Cost-Benefit Comparison: Electric Bike "Chain-Suck" Failure, Chains, Gears and Belts

Discussion in 'Help Choosing an Ebike' started by Mike leroy, May 1, 2015.

  1. Mike leroy

    Mike leroy Active Member

    Chain links pulled around the chainring can be stressed to unimaginable levels (300kg per square mm) which create microscopic gaps (0.1mm) in the chain links. Recall when accelerating very hard that the entire bike force is directly centered on the forward most chain link. To appreciate the pressure, quickly lift your bike over your head only using the tip of your pinky finger. Oh, yeah!

    The gap in the chain link is half the thickness of a human hair. Dirt and mud can clog chain link rollers by entering imperceptible gaps. Clogged rollers can bring a bike to a sudden and dangerous standstill, that ejects the rider from the bike.

    640px-Roller_Chain_Render_(with_numbers).png

    Layout of a roller chain: 1. Outer plate, 2. Inner plate, 3. Pin, 4. Bushing, 5. Roller
    The chain link rollers serve the critical function to release a chain link from the chainring, when the link reaches the bottom of the sprocket. If the roller cannot rotate, then chain-suck will likely cause the entire crankset to seize up. The risk of being ejected from the bike is real.

    Chain-suck diagram:

    images.jpeg

    The amount of stress exerted on a chain depends on the number of teeth on a sprocket. The ratio of teeth between front (i.e., chainring) and rear sprockets (i.e., cassette gears) also affects the amount of pressure exerted on each chain link.

    ChainringRatios.png
    Finally, the alignment between front and rear sprockets affects the amount of pressure applied to a chain. In a single front and rear sprocket configuration like a motorcycle, all pressure is directly aligned along the chain. As more, thicker gears are added to the rear cassette, alignment between front and rear sprockets decreases. More gears also implies thinner chains.

    ChainTwist.jpg

    A chainring/rear sprocket tooth ratio greater than 0.55 for a rider under 100kg is mandatory for
    Rohloff chains. Rohloff manufactures the strongest and most durable bike gear systems, which often last over 60,000 miles ridden by professionals.


    Bosch motor sprockets (16 tooth chainring) connected to an 11 gear rear cassette represent the high wear scenario. A motorcycle configuration of just one front and rear sprocket is an example of least chain wear.

    On a Haibike XDuro, which has chain-suck issues, the tooth ratio may be as low as is 16 / 36 = 0.44, or 22% lower than the Rohloff hard limit for a straight chain. I will actually have the reverse on my bike, 26/13 because the Rohloff IGH has a 528% gear ratio. So, the front/rear tooth ratio for Rohloff is four times higher than Bosch/Haibike XDuro ratio.

    wirkungsgrad_en.png

    Put this into perspective with a conventional mountain bike. The Santa Cruz Heckler, for example, uses Sram S1000 2x10 22/34 crankset. The Bosch has 16 teeth, or 25% fewer teeth than the 22 tooth Heckler.

    The Zero motorcycle has an outrageous front/rear tooth ratio, like Bosch. I am beginning to think the problem with mud in chains that stops the Bosch motor is related to the chain construction or the cassette twisting the chain. Might also be due to the huge wear on the pins that causes the chain to stretch excessively. My hunch is the chain is stretched so much that dirt builds up to the point that the chain links cannot bend around the chainring. Like so many small wedges stiffen the chain. Alternatively, the link pitch angle is altered to the point that the links cannot bend around the sprocket.

    zero-mx-17_600x0w.jpg
    If you have experienced chain-suck, your cassette may have too high a gear ratio for the Bosch chainring. You might consider replacing the entire drivetrain. Replacing the chain without also replacing the chainring is one of the most dangerous changes.


    Chain-suck process.
    CS-Mech-small.gif

    Obviously, any chain angle, weaker chain brands or heavier riders will raise the risk. I do not want to publicly speculate about how low the limit falls, but it should be obvious to anyone who takes a close look at the hooked teeth on a damaged chainring . The high Risk, low Cost and low lifespan Economy of this configuration is illustrated in the following Star Plot:

    StarPlotChain.png
    To discuss related topics of a personal nature, please join the conversation.
     

