SRAM / Zipp Hub and quick release lever recall!!

Hey everyone, we were talking with Zipp this morning about a repair and found out that there is a newly released recall of most of their front hubs (88v6, 88v7, and 88v8) because of a possibly failing at the retaining ring that holds the spokes in the hub.  The description reads: “This recall includes SRAM’s Zipp bicycle wheel hubs. The model names of the affected hubs are ZIPP 88v6, 88v7 and 88v8. The Z logo is printed on the hub. The wheel hubs come in black, silver and falcon grey. The diameter of the clinch nut is approximately 1.46 inches. Some of the hubs were sold as part of wheel sets installed on new bicycles. SRAM will post a list of affected bicycle brands and models on its website at www.sram.com.”

The link for this recall is here

Also, several minutes after seeing it posted on the CSPC site, they posted another recall for their quick release skewers. Only quick releases without a marking at the center of the underside of the lever are included in this recall.  The description reads: “This recalls involves SRAM’s Zipp stainless steel or titanium quick releases. They were sold as aftermarket components or as part of the 202 DB V2, 303 DB V2, 404 Firestrike V2, 202 Firecrest V3, 303 Firecrest V3, 404 Firecrest V3, 808 Firecrest V3 or 808 NSW wheels. The quick release has a curved, black lever. Zipp appears on the lever. Only quick releases without a marking at the center of the underside of the lever, below the Zipp logo are included on this recall.

The link for this recall is here

 

Feel free to drop by the shop with your wheels so they can be processed as soon as possible with the season starting up!

 

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What was in the stand yesterday (and today)?

So I had a rather interesting limited edition bike come through the shop for an appointment for general servicing and, as some projects occasionally do, it had a complication that was a good call for photos and explanation of a component that shifts the bike through an internally geared hub developed by SRAM around 2006 called an iMotion 9 hub.  It has nine gears or varied range and changes the gearing with moving the chain.  A wire cable runs from the inside of the hub to a long barrel adjuster and then up the frame of the bike to the shifter. The bike is a limited run of commuter style Cannondale hybrids with a Headshock lefty fork and no non-drive side chain or seat stays, hydraulic quad piston brakes, slick commuter style tires, and a fully enclosed chain.  Take a look:

WP_20150504_004

The client mentioned shifting issues, which usually happens with most bikes as the cables stretch.  Tighten them up to the correct tension and the cable pulls the gears in the hub into an easier or harder gear each time you twist the shifter (smoothly and quietly).  I initially installed a new cable and with a bit of a learning curve and several adjustments of cable length (pretty specific without using up one of the two available barrel adjusters)(I would also mention maybe trying an additional one as an inline adjust about a foot from the shifter).  I went to test it outside (where it was much nicer) and after sever shifts I noticed the cable went slack so I felt the shifter and could feel a bit of play in the cable and stopped the bike.  Once back in the stand, I noticed something I had not previously seen due to it’s hidden position behind the chainguard housing.  A crack in the entry point of the cable into the hub had separated about half of it’s cylindrical length (about 7mm).

WP_20150504_002(This is inconveniently located in my photo underneath the greased up axle bolt.  I will take a photo of the fixed piece or possibly the still broken piece if I can’t repair it today.)

This part is made of plastic and, after a bit of research, I realized that apparently none of these parts are sold separately, even in the normal version of this hub.  This is when a little fabrication and small detail work will hopefully save the day.

I took apart the wheel and have opened the hub to examine any other issues and make fixing the piece much easier.  A little epoxy was applied to both pieces after greasing the cable running through (proprietary piece of cable that can’t be removed) so I can reinforce it with a collar of sorts today.  Here are a few photos of the hub being taken apart.  The spring in the third photo will likely be a challenge to get back into the shell, but can be done with a bit of concentration and effort (and persistence). The first photo shows the plastic threaded piece coming out from the circular housing.  The spring keeps enough tension on it in the photo to join the broken piece with the rest of the body, but moves significantly under load.

I will take a few more photos today and update the situation in tomorrow’s article.  It’s supposed to hit the upper 80’s around DC today.  Make some time and go for a ride!  I will certainly be taking thorough test rides after tuneups today.  Follow @pixalias on Twitter for updated photos and good tech that rolls through the shop!

Mavic Ksyrium ES (Helium Anniversary Edition) Hub Overhaul and Other News

I thought it would be a good article to review a hub overhaul on a nice set of Mavic wheels before your spring riding season heats up (at least on the East coast).  Mavic wheels are quite popular today and the first important thing to remember is that with only minor variation, most Mavic hubs are built similarly and can use the same freehub body on any of their wheels (Occasionally an older freehub will need a sleeve included with new freehub bodies today, but otherwise is the same).  These wheels have a simple yet elegant design that holds up under a variety of riding conditions, is tubeless and 11 speed compatible, and resists corrosion and wear exceptionally well.  The Ksyrium (pronounced “Seerium”) is Mavic’s most prominent wheel and is competitive in both weight and ride quality to most other major wheel manufacturers.

