RadPowerBike RadCity Commuter
- Thread starter Alan B
- Start date
markz
100 TW
More power is ALWAYS BETTER!
Alan B
100 GW
The Kenda Tire Sidewalls say min 30 max 80. He's way above the minimum tire pressure. He's pretty thin, so weight is not a factor.
Most of the things you (Bking) have told us are riddled with non-facts. Are you in sales? Do you sell Radbikes? Have you any experience building ebikes or modding ebikes?
Now if you tell me the stock tires are junk and we should change them, that might be useful info.
The rear tire of the Radcity is flat at this point, he's riding the 9C at the moment. He definitely prefers it because it goes uphill better. I just pinch tested the non-flat tire, and it is not low. That's just not the problem here.
I appreciate your effort to help, but we've compared the Radcity with a common inexpensive aftermarket ebike kit and find the Radcity inferior in hill climbing using the same battery and the same rider even after we made improvements. The Radcity appears to be an okay ebike but they apparently cut corners on the motor system. They put some effort into features so they could tick off the boxes, it has great racks, fenders and kickstand. The newer model seems inferior in the rack area, so they are focusing on reducing costs perhaps.
If your commute is level this is won't be a problem.
Maybe we'll swap in a better motor and controller at some point. When I bought it I wasn't planning on another project. I have plenty of those already.
Most of the things you (Bking) have told us are riddled with non-facts. Are you in sales? Do you sell Radbikes? Have you any experience building ebikes or modding ebikes?
Now if you tell me the stock tires are junk and we should change them, that might be useful info.
The rear tire of the Radcity is flat at this point, he's riding the 9C at the moment. He definitely prefers it because it goes uphill better. I just pinch tested the non-flat tire, and it is not low. That's just not the problem here.
I appreciate your effort to help, but we've compared the Radcity with a common inexpensive aftermarket ebike kit and find the Radcity inferior in hill climbing using the same battery and the same rider even after we made improvements. The Radcity appears to be an okay ebike but they apparently cut corners on the motor system. They put some effort into features so they could tick off the boxes, it has great racks, fenders and kickstand. The newer model seems inferior in the rack area, so they are focusing on reducing costs perhaps.
If your commute is level this is won't be a problem.
Maybe we'll swap in a better motor and controller at some point. When I bought it I wasn't planning on another project. I have plenty of those already.
I think Rad just received a $150 million cash infusion (not their first AFAIK). There will be bean counters wanting immediate profits and finding ways to cut costs. There are plenty of studies proving that higher tire pressure doesn't always improve speed. It would be interesting to have you plot the times up a short hill with a range of pressures from 20 - 60 or 80 (whatever the max the tire can take). Bet the times from 40 - 80 psi don't change by as much as 10% if at all.
BlueSeas
100 W
AHicks said:
Why do you suggest this? I admit my builds aren't Rad level cost driven solutions. But I have studied the simulations at Grin, and for 72V systems, I don't see the advantage looking at GMAC vs. 9C or QS. Especially with fins and statoraid or equal. Am I missing something?
BlueSeas
100 W
Bking said:
I could be mistaken? But my understanding is phase voltage is always less than battery voltage until max RPM. There is some loss, but generally phase watts more or less equals battery watts. Assuming both statements are true, phase amps are almost always more than battery amps. Amps, or current determines wire size needed, regardless of voltage.
The disputed issue is the 3 phase component. Yes there are 3 wires to the motor, and only 2 between the battery and controller. But what is the current on each phase on the motor side. 3 phase is only easily researched in conjunction with AC, not DC current. How does this relationship really work?
Alan B
100 GW
I have a couple of geared hubs, and they are quite interesting and they develop good torque at low power. I have one of each on a 2wd ebike that is featured in detail on another thread here on ES. Balancing a DD vs a Geared hub was interesting for sure.
The problem I have is on a commuter, I don't want plastic gears. They just wear out too often for my liking. I commuted with DD motors for years, had plenty of hill climbing power, and all I had to do was charge the batteries and fix the occasional flat tire and replace tires when the tread was gone. Never a problem with the motor. The gearmotors WILL wear out and require maintenance. That's just my preference. It is rather like an electric car vs a gas guzzler. Less maintenance. But gearmotors do a great job at putting out torque in a small motor. However the larger DD motor can take a LOT more power. But that's another story.