    Attached Files:

    Last edited: May 4, 2015


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  3. Mike leroy

    Mike leroy Active Member

    Useful automatic chain lube concept.



    "How can you check when your chain should be replaced? The standard formula is that your chain should be replaced when it has been stretched more than 0.1mm per link. With the chain wear indicator Rohloff Caliber 2 you can check with one glance whether it is time to replace the chain by hooking it between the rollers of the chain. With two different gauges you can adjust your checking to the type of sprockets you use. If you use aluminium sprockets, you should replace the chain even before the stretching of 0.1mm per link. Problems of the power transmission are not always caused by the chain. Modern sprockets with low and thin teeth and mass production of low quality material are just two reasons, why sprockets can be damaged even before the chains in worn.

    In order to check the wear of sprockets, Rohloff has developed the HG-IG-sprocket (IG Link) wear indicator Rohloff HG-Check. Without a tool it is nearly impossible to spot the wear of HG and IG sprockets so that very often the sprockets are replaced with the chain.

    With the Rohloff HG-Check it becomes possible to check the sprockets which gives a clear answer whether it is necessary to replace them or not. Therefore, this inexpensive tool should be found in all workshops.

    Bosch motor owners take note:

    ... high performance use, the bicycle chain receives up to 500kg of force. Therefore, an extremely high level of surface pressure of 300kg/mm2 is to be found here within the chain links.

    The smaller the chainrings are up front, the greater the amount of force is which is applied to the chain and with it, the amount of surface pressure applied to each individual chain link (e.g. all MTBs running compact drive, microdrive, and hyperdrive C). The amount of surface pressure also increases when the chain is running at an angle because the contact area is proportionately reduced. [more front/rear gear alignment difference, the larger the angle].


    The Rohloff SPEEDHUB 500/14 has been developed for racing which means that it can handle the heavy loads encountered during competition. Maximum torque loads in extreme conditions can be as high as 250Nm on the crank (= 150kg on the pedal). This will not damage the gear box because the high chainring/sprocket ratio transforms the low number of crank revolutions into a higher number of revolutions at the cog.

    Bosch motor owners take note:

    The higher the chainring/sprocket ratio, the lower the input torque to the gear-unit. It is imperative therefore that the chainring/sprocket factor does not drop below 1.9 (e.g. 34/17=2.0). The smallest permissible sprocket ratios for a rider weighing less than 100kg are: 32:17, 30:16, 28:15 and 26:13.

    These are the equivalent to a 22:40 combination on a conventional drivetrain. There is no limit whatsoever for higher ratios which means that you can mount bigger chainrings than shown on the table for extreme downhill racing.

    If the SPEEDHUB is mounted on a tandem bicycle or if the rider weighs over 100kg, a chainring/sprocket factor of 2.5 (e.g. 42/17=2.5) must be upheld. This equates to sprocket ratios of: 42:17, 40:16, 38:15 and 34:13.

    Even though the Rohloff chain with its optimal patented linkage system greatly reduces the amount of wear caused by this surface pressure, it still needs to be lubricated the same as any other type of bicycle chain. Without this lubricating film between the contact surfaces, an abrasive friction will occur accelerating the level of chain.

    One of the essential wear factors is the amount of dirt which has penetrated the chain linkages. Hard particles (e.g. sand) could enter the chain and lie on the above surface of the bearing collar, this sand then starts to work identically to sandpaper. Material from the pin surface will slowly be worn away, a little lubrication helps even if this occurs. To fully understand this effect, we will turn back to the sandpaper example: Dry sandpaper is very abrasive. When however, it is used with a lubricant (e.g. water), the abrasive effect is conciderably reduced. With oil as a lubricant, the abrasiveness of the sandpaper has hardly any physical effect. "

    "Particles already in the link can hardly be removed by any cleaning method (not even with an ultrasonic bath). In order to prevent particles being transported into the link in the first place, the chain should be kept dry and clean on the outside by wiping it regularly with an oily cloth. Additionally, sprockets, pulleys and chainrings should be kept as clean as possible because these parts are in direct contact with the rollers of the chain.

