Alternatives to the "Traditional" Chain

Almost all bikes today have chains that are remarkably similar to each other and to chains of 100 years ago. All chains have pins that are 1/2 inch (and not some metric distance) apart - this means that it is fairly easy to check if a chain is "stretched" without special tools. (It isn't really that the chain stretches so much as that the pins bend, resulting in a longer chain.) Simply matching up a ruler to a straight length of the chain for 12 inches will show whether the chain is longer than it should be or not. If the chain is stretched more than a few percent longer than it won't match up with the teeth on the cogs and rings and can ruin them - and chains are cheaper than cogs and rings. If you let it go long enough, chains can break - I once saw a fellow break a chain while crossing 14th St on Independence in DC. Rather an abrupt stop.

I'm told that at some time in the 1990s Shimano introduced a chain with one centimeter between pins - the resulting links were closer together and of course the cogs and rings had to be with teeth that were also closer together. Like many "innovations" that represent a pointless departure from traditional approaches, it didn't catch on.

An idea that is presented as new but is actually from the 1890s is to replace the chain and rings with a drive shaft - in other words, before there were cars with drive shafts, there were bicycles with them. Wikipedia's article on bicycle chains notes that a bicycle chain is more than 98 percent efficient in transmitting power, so the big problem with other systems has been that they are usually less efficient.

This 1900 catalog has a shaft drive bike listed first:

Columbia and Hartford Catalog, 1900

The superiority of bevel gears for power transmission in the bicycle has become established beyond question.

Actually this is clearly not true, but the next statement about how well the shaft drive lasts (29,000 miles!) compared to a chain of those days was probably a strong favorable consideration.

At 65 dollars, the shaft drive bike is the most expensive model that this company was selling at the time. Presumably the big plus was that the shaft drive was cleaner than a chain, and for women didn't require netting over the rear wheel and chain guards to keep skirts out of the chain system. One suspects the absence of systems to demonstrate the lesser efficiency may have also contributed to a continuing interest in chain drives. Note that the drive shaft took on the role of the right side chain stay in the bike's structure.

For whatever reason, some early bicycle manufacturers pushed shaft drive bicycles for some time. They were even used by cycle racers - the African American rider Major Taylor rode shaft drive bikes in races, for example. But eventually they fell out of favor - for one thing, they were always more expensive than the comparable model with a chain. Also, removal of a rear wheel to work on a flat tire appears to be more complicated on a bike with a chain drive.

Notwithstanding all that, there have been attempts in recent years to introduce bikes with shaft drives, generally on bikes where the perceived lower maintenance and cleaner aspect of a shaft drive would be attractive, usually paired with an internal hub shift system.


In this modern example, there is a chain stay and the drive shift.

Another, probably more sensible approach is to use a drive belt to replace the chain. The belt is based on timing "chain" (or belt) technology developed for cars and these belts are incredibly strong - and require no grease or lubrication, so they stay clean. Ixi Bikes makes a small easy-to-disassemble (but not folding) bike with a belt. Trek makes several different full size bikes with belt drives, such as the District single speed, below. The belt drive seems to be pricey compared to a chain but is almost certainly just as efficient.

The Bicycle Chain - 1896

The technological improvements in modern bikes over those of the 1890s are much less than the 120 years would suggest likely. One of the critical "ingredients" for the first "safety bicycles" was the use of a chain to connect the rear wheel to a drive shaft with pedals (rather than pedals at the center of a large front wheel). The basic structure of a bicycle chain has not changed in all that time, but I was surprised to see that there were variations - the 1896 Victor Bicycle catalog (from Overman Wheel Co.) shows a chain where the sprocket teeth are spaced further apart and engage the chain only between every other (rather than every) link.





Commercial catalogs collection. Overman Wheel Co. Victor bicycles. 1896, University of Michigan.
Available online: http://hdl.handle.net/2027/mdp.39015071455961


Perhaps the perceived advantage was that each of the sprocket teeth could be much more substantial, but the trade-off of having half as many teeth makes this seem a wash and somehow the symmetry of the chains we use today seems more efficient (and in any event, that chain won out). Would this approach mean that the pins would bend less? (That may have been a problem in those days.) And maybe the relative cost of chains was more than today so a sturdier chain for the money seemed wise. Hard to know at this distance in time.

Cheap Spokes = Bad Idea!

My impulse buy bike, a Traitor Ruben steel sort-of cyclocross sort-of urban something-or-other bike had pretty good components but the wheels were no-name (other than the name of the company, Traitor) and the spokes were these black-coated anonymous things, 32 per wheel.

Anyway, a few months ago they started popping at the nipple end on the rear wheel. First one - replace it, then another - replace it. Now after the third has blown I have given up on one-at-a-time and am having the black crap spokes cut off and having the wheel rebuilt with new DT Swiss spokes.



A drive (ok, rear) wheel of a road bike with disk brakes has to work really hard, so the spokes need to be something other than junk selected to make the bike look "cool." (Assuming someone is going to ride the bike and not just admire it.) 2,000 miles or so isn't that long for the wheel to go through, so it is poor performance for the spokes to fail already. (No, I don't wait 220 pounds or carry panniers full of bricks.)