Now onto the motor topic. First of all, this is covered thoroughly on ES in many threads on controllers. There are folks here who have designed them and I have participated in those threads and learned a great deal, even being an EE - it is a specialized field of design. Look for them if you really want to understand this stuff. Prepare to be surprised, things are often not what you would have thought. But in the end it is all straightforward physics - electronics and magnetics.
In any case there is very little voltage loss through the wiring and controller from battery to motor. On a high powered rig there is more or when trying to climb steep hills at low speeds with marginal wiring, but it is usually small compared to the voltage. So what we have left is the duty cycle and the current. The ONLY thing the controller can do is adjust the duty cycle, which lets some energy from the battery into the controller, or not. I'm going to ignore commutation switching which is also going on, that just follows the windings around. And we'll talk about trapezoidal controllers because sinusoidal is another level. So we have three wires to the motor and the commutation selects which two get power. The third is disconnected, or used as a sense wire for sensorless operation, which we'll also ignore here. So the operator opens the throttle, and the controller begins switching current into those two motor wires. The current is the same in all the wires (battery to controller to motor), the controller is only a switch at this moment. But if you have the throttle only 10% open, the switch is only open 10% of the time. So 10% of the time the current flows from the battery and 90% of the time it cannot flow from the battery because the switch is open.
Now here is where things get interesting. The motor is an inductor. So it resists current changes and it has stored energy in the magnetic fields. So it continues to push the same current even though the battery switch is open. The controller effectively has diodes to allow this current to flow - motor to controller to motor. So we have 90% of the cycle flowing this circulating current while the battery flows nothing. Then the cycle ends and the switch in the controller closes and again battery current flows. This cycle is the controller's frequency and it's what you can sometimes hear, often about 10khz or 10 times per millisecond.
Note that the circulating current is not free energy, it is from the magnetic field in the motor, and it is declining through the cycle, but the cycle is chosen to be short compared to the time constant of this current. When the power is switched back on the current also increases with a similar time constant so it makes a little sawtooth waveform. The voltage is a square wave, the current is sort of a constant value which is related to the torque the motor is producing.
So step back a moment and see what's going on in the system. The voltage is pretty much constant throughout the system. The current from the battery is let's say 20 amps, but for 10% of the time only, so the battery only drains at 2 amps average. The motor current is 20 amps for the whole time. So the motor current is multiplied by 10 compared to battery current in this case. The actual numbers in real life will vary and depend on the real values of resistance, etc. But the physics is unavoidable - the motor and motor wires see a lot more current than the battery leads.
Now one thing we can add to this - the current rotates between the three wires, but only uses two at a time. So the third wire has a chance to cool off. So that reduces the average current in each wire to 2/3 of the motor current. But that's still more than the battery current in our example.
The heating in the wires is from current, not voltage. I squared R is the power loss in the wire. Squaring the I really makes the wire power loss dependent on the current and it rises quickly as the current increases (doubling the current causes four times the loss). Multiplying by R means that thin wires also multiply the power loss in the wires. Power loss in the wires causes two things. One is loss of power that should be in the motor (it reduces the voltage to the motor). The other is heating and physically damaging the wiring and connectors. To save money vendors can put in smaller wires and connectors (partly because it looks better and more copper is more costly), and then they set the controller software to keep the current low. You'll still see full power at middle speeds, but you won't see it at low speeds, which is where we are climbing hills..... Which is exactly what we seem to be seeing here.
Incidentally phase voltage and current are misnomers for motor voltage and current.
The problem I have is on a commuter, I don't want plastic gears. They just wear out too often for my liking. I commuted with DD motors for years, had plenty of hill climbing power, and all I had to do was charge the batteries and fix the occasional flat tire and replace tires when the tread was gone. Never a problem with the motor. The gearmotors WILL wear out and require maintenance. That's just my preference. It is rather like an electric car vs a gas guzzler. Less maintenance. But gearmotors do a great job at putting out torque in a small motor. However the larger DD motor can take a LOT more power. But that's another story.
Now onto the motor topic. First of all, this is covered thoroughly on ES in many threads on controllers. There are folks here who have designed them and I have participated in those threads and learned a great deal, even being an EE - it is a specialized field of design. Look for them if you really want to understand this stuff. Prepare to be surprised, things are often not what you would have thought. But in the end it is all straightforward physics - electronics and magnetics.
