Sachs Orbit Hybrid Hub Overhaul

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Sachs Orbit hub on 1973 Jack Taylor

Wanting to continue my deep dive into internally geared hubs, and looking for a few good projects to stave off the winter doldrums, I decided to overhaul the Sachs Orbit hybrid hub on my 1973 Jack Taylor, as it has been feeling a little sluggish and probably needs some attention, given that I’ve done nothing to it since I acquired the bike years ago except to give it a drop of oil now and then. The previous owner of my Jack Taylor had modified the original rear wheel to include this hub, instead of a standard freewheel type hub, thus allowing the removal of the front derailleur and one chain ring.

In researching the history of the hub, I discovered that the Orbit was part of a component group (the “Commander”) that featured index shifting and was introduced in the early 1980’s by Sachs-Huret, the original company Fichtel and Sachs having purchased a controlling interest in Huret at about this time.  This gave Sachs-Huret the jump on Shimano, who came out with their S.I.S. indexing system in 1984.  It should be noted that SunTour introduced its unpopular version of index shifting in 1969, and of course, index shifting existed far earlier than that with the Schulz Funiculo derailleur patented back in the early 1930’s (these derailleurs could also handle 40T cogs!).

The above catalog scans of the Commander groupset feature the six speed version of the 2 speed hybrid hub, giving 12 gears overall.  The Commander’s method of indexing used a clicking shifter paired with a cam on the derailleur parallelogram.  It never caught on, perhaps because of the clunky looking shifters and the mysterious hub, as well as the use of a cam on the derailleur which meant a little more difficulty in tuning the derailleur properly.  The whole thing may have been a bridge too far, and once Shimano came out with its easy to set up and use indexing, there was simply no way the Commander groupset could compete.  And that may explain why these hubs are so rare. Over its relatively short lifespan the Orbit was offered in 5, 6 and 7 speed versions, and many of these hubs came with drum brakes.

What is a hybrid hub? It’s an internally geared hub (IGH) that also has room for more than one cog on its driver/freehub.  This means that for bikes that cannot have a front derailleur (folding bikes come to mind), for bikes with small wheels that need taller gearing, or for cyclists that prefer not to have more than one chainring up front, adding a hybrid hub can provide the same gear range as a wide ratio triple crankset.  Over the next few decades SRAM went on to offer a whole range of hybrid hubs, but currently I believe that only Sturmey Archer is in the hybrid hub business.

Early 1990’s NOS Sachs Orbit hub

Because of the difficulty in finding parts for these hubs, I purchased a NOS version a while back.  This one was built in the early 1990’s.  Before overhauling the hub on my Jack Taylor I thought it wise to use the NOS hub as my learning platform.  In the process I noted some differences between the older and newer versions, which I will comment on below.

John Allen, on the Sheldon Brown site, has some good information on the Orbit hub as well as some links to other sites with helpful resources.  In addition, disraeligears.co.uk has extensive commentary regarding the Commander groupset and useful catalog scans as well.

Sachs Orbit schematics

Catalogue scan courtesy of disraeligears.co.uk

With its relatively simple operation, as compared to a three speed hub, I hoped to be able to overhaul the Orbit even though there are no service manuals available. The above hub schematics are useful, but don’t take the place of a step by step service manual.

The first step for my NOS hub was to remove the cogs (this hub unfortunately has no outer hardware, but if it did, you would remove that first).   The larger cogs are splined, and the smallest two cogs are threaded.  Each cog is separated with a spacer.  From there, it should be noted that the drive side cone is machined to the axle, so all work is done from the non-drive side.  These hubs do not use anti-rotation washers, and should work with fine with any kind of rear drop out, vertical or horizontal because the hub uses a derailleur for chain tensioning. The axle’s M10x1 threading is not compatible with Sturmey Archer, nor with other Sachs/SRAM hubs.

