Tag Archives: Jack Taylor Tandem

Eccentrics in Cycling

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1958 Eccentric bottom bracket on Rene Herse Tandem – Daniel Rebour drawing.

Eccentric bottom bracket on 1977 Jack Taylor tandem

As part of restoring my 1977 Jack Taylor tandem, I needed to rebuild the eccentric bottom bracket and set it up correctly.  There’s been a bit of a learning curve, since I haven’t previously restored a vintage tandem.

The use of an eccentric appears to first date to the steam engine era, to optimize the efficiency of a rotating shaft.  And eccentric bicycle components have been around for over 100 years.  Yet, it can feel foreign, and daunting to work on a bike that features this technology.

What is an eccentric?  The official definition from Wikipedia is:  “in mechanical engineering, an eccentric is a circular disk (eccentric sheave) solidly fixed to a rotating axle with its centre offset from that of the axle (hence the word “eccentric”, out of the centre).”  The above photo depicts an eccentric pedal design introduced in 1903. 

Here’s a dual eccentric bottom bracket that can alter the gearing ratio at the crankset, also introduced in 1903.

Fred DeLong’s experimental fork dropouts

Fred Delong even spec’d a bike that had offset fork dropouts, to enable him to quickly change his bike’s rake and trail characteristics.  Although not technically an eccentric, this dropout design allowed him to choose when to optimize for trail and wheel flop, as shown in the table above.  A similar result could be achieved with an eccentric front hub.  Currently, eccentric hubs are limited in application to the rear where they are used to adjust chain tension on fixed gear bikes.

My Jack Taylor tandem features an eccentric bottom bracket that is similar in design to the 1958 model depicted at the top of this post. The threaded portion features a T.A. spindle and cups. There is a single hole drilled into the offset section.  Newer eccentric bottom brackets have multiple holes drilled, so that a pin spanner can be used to ease the adjustment process.  I can’t quite make out the lettering on this model – does it say “Rogers”?

I had wanted to rebuild the bottom bracket while it was off the bike – one of the benefits of this design.  However, when it came time to install the rebuilt BB back into the shell, the fit was very tight and needed to be accomplished with a mallet.  Not wanting to damage the cups or bearings, I disassembled it and then rebuilt it again once installed in the shell.  But, when I did so I ended up positioning the spindle toward the front rather than the rear of the bike.  That’s not what you want, since the whole idea of this design is to allow one to move the spindle toward the front as the timing chain stretches with wear.

I made this video showing how to adjust the eccentric bottom bracket on a model where only one hole is drilled. After loosening the bolts in the shell, and using an Allen wrench inserted into the hole and then leveraging that with a heavy duty screwdriver against the spindle, you can get the eccentric positioned where you want it to be.  It’s clear to me now that overhauling a tandem is much more involved than a typical restoration.  Still, it’s been fun to learn new techniques.  I’m looking forward to the rest of the process.

1977 Jack Taylor Tandem Restoration- the Beginning

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Mafac hood with dual cables

I’ve been waiting to get in the right frame of mind to begin restoration of a 1977 Jack Taylor Tandem that I had shipped from England back in 2012.  Clearly, I’ve been waiting quite a while, but during that time I have corresponded with the original owner’s son, who has provided valuable information about the bike’s history as well as a few family photos of the tandem’s exploits.

Jack Taylor frame at bottom left

I also needed more shop space to enable me to use two stands to aid with disassembly.  That finally happened last Fall, and I now have not only more shop space, but additional bike storage space as well, all in one location.

So I was finally able to remove the components to begin the process of bringing this tandem back to its original glory.  I had already removed the 650b Maxi-Car wheelset and worked on getting the wheels back in order.

I still need to re-glue one of the brake shoes in the front drum hub, but the rear wheel has been overhauled and adjusted.

Jack Taylor frames are built with Reynolds 531 tubing.  The specs for each Reynolds tubeset will vary based on customer request and on the particular application.  A serial number is stamped on the rear drop-out and the steerer tube.  You can see the matching numbers in the above photo – 7183 – indicating this is a probably a 1977 frame, based on the helpful chart provided by Joel Metz at his blackbirdsf.org site.  This chart was developed from information provided by Mark Lawrence, who happens to be the individual I purchased this tandem from.  He sold the bike on behalf of the original owners.  Mark was a long-time friend of the Taylor brothers.

Tandems differ from regular bikes in a number of ways.  There are naturally two bottom brackets, one of which is an eccentric, which aids in adjusting the timing chain so that that both sets of cranks are positioned at the same angle on the spindle, and so that chain tension is properly maintained.  The matching crank arm position is important for cornering, as you want both crank arms upright when descending at speed while leaning over.  Both bottom brackets are T.A. models, and the threaded eccentric appears to say “Rogers”.  It taps out of the frame after loosening the bolts.  Adjustment is made by loosening the bolts, twisting the eccentric to the desired position, and re-tightening.