In any case there is very little voltage loss through the wiring and controller from battery to motor. On a high powered rig there is more or when trying to climb steep hills at low speeds with marginal wiring, but it is usually small compared to the voltage. So what we have left is the duty cycle and the current. The ONLY thing the controller can do is adjust the duty cycle, which lets some energy from the battery into the controller, or not. I'm going to ignore commutation switching which is also going on, that just follows the windings around. And we'll talk about trapezoidal controllers because sinusoidal is another level. So we have three wires to the motor and the commutation selects which two get power. The third is disconnected, or used as a sense wire for sensorless operation, which we'll also ignore here. So the operator opens the throttle, and the controller begins switching current into those two motor wires. The current is the same in all the wires (battery to controller to motor), the controller is only a switch at this moment. But if you have the throttle only 10% open, the switch is only open 10% of the time. So 10% of the time the current flows from the battery and 90% of the time it cannot flow from the battery because the switch is open.
Now here is where things get interesting. The motor is an inductor. So it resists current changes and it has stored energy in the magnetic fields. So it continues to push the same current even though the battery switch is open. The controller effectively has diodes to allow this current to flow - motor to controller to motor. So we have 90% of the cycle flowing this circulating current while the battery flows nothing. Then the cycle ends and the switch in the controller closes and again battery current flows. This cycle is the controller's frequency and it's what you can sometimes hear, often about 10khz or 10 times per millisecond.
Note that the circulating current is not free energy, it is from the magnetic field in the motor, and it is declining through the cycle, but the cycle is chosen to be short compared to the time constant of this current. When the power is switched back on the current also increases with a similar time constant so it makes a little sawtooth waveform. The voltage is a square wave, the current is sort of a constant value which is related to the torque the motor is producing.
So step back a moment and see what's going on in the system. The voltage is pretty much constant throughout the system. The current from the battery is let's say 20 amps, but for 10% of the time only, so the battery only drains at 2 amps average. The motor current is 20 amps for the whole time. So the motor current is multiplied by 10 compared to battery current in this case. The actual numbers in real life will vary and depend on the real values of resistance, etc. But the physics is unavoidable - the motor and motor wires see a lot more current than the battery leads.
Now one thing we can add to this - the current rotates between the three wires, but only uses two at a time. So the third wire has a chance to cool off. So that reduces the average current in each wire to 2/3 of the motor current. But that's still more than the battery current in our example.
The heating in the wires is from current, not voltage. I squared R is the power loss in the wire. Squaring the I really makes the wire power loss dependent on the current and it rises quickly as the current increases (doubling the current causes four times the loss). Multiplying by R means that thin wires also multiply the power loss in the wires. Power loss in the wires causes two things. One is loss of power that should be in the motor (it reduces the voltage to the motor). The other is heating and physically damaging the wiring and connectors. To save money vendors can put in smaller wires and connectors (partly because it looks better and more copper is more costly), and then they set the controller software to keep the current low. You'll still see full power at middle speeds, but you won't see it at low speeds, which is where we are climbing hills..... Which is exactly what we seem to be seeing here.
Incidentally phase voltage and current are misnomers for motor voltage and current.
BlueSeas
100 W
Alan,
Thanks for the explanation. I'm on about the 5th reading so it sinks in. And another day I will have to go search out those threads on controllers.
Bob
Thanks for the explanation. I'm on about the 5th reading so it sinks in. And another day I will have to go search out those threads on controllers.
Bob
BlueSeas said:
I don't think you're missing anything. I was coming from a different direction/set of priorities. My belief is few are going to want to mess with 72v batteries, statoraid and fins for a bike that needs to be reliable enough to be ridden daily - without a lot of maintenance.
Maybe I'm just getting naive in my old age, but it would seem to me there are thousands of 48v batteries in use for every 72v? What does that say about the practicality of the 72v to Joe average rider? It's not just a question of if it's possible that it will work or not, there's another question regarding just how practical it's going to be when it's put to use.
And as for wearing gears out too quickly, unless there's abuse involved (heat), not buying into that.
