The purpose of this post is to help other new Ludicrous riders with Lessons Learned from my experience learning to ride the bike without failing it.
See my update regarding programming settings that reduce failures at the bottom.
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When I bought a bike with Ludicrous, I had a lot of experience riding bikes and some experience with a more conventionally-powered e-bike. I also knew Ludicrous is only intended for experienced e-bike riders. Even with this background, I experienced a long learning curve including failing several parts. It's advisable to gain experience with a lower-powered motor before buying Ludicrous. However, the cost associated with buying twice is out of budget for many of us. This article is intended as a summary intro-to-Ludicrous to help others save time and money by avoiding the pitfalls that I dealt with due to my lack of experience. One potential alternative to buying twice could be to buy the programming cable from Luna and set your Ludicrous motor to the street-legal power level until you gain experience with it.
The chainring and cogs in particular can be described as both delicate and strong and reliable. They will fail quickly if exposed to unusual stresses but will last forever as long as the rider is aware of the risks and how to mitigate them.
The Golden Rule of riding Ludicrous is to use all the gears and stay in the lowest gear you practically can at all times. This essentially prevents at least two failure modes: Melting the nylon gear in the BBSHD, and stripping the rear cogs, mostly the smallest cog (highest gear). Even with an awareness of this, I heated up the motor to moderately risky temperatures on my first ride and subsequently stripped the rear cogs not once but twice before I learned the criticality of staying in the lowest practical gear.
The primary reason I stripped my smallest cog twice is it was subject to too much torque. A small cog made out of the standard material is no match for 2500 watts of power at low to moderate speeds. At any given power level, a lower gear puts less stress on the motor and cogs. With throttle only, never use the highest gear unless your speed is at least 25 MPH. Do not use the second-highest-gear unless your speed is at least 20 MPH. With PAS, these minimum speeds will need to be lower in order to keep up with pedaling but be mindful of this at all times. In other words, use lower gears with the throttle than you do with PAS at any given speed. I have been mitigating the risk of overtorquing the motor and cogs by using PAS 3 as opposed to 4 and 5. With the stock profile, the PAS power doesn't cut back quickly enough when torque is lessened to prevent shifting under load, even with the installed gear sensor (highly recommended). The motor power is present even with minimal torque when pedaling at PAS 4 and 5. With Ludicrous, PAS 3 is plenty of power. If you choose to use PAS 4 or 5, approach with caution and learn to use 3 prior to 4 prior to 5. I recently found out from Luna that their Limitless profiles should be a resolution to this because they're programmed to cut the torque as quickly as possible while the stock Bafang setting waits a short time before cutting torque. I will be ordering the programming cable and switching to a Limitless profile.
If your chain skips even once, or you hear a hard shift, immediately downshift or cut back on power until you can understand what caused it and prevent recurrence. With the power of Ludicrous, it doesn't take much skipping before your cogs require replacement. At a certain point, skipping will cause a secondary failure of your front chainring. Before I understood that skipping was a serious issue, it caused a tooth to break off my front chainring. A replacement chainring cost me $90 plus the shims required to accommodate the style of chainring Luna sells as a spare part. Nothing was wrong with the chainring. The sudden jolts of speed under load from the chain skipping over the stripped smallest cog caused the failure. The bike was inoperable until the replacement chainring and cogs arrived. Not to worry - this shouldn't cause you to use less power or speed than you otherwise would. After the learning curve, Ludicrous will provide as much acceleration and speed as you expect it to. Approach Ludicrous slowly and with caution and ramp up the amount of power you use as you gain experience with staying in the lowest practical gear and avoiding hard shifting. Also, I recently replaced my stock Shimano cassette with a stronger steel Sunrace cassette. Initial indications are that the extra strength is helping avoid stripping.
It's well-documented that the nylon gear in the BBSHD will fail at high temperatures. The guidelines developed by Karl Gesslein say to stop riding and let it cool at 140F. This is a controller side temperature. I have not opened my BBSHD to add a thermometer but based on measuring the outside with a laser thermometer the motor side always appears to be warmer than the controller side. When the far end face of the motor measures 140F, I can hold my fingers on it for about 2 seconds before feeling the uncontrollable urge to pull my hand away. When it measures 130F, I can hold my fingers on it for 4 seconds. 120F is the upper limit of being able to hold my fingers on it indefinitely. Bottom line, if you feel the far side of your motor and cannot hold your fingers on it for 2 seconds, it's probably time to let it cool or use minimal power.