Once the non-drive side cone is removed, you can lift the hub shell out of the hub body.  The hub shell has ratchets on the inside to engage the pawls.  The hub body now consists of the driver, the planet cage and the pawl cage, as well as the clutch spring and “clutch pin”, also called the “sliding selector block” on the schematics.  There’s a circlip holding the clutch spring in place which is removed next, and the clutch spring comes out along with a stepped washer.  Then, the pawl assembly comes off.  You’ll note that the assembly has two sets of pawls, one set on the inside and one set on the outside.  You can also see that there is an outer gear ring on the pawl assembly that engages with the inner gear ring on the driver.

When the pawl assembly is off, the “clutch pin” has probably fallen away.  This is where the indicator spindle will connect so that the pawl assembly can be shifted.  The planet cage comes out next, but not before removing another circlip and washer, which hold the planet cage in place.  The washer is keyed and needs to be rotated to match the axle so that you can remove it.  The planet cage has another gear ring on its head portion that connects to the inner pawls of the pawl assembly.

There’s another piece inside the driver that helps to orient the planetary gears.  Once the parts are all out, the driver’s dust cap can be removed.  Note that it is “right side up” on this hub.  From here, I soaked all the parts in citrus degreaser, cleaned them with alcohol and then was ready to start re-assembly.  Since this is a NOS hub, there wasn’t much scrubbing involved.

Clean and shiny parts ready to go.

Clutch pin installed with spindle attached

Pulling up on the spindle the gear ring disengages from the driver

The pawl assembly at rest

The reassembly process went okay, except for a few problem areas to note:  you must reattach the spindle to the clutch pin after assembling the planet cage but before adding the pawl assembly.  When shifted, the pawl assembly is moved to the left side of the hub, disengaging it from the driver’s gear ring.  The inner pawls of the pawl carrier then engage with the planet cage’s smaller gear ring, thus giving a lower gear (about 25% lower).  Another difficulty in the reassembly is that the clutch spring must be compressed and held down while also trying to push the circlip into place, something that can take more than a few tries to complete.  And, don’t let your hands off the circlip, as it can go flying around if you fail to push it on to the axle, and since it is a small part it can be hard to locate.

Now it was time to overhaul the early 1980’s hub on the JT.  The first thing I noticed was that the older hub has a sealed bearing mechanism which includes a dust cap on top, as part of the cone, and an “upside down” dustcap underneath, which creates a seal, on both sides of the hub axle.

Whereas the newer hub has one regular dustcap on the drive side, and one upside down dustcap on the non-drive side.  No seal is created with this method.

Upon disassembly I found the JT hub to be pretty dirty, with a lot of black greasy oil accumulated around the planetary gears.  Also, there was an extra part on the planetary gear assembly that sits at the base that wasn’t part of the newer hub.  Its purpose may be to reduce drag, but I’m not sure about that.  Everything cleaned up fairly easily except for the tiny grooves in the gear rings, which needed extra cleaning with a brash brush and pipe cleaners.  The quality of the machining and the metals used seemed identical between the two hubs, and both appear to be well built and solid.

I was unable to remove the cogs on the older hub, but that fortunately did not interfere with the overhaul process as it’s easy to just leave the cogs on the drive.  It was a little more difficult to get the cogs clean, however.

Lubrication is important in these potentially inefficient hubs. While reassembling the NOS hub, I simply applied Phil’s waterproof grease to all the parts, plus some Tenacious Oil on the pawls, to protect it from shop wear.  But for the hub I am using I needed to gather together the MANY lubricants needed for these types of hubs:  marine grease for the troughs of the upside down dustcaps (to make a waterproof seal), Phil’s waterproof grease for all the bearing assemblies (less viscous than the marine grease), Sturmey Archer lithium grade “00” grease for the gear rings and planetary gears, and Phil’s Tenacious oil for the pawl springs and pawl bodies, then 10-30 automotive oil on all the rest of the internals.  After much reading on this subject, this combination seems best for weather protection and drag reduction.  Guidance on internal hub lubrication can be found at the Sheldon Brown site, the bikesmithdesign site, and at the Aaron’s Bike Repair Site.

The hub is now back together and ready to be taken for a test ride.  Hopefully it will feel more lively after being cleaned and with fresh lubrication.  I’ll have to save that for another day – it’s snowing outside!  Meanwhile, I plan to tackle the overhaul of a few more IGH hubs over the winter.