BlueSeas
100 W
AHicks said:
I didn't mean to imply 72V was better for hill climbing. Increasing the voltage only increases top speed. For hill climbing, if you maintain the same max speed uphill as a 48V system, the motor temp will be identical. But...who will do that? We all have heavy thumbs. So 72V is arguably worse for hill climbing.
But for acceleration and top end it's worthwhile. The energy available in a battery pack can be configured lower voltage/higher amp hours or higher voltage/lower amp hours. Same, or similar number of cells required. Both have similar kWh available. On flat terrain, at legal speeds of 28 mph as the limiting constraint, I see no additional complexity and better performance with little impact on range. The only reason lower voltage is mainstream, is that's what is easily purchased. And the controllers are a tad less expensive.
But back to the hill climbing issue. The 9c212 motor (without fins or statoraid) compared to a GMAC, max power, same controller, reaches temp limits climbing hills at essentially the same speed and same timeframe. Add just statoraid, not exactly a high maintenance item, and it beats the GMAC by a good margin on temperature. The only edge I saw for the GMAC was a slight efficiency advantage that disappears on the flats.
Maybe you mean mid-drive using the bikes gears? I haven't studied those.
Alan B
100 GW
It would be interesting to know how many miles the plastic gears (and low quality grease) actually last. Often the clutches, which are metal, fail as well. I see lots of failures in fairly short lifetimes on ES (but it is difficult to draw accurate conclusions from that data). I don't think plastic gears are used in electric cars, nor do they have similar clutches. Most Ebikes aren't really designed to last.
My daily driver was 18S and 75V max, and the hills were up to 15%, and 26 miles round trip. Charged twice per day. Wore out many sets of tires in a few years before I retired from the daily drive. Zero motor issues. Burned up one controller 5 times, changed to a different type, then zero issues with that. Smooth as silk sinewave torque mode. Give it a little throttle, bike just glides off. With variable regen saves the brakes without the jerky on/off type regen controls most have. It has it's own thread here.
48V batteries are 13S or 14S, not that different. We are running 14S here.
One thing I was thinking about on the RadCity is that the battery we are using is just adequate for the uphill commute. The same battery is now used on both ebikes. If the RadCity was wasting a lot of energy on tire losses it would fail to complete the commute on the same battery. The RadBike 13S battery was very marginal for the 16 mile uphill commute. The 14S Luna battery has a little margin, but not much. It is old and well used by now. Since the Luna was doing better we refitted the RadCity to accept it and with the Bolton controller we were able to use that battery on the RadCity as well.
It is interesting to note that RadBike sells geared motors on their non-commuter ebikes and a DD motor on their one designated Commuter ebike, or at least they did when we were shopping. RadBike must have a reason they didn't use their geared motor in their commuter ebike. Commuting implies lots of miles. Most ebikes not used for commuting rack up far fewer miles.
Geared motors are impressive and fun until they fail. I have several, but they're not commuters for me. My commute would have eaten them alive.
If you want the most reliable system, keep it as simple as possible. No clutches, gears or grease. DD does that. There's a cost in weight, and it requires a bit more more power to work. Simplicity has some tradeoffs. As do most things. It's a choice.
My daily driver was 18S and 75V max, and the hills were up to 15%, and 26 miles round trip. Charged twice per day. Wore out many sets of tires in a few years before I retired from the daily drive. Zero motor issues. Burned up one controller 5 times, changed to a different type, then zero issues with that. Smooth as silk sinewave torque mode. Give it a little throttle, bike just glides off. With variable regen saves the brakes without the jerky on/off type regen controls most have. It has it's own thread here.
48V batteries are 13S or 14S, not that different. We are running 14S here.
One thing I was thinking about on the RadCity is that the battery we are using is just adequate for the uphill commute. The same battery is now used on both ebikes. If the RadCity was wasting a lot of energy on tire losses it would fail to complete the commute on the same battery. The RadBike 13S battery was very marginal for the 16 mile uphill commute. The 14S Luna battery has a little margin, but not much. It is old and well used by now. Since the Luna was doing better we refitted the RadCity to accept it and with the Bolton controller we were able to use that battery on the RadCity as well.
It is interesting to note that RadBike sells geared motors on their non-commuter ebikes and a DD motor on their one designated Commuter ebike, or at least they did when we were shopping. RadBike must have a reason they didn't use their geared motor in their commuter ebike. Commuting implies lots of miles. Most ebikes not used for commuting rack up far fewer miles.