    Only a very dirty chain should be cleaned intensively. We do not recommend any of the currently available chain cleaning devices because the liquids used normally have a very negative effect in the chain links. The links will not be free from particles after the application but the cleaning liquid will mix with the lubricant which in most cases destroys its lubricating feature. Therefore, before using a cleaning liquid, test it by mixing it with the lubricant you use.

    We recommend cleaning liquids which do not have 100% degreasing effect, such as diesel or paraffin. Products based on modern washing-up liquids are generally environmently more friendly. These work quite well and can be easily washed out of the link with water.

    A constant lubricating film in the link can improve the durability of the chain substantially. However, this is not easily achieved due to the link movements being so small and the pressures applied being so great. Achieving a sustaining film of lubricant proves incredibly difficult.

    Only special lubricants will be able to cope with the unique conditions that are to be found in a link of a chain:
    • Firstly, the lubricant must be able to creep into the link and between the moving parts. Secondly, the lubricant must be able to withstand the high forces applied to each link.
    • A lubricant without this extremely important property will be displaced by the pressure with the effect that metal rubs on metal as if there were no lubricant present at all.

    Our tests have shown that most available lubricants do not fulfill these requirements. Most products do prevent rust and are better than no lubrication at all, but are not suitable for the extreme conditions found within a chain link.

    These lubricants are in particular the popular silicon and teflon products, but also all the very thin oils. All products which claim to have a cleaning and/or rust removing effect are in our opinion also unsuitable for the correct lubrication of the bicycle chain.

    In order to give the consumer a secure alternative in terms of lubricating the chain, we have developed the automatic chain lubrication system Rohloff LUBMATIC and the biodegradable, pressure resistant Rohloff special chain lubricant Oil of Rohloff. This high performance lubricant creeps under water and has a stable viscosity over a wide temperature range.

    For off-road trips and riding through cold climates you can additionally protect your chain by using a wax spray. However, the wax does not lube your chain, therefore it should only be used after lubrication. The wax film reduces the amount of dirt sticking on the chain and partly protects the link against dirt and water. Please only use thick wax products which leave a noticeable white wax film.

    Any chain becomes longer due to wear. Because of constructional reasons, this only effects the pitch of the pin link plate so that the pitch of the chain changes due to wear: the originally identical distances between the rollers change into the so called S-O-S pitch, long-short-long-short.

    The stretching of the chain and the inhomogeneous pitch result in increased wear of the sprockets and chainrings. In principle, one can use a chain as long as the chain does not spring. Normally, chains are replaced before that moment because a worn chain does not shift very well.

    In case of relatively cheap sprockets and chain rings and normal riding conditions one can use the chain as long as it words well. If you replace the chain you then replace sprockets and chain rings as well.

    If expensive sprockets and chain rings are used, the chain should be replaced before it starts to damage the sprockets and chain rings due to excessive wear. Furthermore, we recommend to use a Rohloff S-L-T 99 chain because it wears sprockets and chain rings less due to its constructional advantages.

    To discuss related topics of a personal nature, please join the conversation.
     
    Last edited: May 4, 2015
  4. Mike leroy

    Mike leroy Active Member

    I choose the Rohloff-14 Internally Geared Hub (IGH) and chain for my custom bike. Substituting sprockets (i.e., rear gear cassette) for gears is a fundamental leap of faith. I am very reluctant to apply motor power to a bicycle wheel with sprockets.

    [​IMG]

    To my mind, gears, rather than sprockets, are the safer and more appropriate mechanism to transmit motor power to a bicycle wheel. Gears are enclosed in an internal oil bath. Oil reduces metal-to-metal wear and operating temperatures. Sprockets are exposed to the environment and contaminants like dirt, water and mud.

