What I didn’t know about electric bikes

After a lot of research this weekend, I learned quite a bit more about electric bikes and how they work.  I particularly concentrated on how the motor in the rear hub operates and how it can provide power without any moving parts.  My first goal from this point will be to open the hub shell of an Ultra Motor brand hub motor in the rear wheel of a Stromer.  I’ll detail all of it in a well-covered post.

Most of the information I found was on just a couple websites which I somehow had not come across yet. Electric Bike is definitely well organized and provided the most information about a variety of hub motors and their corresponding controllers and diagnostic procedures.  Ypedal has an amazing and vast knowledge of the systems and has created tons of custom setups as well as details repair on several Youtube videos that is a complete procedure and well explained.

Most of the motors have a similar layout:  An outer shell to protect and encase the motor, then a ring of magnets that are positioned between the shell and coils of copper wire.  Other than a couple sensors and wires that exit through the center of the wheel near the axle, that’s about it.  Very simple and once familiar with the parts, moderately easy to work on.  I chose to first learn about the motor because it seems like this is the only component that I haven’t been able to service other than to simply install a replacement wheel.  To have the ability to fix the motors once the manufacturer’s warranty expires will be essential — especially as the number of electric bikes is increasing and they are becoming more common.

Back to the sensors and wires in the motor.  Usually there are three small square shaped sensors that are positioned between two of the outer magnets in line with each other.  These are called Hall sensors and they measure the electrical current coming out of the motor as the wheel spins.  A tapered side of the sensor body is always positioned outward and usually is set with a tiny amount of JB Weld or epoxy. Out of the top of each sensor are three uncovered wire leads that are soldered to colored wires carefully running to the center of the hub and exit from the wheel to the controller and potentially a torque sensor.  A torque sensor is generally on higher end electric bikes while cheaper versions simply use a cadence magnet to calculate the input of added power.  The torque sensor is nicer because it adds power based on a direct measurement of the deflection of the wheel backward against the rear dropout when you put pressure on the chain and pedals.  Most are robust and work accurately, giving the rider a better feel of added power when accelerating.

In some situations, I read that one or more of the Hall sensors can go bad and with the right tools, it is a small project for an afternoon that will avoid a replacement ($500-750) or service elsewhere ($100/hr).  Even if you aren’t up to doing the task yourself, you will be better able to diagnose and familiarize issues that occur.  For the avid mechanic, it is possible to upgrade your hub motor for minimal cost.  Larger wires (if they can fit through the frame and center of the wheel) will boost available power and a better controller or throttle can more accurately distribute the power.  Unless you have an extreme desire to mod your electric bike, the magnets and copper wire are difficult and costly to replace.  Some motors are spun low with larger gauge copper wire which can provide more power, but less torque on hilly terrain while high spin copper will have better power at a high cadence and will last longer.

In order to remove the motor from its hub shell, a car bearing puller is necessary.  It is an extractor style tool with three arms that pull on the shell while a center bolt pushes the axle and opposite hub shell side.  It is helpful and recommended that you tap the shell with a mallet during this process to aid in freeing the two halves.  Otherwise, direct extraction with the bearing puller could break the hub flange and then you’ll be left with a useless motor and no shell.

Considering the Stromer that was detailed in the review and diagnosis, I believe that the torque sensor was overloaded in the frame without that necessary bolt and the motor overheated and fried one or more of the sensors.  This would explain the NO_COMM lack of communication between the LCD controller and the motor.

Missing nut and spacer on axle. note the fine shavings of aluminum.

Note the scoring around the dropout.

It makes a lot of sense once the elements are broken down like that.  I also think that one of the wires exiting the rear hub is a faulty wire with a weak spot somewhere near the center of the wheel.  The torque sensor itself seems okay.  I am going to check current through each of the wires to determine the faulty one and then solder in a new one along with the replacement of the sensors.

I was very happy to find this information and come to realization that these bikes can be fixed from the ground up if necessary.  Why wait a week or weeks for new parts to install when the local hardware store and Radio Shack have all the necessary parts for a solution?  I am going to continue to do more research into the motor repairs as well as connecting different controllers to the bike for operation.  It is exciting to realize that with the right research, I can create incredibly fun bikes that are useful for both fun and transportation. Now, once I can locate a car bearing puller, I’ll open the motor and take photos of everything so you can see it.  Stay tuned!

