to keep your speed down under 10 mph, I think the right guy could go 10 miles. The challenge provides no interest here, but I'm pretty sure others have risen to the occasion.
Or, are you wanting to ride it 10 miles for exercise reasons? I think that answer is going to depend on how good a shape you are in. Mine broke down one day (the only time it's done that, turned out to be the battery key switch) and I had to ride it home, a distance of maybe 3 miles. Hardly flat or ideal conditions (grass path and rolling hills), that was some excersize I'd rather not repeat. 'Bout killed me - but - I'm hardly the picture of health or fitness (6'2/315 68 years young).
As mentioned in another note already, when pedaling with the assist turned off (PAS=0) there is little doubt you are riding on a direct drive bike. If you are in decent shape though, and willing to keep your speed down under 10 mph, I think the right guy could go 10 miles. The challenge provides no interest here, but I'm pretty sure others have risen to the occasion.
phoenixtoohot
Well-Known Member
Thanks AHicks. I did a little more digging and it seems that it's really not practical to get home on a empty battery. Time to call Uber I guess, lol. Perhaps a result of the weight AND the DD drag.
AHicks
Well-Known Member
- Region
- USA
- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
On my ride, I don't believe the bike's weight was a factor. It was the motor, and the fact I was riding in miserable conditions. The heat at the time was well over 80, with Florida's humidity a factor for sure.
phoenixtoohot
Well-Known Member
Who knows, maybe Rad will standardize it's 2020 lineup with the geared hub motor like on the Rover, Mini and Runner. Never made sense to me why they put the DD on the RadWagon and RadCity, especially since they have standardized the batteries, drive line, shifters, etc. Perhaps the motor choice is dictated by their Chinese supplier, I don't know.
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AHicks
Well-Known Member
- Region
- USA
- City
- Snow Bird - Summer S.E. Michigan, Winter Gulf Coast North Central Fl.
Rad offers so few options on their bikes, making a wish for that is likely a waste of time. The Radwagon is a serious error in logic. That needs to be changed to a gear drive. Then, maybe a bike similar to the 'City, with a gear drive, would make a good addition to their line up?
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