Geared motors are impressive and fun until they fail. I have several, but they're not commuters for me. My commute would have eaten them alive.
If you want the most reliable system, keep it as simple as possible. No clutches, gears or grease. DD does that. There's a cost in weight, and it requires a bit more more power to work. Simplicity has some tradeoffs. As do most things. It's a choice.
Alan B-
Rad is not real well known for logic when it comes to selecting DD vs. geared hubs. For proof, they build a cargo bike (RAD Wagon) that came with that same Rad City DD hub for many years. Complete pig. They FINALLY came around to the fact that was a really poor selection for that bike's intended purpose, and went to the geared hub they use on their other bikes.
My bet is, they'll see the light and do the same for the City soon. That or they'll bring out a geared version for city use, and a DD for commuting.
I get your point when it comes to direct drive hubs and long distance. They're the only thing that will stay cool running the kind of distance you're talking about at 20mph plus. I'll even grant you the KISS logic. You'll need to admit though, that when it comes to the bigger picture, the number of folks that can utilize those features are darn few and for between when it comes to e-bikes in general.
The RAD batteries, if the one I have is "normal", aren't all that bad either. At 4 years old now, powering a MAC 12t w/35a KT controller, has not lost any of it's original capability - not yet anyway. -Al
Rad is not real well known for logic when it comes to selecting DD vs. geared hubs. For proof, they build a cargo bike (RAD Wagon) that came with that same Rad City DD hub for many years. Complete pig. They FINALLY came around to the fact that was a really poor selection for that bike's intended purpose, and went to the geared hub they use on their other bikes.
My bet is, they'll see the light and do the same for the City soon. That or they'll bring out a geared version for city use, and a DD for commuting.
I get your point when it comes to direct drive hubs and long distance. They're the only thing that will stay cool running the kind of distance you're talking about at 20mph plus. I'll even grant you the KISS logic. You'll need to admit though, that when it comes to the bigger picture, the number of folks that can utilize those features are darn few and for between when it comes to e-bikes in general.
The RAD batteries, if the one I have is "normal", aren't all that bad either. At 4 years old now, powering a MAC 12t w/35a KT controller, has not lost any of it's original capability - not yet anyway. -Al
markz
100 TW
Even Dyson uses generic, off the shelf motors in their over priced vacuums.
AHicks said:
Alan B
100 GW
The Rad battery seems ok. We should sell it and the base, two chargers, plus the controller we pulled off. Another thing to put on the todo list.
When I started the gearmotors were very expensive and so I didn't mess with them until much later. Some say they'll last 10k miles, my front tires last that long. I don't know what the true number is, but I'd like a 50k rating. I hear in China where most of this stuff is made, they just buy a new one at the grocery store when it fails. Here just having a new wheel laced costs quite a bit. My first gearmotor, professionally laced in a quality wheel, was about $1,000. Far more than my first whole DD kit. But things have changed. Good cargo bikes have very heavy axles and extra load rated bearings. They can haul a lot of weight. Sounds very appropriate for a gearmotor, but something extra stout I would hope.
We had the Luna and chargers here with a bit more voltage and capacity, so we stuck it on the Peugeot and I already had the spare socket for it. It probably did increase speed up the hills a bit and it did not run out of juice on the way to work. I don't recall the details but it is probably reported earlier in this thread. Then we bought the RadCity. The Rad battery did on a few occasions run out of capacity as he was getting to work. So it's not bad, it's just a bit shy on capacity for his present route. That hasn't happened with the Luna on either bike. So unless it was an incomplete charging problem the old Luna is exceeding the new Rad. We charge the Luna with a Satiator at home, so it gets a good charge and we get some numbers. At work he's using a Luna charger on the Luna battery so we don't get much data on that side. We used Rad chargers on the Rad battery.
I have been looking at getting a newer battery but not a lot in the 14S world unfortunately. I'm pretty much done with 13S, even 14S is marginal for many of my bikes. My EGO tool packs are 14S, my Luna packs are mostly 14S. Seems like a good standard to stick with. Not too many 14S packs are junk, many 13S packs are poor. There are more cases made now to support 14S. It is a small step up.