– SNC

Park Tool Summit 2013 In Review

I was able to attend six of the eight classes offered at the 2013 Park Tool Summit.  They were the following: Campagnolo, Cane Creek, FSA, Fox, Mavic, and Shimano.  I am going to cover each one and what I thought were the best points to take and apply in the shop. Right below is a slide show of photos I took (sorry for fair quality with cell phone) before the summaries of each class.

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Campagnolo:

The same instructor, who deals with just about every Campy warranty and issue in the US department, was informative and innovative considering that a pallet of half the working material was still somewhere between the headquarters and the summit.  Inside views of the Romanian factories and the home factory in Vicenza, Italy.  Before recently, Campy was high on security and secrecy to protect larger companies from gaining insight on their special technologies and process.  Now, however, they have adopted a much more transparent view of both the parts diagrams and breakdowns and the environment itself in which the parts are produced.  Because of the demand for such quantities of these quality components, special precise training was exacted for the employees of their two Romanian parts manufacturing facilities dubbed Mechrom 1 and Mechrom 2.  Most of the final assembly of parts is done in these facilities.  They have a great traceability program to ensure that the products and parts are accounted for and distributed correctly.  For instance, every wheel built has a dot matrix code attached that contains information as to the individual that built the wheel and the exact final tension specs, ensuring the rider that the product is as perfect as possible.

Also, various innovations have been discovered and engineered by Campy that have spread to other industries because of the care and accuracy they hold their standards to.  NASA aerospace chassis designs, the formula for casting magnesium (a very very light material), and the first magnesium wheelset are but a few of them.

Great focus on chain design was taught.  Every chain created undergoes over 1200 lbs of force to “pre-stretch” them so they last longer and run smoother than any other chain.  No rider can exert this type of force which entails literally zero broken chain other than if the installer does not install it correctly.  Also, as a side note, installing a “quick link” voids the warranty as they believe only their chain pins meticulously pressed in will be strong enough to support it.  In addition, they recommend installing the chain in the smallest chainring and smallest cog to get the right amount of tension.

Cane Creek:

It was obvious for this seminar that Cane Creek is highly focused on connecting riders together and sharing their experiences for the best ride possible.  They seem to have an attitude of figuring out how to make each rider’s bike settings and technologies work best for that individual by developments in things like changing the angle of the fork and detail tuning their new Double Barrel rear shock.

One surprising note to mention in regards to their very successful headset sizing system (S.H.I.S) is that almost all headsets on the market have been narrowed down to 6 top bearings and 4 bottom bearings, making the system even easier.  As far as changing the angle of the fork mentioned earlier, bowl-shaped cups hold the bearings that are placed in eccentric matching cups in the headset for several different angles that they include as one set, so you can try different combinations for better climbing or better descents, etc.  Also, even with this new system, Cane Creek has a headset fit finder with a database of over 10,000 bikes already and adding new ones each day when submitted by mechanics and other in the industry.  This is awesome as it compiles so much data from so many companies and locates it in one place, leaving the guessing game far behind.

The biggest highlight for me was a detailed summary of their 110 headset.  From cutout diagrams, you could see the multiple seals keeping the bearings sealed up nicely and backing up the 110 year warranty.  Essentially, it is waterproof and to me, rivals the Chris King headset that is also popular by name and by its own sealed system.  I mainly think it is just good to have a choice of two almost indestructible headsets.  Plus, regardless of which one it goes with, they will quickly replace it if you somehow are able to destroy it.

The Double Barrel rear shock is a great product to explore as well and has so many options for fine tuning without problematic issues that usually arise with other rear shocks with leaking, etc.  Seal replacement was very easy and clear to understand and the hands-on experience of doing so really “sealed” in the information.