Well, there you have it. When evaluating a bike to buy, the wheels and the spokes should meet the same quality assessment as the derailleur (let's say). A 105 or Ultegra derailleur doesn't make up for crummy spokes.

Fiddlesticks!

Steel Bike in Morning

On my commute I sometimes am lucky enough to chat with some interesting riders. Friday I came upon a young fellow riding a 1985 Fuji steel racing bike that he had "restored" and somewhat updated.

This is a similar looking Fuji from that year. (I should keep my camera in a more reachable location when riding, I guess.)

The bike was beautiful - it looked new (well, other than the design) although he had removed all the decals so I had to ask him what it was. Very nice lugged frame and fork. He had reused the original derailleurs, shifters, and even brake levers. The one concession to modern cycling was to replace the so-called 27 inch wheels with 700 size that he hand built and to put on modern Campy dual pivot brakes.

I interested to see he was riding on 32 mm tires rather than 23 or some more racing bike-typical size. Hmmm. And he reported that while he had started putting in 80 PSI he was now closer to 60 and it seemed fine, speedy enough. And he obviously finds people like me, die hards in the "tires can't be too thin and have too much PSI" camp amusing. (23 mm and 120 PSI in rear, 110 in the front is what I have. I am rethinking this.)

No Bike Parking, Please (Capitol Hill, LoC)

How not very friendly. At the Adams Building, Library of Congress, Washington DC (on Capitol Hill).

What they mean is that they don't want bicycles locked to the railing blocking the ramp for the disabled, but do they provide a bike rack close by? No. Do they indicate where the nearest LC bike rack is (about 100 yards away, out of sight, across the street)? No. And so on. So instead people have bikes locked to sign posts up and down the street. Could be done better.

And the sign itself actually takes up more of the relevant real estate than any bike ever did. Oh well!

Motor Scooter Parked as Bike

I find this hard to understand - in a parking garage protected by the US Capitol Police, the owner of this thing feels it is worth locking up his scooter at a bike rack??

Tires for Road Bike -> One on Front, Different on Back

If the weather is good (not wet, not below freezing, generally) I will commute the ten miles each way to Capitol Hill on my carbon fiber road bike rather than my steel road bike that has disk brakes.

One of the main issues I have had is with tire wear. I had Michelin ProRace2 tires and then after they were discontinued, the successor model ProRace3. They are a bit pricey, though, often listing for more than fifty bucks each.

More importantly, I haven't been happy that the ProRace tire on front wears well while the one on back wears quickly. In particular, the center of a new ProRace tire is raised in a pronounced way that I like to imagine reduces the rolling resistence but on the back this wears away in about 500 miles, leaving a flat spot instead. You can switch the tires front to back, but then the one that was in good shape on the front is quickly in same not-so-good state.

Performance has a tire from Vredestein, the
Fortezza SE Road Tire that for a while was often on sale for around 25 bucks (although now they are $34) and customers mostly seemed to have given them good reviews. I thought I would try a set of those and bought a pair - as it happened, I then got a slash ruining a not-very-old ProRace3 so now I have a Fortezza SE on the back and a ProRace3 on the front. This has worked very well - better, I think than having a Fortezza front and back. The Fortezza is a strange clincher that takes up to 160 PSI and says it needs a minimum of 110! (The ProRace3 has a max of 116 PSI.) I tried putting 140 in the back tire but the back end of the bike become too "lively" so I run with about 120 in back, 110 in front and it seems to work fine.

I can't say that I have a lot of confidence in the grippiness of this set up for high speed sharp turns, or even moderate speed ones in rainy weather, but I don't make high speed turns (much) and try not to ride this bike in the rain - problem solved. The road grip of the front tire, the ProRace3 is probably fine, but I'm a little suspicious of the Fortezza in back, but really I am not sure. I'm not testing it.

Michelin has a new tire that takes the same approach - the Michelin Pro Optimum has different characteristics for the front tire version and the back tire version:

Michelin has developed separate front and rear tires to take into account their specific requirements: The front tire carries 30% of the weight load and absorbs 100% of the braking effect. For this reason, Michelin engineers made it a priority to develop a tire with added grip, capable of providing maximum safety to users on cold, wet surfaces. The rear tire carries 70% of the weight load and absorbs 100% of the torque generated by the bike's forward motion, which affects its efficiency and wearlife. In order to achieve consistent performance, the rear tire now has a longer life, meaning that MICHELIN Pro Optimum Front and Rear tires now have comparable lifespans.

(Michelin Pro Optimum Front & Rear)

I suppose comparable tire life spans seems something to suggest as a "feature" since many folks buy the in pairs but as a goal it seems less important than simply having good riding characteristics. And it just seems unlikely - rear tires are going to wear faster, period. I'm figuring I'll go through two Fortezza tires on the rear to one ProRace3 on the front.

Mix and match - a good idea, it seems.