    The hills in my neighborhood are 10-20% grade, or about as steep as roads are built without switchbacks. On steep hills, extreme pressure is applied to chain. The risk of chain-suck is vastly increased in my situation. A chain is unsafe for my purposes. The decision for or against a Gates Carbon Belt is a foregone conclusion.

    320px-Belt-drive_internal-geared_multi-speed_rear_hub.JPG

    What type of bicycles support Gates Carbon Belt Drive? A triangular frame must be opened to install a belt. Almost all bicycles are incompatible with belts. Unless your triangular framed bike was sold with a belt, it almost certainly lacks a splittable joint. Swingarm suspensions bikes are open by design, so swingarms are naturally belt compatible.

    Splittable frames must also be strong enough for the Rohloff IGH. Very few eBikes manufacturers appear in the sanctioned list. Also, a snubber must be installed. A Snubber prevents the belt from ratcheting over sprocket teeth when belt tension is lost. Subsequently this small component greatly reduces the accident risk level.

    Some of the reasons I chose the following frame are:
    1. Split frame for belt compatibility. Only weighs 19 pounds.
    2. The battery tank capacity is enormous, 26 Amp-hours! 52V, 26Ah NMC batteries only weigh 24 pounds.
    3. The swingarm suspension for safe driving at 45+ mph downhill coasting speeds. My neighborhood also has 15mph speed bumps on hills with 30mph downhill coasting speeds. I will also take dirt paths that cut across residential streets. About ten concrete curbs meet the dirt paths at the street intersections. The ride is jarring. The 40mph downhill, potholed, tree-rooted, backroads.
    4. Either a mid-drive or rear hub motor up to 6000 Watts can be installed. The bottom bracket is a generic standard, rather than a proprietary brand. My current choice is a 20 amp, 1000 watt mid-drive, that has not yet reached production.
    5. Must weight under 50 pounds to meet Amtrak regulations. Weight without front wheel and battery pack.
    6. The upcoming Samarium-Cobolt magnets are more powerful than neodymium. In California, 1000 watts is the legal limit for "motorized bicycles". If the motor is restricted to 1000 watts of electrical power, then find the motor that generates the greatest torque for 1000 watts. The BBS02 generates 120Nm of torque. I see 180Nm at 20mph as an achievable goal for a 20amp, 52V, 1000 watt motor with powerful magnets.
    7. Has a throttle. 20mph cut-off. I also want the flexibility to upgrade to 45+ mph rear hub, if the side roads do not work out.
    8. All wires routed internally.
    9. U.S. DOT VIN number to register in CA as legal motorcycle, should I choose that option.
    10. A mail-order and service bike, so components must be the most reliable.
    11. Highest gear ratio possible in IGH to facilitate pedaling the largest chainring my legs can tolerate. Rely on motor to power me through low speeds with over-sized chainring. Speeds over 20mph only from leg power.
      • Schlumpf mountain drive probably unnecessary.
      • Conceptually the front/rear sprockets are like a BMX. The IGH provides gearing. The front/rear on a BMX is approximately 27:9, or 3:1. The Gates 55:19 is closest at 2.8:1 . Use this chart and calculations for the previous PDF doc to customize for your situation. I probably need about a 1.6m display, so a 50:20 (2.5:1) is probably the closest match for my fitness level.

    RevolutionGates.jpg


    http://fat-bike.com/2013/09/about-the-rohloff-and-gates-carbon-belt-drivetrain/

    "Doing it right is important because these are not cheap parts. This set up will cost you double or more the price of a conventional drivetrain, so you don’t want to damage anything. This cost is another bug bear of the detractors, but I take a long term view. Rohloff hub maintenance requires the oil to be changed every 5000km, and … that’s all. There are Rohloffs out there with 100 000km on them. Gates belts, as best I can ascertain from the Net, if looked after, can last 10 -20 000km, and never need greasing. So a $60 chain lasts me 1000km, a $90 belt lasts ten times as long, and the hub will outlast many many clusters; that doesn’t seem expensive to me, especially taking into account the ongoing lack of maintenance. Double the cost, twenty times the endurance, on paper, this seems like a great system. It just has to work. Does it?"