FSA:

FSA (Full Speed Ahead) was all about ensuring that their products get better and better and flaws and defects get smaller and smaller with genuine rider honesty of feedback and a willingness and commitment of the company to fix any problem.  They were the first company to develop a carbon crank with longevity.  Their SLK series has been continually refined with each season of testing as well as their Gravity line for downhill bikes.  Being that they are located near Whistler and other major downhill areas, the testing grounds put the equipment and research through extreme trials to bring us what we have today.  One cool addition for customer service was a placement of an office on the East Coast to help eliminate the waiting period of time zones to contact representatives.  This creates a faster turn around and closer connection of rider to mechanic to rep.

They also have a headset that was developed much like the one I mentioned earlier with Cane Creek, but their point of interest was to develop one that had fewer parts and a more robust interface that could be depended on in harsh conditions.  Great length was also taken to “creaks” and “clicks” in integrated bottom brackets, so naturally I wanted to turn a keen ear since I wrote an earlier article on bottom brackets and issues that arise.  Several things like the correct materials for installing bearings and retaining them with loctites and compounds that wasn’t as clear before as to how essential it is to choose the correct one.  Moving from so many different types of crank spindles and bottom brackets has led them to the development of their BB386 spindle and bearings that is the same size for all of their cranks.  They make different qualities of these, but all of the are the same so compatibility is a non-issue.

Fox:

Fox seemed to hold a different approach than any other class.  They split theirs into three separate mini-classes with hands-on working at each.  The groups rotated and gained insight on several areas from bushing and seal replacement on forks to lockout tuning and rebound damper adjustment.  The most useful in a business sense that they now offered is the bushing and seal replacement.  Developing a new tool with Barnett’s Institute, it allows bushing replacement on any fork including Fox and passes the ability to do some services at the shop level rather than always sending it to Fox to have work done.  This means that I can get a rider back out on the trail faster and that makes a happier rider.

After the first day of learning, I got to speak with the Fox rep at the social hour following the day.  He showed me a suspension unit that is installed on the new Raptor off-road truck.  I lifted it and it was quite heavy as trucks are far less concerned with being light rather than strong.  It led to something that I wouldn’t have expected.  He said that most people think that the bike fork technology and suspensions are derived from their larger parts on off-road trucks and ATVs, etc.  He said that this was quite the opposite.  The bike technology was hardest to innovate because it not only had to be really strong, but also light enough to ride and that this technology was what actually trickled up to ATV suspensions and then to off-road vehicle suspensions.  Pretty cool.  They also seemed to be having the most fun out of the other companies.

Mavic:

Mavic was, personally, a beautiful sight to see.  Slick blacked-out wheels and carbon spokes all over the place with matching yellow hinting everywhere was the realm of high-end wheels and superior technology.  Not only were several points of misconceptions I had cleared up, but it was also confirmation of several things I had been doing right.

Mavic has a philosophy that their wheels are made as a system from the center of the hub all the way to the ground — including the tire.  This is why all of their wheels are sold with tires installed.  From flashy animations of hub overhaul procedures to French dialogue speaking of dedication to ultimate advancement in technology, they covered essential procedures for replacing carbon spokes in two different wheels (R-SYS and Cosmic Carbone).  Plus, the guys teaching the class were the guys that fix the wheels or rebuild them when we send one back for service.  It was like finally meeting the guys who had done all the great work I see coming back in shipments and on display in the shop and getting a flavor of their standards and tips.

One thing that really stuck out that I didn’t know before was that they use mineral oil inside the freehub body with a bottom seal.  Mineral oil, they said, wasn’t some magical liquid, but just that it was exactly the right “weight” to stay inside and give the freehub years longer of usage and, in its absence, is why some riders have described a high-pitched squeal at times on fast descents.

Shimano:

While much of the material that was covered in the presentation part of the class was what I had recently just finished training on, it was still reinforcing and provided confidence in the hands-on tuning of the new Dura-Ace 9000 drive-train.  With its sleek machined appearance and unbelievably improved smooth performance, I have to contend that all three major companies (Shimano, Campagnolo, and SRAM) have narrowed the gap between each other and the game is at its highest level ever.

The new and improved cables and casing also surprised me to its superior feel and had me thinking they snagged the designer for the Gore Ride-On cables that were just discontinued.  Coming now in seven colors, the PTFE coating is uniquely applied so wear doesn’t affect performance nearly as much as before, allowing riders to use them for longer with better results.  The motto, “friction is the enemy,” really rang true here and great effort was placed into decreasing it and its effect on rider fatigue.

