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Chainlines, Idlers, and Tubes, oh my!

Chain lines on trikes seem to generate a lot of experimenting and novel approaches.  The pictures below show a bunch of different approaches to making a chainline quiet and efficient, on all Catrikes I believe.

Hopefully the creators of these setups or those who have tried similar ones will comment on the likely quietness and efficiency of each of these setups.  Send additional pics of chainlines of any type of bent, and I’ll post them.

Bruce's speed.40

Above: Bruce’s Speed. Bruce says this is the cleanest, quietest, most efficient setup he has used.   

dr duk

Above: Dr. Duk’s version of chain tubes.  Says Bruce: “…shows the easiest, and best way to give the tubes the loosest float possible, and this is a good thing.”

Flying Tiger

Above: Flying Tiger’s version

Bruce's orange speedBruce’s orange Catrike.  “This is the overly complex, and expensive, chainline that I tried on two of my Speeds.  I had four goals for it:  lift the return chain higher off the ground, push the power chain under the front axle, raise everything above the bottom of the main frame tube, and eliminate all tubes.  It did all four quite well, but at the expense of expense and more noise.  Both trikes are back to a single tube on the return chain, with just some tape on top of the axle to protect against the power chain slap. ”

Jerry McKee.50

another trike set up, by Jerry Mckee.

Bruce: “Jerry McKee’s is close, but the idlers should have been placed behind the front axle. Also, by pushing the power chain under the front axle, you alter the angle of the power chain to the der post and der. This can hurt the shifting, and at the least, it limits how small you can go on the small ring. I know this because on my Tony Trike, I couldn’t go smaller than a 30 tooth ring when I did this arrangement.”

John Rooker.50

Above: John Rooker’s Expedition.   Says John: “I have the same setup on my present Trail.  This is simple, effective, quiet and costs almost nothing once you’ve purchased the return side idler.”


Utah Trikes photo, on an Expedition.  “…just insanely wrong! All of the Expo’s cherished ground clearance is lost with that arrangement. That idler should have been placed in front of the axle, as Pat Franz has designed those clamp-ons to be placed.”



photofinish 3.80

photofinish 2


photofinish 3

Bruce’s opinion – “Photofinish’s setup is a good example of a common myth about chainlines, that running the return chain in a straight line gives less drag. Wrong! It increases the drag compared to a slightly curved tube run underneath. If you let the chain hang naturaly with no tube, it has no frictional drag, so what better way to “tube” it than to run it through a tube that follows it’s natural curve as much as possible. Ideally, if the tube’s curve matches the chain’s curve, the tube will not be supporting the chain at all, and therefore will not induce any drag. But, if you lift the chain up and run it through a straight tube above where it wants to hang naturally, the tube is then carrying all of the chain’s weight, and that creates a LOT of drag, not to mention more noise. It may look cool, but it will cost you in pedal effort and extra noise. If you look at the first pic of my Holey Spokes, the tube has been curved to match the natural droop of the return chain as close as possible. With generous flares, it is almost silent all the time.”



Bruce’s Opinion – “pretty close to stock and about the best you can get. Quiet and efficient!”

Utah trike

another one from Utah Trike

HP velocotech lg_chaintube_sideangle

Chain tube attachment by HP – Velotechnik, sold at Hostel Shoppe. A long spoke held under the idler bolt and tied to the tube as far along the tube as possible will allow the tube to move around as much as it needs to in reaction to chain movement, with very little restriction.  The longer the spoke, the more flex is would have.  

tcycle floating tube holder

Terracycle floating tube holder.  They also sell flared sections of chain tube.  Although the floating tube holder is cool, the bike has chain routing and crossover issues. Without tubes the chain would rub itself, causing it to “snag” on itself as the pin ends catch each other.  Also, the chain runs along the side of the fork, rubbing it almost constantly.  Even with a tube, the tube rubs the fork.  It also limits the turn radius, because the tire will rub the chain with very little turn input.  Bruce  


PhattKat’s setup, from his blog. Note the attachment of both the power side tube and the return side tube to the idler.  These attachments look solid. Also full coverage of the chains, as shown below.  How does one keep a chain so clean!!??  My trike is a mess by comparison.


Phatkatts chain tubes.

Joules, the cycling robot

Specifically, Joules is a robotic stoker for your tandem bike, when you are riding solo on a tandem.


This project definitely has a steam punk flair, and combines some art, whimsy, and a good deal of engineering.  Joules was built by engineer Carl Morgan with his son, a former pro cycling racer.  The web page with more information on Joules is here.

Carl has a great U tube video also, linked below.

Front Wheel Drive Recumbent, 1950

What is the big deal about front wheel drive recumbents?  Here is one that is really cool, from 1950.  It has an internally geared hub, and a very stylish body.  This would be a cool bike!

fwd recumbent 1950.40

Early FWD Recumbent

Thomas Traylor’s 1982 design patent for a front wheel drive two wheeled recumbent, very similar in design to a Cruzbike Silvio.  Considering Maria Parker’s new 12 hour record, set on a Cruzbike, maybe Traylor was ahead of his time!

fwd recumbent30

Rear Suspension Bike, 1891

Here is a rear suspension bike from 1891 which used springs in a tube to give some give to the rear wheel.