Easier Gearing on Older Three Speeds

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There’s nothing like the comfort, reliability, and just plain fun of riding vintage three speed bicycles, especially those made by Raleigh and other U.K. manufacturers.  For decades, these bikes were the transportation of choice for the working class.  They are built to last, and their utility has already spanned across two centuries.  Properly cared for, these well built machines may outlast even our children’s children, and are a wonderful treasure to pass on to the future.

However, as built, these bikes are geared high and are difficult to ride uphill.  In practice, walking steep hills was the norm, as these bikes are also pretty heavy.

My 1950 Raleigh Sports Tourist, weighing in at 45 lbs., is no exception.  Its gear inch range is 47-84 with its original 19T cog and 46T chainring.  Using the bike in my hilly neighborhood has meant being in the right frame of mind and sufficiently rested to be willing to put forth the physical exertion required.  But, why not gear it lower and get more enjoyment out of the bike given the environment in which I ride?

Well, one reason is that it is a sort of major PITA to remove the rear wheel.  Owning a bike with a full chainguard means a few extra steps to rear wheel removal.  Fortunately I’ve never had a flat in all of the 15 years I’ve had this bike, so I’ve lucked out in that regard but have of course removed the rear wheel on the few times over the years when I’ve given the bike a complete overhaul.  It rarely needs servicing, just a few drops of oil in the hub every now and then, so I’ve had this, one of my oldest bikes, in the shop stand much less often than my other bikes.

But, it’s actually not that bad once you get started.  There are two screws at the back and bottom of the chainguard which when removed allow you to remove a back section of the guard, and then the wheel can be dropped out (after first disconnecting the indicator spindle from the cable of course).

And, to remove the rear wheel I’ve found it easiest to flip the bike upside down rather than hoist it into the work stand.  You can see what you are doing much easier, and there’s less likelihood of “losing” the chain inside the chainguard.  Even so, I like to place something there to keep the chain accessible, such as this wrench pictured above.

At this point, the fairly straightforward process of swapping the old cog for a new one with more teeth would be the next step.  However, you can see from the above photo that my cog is threaded to a threaded driver.  There aren’t 3 little notches which line up to the splines on the driver.  Uh oh!

Sturmey Archer began using splined drivers in their hubs in 1951, making swapping cogs relatively easy.  Because my Raleigh was made earlier, it has a threaded cog/driver, not a splined one.  So, an easy cog swap was out.  After doing some research, I concluded that I had two options if I wanted to lower the gearing:  remove the original cog and screw on a track cog (which is said to have the same threading) or swap out the driver for a newer splined driver.

Thinking that the simplest approach would be to simply unscrew the old cog and screw on a suitable replacement, I needed to find a way to hold the driver in place while using a chain whip (as I had already removed the driver from the hub).  Thanks to a helpful tip from bikesmithdesign.com I took a couple of matching Shimano 600 headset removal tools (I needed two to make the platform wide enough) and lined the handles up in my vice so I could place the slots between the driver’s “legs” over them.  It’s probably better to use aluminum bar stock as recommended, but my hack worked fine. A better approach would have been to leave the driver in the hub so that it’s still attached to the wheel, which provides more leverage. Trying it both ways I still couldn’t get the cog to unscrew, even after soaking it in some penetrating oil. It’s been on there for 72 years and doesn’t want to budge.

So, I switched to Plan B.

I harvested a splined driver from a 1978 hub, shown above, first removing the outer nuts and then the locknut and lock washer.  I had previously removed the cog, circlip, dust cap and spacers.

Then I put the left side axle in the vise and began to unscrew the cone on the right side.  The driver sits right underneath the cone and carries the bearing cup.  Removing the driver helps you to see why you must never do your cone adjustment from the right side:  the driver’s position is controlled by the spring underneath pushing up into the cone above.  It needs to be adjusted exactly as specified by Sturmey Archer so that the correct movement of the driver when the clutch is engaged by the shifter is achieved.

Making sure not to dislodge the plastic washer atop the clutch spring, you can remove the driver, but leave the clutch spring intact along with the washer sitting on top.  The recipient hub is going to get the driver, the dust cap, spacers, and circlip.  I also transferred the cone as well, since it was in better shape the original.