    To discuss related topics of a personal nature, please join the conversation.
     
    Last edited: May 4, 2015
  5. Mike leroy

    Mike leroy Active Member

    In the previous post, I touched on the Gates sprockets. My goal is the Highest gear ratio possible in IGH to facilitate pedaling the largest chainring my legs can tolerate. Rely on motor to power me through low speeds with over-sized chainring. Speeds over 20mph only from leg power with appropriately matched gears.

    Conceptually the front/rear sprockets are like a BMX. The IGH provides gearing. The front/rear on a BMX is approximately 27:9, or 3:1. The Gates 55:19 is closest at 2.8:1 .


    Toby uses a 42:15 ratio on his Surly. The max speed is 25mph. On KMR (16% grade), Toby used the bottom gear only once.

    Toby.png

    Use this chart and calculations for the previous PDF doc to customize for your situation. I probably need about a 1.6m display, so a 50:20 (2.5:1) is probably the closest match for my fitness level.

    I plan to elaborate on the chart and calculations here.

    [​IMG]


    To discuss related topics of a personal nature, please join the conversation.
     
    Last edited: May 5, 2015
  6. Mike leroy

    Mike leroy Active Member

    I want to go into motor power more deeply here. I want to explore how motor power contributes to chainring damage. I wonder if volts or amps contribute to chainring wear. Higher volts result in higher RPMs. Greater amperage means more power flowing through the wires surrounding the magnets. You might use the analogy of volts is to acceleration, as amps are to hill climbing torque.

    The Bosch system is 36V, 10A, 350W. I wonder if the ratio of 0.36 amp-volt ratio may play a part? A more performant 26A, 54V, 0.5 amp-volt ratio, 1400W BBS02. Perhaps the Bosch motor is too inefficient at some point, i.e., spinning too fast and/or straining due to too few amps?

    Personally, I cannot relate to a ten amp system -- just too wimpy. I need at least 25 amps. I also cannot relate to 36 volt systems. I need at least 48 volts. The ideal ratio is probably around 0.75, which runs cool at high torque levels. A 0.75 amp-volt ratio implies a larger magnet and heavier copper windings. So, weight ultimately becomes the decisive factor determining the amp-volt ratio. One thing is for damn sure -- 36V, 10A EuroMotors fall far short of the mark. The EuroBikes are designed for EuroLaw 15mph top-speed. I need USA 20mph top-speed in hilly areas.

    A 0.8 amp-volt ratio at the extreme end. "Cromotor at up to 100V X 80A for a brutal 8,000W. On frames this light, you would be shocked at how easily it can out-accelerate some VERY expensive and exotic sports cars at that power level."

    In the first post, I touched upon how the upcoming Samarium-Cobolt magnets are more powerful than neodymium. In California, 1000 watts is the legal limit for "motorized bicycles". If the motor is restricted to 1000 watts of electrical power, then find the motor that generates the greatest torque for 1000 watts. The 1400W, 29mph, BBS02 generates 120Nm of torque. I see 180Nm at 20mph as an achievable goal for a 26A, 52V, 1400 watt motor with powerful magnets. In CA, 1000 to 1500 (2 HP) is a M2 scooter, which is prohibited from bicycle paths.

    A basic battery pack decision is 52V for mid-drive or a 72V battery pack and controller for rear hub motor. I opt for 52V to minimize motor weight. My main goal is sub 20mph speeds, rather than 30+ mph top-speeds. The 72V controller has a minimum cut-off around 60V.

    I will overbuy on motor amps to experiment with different Watt settings, provided the controller permits the amp level to be set from the Cycle Analyst display. I will buy a motor between 25 and 50 amps, depending upon cost and minimum voltage required by the controller.