However, despite all of these great points, the hubs still need servicing to remain in top shape and performance and doing so will greatly extend the life of the wheel.  A lack of maintenance can lead to a slower wheel, and when coasting, a high pitched squeal.  This is indication that the inside of the freehub body is dry as well as the rubber seal the freehub sits on.  Dirt and water can still invade the bearings even though they are “sealed” and the dirt can cause wear on an otherwise forever-lasting freehub body.  Most of the wheels that need the freehub body actually replaced are due to a lack of scheduled maintenance rather than it simply wear out due to riding alone.  Let’s dig in!

The front hub is really easy.  it requires the Mavic tire lever and a 5mm hex key.  On the end of the tire lever is a U-shaped curve with two pins on each side.  These pins fit exactly into the holes on the non-drive side of the front hub.  the 5mm hex key is inserted into the opposite side of the hub through the axle.  Loosen the axle with the 5mm hex key (CCW) while holding the tire lever in the preload cap with the pins.  When reassembling, we will discuss its purpose.  Once the preload cap is off of the hub the axle can be pulled out through the side with the hex key.  Inspect the bearings on each side as seen below.

Front Ksyrium hub with axle removedPreload cap for front hubYou’ll likely notice a bit of grease and dirt on the bearing seals. With a bit of isopropyl alcohol, clean the hub area around the bearings and then rotate the bearings to check for gritty spots or rough turning.  You should feel continuously smooth rolling with no drag points if the bearings are in good shape.  If they do need replacement, they can be ordered from your local shop and easily installed with a small bearing puller and bearing press.  This article doesn’t cover the actual replacement of the bearings, but a video is being planned to detail appropriate bearing removal and installation.

Continuing on, if the bearings are in good shape, use isopropyl alcohol to wipe down and clean the preload cap and the axle.  be sure to pop the end of the axle off that are fitted by compression using o-rings.  It is a great idea to apply a small amount of light grease to these so that they will not creak or be difficult to remove for cleaning.  Inspect the o-rings for cuts or abrasions and replace as necessary.

Axle and preload cap and end caps and quick release for front hubThis is the axle and corresponding cap and end cap for each side.  Note that the large circular caps have one with the preload pin holes and one does not.  The one that does not just slides onto the axle until it hits the lip on the right side of the axle in the photo above.  The preload cap with the pin holes threads onto the axle after inserting it through the hub.  be sure to grease the axle before so it installs easily. Using a 5mm hex key and the preload end of the Mavic tire lever, thread the cap on the axle until it starts to tighten up.  Then, back the preload cap off bit by bit will wiggling the axle to detect any play.  As soon as the play is gone, stop.  The hub now will spin as freely as possible without having bearing play.

Now, onto the rear hub!  The rear is a little more complex, but works on the same principles as the front for most of the axle assembly.  The rear hub also has the 5mm hex key opening on the drive side of the axle.  On the non-drive side the end cap can be pulled off with your hand.  It is fitted onto the axle with a compression o-ring, much like the smaller end caps on the front hub.  This is where greasing the o-ring will help greatly.  If the o-ring is dry, it may be difficult to pull off.  In that case I take a cone wrench slightly bigger than the cap and use it to pry the cap off.  Also, an axle vise works great in this case.  Drip a couple drops of Triflow on the cap so that the o-ring is lubricated.  Once removed, look at the inside of the hub.  You’ll see flats for a 12mm hex key.  Insert a 12mm hex key into the non-drive side and a 5mm hex key into the drive side and turn each CCW.  Reference the photo below.

Removing the axle for a Mavic Ksyrium rear hub. The non-drive side end capAbove is the removal of the axle and the non-drive side end cap removed from the axle.  The non-drive side of the axle will stay installed in the hub for the moment and you’ll notice the drive side of the axle threading itself out of the axle.  Once unthreaded, pull the drive side axle out and set to the side.  Then, carefully pull the freehub body off of the hub.  It usually does not take much pressure.  However, two pawls and springs that cause the ratcheting mechanism of the freehub body to work are right under the freehub on the hub shell itself and can spring right off into space if you aren’t careful.  If the springs somehow are lost, don’t even both searching for them unless you don’t have new spare ones.  You will literally never find them until your next shop winter cleaning.  Maybe not even then.  I have searched and searched for these things and generally come up empty-handed.  I mention this in such importance because it is easy to lose these springs.  For that reason, if you are a shop, buy spare parts for these wheels.  They can be used in all Mavic hubs and are cheaper than the time you’ll waste looking for the old ones.  If you are a home mechanic, buy some too, but put the springs upon removal from the hub directly into a magnetic parts bowl.  They will stay put and can even be cleaned easily in the bowl.  This is what the removal of the freehub body looks like.