The components on this tandem indicate that it was the Super Touring Deluxe model, spec’d with Mafac Tandem cantilever brake calipers (plus a Maxi drum brake up front), Stronglight headset, Campagnolo derailleurs and shifters, Campagnolo drop-outs, SunTour Perfect 5 speed freewheel, T. A. cranksets, plus Maxi-Car 650b wheels.

1977 Jack Taylor Tandem with kiddie crank and trail-a-bike

Four cranksets was one more than expected.  Upon corresponding with the son of the original owners, I learned that this was needed to set up the “kiddie-crank” for the young stoker.  His sister contributed to the effort on her trail-a-bike.

As originally purchased 1977 Jack Taylor Tandem

As I’ve researched the history of Jack Taylor Cycles I’ve come across a few sites I hadn’t accessed before.  One of these is the Stockton-on-Tees History site, which has several wonderful posts regarding the history of the “works” building and of the Taylor brother’s exploits:

Jack Taylor Cycles

Jack Taylor Cycle Maker

While the restoration process may take some time, I’m hopeful about the result.  This is a machine worth preserving.

Overhauling Maxi-Car Hubs, Part 2 (hmmm…)

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When I left off from part 1 of my Maxi-Car hub overhaul project, I was having trouble disassembling the 1950’s Type 2 hubs that I was using as my training ground for learning the process of servicing and adjusting these well-regarded vintage components.  Those hubs are still soaking in penetrant in the hopes of freeing up the axles from the inner races of the annular bearings.  Now, I have pulled the Maxi-Car wheelset off of my 1977 Jack Taylor tandem, and am looking forward to achieving better results.  That hubset is laced to 650b rims, and features a front hub with a drum brake (as an addition to the front cantilevers), and a rear hub with a freewheel.

The freewheel, axle and nuts were showing some rust, so I was prepared for the eventuality that it would not come off on the first try.  That meant that the rear wheel of my 2nd Maxi-Car project is also soaking in penetrant, so I turned my attention to the front hub, which I was hoping to put off due to also having to address servicing the drum brake.

I don’t have a lot of experience with drum brakes and am not a big fan.  But, they can work well for some applications.  In this case, a tandem needs more than one front brake to safely descend steep hills, so the drum brake (which is actuated by the same lever as the front cantilevers – a double-cable mafac brake lever) is meant to augment the effectiveness of the rim brakes.

I started the process of removing the outer nuts and washers of what I thought was the fixed end of the hub, documenting each step as I went along.  When it came time to remove the drum brake shoes from the hub shell, the component came out easily by gently lifting it up from the axle.

However, one brake liner was left behind, having become dislodged from its proper position on the shoe.  Rather than worry too much about that, I continued with my process, thinking I would find the fixed side’s dust cover underneath the brake assembly.

But, that’s not what happened. Instead, I saw a black dust cap underneath the nuts and washers, with no holes for a pin-spanner.  Hmmm…

When I flipped the hub over to the “adjustable side” that’s when I realized that this hub looks different from other Maxi-Car hubs.  The dust caps are anodized black, and don’t have holes.  Are these cup and cone hubs?  The answer is yes!

I was kind of almost overjoyed to see these bearings peaking out from underneath the dust cover.  But then I realized that I may not in fact be overhauling a Maxi-Car hub, but some other kind of hub.  What could it be?

I took a closer look at the hub and saw that it is completely unbranded.  There are no markings anywhere on the hub.  The flanges and drum are steel, and the hub body is aluminum.  The style of the rivets and the flanges matches up to a number of older Maxi-Car hub styles.   Did Maxi-Car build regular cup and cone hubs?  I don’t know.  I do know what the hub is not.  It is not a:  Sturmey Archer, Sachs, Arai, or Shimano.  The hub appears to be of older vintage than its rear counterpart.  Perhaps the wheel was built up by Ken Taylor with the customer’s favorite older front hub?

Cam with spring on the right, pivot on the left, lower brake lining missing.

Brake drum before cleaning

Brake drum after cleaning

While those thoughts cogitated, I went forward with cleaning all the parts and thinking more about how to attach the dislodged brake liner to its shoe.  I know that drum brakes can build up a lot of heat, so using an adhesive that can tolerate high temperatures will be critical.  The liners still have about 2.5 mm thickness, so if the adhesive problem can be solved, then I can complete the hub overhaul.  If not, I’ll have to discard the hubs and build up a new 650b wheel using the original Weinmann rim, which is in good shape, and decide on what kind of front hub to use that would be appropriate for the 1977 JT.  But, the next step for now is to get the freewheel off of the rear hub.  Stay tuned!