Good news is if you proactively stay in the lowest gear you can to maintain your speed, it's rare for the BBSHD to get too hot. The common mistake that causes nylon gear failure is using higher gears than necessary. Per Luna, "the motor likes to spin fast." The motor can put out a lot of power yet remain cool if it's spinning fast. It can put out the same amount of power but heat up quickly if it's in a higher gear.
The shifter cable will probably stretch early on causing gear skipping and shifting that is not smooth. This is normal for a new shifter cable. I was unaware of this until after my chainring failure. It was a major contributing factor. For the first few hundred miles, periodically check the derailleur positioning to make sure it's in alignment with each gear. Check immediately any time your chain skips and adjust if needed.
Know that riding with Ludicrous will wear heavily on your brake pads. Have spare pads on hand.
This may sound like a lot of information but it's nothing to worry about as long as you have the time to learn. Bottom line, always use the lowest practical gear and try not to shift under load. Buy the optional gear sensor. It won't be long before you learn what to watch out for and have many years of speedy Ludicrous rides to look forward to.
**UPDATE** 2/25/20: I discovered after ordering the programming cable and pretty much adopting "Karl's Special Sauce" settings (aqua numbers) from the following page that I'm no longer (or at least far more infrequently) failing cogs and chains !!
https://electricbike-blog.com/2015/0...ing-the-bbs02/
I believe this is a combination of updating the following three variables:
Time of Stop on the PAS tab: I set this to 5 to resolve the issue described above where the PAS does not cut off quickly enough before shifting, causing wear. It seems to shift very well now when I use PAS.
Start Current (%) on the PAS tab: Adopting Karl's recommendation here may have helped as well.
Start Current (%) on Throttle Handle tab: I believe this variable was originally set significantly higher than Karl's recommendation of 10. I believe the power jerk upon startup wore on my cogs and chain. Related tip: Start the throttle slowly. Don't jam it down suddenly.
I would recommend adopting Karl's Special Sauce for all variables except Time of Stop, which I'd recommend setting to 5.
See my update regarding programming settings that reduce failures at the bottom.
----------------------------------
When I bought a bike with Ludicrous, I had a lot of experience riding bikes and some experience with a more conventionally-powered e-bike. I also knew Ludicrous is only intended for experienced e-bike riders. Even with this background, I experienced a long learning curve including failing several parts. It's advisable to gain experience with a lower-powered motor before buying Ludicrous. However, the cost associated with buying twice is out of budget for many of us. This article is intended as a summary intro-to-Ludicrous to help others save time and money by avoiding the pitfalls that I dealt with due to my lack of experience. One potential alternative to buying twice could be to buy the programming cable from Luna and set your Ludicrous motor to the street-legal power level until you gain experience with it.
The chainring and cogs in particular can be described as both delicate and strong and reliable. They will fail quickly if exposed to unusual stresses but will last forever as long as the rider is aware of the risks and how to mitigate them.
The Golden Rule of riding Ludicrous is to use all the gears and stay in the lowest gear you practically can at all times. This essentially prevents at least two failure modes: Melting the nylon gear in the BBSHD, and stripping the rear cogs, mostly the smallest cog (highest gear). Even with an awareness of this, I heated up the motor to moderately risky temperatures on my first ride and subsequently stripped the rear cogs not once but twice before I learned the criticality of staying in the lowest practical gear.
The primary reason I stripped my smallest cog twice is it was subject to too much torque. A small cog made out of the standard material is no match for 2500 watts of power at low to moderate speeds. At any given power level, a lower gear puts less stress on the motor and cogs. With throttle only, never use the highest gear unless your speed is at least 25 MPH. Do not use the second-highest-gear unless your speed is at least 20 MPH. With PAS, these minimum speeds will need to be lower in order to keep up with pedaling but be mindful of this at all times. In other words, use lower gears with the throttle than you do with PAS at any given speed. I have been mitigating the risk of overtorquing the motor and cogs by using PAS 3 as opposed to 4 and 5. With the stock profile, the PAS power doesn't cut back quickly enough when torque is lessened to prevent shifting under load, even with the installed gear sensor (highly recommended). The motor power is present even with minimal torque when pedaling at PAS 4 and 5. With Ludicrous, PAS 3 is plenty of power. If you choose to use PAS 4 or 5, approach with caution and learn to use 3 prior to 4 prior to 5. I recently found out from Luna that their Limitless profiles should be a resolution to this because they're programmed to cut the torque as quickly as possible while the stock Bafang setting waits a short time before cutting torque. I will be ordering the programming cable and switching to a Limitless profile.