I have one picked out but haven't pulled the trigger on it yet. Having fun with a 3d print design today for tennis ball pressurizers, so way off topic. Just recovering from my second Covid vaccination, been quite a roller coaster ride, also off topic for this thread.
I did want to thank those who stepped in here and made good points and supported things and kept the thread on track. Appreciated.
When I started the gearmotors were very expensive and so I didn't mess with them until much later. Some say they'll last 10k miles, my front tires last that long. I don't know what the true number is, but I'd like a 50k rating. I hear in China where most of this stuff is made, they just buy a new one at the grocery store when it fails. Here just having a new wheel laced costs quite a bit. My first gearmotor, professionally laced in a quality wheel, was about $1,000. Far more than my first whole DD kit. But things have changed. Good cargo bikes have very heavy axles and extra load rated bearings. They can haul a lot of weight. Sounds very appropriate for a gearmotor, but something extra stout I would hope.
We had the Luna and chargers here with a bit more voltage and capacity, so we stuck it on the Peugeot and I already had the spare socket for it. It probably did increase speed up the hills a bit and it did not run out of juice on the way to work. I don't recall the details but it is probably reported earlier in this thread. Then we bought the RadCity. The Rad battery did on a few occasions run out of capacity as he was getting to work. So it's not bad, it's just a bit shy on capacity for his present route. That hasn't happened with the Luna on either bike. So unless it was an incomplete charging problem the old Luna is exceeding the new Rad. We charge the Luna with a Satiator at home, so it gets a good charge and we get some numbers. At work he's using a Luna charger on the Luna battery so we don't get much data on that side. We used Rad chargers on the Rad battery.
I have been looking at getting a newer battery but not a lot in the 14S world unfortunately. I'm pretty much done with 13S, even 14S is marginal for many of my bikes. My EGO tool packs are 14S, my Luna packs are mostly 14S. Seems like a good standard to stick with. Not too many 14S packs are junk, many 13S packs are poor. There are more cases made now to support 14S. It is a small step up.
I have one picked out but haven't pulled the trigger on it yet. Having fun with a 3d print design today for tennis ball pressurizers, so way off topic. Just recovering from my second Covid vaccination, been quite a roller coaster ride, also off topic for this thread.
I did want to thank those who stepped in here and made good points and supported things and kept the thread on track. Appreciated.
JackFlorey
100 kW
Sorry if this has been answered already -
What motor does the RadCity Commuter (v4) use?
What motor does the RadCity Commuter (v4) use?
Alan B
100 GW
I certainly don't know, they probably have something made for them so it may not be a standard motor. We should weigh the motor wheel, that would give some idea of the materials. Ours is probably not the V4 but it seems a bit weak compared to an old 9C.
Alan B
100 GW
Next installment of the RadCity Saga
We're at about the 2 year mark now and the freewheel has failed. Spins freely, no pedal engagement. I don't see any replacement freewheel on their site, and when I tried to fill out a request for information it didn't seem to have anything for any but new bikes. Respect for RadBike falls even lower.
I ordered a similar freewheel from Amazon. It came next day. It looks like the same unit. Over $40. We replaced it today. It was a little easier than fixing a flat tire, but required more specialized tools, which I luckily had on hand.
Anyone know if the broken clutch can be repaired? Or must we toss the entire assembly away for some tiny broken bits inside. It still looks like new.
This is not good reliability for the Radcity. My adult son has ridden this bike averaging about 1-2 days a week commuting 32 miles round trip for 2 years. The failure essentially stranded him since the motor is fairly weak (in hilly terrain) and needs help from pedaling.
The bike he rides the other half of the time has an ancient 9C hubmotor which is stronger and the freewheel is still going strong, even though it is much older and has many more miles. The rim has worn out and needs replacement, a victim of the rough pavement and many more years of service.
We're at about the 2 year mark now and the freewheel has failed. Spins freely, no pedal engagement. I don't see any replacement freewheel on their site, and when I tried to fill out a request for information it didn't seem to have anything for any but new bikes. Respect for RadBike falls even lower.
I ordered a similar freewheel from Amazon. It came next day. It looks like the same unit. Over $40. We replaced it today. It was a little easier than fixing a flat tire, but required more specialized tools, which I luckily had on hand.
Anyone know if the broken clutch can be repaired? Or must we toss the entire assembly away for some tiny broken bits inside. It still looks like new.