Pawls and springs and hub shell Inside of the freehub body and drive side axle end.The top photo is of the hub shell under the freehub body and the bottom photo is of the freehub body inside and the drive side axle end.  Notice the dirt, grime, and dirty grease present on the white/tan bushing on the inside of the freehub body.  This bushing is identically machined to each Mavic wheel hub shell when they are made, which creates an amazingly amooth and wear free part.  The killer to the eternal lifespan though is allowing this bushing, the inside of the freehub body, and the pawls and springs to get dry and/or dirty.  Using isopropyl alcohol, clean each part thoroughly and inspect the bearing in the freehub body from wear.  This bearing is a #608 and another is on the outside of the drive side hub shell as seen in the top photo.  The non-drive bearing is a #6903.  Here is a photo of the pawls and springs removed for inspection and cleaning.

Pawls and springsThe left pawl is showing the outside edge.  Once cleaned, inspect this edge.  If there is a shiny wear mark , it is time to replace them.  If the coloring of the pawl is even almost out to the edge, they should be okay.

Freehub body sealOnce you have removed the pawls and springs, use needle nose pliers and gently pull the freehub body seal off of the hub shell.  When this is not properly lubricated, that is what causes the high-pitched squeal when coasting down hills.  It also keeps the mineral oil we will use for the freehub body to stay inside the freehub — allowing better lifespan and performance.  Clean the hub shell as well.

Using the 12mm hex key and the Mavic tire lever, insert the 12mm into the non-drive side of the axle and insert the preload adjustment into the preload cap.  Unthread the preload cap and pull the axle out of the hub shell.

Rear non-drive side hub shell and axleInspect this bearing as well and clean the axle and preload cap with isopropyl alcohol.  Be sure to add grease to the preload cap threads when reinstalling for smooth adjustment.

Rear non-drive side axle and freehub bodyOnce everything is cleaned and inspected, it’s time to reassemble the hub.  Insert the axle with a small amount of grease through the non-drive side of the hub shell and thread the preload cap on just a couple turns.  We will come back later to adjust it.  Tightening it down now will cause the bearings to bind when the drive side of the axle is installed and tightened.

Freehub body with fresh mineral oil from MavicMavic freehub mineral oil (15wt)Drip about five drops of mineral oil (15wt) from Mavic into the freehub body and set on its side so it doesn’t drain out.  Then, apply a bit of mineral oil to the washer between the freehub body and hub shell, seen at the bottom of the above photo and also again slightly set to the side in the photo below.

Freehub body washerIf this washer is not installed, the axle and bearings will bind terribly.  It spaces the freehub away from the hub shell properly so the compression of the freehub seal is not too tight.

Pawls and springs reinstalledNext, install the rubber freehub seal and the pawls and springs.  The springs fit over a pin on each pawls and then into a corresponding hole on the hub shell where they sit.  I usually drip a drop of mineral oil on these two and press them a few times to make sure they spring back open properly and smoothly.  Once these pieces are installed, slide the freehub body onto the hub shell.  When it hits the open pawls, use two fingers to depress the pawls and continue sliding the freehub body on.  Once fully seated, insert the drive side axle with a bit of grease or light loctite and thread into the non-drive side axle until tight (about 8-10Nm).  Turn the freehub body and listen for the correct and constant ratcheting of the pawls.

Installing the rear drive side axleFlip the wheel to the non-drive side and using a 12mm hex key and preload adjustment lever, tighten the cap down as mentioned in the front hub overhaul procedure and back it off until any play in the axle is gone.  That’s pretty much it.  Other than cleaning the rest of the wheel and truing it, the hub overhaul is complete and your wheels will be ready for another season of riding.  I am convinced that if you do this with your wheels before and after winter, you’ll keep your Mavics running for years and years without trouble.  As always, feel free to comment or send questions.

In the next few weeks, I am attempting to film some short repair videos and have had a request for one for the Dura-Ace 9000 front derailleur setup.  This will be the first one with clips on the variations in setup for the Ultegra and 105 level components.

– SNC

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.

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

Wheel Truing and Specialized Turbo Long Term Review

I will be posting a short article tomorrow evening on wheel truing and will also post Part 1 of all the info and tuning/adjustments I have been through and discovered with the Specialized Turbo S Pedelec bike. I look forward to your thoughts!  Stay tuned for for great info and photos.

P.S.  I also edited the Dura-Ace 9000 front derailleur setup article after reviewing a few comments from readers and my own experiences with the setup.

 

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– SNC