I carefully installed the new replacement driver onto the 1950 hub, and screwed the cone down finger tight, then backed it off 1/2 turn as per the S.A. instructions.  From there, the lock washer and locknut are installed.  I checked the hub for free play and then did a slight cone adjustment on the left side (NEVER ON THE RIGHT!), leaving just a tiny bit of free play, as recommended.

Then the exciting part:  installing the new cog.  Not knowing how much room I would have inside the chainguard I went with a 22T cog.  I didn’t want to risk having the chain rub against the inside of the guard.  So, fingers crossed that this one will work.  After noting the dishing on my original cog:  “bubble side down” I oriented this cog the same way.  I installed the dust cap underneath first, and found I also needed an extra spacer which I fortunately had on hand, pushed on the cog and snapped in the circlip.

After adding two chain links to accommodate the larger cog I tried mounting the wheel to first make sure that I had the right chain length.  The axle should sit comfortably in the middle of the dropout, which it does.  From there I installed the outer washers and nuts.  At this point, I turned the bike over and put it into the shop stand, as it was time to reinstall the hub spindle and check that the shifting was working and that there were no other issues such as a chain line problem or chain rub on the guard.  Fortunately, all was in order and shifting was perfect once I retuned it.

1951 Raleigh Catalog

My new gearing gives me 41-54-72 gear inches.  My first test ride gave me a glimpse of the fun I’m going to have.  The 54 is a comfortable “cruising gear”, which I define as an easy cadence on flats.  The low 41 gear, although NOT a 30, is still much better than it was, and the high gear of 72 is just fine as I really don’t need to blast down the hills.

The hub on this bike has always seemed almost self propelling.  It spins very well and has little friction, especially as compared to my other Sturmey Archer equipped bikes (older is better?).  I plan to spin my way into the coming seasons and hope that I’ve given this bike a chance to keep on spinning for another 70 years or more.

About a Brompton: C line Electric Review

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I’ve developed an interest in folding bikes as well as small wheeled bicycles over the years.  Lately, I’ve also wanted to explore the growing world of e-bikes.   I combined all of these interests together in purchasing this Brompton C line electric bicycle.

Before delving in to my impressions of the bike, there’s first a lot to unpack about Brompton bicycles in general and the e-bike version specifically.  First and foremost, this is a folding bike with tiny 16 inch wheels.  It folds into a squarish size that can easily fit behind a desk or in even the smallest hatchback.  The folding process is quick, involving only a few steps, and is arguably ingenious as there’s no other (rideable) small wheeled bike that folds up this small and this easily, to my knowledge.  I won’t go into the folding process here, as there are multiple resources on the web to help you learn.

In practice, I have rarely fully folded the bike, but have found this “kick stand mode” very useful, both outdoors and inside.

Of the many quirks and oddities of Brompton bicycles, the most important is the fact that since this is both a folding bike and a “one size fits all” bike, virtually every component is purpose built and cannot be upgraded or swapped without voiding the 7 year warranty (frame only, 3 years for the e-bike components).  Essentially, everything on the Brompton, down to the cables and their housings, is custom made.  I learned this after purchasing the bike with the taller version of the handlebars.  Only one style of handlebar is available with the e-bike version, and it comes in two different heights, achieved by different stem lengths.  Swapping bars is an expensive undertaking and can only be done by the dealer.  Fortunately, having only a few miles on the bike, I was able to swap it out for a different model with the shorter stem.  Even so, I find the medium height bars too tall for ideal comfort.

Likewise, the shape of the bars, necessary for the bike to fold, means that there is no swept-back angle on the grip portion, which instead are perpendicular to the stem.  This rotates your shoulders forward and twists your thumbs and wrists into an uncomfortable position.

I removed the stock grips and wrapped multiple layers of cloth tape to the grip area, opting for a funky two tone look.  This helped to make the grip area less thick, making it less painful for my thumbs to lock under the bar, and I like the feel and moisture absorbency of cloth tape.

Because of the bike’s non-standard design, all of the visual cues that one might use to set up the ergonomics are missing. I needed to get out my angle finder and tape measure to get the bars and saddle set up in the most tolerable position for riding.  One size fits all means some ergonomic compromises.