1891 rear sus2

Harry Lawson’s Bicyclette

James Starley’s Rover of 1885 was the first successful bike in which pedals and a crank drove the rear wheel with a chain, but he was not the first with that design.  In 1879 Englishman Harry Lawson  designed and patented a version of a large front wheeled bike with a smaller rear wheel driven by cranks and a chain.   Lawson’s bike was not very well received, and he went on to design bikes using levers for power transmission.  The Bicyclette was a commercial failure, but he had hit upon a superior design feature.

lawson bicyclet

This artwork of the Bicyclette is a version featured on cigarette cards.  This and other bicycle art is found at  Framed versions of these beautiful cigarette cards, posters , cards, and other bicycle art  recognize that brilliant design is art.

The First Rear Suspension Bike, 1891

Here is another candidate for the first rear suspension bicycle design, from 1891. Its modern counterpart is shown below.


rear sus modern

Facing Bottom Bracket Shells on the Catrike

Yesterday I did a bottom bracket shell facing and thread cleaning job on Bob Shaver’s Speed. I took lots of pics of the job showing the steps in getting clean faces on each end of the shell.

After reading the text below each pic, it’s very interesting to watch them all in slideshow mode. The progress shows up much better that way.


This is the bottom bracket face before it was faced, showing the layer of powdercoat. The external bearing cups press down on this face, and if it is not perfectly flat the bearings are cocked to one side.


This is the Park tool for facing the bottom bracket faces.


This is the cutting tool cutting away the powdercoat layer, and a tiny bit of metal.


This is the face showing slight chatter marks from the tool.


The chatter marks are smoothed off and the face made perfect with emery cloth pressed in by the cutting tool.


The face after the final smoothing and polishing.

This facing of the bottom bracket edge is part of Bob’s upgrade to ceramic bearings in the BB. They are typically much tighter than the steel bearings that come in most bottom brackets, so they will not tolerate as much misalignment as the steel bearings. This is why the faces of the shell must be absolutely parallel with each other and perpendicular to the axis of the bottom bracket spindle when converting to ceramic bearings. The Park Tools threading and facing tool is a very precise piece of equipment that does a beautiful job of truing up a BB shell, even if it is very expensive. Most shops will do this job for about $50 if they have the tool, but most mechanics, in fact very few, know how to do the job correctly. They usually leave the chatter marks. That’s OK, actually, as long as they are even all the way around the face.

As can be seen in some of the pics in Bruce’s flicker photos (linked below), a lot of powder coating gets deposited on the surfaces where the bearing cups tighten. This uneven buildup causes the cups and bearings to cock sideways, as the powder coat is never perfectly smooth. Cheaper and sloppier steel bearings will absorb a lot of this alignment displacement, but better ceramic bearings won’t, and it will often cause bind in the better, tighter bearings. Pictures iL1, L2 and L3 in Bruce’s flicker pics show the non-drive side of the BB shell with a huge buildup of powdercoating. This is enough to cause bind in even a steel bearing. If you look really close at these pics, you can also see the only three small areas of contact that the bearing cup had with this face!

Besides the powder coating buildup, warpage from welding will distort the shell faces. This is shown in the pics as small areas at a time of bare aluminum showing up as cutting progresses. If they had been absolutely true from the start, the aluminum would have shown up all at once as soon as the powdercoating was removed.

If any Catrike riders intend to put ceramics in your BB, or you feel some resistance and just want to feel sure about your’s, and your lbs can’t do this job. Contact Bruce and if you ask nicely he may do it for you. You will need to send him your bare boom/BB and return postage. (Oh, and a pan of brownies!)(Hey! it never hurts to ask!) Contact Bruce at

This is the link to Bruce’s pics on flickr


P.S.  mikeatlbch made a comment that jogged Bruce’s memory, and he is right.  mikeatlbch notes that facing the bb is needed only for external bearings, not for cartridge bearing assemblies.  Thus the Speed, Expedition, and 700 model Catrikes, which all have external bearing assemblies,  need to be faced.  Other Catrike models or any bike/trike with cartridge bearings don’t need to be faced.

Gear Shift Bike, 1897

Even after bikes were built using chains, other power transmission modes were tried in early years and continue to be tried today. The chain is just so efficient its hard to beat. An early alternative to the chain and gears utilized a drive shaft. Some added gears to the drive shaft to form a transmission like the early cars were using. This one from 1897 even had a shift lever and a real transmission and a drive shaft that operated with bevel gears to the rear wheel. Having machinery and machinists capable of making bevel gears and transmissions such as this made the transmission to automobiles much smoother and faster.


1869 Tadpole Recumbent Trike

This figure from a U.S. patent from 1869 shows a tadpole recumbent trike. It is powered by the user’s hands and feet. The feet work a treadle, and the hands work the rods. Rod and lever propulsion was common in those days, because reliable chains had not been developed yet, and the crank and chain was not proven as the best way to transfer power. This wheel and frame configuration is about 140 years ahead of ahead of the Catrike and other trikes, which have similar frame and wheel configuration.