If your chain skips even once, or you hear a hard shift, immediately downshift or cut back on power until you can understand what caused it and prevent recurrence. With the power of Ludicrous, it doesn't take much skipping before your cogs require replacement. At a certain point, skipping will cause a secondary failure of your front chainring. Before I understood that skipping was a serious issue, it caused a tooth to break off my front chainring. A replacement chainring cost me $90 plus the shims required to accommodate the style of chainring Luna sells as a spare part. Nothing was wrong with the chainring. The sudden jolts of speed under load from the chain skipping over the stripped smallest cog caused the failure. The bike was inoperable until the replacement chainring and cogs arrived. Not to worry - this shouldn't cause you to use less power or speed than you otherwise would. After the learning curve, Ludicrous will provide as much acceleration and speed as you expect it to. Approach Ludicrous slowly and with caution and ramp up the amount of power you use as you gain experience with staying in the lowest practical gear and avoiding hard shifting. Also, I recently replaced my stock Shimano cassette with a stronger steel Sunrace cassette. Initial indications are that the extra strength is helping avoid stripping.
It's well-documented that the nylon gear in the BBSHD will fail at high temperatures. The guidelines developed by Karl Gesslein say to stop riding and let it cool at 140F. This is a controller side temperature. I have not opened my BBSHD to add a thermometer but based on measuring the outside with a laser thermometer the motor side always appears to be warmer than the controller side. When the far end face of the motor measures 140F, I can hold my fingers on it for about 2 seconds before feeling the uncontrollable urge to pull my hand away. When it measures 130F, I can hold my fingers on it for 4 seconds. 120F is the upper limit of being able to hold my fingers on it indefinitely. Bottom line, if you feel the far side of your motor and cannot hold your fingers on it for 2 seconds, it's probably time to let it cool or use minimal power.
Good news is if you proactively stay in the lowest gear you can to maintain your speed, it's rare for the BBSHD to get too hot. The common mistake that causes nylon gear failure is using higher gears than necessary. Per Luna, "the motor likes to spin fast." The motor can put out a lot of power yet remain cool if it's spinning fast. It can put out the same amount of power but heat up quickly if it's in a higher gear.
The shifter cable will probably stretch early on causing gear skipping and shifting that is not smooth. This is normal for a new shifter cable. I was unaware of this until after my chainring failure. It was a major contributing factor. For the first few hundred miles, periodically check the derailleur positioning to make sure it's in alignment with each gear. Check immediately any time your chain skips and adjust if needed.
Know that riding with Ludicrous will wear heavily on your brake pads. Have spare pads on hand.
This may sound like a lot of information but it's nothing to worry about as long as you have the time to learn. Bottom line, always use the lowest practical gear and try not to shift under load. Buy the optional gear sensor. It won't be long before you learn what to watch out for and have many years of speedy Ludicrous rides to look forward to.
**UPDATE** 2/25/20: I discovered after ordering the programming cable and pretty much adopting "Karl's Special Sauce" settings (aqua numbers) from the following page that I'm no longer (or at least far more infrequently) failing cogs and chains !!
https://electricbike-blog.com/2015/0...ing-the-bbs02/
I believe this is a combination of updating the following three variables:
Time of Stop on the PAS tab: I set this to 5 to resolve the issue described above where the PAS does not cut off quickly enough before shifting, causing wear. It seems to shift very well now when I use PAS.
Start Current (%) on the PAS tab: Adopting Karl's recommendation here may have helped as well.
Start Current (%) on Throttle Handle tab: I believe this variable was originally set significantly higher than Karl's recommendation of 10. I believe the power jerk upon startup wore on my cogs and chain. Related tip: Start the throttle slowly. Don't jam it down suddenly.
I would recommend adopting Karl's Special Sauce for all variables except Time of Stop, which I'd recommend setting to 5.
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