    In the unlikely case that a rear hub actually becomes the motor of choice, 3600W, 72V X 50A. The Crown, also from Crystalyte. It uses a 40mm wide stator, which is bigger than the H35, and less than the 50mm stator on the Cromotor. The Crown also has deeper stator slots, so it can hold more copper mass in the windings.

    The H40-Series base on the H35 series but the stator and magnet + 5mm width. In order to increase the motor power and torque.

    From https://www.electricbike.com/12-kit-power-levels-360w-to-8000w/
    "
    1200W, 48V X 25A 0.5 amp-volt ratio. Large diameter rear Direct-Drive hub…9-Continents (9C)/E-Bikekit.com/ebay:Yescomusa/Magic Pie/MXUS - the large diameter (which helps the leverage of the magnets to produce more torque-per-watt).

    These often come with a 20A max controller, but there is a significant increase in acceleration when going to 25A, and also at 30A. Somewhere between 30A and 40A, they will be in danger of overheating, depending on how much time they spend at the max amps.

    As to copper mass, these typically have a 28mm wide stator. But…if you ride up a hill that is long enough and steep enough…even just 30A will fry it… Any amperage above it’s saturation point will make a lot of waste heat, which is inefficient.

    1200w, 48V X 25A, 0.5 amp-volt ratio. Rear geared Hubmotor…10T MAC

    The MACs stator is 25% wider than the BPMs, so the extra magnet width provides about 25% more power per watt that’s applied. The extra 25% of copper mass also allows more amps to be used, so I am recommending a 25A limit when you only have mild hills.

    Once you move the battery weight to the center of the frame, the bike will have a much better balance and feel when riding. A 10T MAC using 48V will provide about a 28-MPH top speed on flat land (45-kph) when using 26-inch wheels, and it climbs mild hills very well.

    Like the DD hub listed above, you can get snappier acceleration when upgrading from 25A to 30A, but you have to watch the heat! Geared hubs have a poor heat-shedding path, so if you think you may want to hot rod the motor later with 40A or 72V…get the DD hub.

    1200W, 48V X 25A, 0.5 amp-volt ratio. Small mid drive…Bafang BBS02 the motor stays up in it’s best RPM range to keep it from getting too hot, unlike a one-speed hub motor.

    1,500W-2,800W, Mid-sized Off-Road Mid drive…LightningRods kit

    This motor has performed well at 30A, and it sheds heat well, since it is an inrunner. At 48V X 30A = 1,440W, 0.62 amp-volt ratio. it’s performance is outstanding! But...it gets better than that. The low pole-count means this motor can be run at very high RPMs without excessive waste-heat produced from eddy-current losses. This means that it was tried and successfully verified to run well at 72V (and also 100V!). 72V X 40A, 0.55 amp-volt ratio. an awesome 2,800w!

    Of course, if you are running at 100V (and 100V X 30A, 0.33 amp-volt ratio, 3,000W), the motor is spinning fast enough that you will not be able to pedal along with the bike to help. If you want to run more than 3,000W, you will have to sacrifice letting the motor use the bikes gears, which is the biggest benefit of a mid-drive. 4,000W will break bicycle chains and sprockets (or at the very least, wear them out unusually fast).

    2520W, 72V X 35A, 0.5 amp-volt ratio, Rear Direct-Drive hub…Crystalyte H35XX (available as an H3525 or H3540)

    If you have sampled 35A in a rear hub…and you like it…you really need more copper mass than the common 28mm wide stators in the 9C sized DD hubs. The Crystalyte H35-series has a 35mm wide stator (25% more copper).

    they didn’t want any more weight out at the rear wheel than necessary, so…they used higher volts in the smallest hub that would satisfy their needs. For the performance of 72V and 35A minimum, the Crystalyte H35 is the most affordable and lightest hub that can reliably provide that.

    If you want to spend a lot of time riding faster than 30-MPH, I recommend a DD hub instead of a geared hub.