Summary:

All in all, as stated above, the technologies are getting more and more efficient and precise with faster rides and sexier designs.  It’s going to be really exciting to see how far they can go in the next couple years.

– SNC

Bottom Bracket Blues

It creaks. I think I hear this clicking sound when climbing. So, when I was pedaling the other day, I hear this pop once when I hit a pothole. The mysteries of the bottom bracket.  It’s quite often other problems on the bicycle are falsely attributed to the bottom bracket.  That’s the number one part of the frame that is stressed the most, ‘used’ the most, and generally welcomes dirt and grime to sit and adopt a patch of their own.  Everyone has a theory of what’s going on whether it be technical torque specs and assembly prep compounds to the daily commuter on a 1984 steel relic rusting from years of rain, snow, grit, and use.

I am going to share a bit of my own experience and knowledge and hope it sheds light on the subject and speeds up your repair or ends your frustration.  Please speak up and contribute any good points I don’t cover. Lastly, common language will be used for the most part, or a photo that explains it better.

There are several types of bottom brackets.  There are a couple more after that categorized into what you hear people call ‘proprietary’ components.  Some of the time, that makes it more difficult to service or replace.  Either way, most of the problems can be remedied by a regular service for the bottom bracket (henceforth called BB) yearly.  That is the part that makes us shop people happy.  Not because of more revenue (it actually will save you money and frustration), but generally because it makes it easier to fix the part and clean it rather than remove a damaged part and then install a new part.  That being said, good information about the subject and a regular check from your LBS, you and your bike will be happier.

Probably to this day, the most common BB is the square taper. There are two types. The difference is how fast the edges taper.  The more uncommon (at least in North America) is the ISO taper.  I see it mostly on Italian road bikes (for good reason).  The most common is the JIS taper.  Many different bikes have this BB.  Here is a photo of one:

Think about the square edges on the sides holding the crank arms and the pedals.  The threads on the edges of the cylinder go with the threads on the frame at the base of the frame.

Most of the time there is something of a seal between the spindle (the darker square taper rod) and the BB cup (the threads of the cylinder).  Inside that crazy monster are two rings of ball bearings.  On the inside, part of the spindle and part of the cylinder have curved channels that the bearings spin around in.  A nice, healthy amount of grease on the threads of the cylinder, the curved channels, and the ball bearings will keep the same one running for years and years.  The only thing necessary to replace regularly is the bearings.  Most standard sizes run 10 cents each.  Nicer ones are about 30 cents. There are usually 18-20 in a bottom bracket.  The grease and the fresh bearings allow the energy that you push onto the pedal to propel you easier.  Plus, no creaks or pops.

But wait. Dude.  My mechanic told me I have this cartridge bearing system and that I have to replace this thing like, around five to ten thousand miles.  It creaks between then.  If it is the BB, it is usually because the threads of the frame and the threads of the cylinder have gone dry.  The grease initially installed on new ones has washed away with the water that enters the frame from rain and temperature and exits through ‘breather’ holes in the frame.  Check on the inside of your frame where the rear wheel connects to the bike.  One on each side for steel, aluminum, and titanium frames and then another on each side at the fork (where the front wheel connects), and then right at the bottom of the bike where that bottom bracket is.  This is why regular service keeps grease inside the bearings and threads and makes it run smooth and quiet as it should.  Cartridge bearings last longer and are generally more expensive, but quality loose bearings in the BB like I explained about at the start can last a long time with less expensive but more frequent cost.

That’s a summary of square taper bottom brackets (BB).  They are generally the easiest to diagnose and service because they are more readily available at your LBS.  They have existed for quite some time and continue to be very reliable BB’s. They can range between somewhere near 30-50 dollars (for cartridge BB) for the majority of bicycles and higher end BBs running around 100-200.  Pristine bearings in these bottom brackets are unbelievably smooth and provide an extremely confident pedal stroke and power transfer from you to the bike.  It makes it move!

More to come next post for Octalink BBs, other ‘like-minded’ BBs, and outboard bearings.  Less like a boat motor and more like a ship propeller.

– SNC