The utilitarian saddle clamp is made less effective by its single bolt design with the bolt positioned so that one must mount the saddle (I removed the uncomfortable Brompton saddle) on the upper rails of the clamp in order to access the bolt.  If mounted on the lower rails, you can see that the saddle can’t be positioned correctly because the bolt becomes inaccessible from the side. Traditional saddle clamps have the bolt accessible from underneath the saddle.  The clamp itself allows for micro-adjustment, however.

I wanted to use my leather Cardiff saddle with this bike, but ended up swapping it for a well worn WTB Deva which provides a little more cushioning, necessary due to the bouncy ride.  Even though the bottom bracket is offset ahead of the seat tube, I still needed to push the saddle back to account for the forward mounted (and must not be reversed for unknown reasons, per the owner’s manual) no-set-back saddle clamp.  I also angled the handlebars inward toward the saddle to bring my hands into a comfortable position with some elbow bend to provide much needed shock absorption.

Rear suspension block

Short spokes make for a harsh ride

Rear wheel not centered between chainstays

Small wheeled bicycles, with their shorter spokes, are improved by front and rear suspension to help smooth out the ride. I’m amazed, given how harshly this bike rides, that Brompton hasn’t invested in engineering some kind of front suspension.  Alex Moulton figured this out back in 1962 when he designed the first Moulton with full suspension front and rear.  It too featured 16 inch wheels.  The folding stem would admittedly present engineering challenges. Brompton has only managed to engineer a simple rear suspension block, perhaps choosing instead to spend its money on branding every single component of the bike, down to the rear fender flap.

The little 250 watt motor housed in a relatively small flange hub, still eats up a big portion of the front wheel’s diameter, making the spoke length very short. I don’t hear riders of regular Bromptons complaining bitterly about the harsh ride, but maybe that’s because they have three things going for them:  longer spokes on the front wheel, a lighter and more flexible fork, and more (and better) tire options.  Brompton has specified only two tire options for this e-bike:  the Schwalbe Marathon Racer and the Schwalbe Marathon, both harsh riding tires with heavy, stiff sidewalls.

My bike came equipped with the Marathon Racers, which measure 34mm wide on the Brompton rims.  I’ve had to experiment with tire pressure, as there is a trade off between rolling resistance and ride harshness, which I’ve found to be balanced at about 70-75 lbs. front and rear.  You’ll note from the above photo that the rear wheel is not centered between the chain stays.  There is only about 2 mm of tire clearance on the drive side, with about 9 mm on the non drive side.  At first I thought that the rear wheel was out of dish, but upon checking I discovered that while out of dish by about 1 mm, the culprit for the lack of centering is that the drop outs are out of alignment, appearing to be so by design.  Theorizing that the purpose for this had something to do with the bike’s folding characteristics, I contacted both my local LBS and Brompton itself via email, several times, and never had a response.

At any rate, the lack of clearance means that it is impossible to install wider tires on this bike.

The drivetrain consists of a wide ratio Sturmey Archer 3 speed hub with two cogs, 16T and 13T, mated to a 50T chainring up front.  This gives a gear inch range of 33 to 100, which is a good spread for just about any kind of riding.  There’s an oddball “chain pusher” clamped to the chain stay that shoves the pulleys, which are plastic, from one side to the other of the the also plastic chain tensioner.  The (plastic again) shifters have the cog shifter on the left side and the internal hub shifter on the right side.  I found the half step gear shifting pattern to be non-intuitive until I made the above gear shifting chart.  Now, it’s easy to remember that any time I am shifting the rear hub, I’ll need to do a double shift to maintain cadence.  The whole system is noisy as can be, with something always whirring and clicking. Combined with the thunking and rattling noises caused by the harsh ride, it’s taken a while to get used to, and has at times caused me to think that something is seriously wrong with the bike.