    2880W, 72V X 40A, 0.55 amp-volt ratio, Crystalyte H40XX (available as an H4040, H4065, H4080)

    This motor has an almost identical construction as the HT35XX listed above, but it has a wider 40mm stator, and the extra copper mass will let it use more amps than the HT35XX (under the same conditions), or…it will run cooler at the same amps.

    3600W, 72V X 50A, 0.7 amp-volt ratio, Rear Direct-Drive hub…The Crown

    In this power category, you could use “The Crown” motor, also from Crystalyte. It uses a 40mm wide stator, which is bigger than the H35 listed above, and less than the 50mm stator on the Cromotor listed below.

    The Crystalyte 4080 also uses a 40mm wide stator, but there are differences between these two motors though…the 4080 has a less expensive steel stamped core, and it also is narrow enough to allow you to squeeze in a 5-speed freewheel (not that you’ll be pedaling much with 2880W), and it uses common spokes.

    The Crown is more expensive than the 4080. It uses a thick-spoked aluminum core that helps absorb temporary heat spikes, so the 4080 would be acceptable on a flatter commute, and the Crown would be preferable for frequent stops and some hills (which require more high-amp peaks). The Crown also has deeper stator slots, so it can hold more copper mass in the windings.

    4300W-8000W, 72V X 60A–100V X 80A, 0.8 amp-volt ratio, Rear Direct-Drive hub…Cromotor

    fitting enough battery mass on a bike frame to supply 72V-100V and also 60A-80A.

    The popular choice by a longshot is the monster Cromotor, with its 50mm wide stator. The most popular frames for it are frame kits from Phasor, the Greyborg Warp, and also Qulbix Raptor. Our friend Martin built a street commuter using a robust downhill (DH) bicycle frame, but he had to order some custom rear drop-outs to accept the Cromotors 145/155mm wide axle shoulder.

    The Phasor has the slimmest frame at 100mm wide (for easier pedaling) but…if you want the absolute highest battery volume, the 160mm wide Raptor is the one. The Greyborgs 110mm wide frame is in the middle…slim enough for easy pedaling, but more battery volume for higher volts and amps.

    72V X 60A is 4300W, which is the minimum watts that make the cost of a Cromotor system worthwhile, but…all of these frames have also been successfully run with a Cromotor at up to 100V X 80A for a brutal 8,000W. On frames this light, you would be shocked at how easily it can out-accelerate some VERY expensive and exotic sports cars at that power level.

    The Cro has the massively wide 50mm stator, but it also has the very thick aluminum stator core to absorb the temporary extra heat of large amp-spikes.

    "
     
    Last edited: May 5, 2015
  7. Mike leroy

    Mike leroy Active Member

    I research and write articles in fits-and-starts, as my spare time permits. Writing an article usually takes one full week. So, check back regularly.

    To discuss related topics of a personal nature, please join the conversation.
     
  8. jawnn

    jawnn New Member

    What kind of spry wax will do the job with out seeping into the oiled parts?
     
  9. Jasonpb

    Jasonpb Member

    Although this post was dug up from the dead, it was a very interesting read.

    I had hoped to purchase a heisenberg xf1 due to the speedhub/belt combination but no chance at all in getting one to AU. The drive train issues with the others just put me off purchasing a mid drive system.

    http://www.hnf-heisenberg.com/xf1-139.html
     
  10. harryS

    harryS Active Member

    Interesting. My Diamondback bike had chain suck. I would pedal and under heavy pedalling, one particular link would ride up on the rear sprocket and cause the chain to jump a tooth. Very irritating. I identified the faulty link, worked on it with penetrating oil and exercised the link a bit so it freed up. That was two years ago.

    I was going to mount my rear hub motor on that Diamondback, but it was an alloy frame, so I used an older steel frame bike, and the Diamond back has been hanging from the rafters.

    So guess what. I just put a BBS02 on that Diamondback last weekend. I plan to add the display and attach a battery this week. I better think about a new chain too.
     

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