This is not good reliability for the Radcity. My adult son has ridden this bike averaging about 1-2 days a week commuting 32 miles round trip for 2 years. The failure essentially stranded him since the motor is fairly weak (in hilly terrain) and needs help from pedaling.
The bike he rides the other half of the time has an ancient 9C hubmotor which is stronger and the freewheel is still going strong, even though it is much older and has many more miles. The rim has worn out and needs replacement, a victim of the rough pavement and many more years of service.
Is this the pedal chain freewheel on the outside of a hubmotor?
Or is this the internal freewheel of a geared hubmotor?
Or something else?
If you can post pics of the failed clutch (is this part of the freewheel? or a separate part inside the motor?) (including internals and the broken bits) it will give us a better idea if there might be spare parts available for the broken bits (which could literally be anything, without further information
).
For the other bike, what exactly does "worn out" mean regarding the rim?
You almost certainly already know this, but for readers of your thread:
Most often the rims don't actually wear out (unless using rim brakes), but there are a number of ways they can fail. With hubmotors, especially OEM wheels, the most common, especially with bad roads / rough riding conditions / heavy loading, is cracked nipple holes allowing spokes to loosen which then allows the rim to warp or bend from loading it's not intended to see. This usually happens from spokes that are too thick (typically 12g, rather than the thinner 14g or 15g which would work better) to allow proper tensioning without overstressing the rim at the nipple holes, which is what causes the cracks.
Or is this the internal freewheel of a geared hubmotor?
Or something else?
If you can post pics of the failed clutch (is this part of the freewheel? or a separate part inside the motor?) (including internals and the broken bits) it will give us a better idea if there might be spare parts available for the broken bits (which could literally be anything, without further information
).For the other bike, what exactly does "worn out" mean regarding the rim?
You almost certainly already know this, but for readers of your thread:
Most often the rims don't actually wear out (unless using rim brakes), but there are a number of ways they can fail. With hubmotors, especially OEM wheels, the most common, especially with bad roads / rough riding conditions / heavy loading, is cracked nipple holes allowing spokes to loosen which then allows the rim to warp or bend from loading it's not intended to see. This usually happens from spokes that are too thick (typically 12g, rather than the thinner 14g or 15g which would work better) to allow proper tensioning without overstressing the rim at the nipple holes, which is what causes the cracks.
Alan B
100 GW
The RadCity uses a standard Freewheel, I replaced it with one from Amazon. Clutch is internal. Sad to throw away the new looking cluster for some small internal broken parts, rather expensive too.
The Peugeot ebike rim was built by Cycle9, my first 9C hubmotor wheel from 2010. Many, many miles on it. Not oversize spokes - was a well built wheel but the cheap rim broke some spokes and is finally cracking near spoke holes, it won't hold proper tension anymore. Aluminum can only take so many flexing cycles.
The Peugeot ebike rim was built by Cycle9, my first 9C hubmotor wheel from 2010. Many, many miles on it. Not oversize spokes - was a well built wheel but the cheap rim broke some spokes and is finally cracking near spoke holes, it won't hold proper tension anymore. Aluminum can only take so many flexing cycles.
I've saved broken clusters to reuse the individual sprockets on them to either replace worn sprockets on working clusters, or to custom-make clusters with different gearing jumps than generally available.Alan B said:
But finding the fiddly internal bits to repair one generally doesn't work out, as I see a lot of different kinds of parts used in various brands and models, and they don't fit each other.
Yeah, mostly long ago, I've broken (non-eyeletted) regular wheels on regular bikes (and trailers) used for heavy cargo stuff because of that kind of problem, though that was mostly before I began learning about wheels enough to check for those problems and replace wheels before they actually broke and stranded me or made me ride home on warped broken wheels.
But unlike yours, almost all of the wheels I have had cracks around the nipple holes were OEM hubmotor wheels using like 12g spokes on cheapo non-eyeletted rims so the spokes did the damage themselves.
Nowadays I just try to always use eyeletted rims to help spread the stress better around the holes, and use or build wheels with thinner spokes, and I don't break many from that problem now. (they do break from unavoidable potholes vs my heavy bike or trike, neither of which has rear suspension, but that is usually rim flange damage or actual ovalling of the core of the rim itself, loosening all the spokes in one direction and overtensioning them in the other).
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