There’s also a lot of friction in the drive train, which you can note by trying to spin the crankset backwards.  It simply doesn’t.  Normally, there would be about a 5-9% loss in power due to the internal gear hub as compared to a derailleur geared bicycle, but this drive train feels more sluggish when “unplugged” than my vintage 3 speed bikes.  I suspect this is caused by the pulley placement on the chain tensioner:  there is almost no clearance between each pulley, barely enough room for the chain to fit through.  Add to that the drag from the front motor, and this becomes a bike that’s not fun to ride with battery turned off.

But, many faults and flaws can be overcome with the addition of a little battery power and a motor. The bike comes standard with a soft case to hold the battery, which clips into a specially designed front bracket.  The case is very small, but can hold a U-lock, cell phone, and wallet.  I opted to purchase the larger commuter bag and have found it very useful, and big enough for a change of clothes or a day’s shopping.

The bike comes with some thick owner’s manuals and the learning curve for this bike is  steep, especially if you haven’t owned a Brompton or an e-bike previously.  But, I’ve learned a few tips that I can now share.  First of all, when you insert the battery onto the bike, make sure it is fully clamped in by giving it an extra shove, otherwise the battery can pop out/turn off unexpectedly while hitting a bump.  Secondly, the battery, sensors, and motor are re-calibrated each time the battery is installed, so do not turn the cranks or move the bike for the first few seconds.  Wait until all the lights come on, and even a few seconds after that.

There are three power modes.  Don’t waste your time on power mode 1, as it is too wimpy to overcome the bike’s drive train flaws.  I’ve found that using mode 2 consistently, with the lights always on, gives me about a 30 mile range before re-charging.  Mode 3 is great for steep hills, hot days, and miserable rain, but will use the battery more quickly.  According to the owner’s manual, the battery likes to be recharged early and often.

As per British e-bike standards, the power cuts out at 15 mph, for which I am thankful.  This little bike with its tiny wheels can be scary on descents, especially if encountering a bump or pothole, which can turn the fork and even swallow the front wheel.  For me, it’s also nice to not overtake super-fit riders.  I’m not riding to get there as fast as I can.

There are many other quirks and “Bromptonisms” that need to be learned.  I’ve found the videos by Brilliant Bikes especially helpful and humorous.

Poorly designed rollers

Roller on fender which doesn’t actually roll

One locking solution for quick stops.

I did consider selling the bike until just recently, as I’ve come to think of it more as a commuting appliance, rather than a bicycle.  There have been so many notable flaws, including the fact that this bike isn’t suited for multi-modal transportation (except via car).  It is too heavy (about 39 lbs. with battery) to comfortably carry up steps, and the poorly designed “rollers” to be used when the bike is partially folded, simply do not work on this bike.  Perhaps because it is heavier than regular Bromptons are, but the bike doesn’t roll when folded on anything but the smoothest polished surfaces.  There are aftermarket rollers available, but it is disappointing that Brompton would not properly engineer these rollers to work with the e-bike.  Because of the weight and inability to roll when partially folded, you can’t take this bike with you into the grocery store, as you can with regular Bromptons.  That means you have to figure out a way to lock it.  I’ve come up with one solution, shown above, that locks the battery as well.  So far, so good.

Likewise, failing to provide for a bottle cage mount is another disappointment.  Fortunately, I found a suitable solution with this clamp made by “Monkii”, but it is puzzling that such an important feature is left for the consumer to problem solve, especially on a bike in this price range.

To end on a positive note, I’ll say that one redeeming feature is this adorable pump, engineered to fit perfectly on the left side seat stay.  It works fine, too.

So, why do I still have this bike?  In addition to commuting on hot days, cycling on unpleasant errands, and riding through rain storms, I’ve also taken this bike on some almost fun jaunts out of town.  I’ve expanded my normal routes to include previously unconquerable hills.  While not my favorite bike by any means, I have found it helpful to have an e-bike on hand when I want to ride even though conditions are bad. Its folding capabilities mean that I can take it with me on out of town trips even when I am bringing another bike, because I can squeeze it in just about anywhere.  But, I cannot recommend this bike as one’s only bike, except maybe in an environment with very smooth roads. Wired Magazine declared this bike un-rideable in its recent review.  Let’s hope that as competition in the e-bike market increases, Brompton will be required to address some of this bike’s glaring shortcomings.