Sachs Orbit Hybrid Hub Overhaul

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.

1973 Jack Taylor Revisited

While I’ve been working on other projects, my 1973 Jack Taylor Tourist bike has been languishing in my storage area, along with far too many other bikes.  I thought it was time to bring it back out again for the coming spring weather, and that meant assessing why I wasn’t riding it so much anymore.

When getting the bike up into the shop stand I realized that I still hadn’t solved the ergonomic issues resulting from its large frame (for me).  Back in 2015 I had replaced the moustache bars with a more upright style, and a short reach, tall stem. But the bar shape didn’t really work for me, and I ended up setting the bike aside a few years back.

I needed some bars with a more swept back profile and with more rise, so I tried out these Sunlite Northroad bars, a set I haven’t tried before.  I cut them down about 2 cm, which turned out to be just right for this bike.  If I were using these bars on a smaller bike I probably would have cut more, but on this bike these bars look well balanced.  As part of the bar swap it was necessary to install new brake housing, which needed to be a little longer due to the swept back shape of the bars.

I made a few other changes as well.  The original Soubitez front lamp was held together with electrical tape and needed to be replaced.  I was able to find an exact match on eBay, shown above.  In the same purchase I acquired a NOS Soubitez dynamo from the same era. This one works more reliably that its predecessor and seems to have a little less drag.  I also replaced the pedals with a vintage Phillips French threaded set.  The pedals are very grippy, more so than the Lyotards previously installed.

When I threw my leg over for a test ride, I was reminded just how tall this bike is.  The bottom bracket height is a whopping 11.5 inches (29.2 cm).  That’s mountain bike territory, and definitely different than many of my other bikes.

This bike features 27 inch wheels rather than 700c. The rear wheel is laced to a Sachs Orbit 2 speed hub which takes the place of a front derailleur.  The big wheels roll smoothly and absorb road shock very well. They have never gone out of true since I acquired the bike 15 years ago.  I have found this to be the norm for any well built wheel, including wheels I have built myself.

The Sachs Orbit hub offers about a 25% drop from the direct drive gear.  As originally equipped, the bike had a 34 tooth chain ring on the front.  That was a bit low for me, so I replaced that with a 36 tooth version.  Gear inch range with this hybrid set up and the 14-28 cog set is 25-70.  Still pretty low, but with the bike’s front and rear racks, the low gearing makes it easy to feel comfortable hauling stuff and climbing hills at the same time!

I had previously changed out the original saddle for this vintage Ideale Model 75.  The leather was very stiff and unforgiving, which made for an uncomfortable ride.  After applying some Brooks saddle treatment and using a hair dryer to heat it up and work it into the leather, the saddle is now more supple.  With the newly installed upright Northroad style bars, this saddle style is perfect.  The springs do a great job at absorbing shock without being bouncy.

So, will I ride this bike more often?  I do think so.  Now that the ergonomics are right for me, the smooth ride quality and easy gearing will make it appealing.  It can handle any kind of weather, and even though I dislike sidewall dynamo lighting, getting caught in the dark will not be an issue for this bike.  This is a bike that can handle a lot of different riding requirements. The Reynolds 531 fillet brazed frame makes it responsive and light weight.  It’s also a beautiful bike and gets a lot of complements wherever it goes.

Hybrid Gearing

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Sachs Orbit 2 speed hybrid hub with 6 speed cassette

I became interested in hybrid gearing after acquiring my 1973 Jack Taylor Tourist, about 9 years ago.  The bike features a single front chainring, 6 speed cassette and a 2 speed Sachs Orbit internal hub.  That gives it 12 gears overall, with a good range for the kind of riding I do, as the internal hub’s lower gear is about a 33% reduction, which is quite significant. For awhile, I didn’t think much about this interesting arrangement, and instead just enjoyed riding the bike, and being able to do a substantial downshift while sitting still at a stop light.

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Sachs Orbit 2 speed hybrid hub with 6 speed cassette.

There are a number of ways to accomplish hybrid gearing.  You can forgo a front derailleur, and use an internal two or three speed hub to take the place of multiple chainrings.  You can also use multiple chainrings with an internal hub, and forgo the cassette/freewheel.  Or, you can be like Sheldon Brown and do both, achieving a 63 speed bicycle – his beloved “O.T.B.”  which used a 3 speed SA hub, a seven speed cassette, and 3 chainrings.  Doing the math:  3 x 7 x 3 = 63.  So with modern technology, let’s calculate the possibilities:  a 14 speed Rohloff hub, paired with an 11 speed cassette, with a triple chainring = 462 gears!  Probably that set up would be a mechanic’s nightmare, so if you really want this many gears, I suggest you purchase a continuously variable NuVinci hub – but be prepared to deal with quite a bit more than a couple of pounds of extra weight.

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Sachs Orbit hub – NOS early 90’s with two optional cassettes

There is really only one source on the internet for information about the Sachs Orbit 2 speed hybrid hub, and that of course is the Sheldon Brown site, with additional information and clarifications by bike guru John Allen.  One of the things I worried about with this hub on my Jack Taylor was being able to find replacement parts, given that the hub was so rare.  Fortunately, a while back I found a NOS Sachs Orbit hub, pictured above, which I could use as a replacement in case something went wrong.

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1973 Jack Taylor Tourist Sachs Orbit hybrid hub

Meanwhile, the original hub is working just fine, and needed only occasional lubrication with automotive oil.  I had sent the hub out for a rebuild nine years ago, and it is working perfectly, still.

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Info on the box of the replacement hub seems to indicate this is a 1992 hub

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Very pretty hub logo engraved into the hub shell

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Be careful with these spindles!

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The replacement hub I purchased is quite lovely, and has two different cassette options – for 5 or 6 speeds. The cassette cogs and spacers slip onto the freehub with tabs to line up the rings, except for the final smaller cogs, which screw onto the freehub.  As one pedals, these smaller cogs with screw-on threads will get tighter and tighter.

Because this replacement hub is so nice, I have been thinking about using it to build into an interesting wheel set for a road/commuter bike, rather than keeping it in reserve for spare parts. One of the convenient features of this hub is that it can be operated by pretty much any front derailleur shifter, as there are only two positions on the hub.  And, if something goes wrong with the hub on the Jack Taylor, maybe I will rethink hybrid gearing altogether.

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1973 Jack Taylor Tourist

The bike’s rear wheel was an alteration from its original 1973 build, and whether or not this rear wheel was built by the Taylor brothers is unknown.  However, I have noted that British bikes built in the 60’s through the 80’s sometimes featured hybrid gearing.  This was especially true for the boutique manufacturers of that era.  Sachs internal hub gears are considered on par with Sturmey Archer, and I will say that is true, based on my experience with riding this Jack Taylor. The hub has been totally reliable.

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This early 90’s Sachs Orbit 2 speed hybrid hub has 36 holes, so it could work with a number of possible rims.  It needs a bit of lubrication to bring it back to full glory, and if I end up needing to rebuild it, John Allen and Sheldon Brown will come the rescue.